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Impact of Pharmacogenetics and Pharmacodynamics on Transplantation

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Long-Term Effects of Calcineurin Inhibitors on Renal Function After Liver Transplantation

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Mercè Brunet, et al.: Impact of PG and PD on Transplantation

107

Impact of Pharmacogenetics and Pharmacodynamics on TransplantationMercè Brunet1,2, Nerea Urtasun1 and Olga Millán1,2

1Laboratory of Pharmacology (CDB), Biochemistry and Molecular Genetics Service, Hospital Clinic, IDIBAPS, University of Barcelona, Barcelona, Spain; 2Center for Biomedical Investigation and Network of Hepatic and Digestive Diseases (CIBEREHD), Barcelona, Spain

Abstract

In solid organ transplantation, new approaches able to reflect individual responses are required to monitor immunosuppressive therapy and to improve its safety and efficacy. In the last few years, preliminary studies about the clinical impact of the measurement of new specific biomarkers of exposure (pharmacogenetic biomarkers) and the biological effects (pharmacodynamic biomarkers) of immunosuppressive drugs have been carried out. Pharmacogenetics, by the association between some polymorphisms and drug dose requirement, combined with pharmacokinetic drug monitoring allows therapeutic concen-trations to be achieved a few days after transplantation. However, there is also a need for pharmacodynamic monitoring that may reflect the degree of immunosuppression achieved in each patient. This pharmacodynamic measurement is based on the analysis of specific biomarkers strongly related with the mechanism of action of every immunosuppressive agent, and shows its immunomodulatory effect on T-cell response. The present article reviews some pharmacogenetic and pharmacodynamic biomarkers that have been proposed in solid organ transplant monitoring. (Trends in Transplant. 2008;2:107-16)

Corresponding author: Mercè Brunet, [email protected]

Key words

Immunosuppression. Biomarkers. Pharmacodynamics. Polymorphism. Pharmacogenetics. Transplantation.

Trends in Transplant. 2008;2:107-16

Correspondence to:Mercè Brunet

Laboratorio de Farmacología (CDB)

Hospital Clínico de Barcelona

Villarroel, 170

08036 Barcelona, Spain

E-mail: [email protected]

trends in transplantation 2008;2

108

Introduction

The strategy used to prevent the toxicity as sociated with immunosuppressive therapy in solid organ transplant recipients is based on mea suring drug blood levels to ensure that concentrations within the established therapeutic ran ge are reached. However, this strategy is insufficient to determine individual res pon ses or to tailor the dose to real requirements. Consequently, new approaches able to reflect individual responses are required to monitor immunosuppressive therapy and to improve safety and ef ficacy. In the last few years, preliminary studies of new specific biomarkers of exposure (pharmacogenetic biomarkers) and the biological effects of (pharmacodynamic biomarkers) immunosuppressive drugs have been carried out.

In 1959, Vogel proposed the term “pharma cogenetics” to describe the discipline that studies the genetically determined variations that explain interindividual differences in drug response. Idiosyncrasy and pharmacologic into lerance have a genetic origin and can also be influenced by environmental factors.

Pharmacogenomics and pharmacogenetics are areas of clinical research that are under constant development and are highly topical. Pharmacogenetic studies allow the pos sible genetic causes of differences in individual responses to a drug to be identified, since these studies investigate the association between the degree of response to a drug and the polymorphisms of genes involved in drug metabolism and transport.

Moreover, some genetic polymorphisms can affect important organic functions, such as the metabolism and regulation of drug transport and drug distribution in the body, that is, some polymorphisms are closely associated with drug exposure and biological effect.

This article focuses on the study of the ge nes codifying for proteins that act as

metabolizing enzymes or as transport proteins for immunosuppressive drugs, as these genes in fluence the pharmacokinetics of these drugs. Immunosuppressive drugs, which include calcineurin activity inhibitors, mammalian target of rapamycin (mTOR) activity inhibitors and ino sine monophosphate dehydrogenase (IMPDH) activity inhibitors, regulate the immune response against the allograft and are strongly able to reduce the incidence of acute rejection. However, there is wide variability in individual response to these drugs, indicating that genetic factors may play an important role in this phenomenon and may also reflect different needs in individual patients.

In transplantation, pharmacogenetics is a helpful tool for the choice of starting dose at treatment initiation. Combined with pharmacokinetic analysis, this tool could allow therapeutic concentrations to be reached as quickly as possible. During the early posttransplant pe riod, optimal drug exposure in the shortest time possible is required to prevent acute rejection of the transplanted organ. Preliminary studies have identified several genetic polymorphisms related to metabolizing enzymes and transport regulatory proteins, which are re levant to interindividual variability in pharmacokinetics and pharmacodynamics in response to immunosuppressive drugs.

Previous studies of immunosuppressive drugs have demonstrated the association between the CYP3A5*1 and CYP3A*1B polymorphisms and dose requirement of tacrolimus1, as well as the association between the UGTA9*3, UGT1A9 275T>A and UGT1A9 2152C>T po lymorphisms and mycophenolic acid (MPA) exposure in transplant recipients1,2. Moreover, other studies have associated the transport re gulatory protein, multidrug resistance (MDR)1, with the risk of toxicity3,4.

To achieve personalized therapy, immunosuppression monitoring is required. Pharma cogenetics and pharmacokinetics allow


109

the rapeutic concentrations to be achieved a few days after transplantation, but there is also a need for pharmacodynamic monitoring based on analysis of specific biomarkers of the effect of immunosuppressive drugs on T-cell response.

Several strategies can be used to eval-uate the biological impact of immunosup-pressive drugs on the immune system, de-pending on their mechanism of action. An initial approach, probably the most specific, is based on target enzyme activity measure-ment for each immunosuppressive drug (cal-cineurin ac tivity for cyclosporine and tacroli-mus, IMPDH activity for mofetil mycophenolate, and P70S6 kinase activity for mTOR inhibi-tors, sirolimus and everolimus). Another ap-proach is to evaluate an intermediate involved in the drug’s mechanism of action (e.g. inter-leukin syn thesis, lymphocyte proliferation, T-cell activity). Finally, biomarkers that reflect the collateral effects induced by immuno-suppressive drugs, but which are unrelated to their mechanism of action (e.g. lympho-cyte surface antigens expression) can be evaluated.

The optimal biological matrix to deter-mine pharmacodynamic biomarkers depends on the methodology used; for example, the en zyme-linked immunosorbent spot (ELISPOT) assay requires peripheral blood lymphocytes, not whole blood. Additionally, there is a ten-dency to use whole blood instead of periphe-ral blood lymphocytes, especially since the in troduction of techniques based on flow cy-tometry. These whole blood assays are faster, re quire less sample manipulation, and need a smaller sample volume than methods re quiring lymphocyte purification. Furthermore, immu-nosuppressive drug level is currently evalu-ated in whole blood, except in MPA monitor-ing which is assessed in plasma. Monitoring in whole blood is the optimal situation to es-tablish correlations between a drug’s concen-tration and its effect.

In the last few years, different immuno-logic parameters have been evaluated as bio-logical biomarkers of the immunosuppressant effect of these drugs. Research is being car-ried out to correlate pharmacokinetics and phar macodynamics, as well as to identify the biomarkers that most effectively predict clini-cal events (rejection, infection, etc.).

Pharmacogenetic biomarkers

Influence of pharmacogenetics on immunosuppressant metabolic disposition and dose requirement

CYP3A polymorphisms

The promising role of pharmacogenet-ics in the discovery of gene polymorphisms of metabolizing enzymes and transporters of im-munosuppressive drugs may help to better select the different drugs involved in the treat-ment and their appropriate initial dose.

Results from some studies in kidney trans plant recipients demonstrate that there is a strong association between CYP3A5*1/*3 and *1/*1 genotypes and tacrolimus pharma-cokinetics and dose requirement5-8. Knowled ge from these studies shows that patients with CYP3A5*3/*3 genotype require low tacrolimus dose to achieve target concentrations com-pared to CYP3A5*1 allele carriers.

Concerning CYP3A4 polymorphisms, the re is a notable controversy. The CYP3A4*1B ca rriers require more tacrolimus to reach thera-peutic concentrations compared to patients carrying CYP3A4*1/*1 genotype5, but several studies point out that there is no association between CYP3A4*1B/*1 genotype and tacro-limus requirement9,10.

Results from our study2 in 123 kidney trans plant recipients demonstrate that patients


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carrying the CYP3A4*1B allele required higher tacrolimus doses to achieve target levels, and showed significantly reduced minimum concen tra tion (C0) doseadjusted or area under the cur ve (AUC) doseadjusted values from months 612 after transplantation. With reference to CYP3A5 genotype, our results completely agree with previous studies and demonstrate the significant association between CYP3A5 *1/*1 or CYP3A5 *1/*3 ge no types and higher tacrolimus dose requirement during all the period of treatment (Fig. 1).

With respect to cyclosporine (CsA), most of the previous studies have shown a lack of correlation between the CsA dose requirement or CsA trough doseadjusted concentrations and the presence of the CYP3A4*1B or CYP3A5*3 allele in kidney transplant patients5,11,12. These studies concluded that genotyping of transplant recipients for CYP3A4 or CYP3A5 is thus unlikely to assist in selecting the best initial CsA dose.

The discrepancy observed between the role played by CYP3As polymorphisms in the effects on tacrolimus and CsA metabolism and disposition is not well understood, but may be explained by the more complex pharmacokinetic profile of CsA, which needs to achieve hig her concentrations (100250 ng/ml) and may interact with many other drugs.

Regarding sirolimus, results from different studies have demonstrate that there is a sig nificant association between sirolimus concentration/dose ratio and CYP3As polymorphisms13,14. A lower sirolimus concentration/dose ratio was observed in the CYP3A5*1 carriers (*1/*3 or *1/*1) than in the CYP3A5*3/*3 carriers, suggesting that CYP3A5 nonexpressors require lower sirolimus dose to achieve the rapeutic concentrations. There is also an as sociation between the CYP3A4*1B polymorphism and higher sirolimus requirement1517.

Concerning the frequency of CYP3A5 ge notypes, results from different studies in

kid ney and pediatric and adult liver transplant recipients are summarized in table 11821.

UGt1A9 polymorphisms

Previous studies about the impact of UGT1A9 polymorphisms on MPA exposure in de novo renal allograft recipients demonstrate that carriers of UGT1A9*3 allele had higher MPA exposure1,22, whereas the 275T>A and 2152C>T singlenucleotide polymorphisms (SNP) of the UGT1A9 gene promoter region are associated with significantly lower MPA ex posure in renal transplant recipients receiving 1 g twice daily of mycophenolate mofetil (MMF)23. Part of this effect may be explained by the interruption of enterohepatic recirculation of MPA. On the other hand, it has recently been shown that the UGT2B7 840G>A SNP is associated with an increase in acyl mycophenolic acid glucuronide metabolite con centrations1,23.

In our study in kidney transplanted patients2, the 275T>A and 2152C>T SNP of the UGT1A9 gene promoter region were associated with significantly lower MPA exposure that was statistically significant only for those patients receiving 1 g/day of MMF during the first month after transplantation, whereas MPA exposu re was similar in carriers and noncarriers from months 312 after transplantation. A possible explanation for that is to consider the significant increase of MPA concentration (about 35% from months 13) which may saturate UGT1A9 enzymes in carriers and noncarriers.

Table 2 summarizes the frequency of CYP3A and UGT1A9 genotypes in Caucasian transplanted patients.

P-glycoprotein (mDR1)

Significant interindividual variations in the expression and function of Pglycoprotein (Pgp) may be the result of genetic polymorphisms.


111

Cyclosporin A is a substrate of P-gp that, when it achieves therapeutic concentra-tions, acts as a potent inhibitor of the P-gp func tion. This pharmacologic inhibition may li mit the potential impact of the genetic vari-ations in CsA disposition. In fact, the results from most studies demonstrate that there is a lack of strong correlation between cy-closporine oral bioavailability and MDR1 3435C>T po lymorphism5,11. The results from Thervet, et al.15 show, in stable Caucasian renal transplant recipients, a weak asso-ciation between CsA exposure and MDR1 1236C>T SNP.

Concerning tacrolimus and P-gp, some studies found that tacrolimus dose require-ment was lower in patients who had one or two mutant alleles in their exon 12, 21, and 26 SNP of MDR115,24. More interestingly, results from liver transplant recipients receiving

tacro li mus demonstrated that there was a strong co rrelation between a higher intestinal mRNA expression of the MDR1 gene and the inciden ce of acute rejection19,20,25. In these studies in pediatric and adult liver transplant recipients, patients who strongly expressed MDR1 sho wed a high incidence of tacrolimus < 7 ng/ml four days after transplantation. These patients required higher tacrolimus doses to achieve, as soon as possible, ade-quate tacrolimus con centrations (> 7 ng/ml) in the first days after transplantation.

Regarding the clinical impact of the MDR1 gene, the role of the MDR1 donor ge-no type has been evaluated with reference to the incidence of nephrotoxicity. The results demonstrate that the 3435T>T polymorphism of kid ney donors was significantly overex-pressed in those patients with CsA nephro-toxicity3.

350

300

250

200

150

100

50

0

Co

TAC

(ng

/ml)/

dose

(m

g/kg

)Carrier vs non-carrier CYP3A5

Non-carrier CYP3A5Carrier CYP3A5

Day 7 Day 30 Month 3 Month 6 Year

Time

*

**

*

Figure 1. Follow-up from week 1 to month 12 posttransplantation of Dose-adjusted TAC trough concentration (C0/Dose) and CYP3A5*1 polymorphism. A significant difference (p < 0.05) in C0/dose was observed between CYP3A5*1 carriers and non-carriers from months 1 to 12 after transplantation2.


112

Table 1. Summary of results obtained in different studies about incidence of CYP3A5 polymorphisms in liver and kidney transplant recipients

Reference Solid Organ Transplant Ethnic Background n CYP3A5 (%)

*1/*1 *1/*3 3/3

Weilin W, et al.,Liver Transplant.2006;12(5):775

Adult liver Chinese 50 13 50 37

Yu S et al., Transplantation. 2006;81:46

Adult liver Chinese 100 11,3 50,9 37,8

Goto M, et al.,Pharmacogenetics.2004;14(7):471

Adult liver Japanese 70 3 38 59

Fukudo M, et al.,Clin Pharmacol Ther. 2006;80:331

Paediatric liver Japanese 130 3 38 58

Hesselink DA, et al.,Clin Pharmacol Ther.2003;74:245

Adult Kidney Caucasian 100 1,6 17,5 81

Bach, et al.,Pharmacogenetics.(Submitted)

Adult Kidney Caucasian 125 2 18 80

Mourad M, et al.,Clin Chem Lab Med.2006;44(10):1192

Adult Kidney Caucasian 90 1 19 80

Pharmacodynamic biomarkers

Biomarkers of T-cell response

Lymphocyte proliferation and t-cell surface antigens

Since all currently administered immunosuppressive drugs can inhibit lymphocyte pro li feration, pharmacodynamic assays to eva lua te this parameter are frequently used as a ge ne ral biomarker of the degree of immunosup pression achieved. Moreover, surface lympho cy te antigens are currently being evaluated as possible biomarkers. These actively participate in the different signals produced in the ac tivation and clonal expansion of Tlymphocytes, especially in costimulation, adhesion, and apoptosis.

Stalder, et al.26 compared lymphocyte proliferation and Tcell activation antigen expression in stable renal transplant recipients at six months posttransplantation and in healthy normal controls. All transplanted patients were treated with CsA, MMF and prednisone. Lymphocyte proliferation, evaluated by proliferating cell nuclear antigen (PCNA) expression, was significantly inhibited in trans planted patients in comparison with that in healthy normal controls. Similarly, the different surface antigens evaluated were decreased in the group of trans plant recipients in comparison with the control group. The most affected surface antigens were CD11a and CD154, whose expression in transplanted patients was 25% of control group expression. The CD25, CD71 and CD95 expression in transplanted patients represented approximately 50% of the expression obtained in the control group.


113

Barten, et al.27 recently published a stu dy where the analysis of biomarkers of the immuno-suppressive effect, in a population of cardiac transplant recipients, revealed that a combina-tion of very low concentrations of calcineurin activity inhibitors (CsA or tacrolimus) and very low sirolimus concentrations can pro duce syn-ergism of action for T-cell proliferation inhibition (measured by PCNA expression) or interleukin 2 (IL-2)- specific receptor expression (CD25). The potential of surface lymphocyte antigen analysis was shown in a study by Chang, et al.28 in car-diac transplant recipients in which CD4+CD25+ T-cell expression, in contrast to cytokine expres-sion, was related to the degree of rejection.

Our group29 evaluated inhibition of lym-phocyte proliferation, among other biomarkers, in a stable transplant recipient population treated with sirolimus monotherapy that sho wed low intra pa tient variability for sirolimus C0. Although all pa tients had sirolimus concentra-tions inside the the rapeutic range (8-12 ng/ml), the results obtained for this biomarker demons-trated wide interindividual variability, with an average inhibition value of 60% (range 31-96%). This finding, which is common in other bio-markers, revealed the im portance of pharma-cokinetic and pharmaco dynamic monitoring of transplanted patients in order to tailor the dose to each individual patient.

Soluble cytokines

Several research groups have evaluat-ed cytokine synthesis as a biomarker, even

though monitoring of cytokine production is dif ficult, especially that of circulating cytoki-nes. These substances have different half li ves and their gene expression is regulated through the cell cycle phases.

The pattern of T-helper Th1/Th2 cytokine expression has been studied by several groups. Barten, et al.30 found that Th1/Th2 cy to kine lev-els measured by cytometric bead array differed significantly in cardiac transplant recipients trea-ted with cyclosporine and MMF in comparison with pretransplantation le vels. Moreover, cyto-kine levels were significantly reduced at two hours after immunosuppressive drug adminis-tration. Interleukin-2 and IL-4, which are highly synthesized in the early phases of T-cell activa-tion and during acute rejection, were significant-ly reduced. After car diac transplantation, inflam-matory cytokines, such as tumor necrosis factor alpha (TNFα) or IL-6, which regulate T-cell clon-al expansion and activation during immunologic response, were increased in comparison with pretransplantation levels. For interferon gamma (IFNγ) and IL-10, no differences were found be-fore and after transplantation.

In a study carried out by our group31 in renal transplant recipients treated with a com-bination of tacrolimus and MMF or CsA and MMF, pharmacodynamic monitoring showed synergism in the immunosuppressive action of MPA combined with calcineurin inhibitors, sin ce the decrease in IL-2 was significantly mo re important in patients treated with both drugs than in those treated with monotherapy.

Table 2. Frequency distribution of CYP3A and UGT1A9 polymorphisms studied in renal allograft recipients2

n = 123 Single-nucleotide polymorphism

CYP3A4 CYP3A5 UGT1A9*3 T-275A C-2152T T-275 and C-2152T

Noncarriers 115 (93,5%) 1 (<1%) 120 (97,5%) 105 (85,4%) 107 (87%) NA

Total No. Of carriers 8 (6,5) 122 (99,1%) 3 (2,4%) 18 (14,6%) 16 (13%) 14

Heterozygous carriers (1/2) 7 (5,7%) 18 (14,6%) 3 (2,4%) 18 (14,6%) 16 (13%) 14

Homozygous carriers (2/2) 1 (<1%) 104 (84,5%) 0 0 0 0


114

In a recently published study of a renal transplanted population in the maintenance pha se treated with sirolimus monotherapy, our group29 found that patients with a higher risk of infection had significantly lower IL10 levels than those free from infection and healthy controls. Inhibition of IL10 in patients treated with sirolimus has been associated with a higher risk of bacterial infection, hyperinflammation and sepsis, as well as with a decrease in cyto lytic activity and, consequently, a lower incidence of rejection32.

Intra-lymphocyte cytokines

Interest in determining which types of cell subpopulations synthesize specific cytokines is growing because the cell type can de termine the immune response.

A study by Ahmed, et al.33 demonstrated that the frequency of CD8+ and CD8– cells that synthesize IL2 and IFNγ correlates with the biological effect of tacrolimus. These authors found that the biological matrix chosen to analyze these biomarkers was whole blood (previously, peripheral blood mononuclear cells were mainly used) because whole blood allows the environment in which the drug usually acts to be preserved.

Results from a study of Boleslawski, et al.34 that evaluated 21 liver transplant recipients treated with CsA or tacrolimus showed that, unlike blood concentration of tacrolimus, the biomarker that reflects the percentage of CD3+CD8+ Tcells that synthesize IL2 is close ly related to the onset of acute rejection, es pecially in patients treated with tacrolimus and prednisone. Furthermore, determination of this biomarker before transplantation sho wed that patients with a higher percentage CD8+IL2+ were those who later developed acute rejection. This finding suggests that IL2 production in these patients could be constitutively higher.

The lack of correlation between drug levels and these intralymphocyte biomarkers might confirm the finding that immunosuppressive drugs produce different effects in different patients, even when levels and doses are similar.

Biomarkers of tolerance

Some transplant recipients achieve a state of immune tolerance spontaneously after reducing immunosuppressive treatment until total suppression (spontaneous operational to l erance). This situation has been more frequently observed in liver transplant recipients (about 20% would be tolerant) than in other solid organ transplants.

Identification of biomarkers could allow strategies to induce tolerance to be developed, which would allow immunosuppressive treatment and associated toxicity to be reduced safely in these patients. Regulatory lymphocytes coexpressing the surface antigens CD4 and CD25 are the bestknown regulatory subtype. Regulatory Tcells (Treg) suppress immune activation and play a major role in maintaining tolerance. Forkhead box protein 3 (FoxP3), a transcription factor highly expressed in this cell population, is decisive in the de velopment of these cells.

Consequently, some studies have evaluated the frequency of CD4+CD25highFoxP3+ as a tolerance biomarker in transplanted patients after gradually withdrawing immunosuppressive treatment. Braudeau, et al.35 identified operational tolerance in a population in which this tolerance is hard to find: renal transplant recipients free of immunosuppressive treatment who were compared with a group of stable renal transplant recipients. The results obtained showed a reduction in FoxP3 transcripts and CD4+CD25+ Tcells in patients with chronic rejection in comparison with patients free of immunosuppressive treatment.


115

Si milar results have been found in liver transplant recipients. San Segundo, et al.36 evaluated the effect of different immunosuppressive drugs on the CD4+CD25highFoxP3+ Tcell per centage in a population of stable renal trans plant recipients. These authors observed that in contrast to sirolimus, anticalcineurin drugs (CsA, tacrolimus) reduce the number of circulating Treg cells. Therefore, these authors suggested that quantification of Treg blood levels could be useful to identify transplanted patients susceptible to immunosuppression reduction.

Conclusions

It is currently known that immunosuppressive treatment in solid organ transplant recipients must be individually tailored to each patient. Consequently, monitoring of this treatment in the near future should not only be ba sed on pharmacokinetics, which is highly useful to ensure that concentrations are within the established therapeutic range for each drug, but should also be based on the patient’s pharmacogenetic characteristics (the pre sence of polymorphisms in the metabolizing enzymes of these drugs), which would be useful in selecting drugs and their initial doses. Besides, evaluation of biomarkers reflecting the real effect of immunosuppressive drugs and tolerance biomarkers would allow candidates for reduction or even withdrawal of immunosuppressive treatment to be identified.

Based on the preliminary studies performed to date on biomarkers, no conclusions can be drawn on which biomarkers are the most appropriate to prevent rejection or adverse effects, for three main reasons: (i) the studies included a small number of patients; (ii) there were no standardized analytic protocols to analyze biomarkers, thus hampering comparison of the results obtained in the different cen ters; and (iii) these studies were usually performed at specific timepoints which did not

allow changes in these biomarkers throughout treatment to be evaluated (sequential pharmacodynamic monitoring). For all these reasons, multicenter trials with a lar ge number of patients are required. Such trials would allow the results of previous studies to be confirmed and the most effective biomarkers to reflect the effect of immunosuppressive drugs on the immune system to be chosen. Furthermore, the most important clinical events that can occur after transplantation (acute rejection, chronic nephropathy, infection, toxicity) could be predicted.

Acknowledgments

CIBEREHD is funded by the Instituto de Salud Carlos III.

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11. Yates CR, Zhang W, Song P, et al. The effect of CYP3A5 and MDR1 polymorphic expression on cyclosporine oral


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dis position in renal transplant patients. J Clin Pharmacol. 2003;43:55564.

12. Min DI, Ellingrod VL. Association of the CYP3A4*1B 5’-flank-ing region polymorphism with cyclosporine pharmacokinet-ics in healthy subjects. Ther Drug Monit. 2003;25:305-9.

13. Lampen A, Zhang Y, Hackbarth I, Benet LZ, Sewing KF, Chris tians U. Metabolism and transport of the macrolide im munosuppressant sirolimus in the small intestine. J Pharmacol Exp Ther. 1998;285:110412.

14. Crowe A, Lemaire M. In vitro and in situ absorption of SDZRAD using a human intestinal cell line (Caco2) and a single pass perfusion model in rats: comparison with rapamycin. Pharm Res. 1998;15:166672.

15. Thervet E, Anglicheau D, Legendre C, Beaune P. Role of phar macogenetics of immunosuppressive drugs in organ transplantation. Ther Drug Monit. 2008;30:14350. **This is a revision of many pharmacogenetic studies of immunosup-pressive drugs.

16. Marquet P, Djebli N, Picard N. Pharmacogenetics and immunosuppressor drugs: impact and clinical interest in transplantation. Ann Pharm Fr. 2007;65:3829.

17. Mourad M, Mourad G, Wallemacq P, et al. Sirolimus and ta crolimus trough concentrations and dose requirements after kidney transplantation in relation to CYP3A5 and MDR1 polymorphisms and steroids. Transplantation. 2005; 80:97784.

18. Weilin W, Jing J, Shusen Z, et al. Tacrolimus dose requirement in relation to donor and recipient ABCB1 and CYP3A5 gene polymorphisms in Chinese liver transplant patients. Li ver Transpl. 2006;12:77580.

19. Goto M, Masuda S, Kiuchi T, et al. CYP3A5*1-carrying graft liver reduces the concentration/oral dose ratio of tacrolimus in recipients of living-donor liver transplantation. Pharmaco-genetics. 2004;14:471-8.

20. Fukudo M, Yano I, Masuda S. et al. Population pharmacokinetic and pharmacogenomic analysis of tacrolimus in pediatric livingdonor liver transplant recipients. Clin Pharmacol Ther. 2006;80:33145.

21. Yu S, Wu L, Jin J, et al. Influence of CYP3A5 gene polymorphisms of donor rather than recipient to tacrolimus individual dose requirement in liver transplantation. Transplantation. 2006;81:4651.

22. Levesque E, Delage R, BenoitBiancamano MO, et al. The im pact of UGT1A8, UGT1A9, and UGT2B7 genetic polymorphisms on the pharmacokinetic profile of mycophenolic acid after a single oral dose in healthy volunteers. Clin Pharmacol Ther. 2007;81:392400.

23. Kuypers DR, Naesens M, Vermeire S, Vanrenterghem Y. The impact of uridine diphosphateglucuronosyltransferase 1A9 (UGT1A9) gene promoter region singlenucleotide polymorphisms T275A and C2152T on early MPA doseinterval

ex posure in de novo renal allograft recipients. Clin Pharmacol Ther. 2005;78:35161.

24. Macphee IA, Fredericks S, Tai T, et al. Tacrolimus pharmacoge netics: polymorphisms associated with expression of cytochrome P4503A5 and Pglycoprotein correlate with dose requirement. Transplantation. 2002;74:14869.

25. Masuda S, Goto M, Fukatsu S, et al. Intestinal MDR1/ABCB1 level at surgery as a risk factor of acute cellular rejection in livingdonor liver transplant patients. Clin Pharmacol Ther. 2006;79:90102.

26. Stalder M, Birsan T, Holm B, Haririfar M, Scandling J, Morris RE. Quantification of immunosuppression by flow cytometry in sta ble renal transplant recipients. Ther Drug Monit. 2003; 25:227.

27. Barten MJ, Tarnok A, Garbade J. et al. Pharmacodynamics of Tcell function for monitoring immunosuppression. Cell Pro lif. 2007;40:5063. **This article reflects the clinical im-pact of biomarkers of immunosuppression monitoring and describes some methodologies of interest.

28. Chang DM, Ding YA, Kuo SY, Chang ML, Wei J. Cytokines and cell surface markers in prediction of cardiac allograft rejection. Immunol Invest. 1996;25:1321.

29. Brunet M, Campistol JM, Diekmann F, Guillen D, Millan O. Tcell function monitoring in stable renal transplant patients treated with sirolimus monotherapy. Mol Diagn Ther. 2007; 11:24756.

30. Barten MJ, Rahmel A, Bocsi J, et al. Cytokine analysis to pre dict immunosuppression. Cytometry A. 2006;69:1557.

31. Millan O, Brunet M, Campistol JM, et al. Pharmacodynamic ap proach to immunosuppressive therapies using CNI and MMF. Clin Chem. 2003;49:18919.

32. Jorgensen PF, Wang JE, Almlof M, et al. Sirolimus interferes with the innate response to bacterial products in human who le blood by attenuation of IL10 production. Scand J Im munol. 2001;53:18491.

33. Ahmed M, Venkataraman R, Logar AJ, et al. Quantitation of immunosuppression by tacrolimus using flow cytometric analysis of IL2 and IFNγ inhibition in CD8() and CD8(+) peripheral blood Tcells. Ther Drug Monit. 2001;23:35462.

34. Boleslawski E, Conti F, Sanquer S, et al. Defective inhibition of peripheral CD8+ T cell IL2 production by anticalcineurin drugs during acute liver allograft rejection. Transplantation. 2004;77:181520.

35. Braudeau C, Racape M, Giral M, et al. Variation in numbers of CD4+CD25highFOXP3+ Tcells with normal immunoregulatory properties in longterm graft outcome. Transpl Int. 2007;20:84555.

36. Segundo DS, Ruiz JC, Izquierdo M, et al. Calcineurin inhi bi tors, but not rapamycin, reduce percentages of CD4+CD25+FOXP3+ regulatory Tcells in renal transplant recipients. Transplantation. 2006;82:5507.

Parveen Dhaliwal, et al.: Is Tolerance in Renal Transplantation Possible?

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Is Tolerance in Renal Transplantation Possible?Parveen Dhaliwal, Simon Janes and Kathryn Wood

Transplantation Research Immunology Group, Nuffield Department of Surgery, John Radcliffe Hospital, University of Oxford, United Kingdom

Abstract

Kidney transplantation remains the optimal treatment for end-stage renal failure by improving patient survival and quality of life. Although modern immunosuppressives have largely overcome the problem of acute rejection, long-term allograft survival rates have not improved since the 1990s as the immunosuppressive drugs that we use to protect the graft ultimately lead to its destruction by causing chronic allograft nephropathy. It is for these reasons that the induction of tolerance remains the ultimate goal in transplantation. While we have made major advances towards achieving tolerance in renal transplantation using animal models, there are still several major hurdles that must be overcome to allow the translation of data from experimental models into clinical trials. This review discusses the four strategies used to achieve tolerance, namely mixed chimerism, co-stimulation blockade, lymphocyte depletion and regulatory T-cell immunotherapy. We examine each technique’s strengths and pitfalls and argue that immunologic tolerance may be possible by using a combination of strategies. (Trends in Transplant. 2008;2:117-28)

Corresponding author: Kathryn Wood, [email protected]

Key words

Transplantation. Tolerance. Mixed chimerism. Co-stimulation blockade. Lymphocyte depletion. Regulatory T-cell.

trends in transplant. 2008;2:117-28

Correspondence to:Kathryn Wood

transplantation Research Immunology Group

Nuffield Department of Surgery

John Radcliffe Hospital

Oxford OX3 9DU, UK

e-mail: [email protected]


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Introduction

One of the goals in transplantation is to achieve tolerance to the transplanted organ. Ray Owen1,2 together with Billingham, Brent and Medawar3 demonstrated this concept of transplantation immunologic tolerance. In this now classic citation, Billingham, et al. demonstrated that tolerance could be induced deliberately by the introduction of donorspecific antigen into neonatal mice and this allowed them as adults to accept skin allografts from the same donor3. While this was a very promising start, the translation of tolerance from animal models to the clinical setting has remained very challenging and elusive.

Definitions of transplant tolerance

The definition of transplant tolerance is much debated. The definition of “true” tolerance is the longterm acceptance of a transplant in the absence of any immunosuppressive drugs in an immunocompetent host, with the transplant displaying normal histologic cha racteristics and function4. In experimental models, this definition of tolerance also requires that the recipient be able to accept a second graft from the same donor, while being able to reject a thirdparty graft. This “functional” definition does not attempt to assign a strategy for the induction, nor a mechanism that is responsible for the tolerant state, and therefore can most probably be accepted by the majority of clinicians and scientists work ing in this very active field.

Achieving tolerance in clinical transplantation, however, is clearly a formidable task and may only be possible in specific groups of transplant recipients. Nevertheless, striving for this goal in clinical transplantation is important as, in the process of defining strategies that will result in transplant tolerance and the mechanisms that are brought into play,

this will lead to innovations in therapy and clinical care that will benefit transplant recipients in the future. For example, the concept that lifelong, highdose immunosuppression is essential in maintaining graft function in everyone who receives a transplant is being challenged as there are clearly subgroups of transplant recipients, notably liver recipients, who can slowly be weaned off immunosuppression5. This weaning off immunosuppression produces a clinical state termed “operational tolerance”, which is defined as the longterm survival of a graft with stable function in the absence of maintenance immunosuppressive drugs6. This may be a more realistic goal to strive for as opposed to “true” tolerance. It may not, however, be possible in all transplant recipients, and reducing or minimizing immunosuppression in the long term may be achieved in these recipients instead.

The Soulillou group have described a subset of renal transplant recipients that exhibit spontaneous “operational tolerance”6. They have studied these patients and identified clinical factors as well as a gene signature that is associated with this state7. These could prove very useful tools in identifying the subgroup of patients that could successfully be weaned off immunosuppression.

The importance of achieving tolerance

The introduction of cyclosporine, a calcineurin inhibitor (CNI), in 1970, revolutionized transplantation by overcoming the problem of acute rejection and allowing longterm graft acceptance. Since then, a variety of immunosuppressive drugs, such as tacrolimus, mycophenolate mofetil, and sirolimus, just to name a few, have been developed. Why is it then that the quest for tolerance is still so sought after, given that we have an array of immunosuppressive drugs? This is because although the CNI (cyclosporine and tacrolimus) have


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dramatically improved patient and graft survival after transplantation, they are often used as part of a cocktail of immunosuppressants that must be continued indefinitely posttransplantation, each component bearing a significant sideeffect profile. Among the most severe side effects are infections, malignancy, ne phrotoxicity, hypertension, and diabetes me llitus8. Furthermore, these very drugs that we rely on to protect the graft actually cause damage in the long term by leading to chronic allograft nephropathy in renal transplant recipients. Moreover, it has been shown that some immunosuppressive drugs, notably steroids and CNI, may have a negative impact on the natural mechanisms the immune system uses to promote the generation of tolerance9, while others, such as sirolimus, may promote tolerance via the development of re gulatory Tcells (Treg)10. Therefore, one of the major goals of new immunosuppressive regimens being developed is to reduce the dose of immunosuppressants and avoid the longterm use of steroids and CNI. Instead, they aim to maintain graft function in the long term by encouraging the development of specific unresponsiveness or tolerance to the transplant.

Why has achieving tolerance in the clinic proved such a formidable task?

The human immune system is a complex interplay of multiple cell types and pathways. The more we understand about this system, the clearer it becomes that our immune system has evolved to include a redundancy within it. Therefore, to achieve tolerance in humans, multiple pathways need to be targeted.

The vast experience of the human immune system, acquired as a result of a constant exposure to environmental antigens, could be one of the critical differences between naive animal models and humans. This

may explain why tolerance induction protocols that are effective in animal models have proved less successful in the clinic. Most tolerance studies have been performed in pathogenfree rodents and nonhuman primates, which lack a large pool of memory Tcells that are present in human transplant recipients. If memory Tcells hinder the induction of transplant tolerance, then we would expect children (who have a relatively small memory Tcell pool) to have better outcomes following transplantation. Support for this theory comes from two large cohort studies following liver transplant recipients, in which pediatric age at transplantation was associated with ability to successfully withdraw immunosuppression11,12.

While immunologic memory is a critical component in the fight against infection, in clinical transplantation it acts as a barrier to tolerance induction due to the presence of alloreactive memory Tcells. These cells are generated pretransplant in sensitised individuals due to previous transplants, blood transfusions or pregnancies, and in nonsensitised individuals as a result of crossreactivity with viral antigens (heterologous immunity)13,14 or via homeostatic proliferation15. Memory Tcells also contribute to late graft loss as memory Tcells that develop after a rejection episode are refractory to current drug therapy16. Furthermore, memory Tcells have different costimulatory requirements than naive Tcells17, and therefore strategies that target the classical CD28B7 or CD40CD154 costimulatory interactions are likely to be ineffectual in controlling the memory cell pool.

Strategies to achieve transplant tolerance

Tolerance can be categorized as either central or peripheral tolerance. Central tolerance refers to the intrathymic deletion of alloreactive Tcells. In experimental studies, mi xed chimerism has been shown to be an


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example of central tolerance. Peripheral tolerance is mediated by a combination of mechanisms, including deletion, anergy, ignorance, or regulation18. Strategies such as Tcell depletion, costimulatory blockade and Treg immunotherapy attempt to achieve tolerance via peripheral tolerance mechanisms.

Mixed chimerism

Chimerism occurs when foreign (donor) hematopoietic cells are present in an individual. Microchimerism occurs when representation of donor hematopoietic cells is < 1%, whereas macrochimerism occurs when donor cells constitute > 1% of host hematopoietic cells. Within macrochimerism, complete chimerism occurs when all hematopoietic cells are of donor origin (for example following myeloablation and transplantation of donor hematopoietic cells), whereas in mixed chimer ism, donor cells constitute > 1% but < 100% of the total, which can occur following nonmyeloablative host conditioning.

Microchimerism occurs in some organ transplant recipients when donor hematopoietic cells from the transplanted organ persist, typically at levels detectable only by polymerase chain reaction19. Theoretically, microchimerism can result in modulation of the immune response to donor antigens. However, the significance of microchimerism in vivo remains unclear, as there does not appear to be any clear correlation with acceptance or re jection. In one study, only onethird of patients with longterm graft survival demonstrated microchimerism20, whereas in others, microchimerism could still be detected in pa tients experiencing allograft rejection21,22, with the level of chimerism fluctuating with time22.

Individuals who have complete chimerism after myeloablative therapy and bone marrow transplantation subsequently accept solid organ allografts from the same donor23.

However, the morbidity and mortality associated with complete myeloablation has precluded the clinical translation of protocols that lead to full chimerism. Mixed chimerism, however, is a more promising alternative as it is associated with a reduced susceptibility to graftversushost disease (GVHD)24, whilst maintaining improved immunocompetence25. Consequently, there has been an intense research focus on strategies to augment mixed chimerism following transplantation.

To achieve tolerance, both the preexisting mature donorreactive Tcells and the developing donorreactive Tcells need to be eliminated or inactivated in a sustained manner. To achieve the former, experimental models of mixed chimerism utilize total body irradiation (TBI)26, cytotoxic drugs, Tcelldepleting antibodies27,28, or the induction of peripheral clonal deletion using costimulatory blockade29. Once peripheral donorreactive Tcells are rendered ineffective, central tolerance in mixedchimerism models is achieved by the following mechanism: donor stem cells engraft in the recipient’s bone marrow, giving rise to cells of multiple hematopoietic lineages including hematopoietic progenitor cells that seed the thymus. In the thymus, these cells can develop into specialized thymic dendritic cells30 that have the capacity to induce deletion of antigenspecific Tcells (clonal deletion). Developing thymic Tcells reactive to antigens expressed on hematopoietic cells un dergo negative selection. Consequently, in mi xed chimerism, both host and donor hematopoietic cells mediate intrathymic deletion of host and donor reactive Tcells31. This renders the host tolerant to host and donor antigens, as long as the donor hematopoietic stem cells persist in the bone marrow.

Early work demonstrated that mice reconstituted with a mixture of recipient and donor bone marrow after TBI, develop mixed chimerism and robust tolerance to donor skin grafts26. Subsequent studies aimed at reducing


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the toxicity of the host conditioning demonstrated similar results, using either depleting antiCD4 and antiCD8 monoclonal an tibodies (MAb)27 or costimulatory blockade32 prior to a nonmyeloablative dose of TBI. Immunocompetence is demonstrated by the fact that these mice are able to reject thirdparty grafts27, whereas protocols that induce full chimerism also induce a degree of immunoincompeten ce33. Interestingly, while mixed chimerism is often sustained indefinitely in mice using these protocols, in nonhuman primates (NHP), mixed chimerism is maintained for only a few weeks34 and yet longterm graft survival is maintained.

These promising animal results posed an interesting ethical dilemma that delayed its translation into human studies: namely, does the benefit of longterm immunosuppressionfree graft survival outweigh the risks of bonemarrow ablative therapy in patients with endstage renal disease (ESRD) and normal bone marrow? This question remained unanswered until 1998, when a trial began in patients with renal failure due to myeloma, who therefore required both bone marrow and renal transplants. Using a protocol developed in NHP, patients underwent thymic irradiation together with antithymocyte globulin (ATG), but with cyclophosphamide replacing TBI prior to simultaneous human leukocyte antigen (HLA)matched bone marrow and renal transplantation. So far, six such transplants have been performed, with all patients accepting their grafts long term35. Interestingly, three patients lost detectable chimerism but maintained graft function without immunosuppression or rejection episodes for up to seven years35. This approach has since been extended to five patients with ESRD but without bone marrow disease. The protocol employed was similar to the previous study, except ATG was replaced with antiCD2 MAb, and bone marrow was from HLA singlehaplotype mismatched livingrelated donors36. All five patients developed transient microchimerism, with four recipients demonstrating excellent renal function

for up to five years posttransplantation following withdrawal of all immunosuppressive therapy36. The mechanism responsible for such excellent results using this protocol remains unclear. In vitro testing of Tcells from the tolerant recipients showed donorspecific unresponsiveness, which is consistent with a central deletion mechanism (as outlined earlier), whereas allograft biopsies performed after withdrawal of immunosuppression had high levels of forkhead box protein 3 (Foxp3) messenger RNA, indicating a role of Treg cells in peripheral tolerance. Another important clin ical aspect of this study is that it successfully employed HLAmismatched bone marrow donors, without any evidence of GVHD. Unfortunately, one patient experienced acute humoral rejection on day 10 and subsequently underwent retransplantation using a conventional regimen.

A similar ongoing trial reported persistent mixed chimerism in one patient who received combined renal transplantation and HLAmatched donor hematopoietic cells, following a conditioning regime of total lymphoid irradiation, ATG, and mycophenolate mofetil for one month posttransplantation37. Allograft function has been normal for more than two years since discontinuation of immunosuppression, with no episodes of rejection. Analysis of this patient’s Tcells after transplantation demonstrated that naive CD8+ Tcells repopulated the periphery faster than naive CD4+ Tcells. This was thought to be due to peripheral expansion rather than thymic generation of new Tcells. Additional analysis indicated that donor lymphocytes present in the recipient were of thymic origin, suggesting a central deletion mechanism37. This study supports earlier work demonstrating that pretransplant total lymphoid irradiation can induce mixed chimerism and immune tolerance to cadaveric renal allografts38, whereas posttransplant total lymphoid irradiation produces transient microchimerism and acute rejection following withdrawal of immunosuppression39.


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Taken together, these studies show that protocols which induce mixed chimerism can lead to longterm donorspecific tolerance following renal transplantation. Although the mechanism remains incompletely understood, the potential therapeutic application of these approaches is enormous.

Co-stimulatory blockade

After binding peptide presented by the major histocompatibility complex (MHC) of antigen presenting cells (APC), an effective Tcell response can only be generated if the Tcell receptor signal is accompanied by a se cond, costimulatory signal. Without this costimulatory signal the Tcell becomes anergic. Consequently, there has been an intense research effort to harness the therapeutic potential of costimulatory blockade.

Naive Tcells constitutively express the costimulatory receptor CD28, which engages CD80 and CD86 proteins on APC, whereas activated Tcells express CD154 (CD40 ligand), which interacts with CD40 on APC. Whereas CD28 augments Tcell function when bound sim ultaneously with the Tcell receptor, CTLA4 (cytotoxic T lymphocyte antigen 4, a CD28 family receptor) inhibits Tcell functioning. Although other costimulatory molecules have been identified, CD154 and CD28 MAb have been the most extensively studied in humans.

Early work demonstrated that simultaneous blockade of the B7CD28 and CD40CD154 pathways produced longterm graft sur vival in rodents40, and CD154 blockade alone was shown to prevent renal allograft loss in rhesus monkeys41. However, subsequent followup studies found that only 50% of recipients in the former study experienced permanent engraftment42 and in the later study repeated antiCD154 was required to prevent acute rejection43. Furthermore, a repeat of Kirk’s rhesus monkey study using older

animals failed to produce permanent engraftment, which was attributed in part to the presence of memory cells in the older host, as secondary immune responses are less amenable to costimulatory blockade44. In addition to agerelated memory cell disparity, environmental exposure and intrinsic immune system differences contribute to the divergent outcomes following costimulatory blockade in rodent and NHP models. For example, viral infection at the time of transplantation can activate tolllike receptors on Tcells, which ren ders alloreactive CD8+ Tcells resistant to costimulatory blockadeinduced apoptosis45.

AntiCD154 alone is clearly not sufficient to induce tolerance. However, administration of Tcellreplete bone marrow at the time of antiCD154 costimulatory blockade leads to robust donorspecific tolerance in mice46, and to a lesser extent in NHP, as although all eight NHP recipients demonstrated graft survival of up to five years following discontinuation of immunosuppression, three had late episodes of chronic rejection47.

Human trials utilizing CD154 blockade have been less encouraging. Acute rejection rates were unexpectedly high, and thrombotic complications limited further use48. Thorough pathologic analysis of seven NHP treated with antiCD154 has revealed that two had thrombotic complications, suggesting that such com plications may be intrinsically related to antiCD154 treatment rather than being a humanspecific effect49. The CD154 is expressed on platelets and activated endothelium, and has recently been found to play an essential role in stabilization of arterial thrombi50. Unless this intrinsic complication can be overcome, it is unlikely that antiCD154 therapy will make the transition from bench to bedside.

The use of CTLA4Ig on its own has failed to produce tolerance in murine and NHP models. This may be related to its lower affinity for CD86 than CD80. Consequently, by modifying


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the CTLA4binding domain with amino acid substitutions, affinity for CD80 and CD86 is increased twofold and fourfold, respectively40. This modified CTLA4Ig (belatacept) produced significant prolongation of renal allograft survival in a NHP model40. However, in this model, belatacept cannot be viewed as tolerogenic, as maintenance therapy with mycophenolate and steroids was required.

Similar to antiCD154 treatment, CTLA4Ig alone does not appear to induce tolerance, but its low incidence of side effects makes it an attractive alternative to traditional maintenance immunosuppression. Belatacept produces longterm survival of pancreatic islet cells when combined with sirolimus in a NHP model by preventing the priming of antidonor T and Bcell responses51. In contrast to the antiCD154 experience, similar results have been found in humans: in a randomized trial powered to show lack of inferiority of belatacept versus cyclosporine, chronic administration of belatacept improved glomerular filtration rates and decreased chronic allograft ne phropathy after 12 months, with similar incidences of acute rejection when compared to cyclosporinebased maintenance therapy52.

Concerns have been raised regarding the safety of chronic immunoglobulin administration. However, to date there appears to be no excess incidence of posttransplant lymphoproliferative disease52, and two largesca le phase III trials are underway to definitively establish the efficacy and safety of belatacept. Thus, belatacept currently appears to provide a promising alternative to traditional maintenance immunosuppressive therapy. It remains undetermined whether or not belatacept can ultimately be used to induce tolerance. A proof of concept trial by the Immune Tolerance Network aims to address this question by withdrawal of sirolimus after one year and belatacept after two years in livingrelated renal transplant recipients who have had no episodes of rejection and no evidence of antidonor alloreactivity52.

In summary, whether or not costimulatory blockade can induce tolerance remains unknown. To date, none of the studies have shown robustly that it does ultimately produce tolerance. It may, however, be useful as an al ternative to conventional immunosuppres sive drugs, if their longterm sideeffect profile is shown to be favorable.

Lymphocyte depletion

As many as one in 10 naive Tcells are able to recognize allogeneic MHC antigens. This results in a large alloreactive Tcell pool that is able to reject an organ on transplantation53. Theoretically, depletion of this pool of Tcells at the time of transplantation prevents rejection by preventing immune engagement at a time when “danger signals” are maximal. Instead, the encounter between the allograft and the alloreactive pool is delayed and occurs within a more quiescent milieu. The theoretical basis for lymphocyte depletion is that this later encounter may shift the immune response towards unresponsiveness rather than rejection18.

Depletion strategies used clinically today take the form of polyclonal preparations such as ATG, or MAb such as alemtuzumab (Campath1H). Despite the profound depletional effects of both these preparations, they unfortunately do not lead to longterm tolerance. Instead, they are used as induction agents at the time of transplantation to allow for lower doses of maintenance immunosuppression.

Campath1H is a powerful, depleting, hu ma nized MAb that targets CD52, one of the most abundant proteins on the lymphocyte surfa ce54. Depletion of lymphocytes by Campath1H at the time of transplantation has been shown to induce a state in which patients are able to maintain stable transplant func tion with minimal immunosuppression55,56. Im portantly,


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some recipients could be weaned off immunosuppression and a state of donorspe cific unresponsiveness demonstrated57. The use of Cam path1H alone, however, at the time of kid ney transplant has unfortunately been unsuccessful and uniformly leads to acute rejection of the graft58. This phenomenon has been attri bu ted to memory Tcells that are relatively resistant to depletion and prevalent at the time of rejection of the allo graft59,60.

Polyclonal ATG is produced from purifying the IgG fraction of the serum of rabbits or horses that have been immunized with thymocytes or Tcell lines. Rabbit ATG (thymoglobulin) and horse ATG (lymphoglobulin) are the most widely used preparations61. As with Campath1H, rabbit ATG use in humans results in a profound depletion that facilitates lower doses of maintenance immunosuppression to be used posttransplantation. Of the two agents, Campath1H was found to be a more effective agent for induction56.

The effects of Campath1H on Treg cells appears to be inconclusive, with some studies showing an increased ratio of Treg to Teffector cells62, and others showing a depletion of Treg cells59. Pearl, et al. also showed that rabbit ATG efficiently depleted Treg cells59.

Therefore, in summary, lymphocyte depletion has allowed a reduction in maintenance immunosuppression in renal transplant recipients, but has failed to lead to tolerance to the allograft. However, this strategy may be useful in combination with other strategies, such as Treg immunotherapy, to render a patient tolerant to his allograft.

Regulatory T-cell immunotherapy

The concept of the suppressor, or regulatory Tcell as it is now more commonly known, was initially conceived in the early 1970s when Gershon and Kondo found that a subset of

Tcells were able to suppress the immune response and were distinct from Tcells that augmented and propagated an immune respon se63. However, it has taken us more than 30 years to establish their presence beyond reasonable doubt and to begin to attempt to translate their use into clinical practice. Today, it is well accepted that they play a crucial role in active regulation of the immune system to self antigens, thereby preventing autoimmu ne diseases64. This physiologic role of the Treg cells has now been exploited and manipulated in various experimental models to allow the host to be tolerant to alloantigens in the form of a transplanted organ.

Subsets of regulatory T-cells

Two main types of Treg subsets have been delineated – the thymusderived or natural Treg cells and the adaptive or induced Treg cells. Natural Treg cells are thymusderived cells that are CD4+CD25+ and Foxp3+ also65. The forkhead transcription factor, Foxp3, was identified in 2003 as critical for Treg development and function66,67. Foxp3 mutations occur spontaneously in Scurfy mice and humans suffer ing from IPEX (immune dysregulation, polyendocrinopathy, enteropathy, Xlinked) syn drome. Both these disorders exhibit a lack of Treg cells and severe lymphoproliferation and autoimmune disorders68,69. This has proved a very useful marker in identifying Treg cells in mice. It has, unfortunately, proven less reliable in humans as it has recently been shown that human Tcells turn on Foxp3 upon activation65. This lack of exclusivity does not diminish the importance of Foxp3 in Treg biology, but it does mean that this marker cannot be used reliably for identifying Treg cells in humans.

Adaptive Treg cells are generated in the periphery by conversion of CD4+CD25–FoxP3– Tcells into CD4+CD25+Foxp3+ Treg cells that also possess suppressive capabilities. The


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ge neration of these cells can occur during an immu ne response to control that response and requires the correct conditions such as an tigenic exposure in the presence of transforming growth factorβ70 or interleukin1071. There is therefore a dichotomy of roles, with naturally occurring Treg cells potentially playing a more significant role in immune homeostasis and controlling autoimmunity, while adaptive Treg cells control and limit an ongoing immune response.

Experimental models of tolerance with regulatory T-cells

Numerous groups have shown that Treg cells are able to prolong graft survival in murine models of transplant tolerance. Our group has shown that CD4+CD25+ Treg cells generated by pretreating mice with a nondepleting antiCD4 MAb plus a donorspecific transfusion are able to suppress cardiac and skingraft rejection in an adoptive transfer model72,73. Several groups in 2002 showed that adoptive transfer of CD4+CD25+ Treg cells were able to prevent GVHD in mouse bone marrow transplantation models7476. Battaglia, et al. and Gregori, et al. have also shown that Treg cells are able to prevent allogeneic isletcell transplant rejection in mice77,78.

It has recently been appreciated that although Treg cells are able to prevent acute rejection and prolong graft survival longterm (to > 100 days), they may not be able to suppress chronic rejection. A interesting study by Joffre, et al. utilizing a combination protocol of hematopoietic chimerism as well as Treg cells in a murine model has been able to show that Treg cells that are able to recognize donor antigen via the direct pathway of allorecognition are able to effectively prevent acute rejection, but these grafts showed histologic damage that correlates with chronic rejection. On the other hand, Treg cells that can recognize donor antigen via both the direct and indirect

pathways are able to prevent both acute and chronic rejection of skin and heart transplants in mice. The grafts showed little or no histologic damage after 100 days79.

Therefore, in this study, the induction of mixed chimerism allowed Treg cells specific for donortype antigen to graft well in the recipients, and allowed not only the acceptance of skin and heart transplants in immunocompetent mice, but also prevented chronic rejection, which has been a major hurdle in transplantation. This is the closest we have come to a tolerant state while not generally immunosuppressing the mice. This regime also allows a realistic possibility of being translated to NHP in the first instance, and then into clinical trials.

Regulatory T-cells in clinical practice

To date, there is no published data on Treg cells and transplantation in humans. The first such clinical studies are currently in progress for the prevention of GVHD in bone marrow transplantation and rejection in solid organ transplantation.

In order to harness the useful properties of Treg cells, however, a number of controversial issues still need addressing. We have not yet identified a surface marker that identifies Treg cells in humans exclusively. The problem with Foxp3 is that it is an intracellular marker and is also expressed on activated Tcells in humans. It has been proposed that low levels of expression of CD127 may be a useful additional marker, and this is proving a promising tool to identify Treg cells in addition to CD4 and CD2565.

There is still controversy in the area of antigenspecificity of Treg cells as both antigenspecific and polyclonal Treg cells have been shown to be capable of promoting


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tolerance in experimental models. However, when translated into clinical practice, the use of Treg cells that are not antigenspecific could mean that should a patient develop a concurrent infection, the Treg cells will also suppress the immune response that is mounted against the infection. Will this result in unchecked infectious and malignant complications in these patients? These questions are unanswered at present and careful analysis of patients treated with Treg cell therapy is required.

A further related issue is the applicability of data from mouse studies on Treg cells to the translation of this approach to human clinical practice. There already exist significant differences between in vivo and in vitro mouse Treg studies. So how do we translate this to the human setting? Perhaps, a more realistic step would be to carry out these experiments in humanized mouse models and NHP prior to translation into clinical practice.

Further issues that require clarification are whether Treg cells should be expanded in vivo or ex vivo? What number of cells should be used? How and when should they be administered? How do we monitor the effect of the Treg cells in vivo? Do we need to include suicide genes into the Treg cells to prevent deleterious side effects?

In conclusion, Treg cells hold much promise in being able to mediate operational tolerance to transplants. They may, however, be insufficient to control the large numbers of effector Tcells that are able to recognize allogeneic MHC. Perhaps a combination of strategies each using a different mechanism would be more feasible in achieving tolerance. An effective strategy that could control this overwhelming allogeneic response is a combination of deletion and regulation. Depletion of effector Tcells at the time of transplantation with Campath or ATG along with the use of conventional immunosuppression may allow a window of opportunity in which Treg cells from

the recipient can be expanded either in vivo or ex vivo and be used to control the subsequent immune response when the postdepletional Tcells begin to recover.

Conclusion

It is clear that we have made significant advances in our quest to achieve tolerance to renal transplants in the last few years. More translational research in the form of clinical trials is currently underway, and these studies will further extend our knowledge in the near future.

The most promising toleranceinducing strategies are mixed chimerism and Treg therapy. Costimulatory blockade and lymphocyte depletion, while not tolerogenic on their own, could also prove very useful as adjunctive treatments. The complexity and innate redundancy of the human immune system means that multiple pathways need to be targeted. For this reason, an approach that involves a combination of strategies is more likely to be successful than one that involves a single strategy. Combining mixed chimerism and Treg therapy would allow both central and peripheral tolerance, and may allow mixed chimerism to be achieved with less intensive pre conditioning. An alternative strategy would be to use lymphocyte depletion prior to Treg therapy. The lymphocyte depletion can be used to shift the effector to regulatory Tcell ratio to one that is more favorable to tolerance, and this could be followed by a Treg infusion that could maintain tolerance by controlling the effector Tcells that gradually repopulate the immune system.

Acknowledgements

Work from the authors’ own laboratory cited in the text was funded by the Wellcome Trust, Medical Research Council, Biotechnology and Biological Sciences Research Council,


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Kidney Research UK and the European Union. Parveen Dhaliwal is funded by a Research Training Fellowship from the Wellcome Trust. Simon Janes is funded by a Research Training Fellowship from the Medical Research Council. Kathryn Wood holds a Royal Society Wolfson Research Merit Award.

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47. Kawai T, Sogawa H, Boskovic S, et al. CD154 blockade for induction of mixed chimerism and prolonged renal allograft survival in NHP. Am J Transplant. 2004;4:13918.

48. Knechtle SJ, Hamawy MM, Hu H, Fechner JH, Cho CS. Tolerance and neartolerance strategies in monkeys and their application to human renal transplantation. Immunol Rev. 2001;183:20513.

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50. Andre P, Prasad KS, Denis CV, et al. CD40L stabilizes arterial thrombi by a beta3 integrindependent mechanism. Nat Med. 2002;8:24752.

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52. Vincenti F. Costimulation blockade–what will the future bring? Nephrol Dial Transplant. 2007;22:12936.

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54. Hale G, Dyer MJ, Clark MR, et al. Remission induction in nonHodgkin lymphoma with reshaped human MAb Campath1H. Lancet. 1988;2:13949.

55. Calne R, Moffatt SD, Friend PJ, et al. Campath IH allows lowdose cyclosporine monotherapy in 31 cadaveric renal allograft recipients. Transplantation. 1999;68:16136.

56. Shapiro R, Basu A, Tan H, et al. Kidney transplantation under minimal immunosuppression after pretransplant lymphoid depletion with thymoglobulin or Campath. J Am Coll Surg. 2005;200:50515; quiz A5961.

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66. Hori S, Nomura T, Sakaguchi S. Control of regulatory Tcell development by the transcription factor Foxp3. Science. 2003;299:105761.

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70. Fu S, Zhang N, Yopp AC, et al. TGFβ induces Foxp3+ Treg cells from CD4+CD25– precursors. Am J Transplant. 2004;4: 161427.

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78. Gregori S, Casorati M, Amuchastegui S, Smiroldo S, Davalli AM, Adorini L. Regulatory T cells induced by 1 alpha,25dihydroxyvitamin D3 and MMF treatment mediate transplantation tolerance. J Immunol. 2001;167:194553.

79. Joffre O, Santolaria T, Calise D, et al. Prevention of acute and chronic allograft rejection with CD4+CD25+FoxP3+ regulatory T lymphocytes. Nat Med. 2008;14:8892. **This pa-per elegantly illustrates that a combination of hematopoietic chimerism and Treg therapy is capable of suppressing both acute and chronic rejection.

Georges-Philippe Pageaux, et al.: Renal Function and Liver Transplantation

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Long-Term Effects of Calcineurin Inhibitors on Renal Function After Liver TransplantationGeorges-Philippe Pageaux, Héla Audin-Mamlouk and Michael Bismuth

Pôle Digestif, University Hospital Saint-Eloi, Montpellier, France

Abstract

The longer survival of liver transplant recipients has emphasized the need to consider complications that develop several years after liver transplantation, such as chronic renal dysfunction. Renal dysfunction has an impact on long-term posttransplant morbidity and mortality. The prevalence of chronic renal disease among liver transplant recipients varies widely from 10 to 78%. This renal dysfunction is multifactorial in origin, but is customarily considered to be secondary to calcineurin inhibitors, tacrolimus and cyclosporine, acute dose-dependent and chronic non dose-dependent nephrotoxicity. With the occurrence of powerful immunosuppressive drugs without renal side-effects (i.e. mycophenolate mofetil and sirolimus), there have been several reports on the management of calcineurin inhibitor-induced nephrotoxicity, with either reduction or complete withdrawal of calcineurin inhibitors. Most of them resulted in an improvement in renal function. The point is to assess if reduction is sufficient to reverse renal lesions. Concerning prevention of renal function deterioration, the best way is on the one hand to try to control the potential contributors to chronic renal failure, such as hypertension, hyperlipidemia, and diabetes mellitus, and on the other hand to decrease the cumulative doses of calcineurin inhibitors. In an attempt to prevent renal dysfunction after liver transplantation, several investigators have published studies designed to reduce the dose and/or to delay the introduction of calcineurin inhibitors, with the use of mycophenolate mofetil and/or anti-CD25 antibodies induction. (Trends in Transplant. 2008;2:129-34)

Corresponding author: Georges-Philippe Pageaux, [email protected]

Key words

Liver transplantation. Renal function. Calcineurin inhibitors, Mycophenolate mofetil. Immunosuppression.


Correspondence to:Georges-Philippe Pageaux

Service d’Hépato-Gastroentérologie et transplantation

CHU Saint eloi

80 rue Augustin Fliche

34295 montpellier cedex 5, France



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Introduction

From 1988 to 2004, 66,393 liver transplantations (LT) have been performed in Europe1. As operative techniques and immunosuppressive management have improved, longterm survival has increased, with fiveyear and 10year patient survival of 70 and 60%, respectively. The main threats to the graft currently are those associated with rejec tion episodes, biliary and vascular complications, and recurrence of the initial liver disease, particularly hepatitis C and hepatocellular carcinoma. However, the longer survival of LT recipients has emphasized the need to consider other complications which develop several years after LT such as chronic renal dysfunction.

Renal dysfunction is a major problem after LT, and has an impact on longterm morbidity and mortality. The prevalence of chronic renal disease among LT recipients varies widely from 10 to 78%25. These variations have many explanations: lack of standard de finition of posttransplant renal disease, confusion between acute (reversible or not) and chronic dysfunction, and variable periods of followup. This renal dysfunction is multifactorial in origin, but is customarily considered to be secondary to calcineurin inhibitors (tacrolimus and cyclosporine) and acute dosedependent and chronic non dosedependent nephrotoxicity6. One important point is the possible interplay of preexisting renal disease and calcineurin inhibitor (CNI) therapy. Moreover, LT recipients may develop diabetes mellitus and hypertension, two conditions associated with renal failure.

Prevalence and consequences of renal dysfunction after liver transplantation

Before considering posttransplant renal dysfunction, two points need to be emphasized.

The first point concerns the definition of renal dysfunction. Numerous studies used a

definition of chronic renal failure as an elevated serum creatinine level. For instance, using a serum creatinine level > 2.5 mg/dl, Gonwa, et al. found an incidence of chronic renal failure at 13 years of 6%3. Limitations of the diagnostic use of creatinine in patients with impaired liver function, as well as LT recipients, are well known: reduced muscle mass, impaired hepatic biosynthesis7. Since “gold standard” methods using direct measurements of glomerular filtration rate (GFR), such as isotopic or nonisotopic iothalamate clearances, are cumbersome, timeconsuming, and too ex pensive for use in clinical practice, determina tion of GFR remains difficult in these patients. Several creatininebased equations, including biochemical, demographic, and anthropometric data, have been evaluated in LT recipients8. It seems that the Modification of Diet in Renal Disease formula, rather than the Cockcroft and Gault formula, is the most accurate to assess renal function after LT. Recently, Gerhardt, et al. have suggested that cystatin Cbased equations had the best overall performance to GFR estimates after LT7.

The second point concerns pretransplant renal function. In patients with cirrhosis, renal failure may be due to prerenal failure, mainly hepatorenal syndrome which is a potentially functional state, and intrinsic renal failure (tubular necrosis or glomerulonephritis), which is a potentially irreversible parenchymal injury9. This point allows to distinguish de novo posttransplant renal dysfunction from preexisting renal dysfunction. The absence of parenchymal kidney disease is usually indicated by proteinuria < 500 mg/day, microhematuria < 50 red blood cells per highpower field, and normal renal ultrasonography10.

The heterogeneity of the definitions used in the literature to assess the incidence and the prevalence of renal dysfunction after LT makes it difficult to understand the results. Acute renal dysfunction, defined by an increased serum creatinine during the first month posttransplant, has been reported with an incidence ranging


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from 12 to 64%11. The etiology of acute renal dysfunction is multifactorial, associating preexisting renal impairment resulting from hepatore nal syndrome, diabetic nephropathy, and cryoglobulinemia, and posttransplant conditions such as acute tubular necrosis, sepsis, and CNI toxicity12.

Concerning chronic renal dysfunction, Ojo, et al. have reported the results of a populationbased cohort analysis involving recipients of nonrenal solid organs in order to determine the incidence of chronic renal failure, the risk factors for this condition, and the risk of death associated with it13. The sample in the analysis included 69,321 patients who received a first nonrenal solid organ transplant in the USA between January 1, 1990 and December 31, 2000. Among them, 36,849 patients were LT recipients. The primary endpoint analyzed was chronic renal failure, defined as GFR ≤ 29 ml/minute/1.73 m² of bodysurface area, or the onset of endstage renal disease, as determined by the initiation of dialysis therapy or preemptive kidney transplantation. The cumulative incidence of chronic renal failure after LT was 8 ± 0.1% at one year, 13.9 ± 0.2% at three years, and 18.1 ± 0.2% at five years. Endstage renal disease occurred at a rate of 11.5% per year among LT recipients. Multivariate Cox regression ana lysis revealed that the risk of chronic renal failure after LT was associated with a number of variables: age, male sex, nonAsian race, pretransplantation GFR, dialysis treatment before transplantation, diabetes mellitus before transplantation, hepatitis C, postoperative acu te renal failure, year of transplantation (before 1994), and use of cyclosporine therapy. Chronic renal failure was associated with an elevated risk of death after LT (RR: 4.55; 95% CI: 4.384.74).

As already mentioned, chronic renal dys function after LT is multifactorial. In a renal histopathologic study performed in 26 LT recipients with chronic renal failure, Pillebout, et al. have demonstrated that renal involvement is often severe and that renal destruction is in

fact multifactorial: not only specific lesions of CNI toxicity, but also lesions related to diabetes mellitus, arterial hypertension, or to volumeexpansion products used in the 1990s in patients with ascites awaiting LT14.

As demonstrated in numerous studies, one of the prevalent causes of renal dysfunction is the longterm use of CNI. High trough cyclosporine levels early after LT and higher cu mulative cyclosporine dosage later after the LT are significant risk factors identified for late, severe renal dysfunction2,15. In a study about longterm renal function after LT, Morard, et al. found that trough levels of cyclospo rine ≥ 150 µg/l and of tacrolimus ≥ 10 µg/l one year after LT and of cyclosporine ≥ 100 µg/l and of tacrolimus ≥ 8 µg/l five years after LT were independent risk factors associated with impaired renal function at five years16. Early clinical studies comparing the chronic nephrotoxic effects of cyclosporine versus tacrolimus have yielded variable and conflicting results, suggesting a better preservation of renal function with tacrolimus compared to cyclosporine5. However, in recent studies designed to compare cyclosporine microemulsion with tacrolimus, it was always concluded that renal dysfunction was the same in both groups1719.

Preservation of calcineurin inhibitor-altered renal function after liver transplantation

With the occurrence of powerful immunosuppressive drugs without renal side effects, i.e. mycophenolate mofetil (MMF) and sirolimus, there have been several reports on the management of CNIinduced nephrotoxicity, with either reduction or complete withdra wal of CNI. Most of them resulted in an improvement in renal function. The point is to assess if reduction is sufficient to reverse renal lesions. It is acknowledged that chronic renal nephrotoxicity is partly dosedependent, but can occur in the presence of low blood levels20. Thus, it was often considered to represent an


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irreversible damage21. It is now suggested by the efficacy of CNI dosage reduction on improvement of renal function, that there is a part of reversible functional impairment in chronic CNI renal dysfunction1522.

In several prospective (most often open) and retrospective studies, the partial (Table 1) or complete (Table 2) replacement of CNI with MMF, in patients with chronic renal dysfunction, resulted in a significant improvement in re nal function, but sometimes an increased risk of acute and chronic rejection2329. We have to be very cautious with the lateonset re jection episodes, which are responsible for decreased graft survival, contrary to the early episodes. Moreover, it is critical to consider the risks associated with rejection therapy, such as a worsening of recurrent hepatitis C with corticosteroid pulses30. We consider that CNI reduction must be preferred to complete withdrawal, especially in the absence of validated monitoring of MMF therapy in the setting of LT. Thus, we have designed a prospec tive, multicenter, random

ized study, which was the first with an untreated control arm, and the results at one year have shown that the introduction of MMF combined with the re duction of at least 50% of CNI dose allowed to significantly improve the renal function of LT recipients, without any rejection episode and without significant sideeffects26. The twoyear results of this study have been presented during the Association for the Study of Liver Di seases (AASLD) meeting in November 200731. They emphasized, on the one hand, the significant improvement of renal function at two years compared to baseline but, on the other hand, the absence of significant impro vement between one and two years, suggesting an incomplete benefit of reducing CNI doses.

Sirolimus has also been used to elimina te CNI because of nephrotoxicity (Table 3)29,3234. In summary, GFR improved or remained stable in the CNIwithdrawal groups at both one and two years. Complete CNI withdrawal was achieved in 50100% of patients, and rejection episodes were unusual35. However, these promising

Table 1. Partial replacement of calcineurin inhibitors with mycophenolate mofetil

Study (n) IS Time to LT(months)

Follow-up(months)

Baseline creatinine

Improvement Rejection

Raimondo, et al.23 18 MMF↓ 50%

32 26 142 µM/l 60% 0%

Cantarovich, et al.24 19 MMF↓ 50%

> 12 12 141 µM/l 71% 29%

Reich, et al.25 18 MMF↓ 50%

13 12 19 mg/l 50% 11%

Pageaux, et al.26 27 MMF↓ 50%

62 12 162 µM/l 72% 0%

IS: immunosuppressor; MMF: mycophenolate mofetil; LT: liver transplant.

Table 2. Complete replacement of calcineurin inhibitors with mycophenolate mofetil


Follow-up(months)

Baseline creatinine


Schlitt, et al.27 14 MMF 76 6 168 µM/l 78% 21%

Stewart, et al.28 9 MMF > 12 3 Not detected 83% 33%

Raimondo, et al.23 16 MMF 45 35 179 µM/l 62% 6%

Fairbanks, et al.29 15 MMF 67 19 29 mg/l 73% 20%

Reich, et al.25 20 MMF 16 12 19 mg/l 63% 30%

IS: immunosuppressor; MMF: mycophenolate mofetil; LT: liver transplant.


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results are hampered by lack of experience and possible sirolimusinduced side effects.

Prevention of calcineurin inhibitor-induced renal dysfunction after liver transplantation

Concerning prevention, the best way is, on the one hand, to try to control the potential contributors to chronic renal failure, such as hypertension, hyperlipidemia, and diabetes mel litus and, on the other hand, to decrease the cumulative doses of CNI. Thus, it has been demonstrated that optimal treatment of diabetes considerably diminishes the risk of de veloping diabetic nephropathy14. Moreover, identification of microalbuminuria should lead to institution of angiotensin converting enzyme inhibitor treatment, which has also been shown to slow the progression of diabetic nephropathy36. The opportunity to use nonnephrotoxic, immunosuppressive drugs, such as MMF, sirolimus, everolimus, or antiCD25 antibodies, could allow to decrease the cumulative dose of CNI in immunosuppressive regimens. In addition, it could be preferable not to begin CNI until 4872 hours postLT, when renal hemodynamic has returned toward normal. At least, we have to take into account the possibility that cirrhosis itself and the attendant abnormalities in renal function may predispose the LT recipient to permanent renal damage when treated with CNI.

In an attempt to prevent renal dysfunction after LT, several investigators have published

studies designed to reduce the dose and/or to delay the introduction of CNI, with the use of MMF and/or antiCD25 antibodies induction. Yoshida, et al. have suggested that delayed lowdose tacrolimus, in combination with daclizumab and MMF, preserved early (month 1 and 6) renal function postLT without the cost of increased rejection37. During the AASLD meeting held in Boston in 2007, two stu dies were presented with conflicting results. In the first one, a prospective, randomized trial on 525 patients, it was suggested that lower (trough target level < 8 ng/ml) and delayed introduction (on day 5) of tacrolimus, together with MMF and daclizumab was asso ciated with better preservation of renal function at one year without any significant adverse impact on patient and graft38. It must be emphasized that in the three groups of this study (standard tacrolimus, lowdose tacrolimus plus MMF, lowdose and delayed introduction of tacrolimus plus MMF plus daclizumab), renal impairment assessed by the CockcroftGault formula was observed, but significantly less in the third group. In the second one, a prospective, randomized trial on 207 patients, delayed tacrolimus administration with MMF and daclizumab was not statistically different to that with immediate tacrolimus administration in terms of benefit on renal function at six months, assessed by serum creatinine39.

In conclusion, LT recipients need to be informed about the longterm risk of chronic renal dysfunction. In case of preexisting renal

Table 3. Complete replacement of calcineurin inhibitor with sirolimus


Follow-up(months)

Baseline creatinine


Cotterell, et al.32 8 SRL 60 ND 24 mg/l 62% 0%

Fairbanks, et al.29 21 SRL 72 16 28 mg/l 71% 5%

Kniepeiss, et al.33 6 SRL 62 4.5 29 mg/l 83% 0%

Sanchez, et al.34 35 SRL 6 24 17 mg /l GFR 42

44% 2.8%

Withdrawn 34%

IS: immunosuppressor; SRL: sirolimus; LT: liver transplant; GFR: glomerular filtration rate.


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disease, the possibility of combined liver and kidney transplantation may be considered. Immunosuppressive regimens using CNIspar ing drugs need to be evaluated in clinical trials.

References 1. European Liver Transplant Registry. www.eltr.org 2. Fisher NC, Nightingale PG, Gunson BK, Lipkin GW, Neuber

ger JM. Chronic renal failure following liver transplantation. Transplantation. 1998;66:5966.

3. Gonwa TA, Mai ML, Melton LB, et al. End stage renal disease after orthotopic liver transplantation using calcineurinbased immunotherapy: risk of development and treatment. Transplantation. 2001;72:19349.

4. Cohen AJ, Stegall MD, Rosen CB, et al. Chronic renal dysfunction late after liver transplantation. Liver Transpl. 2002;8:91621.

5. Wilkinson A, Pham PT. Kidney dysfunction in the recipients of liver transplants. Liver Transpl. 2005;11:S4751.

6. De Mattos AM, Olyaei AJ, Bennett WM. Nephrotoxicity of immunosuppressive drugs: longterm consequences and challenges for the future. Am J Kidney Dis. 2000;35:33346.

7. Gerhardt T, Pöge U, StoffelWagner N, et al. Estimation of glomerular filtration rates after orthotopic liver transplantation : evaluation of cystatin Cbased equations. Liver Transpl. 2006;12:166772.

8. Gonwa TA, Jennings L, Mai ML, Stark PC, Levey AS, Klintmalm GB. Estimation of glomerular filtration rates before and after orthotopic liver transplantation : evaluation of current equations. Liver Transpl. 2004;10:3019.

9. Moreau R, Lebrec D. Diagnosis and treatment of acute renal failure in patients with cirrhosis. Best Pract Res Clin Gastroenterol. 2007;21:11123. **Good review about renal function and cirrhosis.

10. Salerno F, Gerbes A, Ginès P, Wong F, Arroyo V. Diagnosis, prevention and treatment of hepatorenal syndrome in cirrhosis. Gut. 2007;56:131018.

11. O’Riordan A, Wong V, McQuillan R, McCormick PA, Hegarty JE, Watson AJ. Acute renal disease as defined by the RIFLE criteria postliver transplantation. Am J Transplant. 2007;7:16876.

12. Gallardo ML, HerreraGutierrez ME, SellerPérez G, Balsera EC, FernandezOrtega JF, QuesadaGarcia G. Risk factors for renal dysfunction in the postoperative course of liver transplant. Liver Transpl. 2004;10:137985.

13. Ojo AO, Held PJ, Port FK, et al. Chronic renal failure after transplantation of nonrenal organ. N Engl J Med. 2003;349:93140. **This article emphasizes the incidence of and the mortal-ity risk related to renal dysfunction after liver transplantation.

14. Pillebout E, Nochy D, Hill G, et al. Renal histopathologic lesions after orthotopic liver. Am J Transplant. 2005;5:11209. **Important to understand the multifactorial causes of renal dysfunction after liver transplantation.

15. Barkmann A, Bjôrn N, Schmidt HH, et al. Improvement of acute and chronic renal dysfunction in liver transplant patients after substitution of CNI by MMF. Transplantation. 2000;69:188690.

16. Morard I, Mentha G, Spahr L, et al. Longterm renal function after liver transplantation is related to CNI blood levels. Clin Transplant. 2005;20:96101.

17. O’Grady JG, Burroughs A, Hardy P, Elbourne D, Truesdale A. The UK and Republic of Ireland Liver Transplant Study Group. Tacrolimus versus microemulsified cyclosporine in liver transplantation : the TMC randomized controlled trial. Lancet. 2002;360:111925.

18. Levy G, Villamil F, Samuel D, et al. LIS2T Study Group. Results of LIS2T, a multicenter, randomized study comparing cyclosporine microemulsion with C2 monitoring and tacrolimus with C0 monitoring in de novo liver transplantation. Transplantation. 2004;77:16328.

19. McAlister VC, Haddad E, Renouf E, Malthaner RA, Kjaer MS, Gluud LL. Cyclosporine versus tacrolimus as primary immunosuppressant after liver transplantation : a metaanalysis. Am J Transplant. 2006;6:157885.

20. Persson H, Norden G, Karlberg 1, Friman S. Glomerular filtration rate after liver transplantation with a lowdose cyclosporin protocol. Transplant Int. 1994;7:1726.

21. Sandborn WJ, Hay JE, Porayko NIK, et al. Cyclosporine withdrawal for nephrotoxicity in liver transplant recipients does not result in sustained improvement in kidney function and causes cellular and ductopenic rejection. Hepatology. 1994;19:92532.

22. Dische FE, Neuberger J, Keating J, Parsons V, Caine RY, Williams R. Kidney pathology in liver allograft recipients after long term treatment with cyclosporin A. Lab Invest. 1988; 58:395402.

23. Raimondo ML, Dagher L, Papatheodoris GV, et al. Longterm MMF monotherapy in combination with CNI for chronic renal dysfunction after liver transplantation. Transplantation. 2003;75:18690.

24. Cantarovich M, Tzimas GN, Barkun J, Deschenes M, Alpert E, Tchervenkov J. Efficacy of MMF combined with very lowdose cyclosporine microemulsion in longterm livertransplant patients with renal dysfunction. Transplantation. 2003;76:98102.

25. Reich DJ, Clavien PA, Hodge EZ. Mycophenolate mofetil for renal dysfunction in liver transplant recipients on cyclosporine or tacrolimus: randomized, prospective, multicenter pilot study results. Transplantation. 2005;80:1825.

26. Pageaux GP, Rostaing L, Calmus Y, et al. Mycophenolate mofetil in combination with reduction of calcineurin inhibitors for chronic renal dysfunction after liver transplantation. Liver Transpl. 2006;12:175560. *First randomized study.

27. Schlitt HJ, Barkmann A, Bôker KH, et al. Replacement of CNI with MMF in livertransplant patients with renal dysfunction: a randomized controlled study. Lancet. 2001;357:58791. *Emphasizes the risk of rejection after complete replace-ment of CNI with MMF.

28. Stewart SF, Hudson M, Talbot D, Manas D, Day CP. Mycophenolate mofetil monotherapy in liver transplantation. Lancet. 2001;357:60911.

29. Fairbanks KD, Thuluvath PJ. Mycophenolate mofetil monotherapy in liver transplant recipient: a single center experience. Liver Transpl. 2004;10:118994.

30. Berenguer M, Prieto M, Palau A, et al. Severe recurrent hepatitis C after liver retransplantation for HCVrelated graft cirrhosis. Liver Transpl. 2003:9:22835.

31. Pageaux GP, Rostaing L, Calmus Y, et al. MMF in combination with lowdoses of CNI for chronic renal dysfunction after liver transplantation: 2year results of a prospective, multicenter, randomized study. Hepatology. 2007;46:233A.

32. Cotterell AH, Fisher RA, King AL, et al. Calcineurin inhibitorinduced chronic nephrotoxicity in liver transplant patients is reversible using rapamycin as the primary immunosuppressive agent. Clin Transplant. 2002;16:4951.

33. Kniepeiss D, Iberer F, Grasser N, Schaffellner S, Tscheliessnigg KH. Sirolimus and MMF after liver transplantation. Transpl Int. 2003;16:5049.

34. Sanchez EQ, Martin AP, Ikegami T, et al. Sirolimus conversion after liver transplantation : improvement in measured glomerular filtration rate after 2 years. Transplant Proc. 2005;37:441623.

35. Flechner SM, Kobashigawa J, Klintmalm G. Calcineurin inhibitorsparing regiments in solid organ transplantation: focus on improving renal function and nephrotoxicity. Clin Transplant. 2008;22:115.

36. UKPDS 39. Efficacy of atenolol and captopril in reducing risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 39. UK Prospective diabetes study group. BMJ. 1998;317:71320.

37. Yoshida EM, Marotta PJ, Greig PD, et al. Evaluation of renal function in liver transplant recipients receiving daclizumab (Zenapax), MMF and a delayed, lowdose tacrolimus regimen vs. a standarddose tacrolimus and MMF regimen: a multicenter randomized clinical trial. Liver Transpl. 2005;11:106472.

38. Neuberger JM, Mayer AD. Delayed and reduced dose tacrolimus with MMF and daclizumab reduces renal impairment after liver transplant: results of a 1year prospective, randomised international trial. Hepatology. 2007; 46:233A.

39. Calmus Y, Rostaing L, Gugenheim J, et al. Evaluation of the benefit on renal function of a delayed introduction of tacrolimus in liver transplant recipients at 13 French centers. Hepatology. 2007;46:482A.

michelle m. Kittleson, Jon A. Kobashigawa: Risk Factors After Transplantation

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Cardiovascular Risk Factors in Cardiac Transplant RecipientsMichelle M. Kittleson and Jon A. Kobashigawa

Division of Cardiology, Department of Medicine, The David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, USA

Abstract

Over the last four decades, cardiac transplantation has become the preferred therapy for select patients with end-stage heart disease. Improvements in immunosuppression, donor procurement, surgical techniques, and post-transplant care have resulted in a substantial decrease in acute allograft rejection, which had previously significantly limited the survival of transplant recipients. Although current immunosuppressive therapies provide excellent protection from acute rejection, it is essential to understand the long-term consequences of these therapies, as well as the impact of conventional risk factors for heart disease. Risk factors for poor outcome post-transplantation can be divided into donor-specific charac-teristics, recipient-specific characteristics, and those risk factors that depend on interactions between the donor and recipient. Donor-specific risk factors for poor prognosis after heart transplantation include older donor age and longer ischemic time. Recipient-specific risk factors for poor outcome post-transplantation include increased recipient age, African American race, ischemic etiology of cardiomyopathy, hypertension, hypercholesterolemia, diabetes, renal insufficiency, the use of specific immunosuppressive regimens, elevated body mass index, tobacco use, obesity, and early post-transplant complications. Certain risk factors are specific to donor-recipient interactions, including the number of human leukocyte antigen mismatches, the presence of donor-specific antibodies post-transplantation, and cytomegalovirus mismatch status. A better understanding of these risk factors will allow providers to individualize therapy and optimize patient outcomes. (Trends in Transplant.

2008;2:135-47)

Corresponding author: Jon A. Kobashigawa, [email protected]

Key words

Heart transplantation. Risk factors. Rejection. Cardiac allograft vasculopathy. Survival.


Correspondence to:Jon A. Kobashigawa

100 UCLA medical Plaza, Suite 630

Los Angeles

CA 90095, USA



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Introduction

Over the last four decades, cardiac trans plantation has become the preferred therapy for select patients with endstage heart disease. Im provements in immunosuppression, donor pro curement, surgical techniques, and posttransplant care have resulted in a substantial decrease in acute allograft rejection, which had previously significantly limited survival of transplant recipients. According to the registry of the International Society for Heart and Lung Transplantation (ISHLT), the median survival of patients posttransplantation is currently 10 years, and up to 13 years for those surviving the first posttransplant year (Fig. 1)1. In contrast, the ma jor impediments to longterm allograft survival are the development of cardiac allograft vas culopathy (CAV) and malignancy. After five years, CAV and late graft failure (likely due to allograft vasculopathy) together account for 30% of deaths, followed by malignancies (22%) and noncytomegalovirus (CMV) infections (10%)1.

Although current immunosuppressive the rapies provide excellent protection from acute rejection, it is essential to understand the longterm consequences of these therapies, as well as the impact of conventional risk factors for heart disease. Risk factors for poor outcome posttransplantation can be divided into donorspecific characteristics, recipientspecific characteristics, and those risk factors that depend on interactions between the donor and recipient (Table 1). The purpose of this review is to examine the current evidence for the role of these risk factors in the longterm prognosis of heart transplant recipients.

Donor-specific risk factors

Donorspecific risk factors for poor progno sis after heart transplantation include older donor age and longer ischemic time.

Donor age

The role of older donor age on the prognosis of heart transplant recipients is controversial. In the most recent report of the ISHLT registry, older donor age was a risk factor for oneyear, fiveyear and tenyear mortality posttransplantation1. In a multiinstitutional analysis of over 7,000 cardiac transplant recipients over a period of 10 years, older donor age was a risk factor for fatal CAV2. In another lar ge, singlecenter study, older donor age was also associated with decreased survival3. Ho wever, programs that actively use older donor grafts have not seen a significant difference in overall survival, or the development of CAV when compared to recipients with younger allografts4. In these programs, highly selective donor and recipient matching may have resulted in the reported acceptable outcomes.

The main issue, however, is whether the difference in survival between older and younger recipients is clinically significant. In a recent analysis of the United Network for Organ Sharing (UNOS) database, heart transplant recipients 60 years and older had more infections (26 vs. 23%; p < 0.001), but had lo wer rates of rejection (34 vs. 43%; p < 0.001) as compared with recipients under 60 years of age. In addition, survival at five years was 75% for recipients under age 60 and 69% for patients age 60 or older. While this difference was statistically significant, it does not appear to be clinically significant5. Thus, in its listing criteria for heart transplantation, the ISHLT re commends that patients should be considered for cardiac transplantation if they are less than or equal to 70 years of age. Patients over 70 years of age who meet specific criteria may be considered for cardiac transplantation. For these patients, use of an alternatetype program (i.e. use of organs from ol der donors) should be pursued6.

Ischemic time

Data from the registry of the ISHLT indicate that the risk of primary graft failure and


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Years

Half-life = 10.0 yearsConditional Half-life = 13.0 years

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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 10 20 21 22

100

80

60

40

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Figure 1. Kaplan-Meier survival data for adult and pediatric heart transplants performed between January 1982 and June 2005. Conditional half-life = time to 50% survival for those recipients surviving the first year post-transplantation. The transplant half-life (the time at which 50% of those transplanted remain alive, i.e. median survival) for the entire cohort of adult and pediatric heart recipients is currently 10 years, with a half-life of 13 years for those surviving the first year (reproduced with permission from taylor, et al.1).

Table 1. Risk factors for poor outcome post heart transplantation, divided into those that are donor-specific, recipient-spe-cific, and those that rely on an interaction between donor and recipient factors

Donor-specific Recipient-specific Donor-recipient interactions

Increased donor age Increased recipient age HLA mismatches

Longer ischemic time African American race AntiHLA antibodies

Ischemic cardiomyopathy CMV mismatch status

Hypertension

Hypercholesterolemia

Diabetes mellitus

Renal insufficiency

Immunosuppressive agents

Tobacco use

Obesity

Early complications

HLA: human leukocyte antigen; CMV: cytomegalovirus.


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oneyear mortality rises as ischemic time increases1. Based on this, the maximum recommended ischemic time for the donor heart is six hours, and an ischemic time of over four hours is considered prolonged. However, several studies demonstrate varied effects of longer ischemic times on outcomes after heart transplantation710.

One study determined that donor ischemic time had no impact on overall survival, although longer ischemic time was associated with worse outcomes for donors over 50 years of age8. Another study demonstrated that even in young donors, longer ischemic time was associated with a need for longer postoperative inotropic support, and lower early ejection fraction, but no difference in right ven tricular function at six months or survival at 12 months9. In further support of this, a recent retrospective review demonstrated that ischemic time over 300 minutes was not associated with increased 30day mortality, but was associated with longer intensive care unit stay, increased incidence of primary graft failure, need for mechanical support, and complications such as acute renal failure10. Thus, the advantage of increasing the available donor pool by accepting donors with longer ischemic time must be weighed against the shortterm increase in perioperative mortality and resource utilization in these patients.

Recipient-specific risk factors

Recipientspecific risk factors for poor out come posttransplantation include increased recipient age, African American race, ischemic etiology of cardiomyopathy, hypertension, hypercholesterolemia, diabetes, renal insufficiency, the use of specific immunosuppressive re gimens, tobacco use, obesity, and early com plications posttransplantation.

Recipient age

Interestingly, the risk curve for recipient age on fiveyear mortality is Ushaped, with the

younger and older age groups having greater risk of fiveyear conditional mortality than the age group between 50 and 55 years (Fig. 2)1. This is likely because younger recipients are more likely to have acute rejection, while older recipients suffer from greater comorbidities, including pulmonary and renal disease, as well higher risk for malignancy over time1.

Race

There is evidence that racial disparity exists, with worse outcomes in African American transplant recipients in some studies, while others show no effect of race on posttransplant outcomes3,11,12. In an analysis of over 7,000 cardiac transplant recipients, African American race was associated with an increased incidence of fatal allograft vasculopathy in a multivariate analysis2. This was supported in a study of pediatric heart transplant recipients, where African American recipients had a lower fiveyear survival rate (51 vs. 69%) with a 1.7fold increased risk of graft failure at five years13. These findings held true even after adjusting for indices of economic disparity, suggesting that immunologic variables may also play a role in this process, and in fact there was a greater number of HLA mismatches observed for African American heart transplant recipients.

Notably, a study of heart transplant recipients at Rush Medical Center demonstrated that compared with Caucasian recipients, African American recipients had more treated rejection episodes, more posttransplant hospitalizations, but no difference in fiveyear survival14. Race may also affect metabolism of immunosuppressive medications. It has been reported that African Americans have a lower trough level for tacrolimus compared to Caucasians and therefore require higher doses of these medications15. Thus, while immunologic factors might confer a worse prognosis to African American heart transplant recipients, it appears that specialized, comprehensive care may eliminate the racial disparity in outcomes after heart transplantation.


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Etiology of cardiomyopathy

Ischemic pretransplant etiology is risk factor for poor outcomes posttransplantation. In the ISHLT registry, ischemic cardiomyopathy conferred a 13% increase in 10year mortality and a 25% increase in 15year mortality, although no effect was observed on one and fiveyear survival1. This is likely because ischemic cardiomyopathy is a risk for fatal allograft vasculopathy, a late complication of heart transplantation. This is supported by the findings of a retrospective study in over 7,000 heart transplant recipients, where ischemic cardiomyopathy was a risk factor for fatal CAV2. Underlying this association, another study demonstrated that patients with ischemic cardiomyopathy pretransplantation are more likely to have other risk factors for poor outcomes, including hypertension and dyslipidemia, which could result in CAV16. Finally, atherosclerotic vascular disease would lead to more complications of stroke, vascular aneurysm rupture, and ischemia to vital organs.

Hypertension

There is a clear link between hypertension and conventional coronary atherosclerosis. Hypertension is also a common problem following cardiac transplantation, related in part to the use of corticosteroids, associated weight gain, and the use of calcineurin inhibitors, and in one study, has been associated with the development of CAV17. Furthermore, some studies indicate that treatment of hypertension may be beneficial in preventing the development or progression of CAV.

Patients randomized to diltiazem had a reduced incidence of angiographic CAV and death at five years18. Similarly, in 32 cardiac transplant recipients, intimal thickness at one year measured by intravascular ultrasound (IVUS) was significantly greater in the untreated control group than in those who received calcium channel blockers, angiotensinconverting enzyme (ACE) inhibitors, or both19. In

Rel

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Figure 2. Effect of recipient age on the risk of five-year mortality (conditional on survival to one year) for recipients of heart transplants performed between January 1999 and June 2001. n = 4,079. The risk curve for recipient age is U-shaped, with the younger and older age groups having greater risk of five-year conditional mortality than the age group between 50 and 55 years. Dashed lines = 95% confidence limits (reproduced with permission from taylor, et al.1).


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a more recent study, the combined use of these agents was more effective than either drug alone at reducing IVUS indices of CAV20, and there is further evidence that use of ACE inhibitors or angiotensin receptor blockers results in improved outcomes12. These results suggest that control of hypertension should be paramount in heart transplant recipients.

Hypercholesterolemia

In heart transplant recipients, hyperlipidemia at six months posttransplantation predicts the development of CAV at three years in one study21, and in another study, lowdensity lipoprotein elevation at one year posttransplantation was the only predictor for the development or progression of CAV by IVUS22. In addition, in a multicenter, retrospective analysis of heart transplant recipients, high total cholesterol was associated with an over fourfold increased incidence of nonfatal major cardiovascular events12.

Notably, treatment initiated within two weeks of transplantation with hydroxymethylglutaryl coenzyme A (HMG CoA) reductase inhibitors is associated not only with decrea sed development of coronary intimal thickening, but also a lower frequency of hemodynamically compromising rejection episodes and improved survival (Fig. 3)23. These agents likely have an immunosuppressive effect in addition to their lipidlowering activity. As hyperlipidemia is so common following transplantation, these findings suggest that all cardiac transplant recipients should receive HMG CoA reductase inhibitors.

Diabetes mellitus

Given that diabetes mellitus is a major cardiovascular risk factor leading to the development of endstage heart disease, diabetes is common in patients pretransplantation. Furthermore, the use of steroids and tacrolimus posttransplantation may cause or worsen diabetes; up to 32% of heart transplant recipients are

p = 0.025

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Pravastatin

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600 2 4 6 8 10 12

Figure 3. Survival during the first year after cardiac transplantation. One-year survival was significantly greater in the pravastatin group than in the control group (94 vs. 78%; p = 0.025) (reproduced with permission from Kobashigawa, et al.23).


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diabetic by five years posttransplantation1. However, the role of diabetes in posttransplant outcomes is not clear. Some studies show increased risk for infections, decreased survival and more CAV in diabetics, while other studies show no differences in outcome between diabetic and nondiabetic heart transplant recipients2426.

In an analysis from the UNOS database of over 20,000 firsttime heart transplant recipients, posttransplant survival among patients with uncomplicated diabetes was not significantly different than that among nondiabetics27. However, when stratified by disease severity and pretransplant diabetic complications, recipients with more severe diabetes had significantly worse survival and increased risk of CAV27. In addition, in an analysis of the ISHLT registry, diabetes was associated with a 1.87fold increased risk of oneyear mortality and a 1.52fold increased risk of fiveyear mortality1. In a recent multicenter study, the presence of posttransplant diabetes was associated with an increased risk of nonfatal major adverse cardiac events12 and, in another study, decreased survival3. Thus, similar to nontransplant patients, glucose control should be of paramount importance to possibly prevent posttransplant complications.

Renal insufficiency

Chronic renal failure after heart transplantation has been shown to predict left ventricular dysfunction, mortality, and nonfatal major adverse cardiac events posttransplantation12,28, with the greatest risk observed in patients requiring dialysis12. Pretransplant renal dysfunction may also predict the development of chronic renal impairment after heart transplantation, although this association is less clear29,30. Other risk factors for the development of renal dysfunction after heart transplantation include older age, hyperlipidemia, and pretransplant diagnosis of ischemic cardiomyopathy28,31,32, which are all themselves risk factors for poor

outcomes, suggesting a confounding effect. The worse outcome of patients with renal dysfunction emphasizes the importance of close followup and consideration of calcineurin inhibitorfree protocols3335 or renal transplantation36, as indicated, in these patients.

Immunosuppressive agents

The choice of immunosuppressive agent may affect heart transplant outcomes. Among calcineurin inhibitors, tacrolimus causes less hypertension, hyperlipidemia, and renal dysfunction than cyclosporine, with no difference in rejection, infection, or CAV37,38. Mycophenolate mofetil (MMF), an inhibitor of the de novo pathway for purine biosynthesis, reduces rejection, allograft vasculopathy, and mortality compared with azathioprine3941.

Sirolimus, a member of the newest class of immunosuppressive agents, the proliferation signal inhibitors, also known as target of rapamycin (TOR) inhibitors, has also been shown to be superior to azathioprine, with a reduction in allograft rejection and the development of CAV42. However, in this randomized trial, no differences in oneyear mortality were noted and sirolimus use was associated with a higher incidence of renal dysfunction and hypertension.

Similar promising results have been noted with everolimus, a related proliferation signal inhibitor. In a randomized, doubleblind clinical trial comparing everolimus with azathioprine, patients receiving everolimus had a significant reduction in the primary efficacy endpoint, a composite of death, graft loss or retransplantation, loss to followup, biopsy proven acute rejection of ISHLT grade 3A or greater, or rejection with hemodynamic compromise. Furthermore, the progression of CAV, measured by IVUS at baseline (46 weeks after transplantation) and repeated at 12 months after transplantation, was significantly less in patients receiving everolimus. However, patients


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receiving everolimus had a higher rate of bacterial infections and renal dysfunction43.

The immunosuppressive regimens containing tacrolimus in combination with an antiproliferative agent may offer the best longterm outcome. In a multicenter study, 343 de novo cardiac transplant recipients were randomized to receive one of three commonly used immunosuppressive regimens: tacrolimus plus sirolimus, tacrolimus plus MMF, or cyclosporine plus MMF, all in combination with corticosteroids44. In the two tacrolimus groups compared to the cyclosporine group, there was a significantly lower frequency of any treated rejection in the first year after transplantation (Fig. 4). In addition, the tacrolimus plus MMF group compared to the other two groups had a significantly lower median level of serum creatinine and triglycerides. Rates of posttransplant diabetes were not significantly different among all three groups. From these data, tacrolimus plus MMF appears to offer more advantages than either tacrolimus plus sirolimus or cyclosporine plus MMF, including lower rates of rejections requiring treatment and a lower sideeffect profile.

Tobacco use

Tobacco use is a risk factor for poor outcomes after heart transplantation in a number of studies. Many studies have focused on smoking pretransplantation, and shown an increase in the development of CAV17, fatal CAV2, and increased mortality45. However, even more importantly, ongoing smoking has also been shown to adversely affect outcomes. This is relevant, since studies indicate that approximately 33% of smokers resume cigarette use after transplantation4648.

In one elegant study, 380 patients heart transplant recipients had urine cotinine levels covertly assessed (with ethical approval)49. Of the 380 patients, 104 (27.4%) tested positive

for active smoking at some point posttransplantation, and 57 (15.0%) tested positive repeatedly. Smokers suffered significantly more deaths due to CAV (21.2 vs. 12.3%; p < 0.05), and due to malignancy (16.3 vs. 5.8%; p < 0.001). In a univariate analysis, smoking after heart transplantation shortened median survival from 16.28 years to 11.89 years (Fig. 5). After correcting for the effects of pretransplant smoking in timedependent multivariate analysis, posttransplant smoking remained the most significant determinant of overall mortality (p < 0.00001). The authors concluded that tobacco smoking after cardiac transplantation significantly impacts survival by accelerating the development of graft vasculopathy and malignancy. These findings highlight the importance of ongoing smoking cessation counseling after transplant.

Obesity

Pretransplant obesity, as defined as bo dy mass index (BMI), is associated with increased risk of death posttransplantation, both at 30 days and up to five years50,51. In one study, the 30day mortality was dramatically higher in obese patients (12 vs. 7.4%)51. These obese patients (BMI > 30 kg/m2) also demonstrated nearly twice the fiveyear mortality of patients with a BMI < 27 kg/m2 (53 vs. 27%), with a shorter time to highgrade acute rejection as well as an increased annual highgrade rejection frequency when compared with normalweight recipients (p = 0.001)51. In a multicenter study of 4,515 cardiac transplant patients, preoperative obesity (> 140% of ideal body weight) was associated with increased fouryear mortality in males and a trend toward increased mortality in females50. Obesity is also a risk factor for the development of CAV52 and posttransplant infections50.

Finally, one study indicated that posttransplant obesity also confers worse outco mes, and patients having a BMI ≥ 33 kg/m2 at any


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time after transplantation had a trend towards increased risk of death12. These studies form the basis for the ISHLT listing guidelines, which note that for obese patients, it is reasonable to recommend weight loss to achie ve a BMI of < 30 kg/m2 or percentage ideal body weight < 140% of target before listing for cardiac transplantation6.

Early post-transplant course

The two major factors of early rejection and early infection impact the longterm survival of heart transplant recipients. Treated

rejection episodes, both early (prior to hospital discharge) and later (after discharge but during the first posttransplant year), were independently associated with a 48% increase in fiveyear mortality in an analysis by the ISHLT registry1. The presence of treated infection episodes prior to hospital discharge was independently associated with a 37% increase in fiveyear mortality.

Supporting this observation, in a singlecenter study, 415 patients undergoing transplantation over a 15year period were examined to determine factors associated with longterm

TAC/SRL

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y

Days from Randomization

Figure 4. One-year incidence of any treated rejection was significantly lower in the tacrolimus groups (CYA/MMF = 59.6%, TAC/MMF = 42.1%, TAC/SRL = 35.1%, p < 0.001) (reproduced with permission from Kobashigawa, et al.44). TAC: tacrolimus; SRL: sirolimus; MMF: mycophenolate mofetil; CYA: cyclosporin A.


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survival3. The 158 patients who survived more than 10 years were compared with the 116 patients who died between two and six years. Longterm survivors had significantly fewer rejection episodes and viral, bacterial, fungal and total infections than did shortterm survivors. In a multivariate analysis, fewer bacterial infections and rejection episodes were associated with longer survival. Thus, better control of infection and rejection during the first year after heart transplantation may improve survival, and closer monitoring of these patients for longterm complications may be warranted.

Donor-recipient interactions

Certain risk factors are specific to donorrecipient interactions, including the number of HLA mismatches, the presence of donor

specific antibodies posttransplantation, and CMV mismatch status.

Number of human leukocyte antigen mismatches

The benefit of matching donor organs and recipients for HLA polymorphism has been well established in kidney transplantation, and sharing of kidneys based on good histocompatibility matching is now standard practice. However, because of poor preservation and short ischemic time tolerated by explanted hearts, HLA matching is rarely done in cardiac transplantation, and the extent of HLA mismatches has been associated with decreased survival posttransplantation. In the ISHLT registry, greater HLA matching (26 vs. 01 antigen matches) was associated with a 22%

1.0

0.8

0.6

0.4

0.2

0.0

Cum

ulat

ive

Sur

viva

l

Years0 5 10 15 20 25

Smoker

Non-smoker

Figure 5. Kaplan-Meier curves demonstrating the impact of post-transplant smoking on survival. Cumulative survival in those with a single positive cotinine measurement was significantly poorer than that for nonsmokers post-transplantation (log-rank, p = 0.0013). Smoking post-transplantation significantly shortened median survival from 16.28 years (95% CI: 15.2-21.6) to 11.89 years (95% CI: 10.4-14.1) in univariate analysis (reproduced with permission from Botha, et al.49).


145

reduction in fiveyear mortality1. At 10 years, more mismatches at the HLADR and HLAB loci were associated with worse survival, while at 15 years, more mismatches at the HLAA locus were associated with worse survival1.

These results are borne out in retrospective studies, which have also demonstrated a relationship between greater HLA mismatch and worse survival5355, and other stu dies report correlation between greater HLA mismatch at the DR locus and rejection5658. Retrospective analysis also suggests a correlation between the extent of HLADR mismatch and the subsequent development of CAV5961. While it is currently not feasible to perform HLA matching in heart transplant recipients, it is now standard practice at many centers to avoid HLA against which the recipient exhibits preformed cytotoxic antibodies62, since the development of HLA antibodies posttransplantation is also associated with worse outcomes, as discussed in the following section.

Development of anti-human leukocyte antigen antibodies

As would be expected, the development of HLA antibodies posttransplantation is associated with poor outcomes. This was de monstrated in a retrospective analysis of over 8,000 heart transplant recipients from the UNOS registry data63. In this study, patients were divided into groups based on the percentage of panel reactive antibodies: 0, 110, 1125, and over 25%. Increased levels of panel reactive antibodies were associated with increased rejection at one year, and decreased 30day and oneyear survival. This is supported by other studies64,65, which have also demonstrated that the development of posttransplant HLA class II antibodies is associated with CAV66.

More compelling that the development of nonspecific HLA antibodies demonstrated

by the panel reactive antibody screen would be the development of donorspecific HLA antibodies. In fact, in one study, the presence of donorspecific HLA antibodies, as determined with single HLA class I or class II beads, was associated with more frequent occurrence of acute rejection, development of CAV, and decreased survival67. Recipients having antibodies only to HLA not in the transplant and those without any HLA antibodies had similar outcomes, suggesting that antibodies against antigens not present on the donor organ did not harm the graft. Thus, the results indicate that testing for donorspecific HLA antibodies may help in the management of heart transplant patients.

Interaction of donor and recipient cytomegalovirus status

Cytomegalovirus infection is a risk factor for poor outcome after heart transplantation. Evidence of prior CMV infection is a risk factor for CAV; evidence of prior CMV infection is more common in heart transplant recipients with CAV than in those without CAV68.

Conclusion

In summary, there are multiple risk factors that can impact the longterm survival of heart transplant recipients, related to the donor, recipient, and donorrecipient interactions. Many of these risk factors are modifiable. For risk factors that are not modifiable, it nevertheless appears that careful monitoring and identification of risk factors may allow for prevention of future complications. Thus, an understanding of the risk factors in cardiac transplantation will allow for better prevention and earlier detection of posttransplant complications.

References 1. Taylor DO, Edwards LB, Boucek MM, et al. Registry of the

ISHLT: twentyfourth official adult heart transplant report, 2007. J Heart Lung Transplant. 2007;26:76981. **This over-view of the ISHLT registry data on outcomes provides the largest experience of all transplants reported to the registry internationally.


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2. Costanzo MR, Eisen HJ, Brown RN, et al. Are there specific risk factors for fatal allograft vasculopathy? An analysis of over 7,000 cardiac transplant patients. J Heart Lung Transplant. 2001;20:152.

3. Radovancevic B, Konuralp C, Vrtovec B, et al. Factors predicting 10year survival after heart transplantation. J Heart Lung Transplant. 2005;24:1569.

4. Drinkwater DC, Laks H, Blitz A, et al. Outcomes of patients undergoing transplantation with older donor hearts. J Heart Lung Transplant. 1996;15:68491.

5. Weiss ES, Nwakanma LU, Patel ND, Yuh DD. Outcomes in patients older than 60 years of age undergoing orthotopic heart transplantation: an analysis of the UNOS database. J Heart Lung Transplant. 2008;27:18491.

6. Mehra MR, Kobashigawa J, Starling R, et al. Listing criteria for heart transplantation: ISHLT guidelines for the care of cardiac transplant candidates–2006. J Heart Lung Transplant. 2006;25:102442. **A useful synopsis of listing criteria for heart transplant candidates, with an excellent overview of risk factors for poor outcome posttransplant, as they would affect patients’ candidacy for heart transplantation.

7. Briganti EM, Bergin PJ, Rosenfeldt FL, Esmore DS, Rabinov M. Successful longterm outcome with prolonged ischemic time cardiac allografts. J Heart Lung Transplant. 1995;14:8405.

8. Del Rizzo DF, Menkis AH, Pflugfelder PW, et al. The role of donor age and ischemic time on survival following orthotopic heart transplantation. J Heart Lung Transplant. 1999;18:3109.

9. Fernandez J, Aranda J, Mabbot S, Weston M, Cintron G. Overseas procurement of donor hearts: ischemic time effect on postoperative outcomes. Transplant Proc. 2001;33:38034.

10. Marasco SF, Esmore DS, Richardson M, et al. Prolonged cardiac allograft ischemic time–no impact on longterm survival but at what cost? Clin Transplant. 2007;21:3219.

11. Cohen O, De La ZD, Beygui RE, Hekmat D, Laks H. Ethnicity as a predictor of graft longevity and recipient mortality in heart transplantation. Transplant Proc. 2007;39:3297302.

12. Kobashigawa JA, Starling RC, Mehra MR, et al. Multicenter retrospective analysis of cardiovascular risk factors affecting longterm outcome of de novo cardiac transplant recipients. J Heart Lung Transplant. 2006;25:10639. **One of the larg-est studies on risk factors for adverse outcomes posttrans-plant, focusing not only on pretransplant variables but ongo-ing posttransplant risk factors as well.

13. Mahle WT, Kanter KR, Vincent RN. Disparities in outcome for black patients after pediatric heart transplantation. J Pediatr. 2005;147:73943.

14. Pamboukian SV, Costanzo MR, Meyer P, Bartlett L, McLeod M, Heroux A. Influence of race in heart failure and cardiac transplantation: mortality differences are eliminated by specialized, comprehensive care. J Card Fail. 2003;9:806.

15. Mehra MR, Uber PA, Scott RL, Park MH. Ethnic disparity in clinical outcome after heart transplantation is abrogated using tacrolimus and MMFbased immunosuppression. Transplantation. 2002;74:156873.

16. Aguero J, Almenar L, MartinezDolz L, et al. Differences in clinical profile and survival after heart transplantation according to prior heart disease. Transplant Proc. 2007;39:23502.

17. Radovancevic B, Poindexter S, Birovljev S, et al. Risk factors for development of accelerated coronary artery disease in cardiac transplant recipients. Eur J Cardiothorac Surg. 1990;4:30912.

18. Schroeder JS, Gao SZ, Alderman EL, et al. A preliminary study of diltiazem in the prevention of coronary artery disease in heart transplant recipients. N Engl J Med. 1993;328:16470.

19. Mehra MR, Ventura HO, Smart FW, Collins TJ, Ramee SR, Stapleton DD. An intravascular ultrasound study of the influence of ACE inhibitors and calcium entry blockers on the development of CAV. Am J Cardiol. 1995;75:8534.

20. Erinc K, Yamani MH, Starling RC, et al. The effect of combined ACE inhibition and calcium antagonism on allograft coronary vasculopathy validated by IVUS. J Heart Lung Transplant. 2005;24:10338.

21. Eich D, Thompson JA, Ko DJ, et al. Hypercholesterolemia in longterm survivors of heart transplantation: an early marker of accelerated coronary artery disease. J Heart Lung Transplant. 1991;10:459.

22. Kapadia SR, Nissen SE, Ziada KM, et al. Impact of lipid abnormalities in development and progression of transplant

coronary disease: a serial IVUS study. J Am Coll Cardiol. 2001;38:20613.

23. Kobashigawa JA, Katznelson S, Laks H, et al. Effect of pravastatin on outcomes after cardiac transplantation. N Engl J Med. 1995;333:6217. *Important randomized con-trolled trial establishing the utility of statin therapy in preven-tion of rejection and allograft vasculopathy in heart trans-plant recipients.

24. Marelli D, Laks H, Patel B, et al. Heart transplantation in patients with diabetes mellitus in the current era. J Heart Lung Transplant. 2003;22:10917.

25. Lang CC, Beniaminovitz A, Edwards N, Mancini DM. Morbidity and mortality in diabetic patients following cardiac transplantation. J Heart Lung Transplant. 2003;22:2449.

26. Czerny M, Sahin V, Fasching P, et al. The impact of diabetes mellitus at the time of heart transplantation on longterm survival. Diabetologia. 2002;45:1498508.

27. Russo MJ, Chen JM, Hong KN, et al. Survival after heart transplantation is not diminished among recipients with uncomplicated diabetes mellitus: an analysis of the UNOS database. Circulation. 2006;114:22807.

28. Veillon S, Caillard S, Epailly E, Eisenmann B, Hannedouche T, Moulin B. Chronic renal failure after cardiac transplantation: predictive factors and influence on mortalityresults of a monocenter study in 141 patients. Transplant Proc. 2002; 34:281920.

29. Vossler MR, Ni H, Toy W, Hershberger RE. Preoperative renal function predicts development of chronic renal insufficiency after orthotopic heart transplantation. J Heart Lung Transplant. 2002;21:87481.

30. Lindelow B, Bergh CH, Herlitz H, Waagstein F. Predictors and evolution of renal function during 9 years following heart transplantation. J Am Soc Nephrol. 2000;11:9517.

31. Satchithananda DK, Parameshwar J, Sharples L, et al. The incidence of endstage renal failure in 17 years of heart transplantation: a single center experience. J Heart Lung Transplant. 2002;21:6517.

32. Esposito C, Semeraro L, Bellotti N, et al. Risk factors for chronic renal dysfunction in cardiac allograft recipients. Nephron. 2000;84:218.

33. Groetzner J, Meiser B, Landwehr P et al. Mycophenolate mofetil and sirolimus as CNIfree immunosuppression for late cardiactransplant recipients with chronic renal failure. Transplantation. 2004;77:56874.

34. Groetzner J, Kaczmarek I, Landwehr P, et al. Renal recovery after conversion to a CNIfree immunosuppression in late cardiac transplant recipients. Eur J Cardiothorac Surg. 2004;25:33341.

35. Groetzner J, Kaczmarek I, Meiser B, Muller M, Daebritz S, Reichart B. Sirolimus and MMF as CNIfree immunosuppression in a cardiac transplant patient with chronic renal failure. J Heart Lung Transplant. 2004;23:7703.

36. Hermsen JL, Nath DS, del Rio AM, et al. Combined heartkidney transplantation: the University of Wisconsin experience. J Heart Lung Transplant. 2007;26:111926.

37. Taylor DO, Barr ML, Radovancevic B, et al. A randomized, multicenter comparison of tacrolimus and cyclosporine immunosuppressive regimens in cardiac transplantation: decreased hyperlipidemia and hypertension with tacrolimus. J Heart Lung Transplant. 1999;18:33645. *Important random-ized trial comparing the two major calcineurin inhibitors, cyclosporine and tacrolimus.

38. Kobashigawa JA, Patel J, Furukawa H, et al. Fiveyear results of a randomized, singlecenter study of tacrolimus vs. microemulsion cyclosporine in heart transplant patients. J Heart Lung Transplant. 2006;25:4349. *Important random-ized trial comparing the two major calcineurin inhibitors, cyclosporine and tacrolimus.

39. Kobashigawa J, Miller L, Renlund D, et al. A randomized activecontrolled trial of MMF in heart transplant recipients. Mycophenolate Mofetil Investigators. Transplantation. 1998;66:50715. *Important randomized trial establishing the superiority of MMF over azathioprine in the immunosuppression regimen of heart transplant recipients.

40. Kobashigawa JA, Tobis JM, Mentzer RM, et al. Mycophenolate mofetil reduces intimal thickness by IVUS after heart transplant: reanalysis of the multicenter trial. Am J Transplant. 2006;6:9937.


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41. Kaczmarek I, Ertl B, Schmauss D, et al. Preventing cardiac allograft vasculopathy: longterm beneficial effects of MMF. J Heart Lung Transplant. 2006;25:5506.

42. Keogh A, Richardson M, Ruygrok P. et al. Sirolimus in de novo heart transplant recipients reduces acute rejection and prevents coronary artery disease at 2 years: a randomized cli ni cal trial. Circulation. 2004;110:2694700. *Important randomi zed trial investigating sirolimus, one of a new class of im muno sup-pressive agents, the proliferation signal inhibitors.

43. Eisen HJ, Tuzcu EM, Dorent R, et al. Everolimus for the prevention of allograft rejection and vasculopathy in cardiactransplant recipients. N Engl J Med. 2003;349:84758. *Im-portant randomized trial investigating everolimus, one of a new class of immunosuppressive agents, the proliferation signal inhibitors.

44. Kobashigawa JA, Miller LW, Russell SD et al. Tacrolimus with MMF or sirolimus vs. cyclosporine with MMF in cardiac transplant patients: 1year report. Am J Transplant. 2006;6:137786. *Important randomized trial, significant in that it compared immunosuppressive regimens instead of single immunosup-pressive agents: tacrolimus + MMF, tacrolimus + sirolimus, and cyclosporine + MMF.

45. Roussel JC, Baron O, Perigaud C, et al. Outcome of heart transplants 15 to 20 years ago: graft survival, posttransplant morbidity, and risk factors for mortality. J Heart Lung Transplant. 2008;27:48693.

46. Basile A, Bernazzali S, Diciolla F, et al. Risk factors for smoking abuse after heart transplantation. Transplant Proc. 2004; 36:6412.

47. Nagele H, Kalmar P, Rodiger W, Stubbe HM. Smoking after heart transplantation: an underestimated hazard? Eur J Cardiothorac Surg. 1997;12:704.

48. Mehra MR, Uber PA, Prasad A, Scott RL, Park MH. Recrudescent tobacco exposure following heart transplantation: clinical profiles and relationship with atherothrombosis risk markers. Am J Transplant. 2005;5:113740.

49. Botha P, Peaston R, White K, Forty J, Dark JH, Parry G. Smoking after cardiac transplantation. Am J Transplant. 2008;8:86671.

50. Grady KL, WhiteWilliams C, Naftel D, et al. Are preoperative obesity and cachexia risk factors for post heart transplant morbidity and mortality: a multiinstitutional study of preoperative weightheight indices. CTRD Group. J Heart Lung Transplant. 1999;18:75063.

51. Lietz K, John R, Burke EA, et al. Pretransplant cachexia and morbid obesity are predictors of increased mortality after heart transplantation. Transplantation. 2001;72:27783.

52. Winters GL, Kendall TJ, Radio SJ, et al. Posttransplant obesity and hyperlipidemia: major predictors of severity of coronary arteriopathy in failed human heart allografts. J Heart Transplant. 1990;9:36471.

53. Frist WH, Oyer PE, Baldwin JC, Stinson EB, Shumway NE. HLA compatibility and cardiac transplant recipient survival. Ann Thorac Surg. 1987;44:2426.

54. Yacoub M, Festenstein H, Doyle P, et al. The influence of HLA matching in cardiac allograft recipients receiving cyclosporine and azathioprine. Transplant Proc. 1987;19:24879.

55. Opelz G. Effect of HLA matching in heart transplantation. Collaborative Heart Transplant Study. Transplant Proc. 1989; 21:7946.

56. Pfeffer PF, Foerster A, Froysaker T, Thorsby E. Correlation between HLADR mismatch and rejection episodes in cardiac transplantation. Transplant Proc. 1987;19:6912.

57. Sheldon S, Hasleton PS, Yonan NA et al. Rejection in heart transplantation strongly correlates with HLADR antigen mismatch. Transplantation. 1994;58:71922.

58. Aziz TM, Sheldon S, elGamel A, et al. Implication of HLA mismatch in the clinical outcome of orthotopic heart transplantation. Transplant Proc. 1998;30:19179.

59. Kaczmarek I, Deutsch MA, Rohrer ME, et al. HLADR matching improves survival after heart transplantation: is it time to change allocation policies? J Heart Lung Transplant. 2006; 25:105762.

60. Hornick P, Smith J, Pomerance A, et al. Influence of acute rejection episodes, HLA matching, and donor/recipient phenotype on the development of ‘early’ transplantassociated coronary artery disease. Circulation. 1997;96:II53.

61. Hornick P, Smith J, Pomerance A, et al. Influence of donor/recipient phenotype and degree of HLA mismatch on the development of transplantassociated coronary artery disease in heart transplant patients. Transplant Proc. 1997;29:14201.

62. Reinsmoen NL, Nelson K, Zeevi A. AntiHLA antibody analysis and crossmatching in heart and lung transplantation. Transpl Immunol. 2004;13:6371.

63. Nwakanma LU, Williams JA, Weiss ES, Russell SD, Baumgartner WA, Conte JV. Influence of pretransplant panelreactive antibody on outcomes in 8,160 heart transplant recipients in recent era. Ann Thorac Surg. 2007;84:155662.

64. SuciuFoca N, Reed E, Marboe C, et al. The role of antiHLA antibodies in heart transplantation. Transplantation. 1991; 51:71624.

65. MoralesBuenrostro LE, Castro R, Terasaki PI. A single HLAantibody test after heart or lung transplantation is predictive of survival. Transplantation. 2008;85:47881.

66. Tambur AR, Pamboukian SV, Costanzo MR, et al. The presence of HLAdirected antibodies after heart transplantation is associated with poor allograft outcome. Transplantation. 2005;80:101925. *This study offers evidence that donor-specific HLA antibodies, rather than nonspecific elevated panel reactive antibodies, are associated with poor out-comes after heart transplantation.

67. Stastny P, Lavingia B, Fixler DE, Yancy CW, Ring WS. Antibodies against donor HLA and the outcome of cardiac allografts in adults and children. Transplantation. 2007;84:73845.

68. Loebe M, Schuler S, Zais O, Warnecke H, Fleck E, Hetzer R. Role of CMV infection in the development of coronary artery disease in the transplanted heart. J Heart Transplant. 1990;9:70711.

Trends in Transplantation 2008;3

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Bidirectional Interaction between Cytomegalovirus and Hepatitis C Virus after Liver Transplantation: A Critical Review of the Clinical EvidenceTwinkle K. Pandian1 and Raymund R. Razonable2,3

1Mayo Medical School; 2William J von Liebig Transplant Center; 3Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, MN, USA

Abstract

Purpose: A bidirectional interaction between cytomegalovirus and hepatitis C is hypothesized to adversely affect the outcome of liver transplantation for chronic hepatitis C. This article reviews the clinical data on this hepatitis C virus-cytomegalovirus interaction. Methods: Review of (i) studies that assessed the impact of cytomegalovirus on hepatitis C virus viremia, recurrent hepatitis C, fibrosis, cirrhosis, graft failure, and mortality and (ii) studies that assessed the impact of hepatitis C virus on cytomegalovirus load, infection, and disease.Results: Eleven studies investigated the impact of cytomegalovirus on hepatitis C outcomes. Seven of these studies reported potential associations of cytomegalovirus with (i) time to recurrent hepatitis C and fibrosis, (ii) severity of recurrent hepatitis C and fibrosis, and/or (iii) incidence of allograft failure and mortality. In contrast, four studies failed to demonstrate these associations. On the issue of hepatitis C virus influencing cytomegalovirus outcomes, two studies reported a higher incidence of cytomegalovirus disease in liver recipients with severe recurrent hepatitis C, while two studies failed to show the association between hepatitis C virus positivity and cytomegalovirus load, infection, and disease after liver transplantation. Conclusion: This comprehensive review highlights the conflicting results of studies on the association between hepatitis C virus and cytomegalovirus after liver transplantation. The contrasting findings could be accounted for by several factors including variability in case definitions and endpoints, patient populations, clinical practices such as anti-cytomegalovirus prophylaxis and interferon therapy, among others. In our view, despite these conflicting results, the proven association between cytomegalovirus and overall transplant outcomes (and possibly hepatitis C virus pathogenicity) should warrant an aggressive cytomegalovirus prevention strategy in hepatitis C virus-infected liver transplant recipients. (Trends in Transplant. 2008;2:148-56)

Corresponding author: Raymund R. Razonable, [email protected]

Key words

Cytomegalovirus. Hepatitis C virus. Allograft failure. Fibrosis. Mortality.

Trends in Transplant. 2008;2:148-56

Correspondence to:Raymund R. Razonable

Division of Infectious Diseases

Mayo Clinic

200 First Street SW

Rochester, MN 55905, USA

E-mail: [email protected]

twinkle K. Pandian, Raymund R. Razonable: CMV and HCV Interaction after Liver Transplant

149

Introduction

Liver transplantation has evolved as an increasingly important modality for the treatment of many endstage liver diseases. In 2007, a total of 6,492 liver transplants were performed for various indications in the USA1. Overall, the most common indication for liver transplantation is endstage liver disease caused by chronic infection with hepatitis C virus (HCV), an RNA virus that infects 3% of the human population or an estimated 170 million people worldwide25.

While liver transplantation prolongs and improves the quality of life of many individuals with endstage HCVinduced cirrhosis6, the longterm outcome of this procedure is impeded by recurrence of HCV infection involving the liver allograft, and this is often characterized by an accelerated course. After liver transplantation, HCV viremia persists in up to 95% of patients7 while allograft hepatitis C occurs in 5060% of patients during the first year8. In many instances, recurrence of hepatitis C leads prematurely to cirrhosis and allograft failure that requires retransplantation or results in death9. Indeed, within five years after liver transplantation, approximately 10% of HCVinfected patients will have experienced allograft failure or death2. Numerous studies have been conducted to identify potentially reversible predisposing factors in an effort to reduce the adverse outcomes associated with severe hepatitis C recurrence3.

One of the correctable variables that has been implicated as a facilitator of hepatitis C recurrence is cytomegalovirus (CMV) infection817. Cytomegalovirus, a ubiquitous βherpesvirus that infects 60100% of humans, is regarded as the single most common pathogen causing significant morbidity among liver recipients12,13,16,18. Without antiCMV prophylaxis, the virus may reactivate to cause asymptomatic CMV infection in 2385%, and symptomatic and often tissueinvasive disease in up to 50% of

liver recipients10,19,20. In addition, CMV possesses potent immunomodulatory properties that could enhance allostimulation, leading to acute and chronic graft rejection and superinfections with other opportunistic bacterial, viral, and fungal infections13,18,21,22. It is in this context that CMV is hypothesized to influence the clinical course of hepatitis C after liver transplantation. Conversely, HCV is also known to possess immunomodulating properties, and accordingly, it has also been hypothesized that HCVinfected patients may be at a higher risk of CMV infection23. Taken together, CMV and HCV may exhibit a bidirectional relationship that could lead to a cycle of virustovirus interaction.

During the last decade, the potential interaction between CMV and HCV after liver transplantation has been the focus of several investigations. In this article, we critically review the evidence supporting and refuting this proposed viral interaction.

Methods

Publications related to this topic were identified through a search of the PubMed database using various combinations of terms such as “liver transplantation”, “CMV”, “cytomegalovirus”, “HCV”, “hepatitis C virus”, and “interaction”. This search strategy yielded a total of 13 unique studies that have specifically addressed the interaction between CMV and HCV1018,2427. A detailed review of the references cited in the articles identified during the primary search was also performed. Several studies have also assessed the interaction between HCV and other viruses (such as human herpes virus 6)8,12,13; however, the focus of this review is on the CMVHCV relationship.

Review of the clinical evidence

The first study describing the negative impact of CMV on hepatitis C was reported in


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1997, when Rosen, et al. described that HCV-infected liver recipients with CMV viremia were significantly more likely to develop cirrhosis and graft failure26. Since then, several studies have assessed the influence of CMV on hepa-titis C (Table 1), and conversely, the impact of HCV on CMV (Table 2)8,10-16,18,24,25,28.

All studies have a retrospective study design and, with one exception25, described populations from single centers. Study popu-lations were as few as 39 to as many as 358 HCV-infected liver recipients. Definitions of CMV as a predictor of outcome varied from serology11 to nucleic acid detection by PCR12,25, viremia by culture10,26, phosphoprotein (pp)65 antigenemia8,18,24, and clinical definitions12. Likewise, HCV outcomes varied from recur-rence of viremia16, to histologic evidence of hepatitis8,12,13, fibrosis8,12,13, and cirrhosis8,12,13, to allograft failure10,12,24 and mortality10,12,24.

Impact of cytomegalovirus on hepatitis C outcomes

Eleven studies assessed the impact of CMV on hepatitis C outcomes (Table 1)8,10-

16,18,24,26. The rate of CMV in these 11 studies ranged from as low as 6.8%15 to a high of 59%8,18. Seven of these studies have sug-gested, by one measure or another, that CMV negatively influences the outcome of hepatitis C8,10,12,13,15,26. On the other hand, four have indicated the lack of association between CMV and hepatitis C11,14,16,24.

Hepatitis C virus viremia

Hepatitis C viremia persisted in all but a very few of HCV-infected liver recipi-ents8,10-16,18,24-26. Whether CMV influenced the degree of HCV replication has been investi-gated by few investigators12,13,16. In a subgroup analysis of 18 HCV-infected liver recipients, including six who developed short-term CMV

viremia that was preemptively treated with ganciclovir, the HCV RNA level during the first 150 days after transplantation was not signifi-cantly different between patients with or with-out CMV DNAemia16. In a study of 92 HCV-infected liver recipients, HCV RNA appeared to be higher at 16 weeks, but not 52 weeks, after liver transplant among 23 patients who developed compared to those who did not de-velop CMV disease (mean ± standard devia-tion, 55.71 ± 50.47 vs. 33.52 ± 47.03 mEq/ml; p = 0.1034), although this did not reach statis-tical significance12. Likewise, HCV load at one and three months were not significantly affect-ed by CMV load, infection, or disease in a cohort of 66 HCV-infected liver recipients13.

Recurrent hepatitis C

Recurrence of hepatitis C occurred in 478 to 62%13. Several studies demonstrated that CMV facilitated the occurrence of recurrent hepatitis C12,13,26. In one study, recurrence of hepatitis C was similar during the first year be-tween those with or without CMV viremia; how-ever, the histologic severity (Knodell score), particularly with bridging necrosis, was signifi-cantly higher in patients with CMV viremia26. In a second study, a non-significant trend was ob-served between CMV disease and the propor-tions of patients with severe hepatitis C recur-rence (21 vs. 8%; p = 0.14)13. In a third study, a trend toward a higher histologic activity index at 16 weeks after transplantation was observed among patients with CMV disease (mean score ± standard deviation, 3.9 ± 2.8 vs. 2.8 ± 2.4; p = 0.06)10,12. In a fourth study, recurrent hepa-titis C occurred earlier among CMV-infected compared to noninfected liver recipients18.

On the other hand, three studies indi-cated that the incidence of recurrent hepatitis C was not significantly different between CMV-infected and noninfected patients8,14,18. While the onset of recurrent hepatitis C may be earlier in CMV-infected patients, its incidence was not


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Table 1. Studies that assessed the impact of cytomegalovirus on hepatitis C virus infection after liver transplantation

Study No, Authors, Year

Study population and groups

Antiviral prophylaxis Outcome

1 Rosen, et al.26

1997n = 43Group 1: CMV

viremia (n = 8)Group 2: no CMV

infection (n = 35)

Acyclovir for 120 days or IV ganciclovir for 7 days followed by acyclovir for 120 days

Comparable time to HCV recurrence (143.4 ± 94.7 vs. 220.9 ± 48.2 days; p = 0.47)

Similar incidence of histological HCV recurrence (7 of 8 [87.5%] vs. 23 of 35 [66%]; p = 0.4)

Mean total Knodell score of final biopsy was greater in Group 1 (p = 0.016), especially with bridging necrosis (p = 0.009)

Incidence of allograft cirrhosis (50 vs. 11%; p = 0.027) and graft failure due to HCV (37.5 vs. 5.7%; p = 0.034) was higher in Group 1

2 Teixeira, et al.14


infection (n = 18)Group 2: CMV

negative (n = 21)

Preemptive therapy with IV ganciclovir for 14 days

Higher mild to moderate rejection in Group 1 than Group 2

No significant difference in fibrosis stage at one year after transplant (2.13 vs. 1.17, respectively)

CMV did not influence incidence and grade of histologic outcome of HCV recurrence

3 Humar, et al.13


infection (n = 26)Group 2: No CMV

infection (n = 40)

Oral ganciclovir prophylaxis x 12 w for CMV D+R– patients

CMV infection, disease and DNA load were not associated with HCV viral load at 1 and 3 months after transplant

Trend towards higher incidence of CMV disease in patients with severe HCV recurrence (21 vs. 8%; p = 0.14)

Fibrosis score greater in patients with CMV disease (mean 1.67 vs. 0.56; p = 0.016) and those with CMV infection (mean 1.03 vs. 0.50) compared to those without CMV infection or disease, respectively

CMV disease was associated with severe fibrosis (44% of patients with CMV disease have fibrosis score > 3 vs. 7% in patients without CMV disease)

4* Burak, et al.10


viremia (n = 25)Group 2: No CMV

viremia (n = 68)

Acyclovir x 4 w or ganciclovir x 8 w

Fibrosis score at 4 months was higher in CMV viremic patients (1.05 ± 1.14 vs. 0.45 ± 0.81)

Fibrosis stage ≥ 2 at 4 months (45 vs. 16.4%; p = 0.01) after transplant is more common in CMV viremic patients

CMV viremia was a significant independent predictor of graft failure (RR: 3.73; 95% CI: 1.658.45)

HCV viral load (mEq/ml) was similar between the two groups (4.1 ± 4.6 vs. 3.0 ± 4.2; p = 0.26)

5* Razonable, et al.12


disease and infection (n = 40)

Group 2: No CMV infection (n = 52)

Acyclovir x 4 w or ganciclovir x 8 w

Patients with CMV disease and infection had higher fibrosis stage (mean, 0.87 vs. 0.43) and hepatitis activity index (mean, 1.0 vs. 0.5; p = 0.05) at 4 months after transplantation

Nonsignificant trend towards higher HCV load at 4 months in patients with CMV disease (mean, 55.71 vs. 35.52; p = 0.10)

Allograft failure and mortality was higher in patients with CMV disease (RR: 3.708; 95% CI: 1.6388.396; p = 0.0017)

6 Singh, et al.8


viremia (n = 30)Group 2: No CMV

viremia (n = 21)

Preemptive ganciclovir upon the detection of CMV viremia

HCV recurrence was comparable (50 vs. 42.8%)Patients who received oral ganciclovir had lower

total Knodell score (mean 5.2 vs. 6.9; p = 0.05) and fibrosis scores (mean, 0.44 vs. 1.005; p = 0.12)


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Study population and groups

Antiviral prophylaxis Outcome

7 Chopra, et al.15



infection (n = 54)

Not reported Patients with CMV infection after transplant had a higher fibrosis progression rate compared with those without CMV (mean fibrosis-free survival, 29.0 vs. 53.0 months; p = 0.0004)

8 Ceccherini-Nelli, et al.11 2003

n = 129 Not reported HCV RNA persisted in all but one patientNo association between CMV seropositivity and

pp65 and recurrent hepatitis C after transplant

9 Firpi, et al.24

2004n = 358Group 1: CMV

antigenemia (n = 53)

Group 2: No CMV antigenemia (n = 205)

Prophylaxis with oral ganciclovir x 3 months

Median fibrosis progression was 0.8 units per year.

Equal distribution of CMV in patients with slow (< 0.8 units/year) and rapid (> 0.8 units/year) (14 vs. 13%)

No significant association between CMV and long-term allograft survival or histologic evidence of cirrhosis

10 Singh, et al.18

2005n = 133Group 1: CMV


infection (n = 97)

Preemptive therapy with ganciclovir

Severity of HCV recurrence as assessed by Knodell score (5.8 ± 0.7 vs. 4.9 ± 0.4) or fibrosis score (0.94 ± 0.5 vs. 0.54 ± 0.1) was comparable

Recurrent hepatitis C occurred earlier in Group 1 compared to Group 2 (median, 4.1 vs. 10.4 months; p = 0.037)

11 Nebbia, et al.16


PCR positive (n = 21)

Group 2: CMV PCR negative (n = 48)

Preemptive therapy with ganciclovir or valganciclovir

HCV replication was not significantly different between the two groups

One-year liver biopsies (in 56 patients, including 17 with CMV infection) did not show significant difference between the two groups in terms of histologic grade or stage

HCV: hepatitis C virus; CMV: cytomegalovirus; PCR: polymerase chain reaction; IV: intravenous administration.*Study numbers 4 and 5 assessed the same patient population at a single center but were different in terms of CMV definitions (CMV viremia vs. CMV disease/infection). Study 5 also investigated the effect of human herpes virus 6 and 7 on HCV outcomes.

Table 1. Studies that assessed the impact of cytomegalovirus on hepatitis C virus infection after liver transplantation (continued)

significantly different compared to patients without CMV (55.6 vs. 49.8%; p > 0.20)18. In another study of 39 HCV-infected patients who were monitored twice-weekly and treated pre-emptively for CMV reactivation, the occurrence of “preemptively treated” CMV viremia did not enhance the incidence and histologic outcome of HCV recurrence during the first year after liver transplantation14.

Allograft fibrosis

In several studies, CMV-infected pa-tients were more likely to have a higher inci-

dence or degree of fibrosis progression com-pared to noninfected patients10,12,13,15,26. In a study of 66 HCV-infected patients, liver re-cipients with CMV infection and disease de-veloped higher fibrosis scores compared to those without CMV infection (1.67 vs. 0.56; p = 0.016)13. In this same study, the per-centage of patients with severe fibrosis (scores > 3) was significantly higher in the CMV-infected compared to the noninfected group (44 vs. 7%; p = 0.009)13. These findings were mirrored in a second study, which dem-onstrated that fibrosis scores and the propor-tion of patients with severe fibrosis (score > 2) were significantly higher in HCV-infected liver


153

recipients who developed compared to those who did not develop CMV viremia (45 vs. 16.4%; p = 0.01)10,12. A third study further demonstrated that patients with CMV had a more rapid fibrosis progression rate compared to those without CMV (mean, 29 vs. 53 months; p = 0.0004)15.

In contrast, several studies showed a lack of significant difference in the incidence, severity, and rate of fibrosis progression between patients with or without CMV16,18,24. In a cohort of 69 HCVinfected liver recipients, shortterm viremia treated preemptively with ganciclovir was not significantly associated with the stage of fibrosis at one year after transplantation16. In the largest study involving 358 patients, no significant difference was

observed in the histologic degree of cirrhosis between patients with or without CMV antigenemia24. In addition, there were similar proportions of CMVinfected patients who developed slow and rapid progression of fibrosis24.

Allograft failure and mortality

The CMV viremic liver recipients had a markedly diminished cirrhosisfree actuarial survival by Kaplan Meier estimates26. In a cohort of 93 HCVinfected liver recipients, the incidence of allograft failure (defined as cirrhosis, relisting for liver transplantation, retransplantation, or death) was significantly higher in patients with CMV viremia compared to nonviremic patients (52 vs. 19.1%; p = 0.002)10,12. In

Table 2. Studies that assessed the impact of hepatitis C virus on cytomegalovirus infection after liver transplantation


Study group Antiviral prophylaxis Outcome

1 Singh, et al.28

1996n = 100Group 1: hepatitis C

(n = 22)Group 2: No

hepatitis C(n = 78)

Preemptive therapy with ganciclovir

Incidence of CMV disease was higher in patients with recurrent hepatitis C (32 vs. 9%; p = 0.12)

2 Humar, et al.13 2002

n = 66Group 1: hepatitis C

recurrence (n = 41)Group 2: No hepatitis

C recurrence (n = 25)

Oral ganciclovir prophylaxis x 12 w for CMV D+R– patients (n = 6)

Median peak CMV viral load was not significantly different between Groups 1 and 2

CMV infection (37 vs. 44%) and disease (17 vs. 8%) was not significantly different between Groups 1 and 2, respectively

Trend towards higher incidence of CMV disease in patients with severe HCV recurrence (21 vs 8%; p = 0.14)

3 Nebbia, et al.16

2007n = 257Group 1: HCV

infected patients (n = 69)

Group 2: Non HCVinfected patients (n = 188)

Preemptive IV ganciclovir or valganciclovir for CMV DNAemia

No significant difference in CMV DNAemia frequency, maximum viral load, doubling time, AUC, decline rate after therapy, between HCVinfected and non HCVinfected groups

4 Humar, et al.25

2007n = 177Group 1: HCV

infected patients (n = 60)

Group 2: Non HCVinfected patients (n = 117)

Valganciclovir or oral ganciclovir prophylaxis for 100 days

Incidence of CMV disease (16.7 vs 27.4%; p = 0.11), CMV viremia (53 vs. 53%), and peak CMV viral load (median peak, 723 vs. 543 copies/ml) was not significantly different between HCVinfected and non HCVinfected groups, respectively

CMV: cytomegalovirus; HCV: hepatitis C virus; AUC: area under the concentration curve: IV: intravenous administration.


154

stratifying the patients, allograft failure devel-oped in 48% of patients with CMV disease, 35% of patients with asymptomatic CMV infection, and 17% of patients without CMV infection10,12. Even after adjusting for significant confounders such as donor and recipient age, year of trans-plantation, and use of mycophenolate mofetil in a stepwise multivariate model, CMV was an independent risk factor for allograft failure and mortality in HCV-infected liver recipients10,12. In contrast to these findings, in a cohort of 358 patients, there was no significant difference in the long-term survival of patients who did or did not develop CMV pp65 antigenemia24.

Impact of ganciclovir therapy

Anti-CMV preventive strategies in the 11 studies varied from prophylaxis24 to pre-emptive therapy8,18 or a combination of both. Reflecting the evolution of clinical practice since 1990, the antiviral drugs for prevention of CMV varied from acyclovir10,12 to ganciclo-vir and valganciclovir24. Hence, it has been difficult to assess the impact of anti-CMV ther-apy on hepatitis C outcomes. In one study, however, patients who received oral ganciclo-vir for preemptive treatment of CMV antigen-emia had significantly lower Knodell scores8.

Impact of hepatitis C virus on cytomegalovirus infection and disease

Since HCV is an immunomodulatory vi-rus that may impair cellular immune respons-es, HCV-infected patients may be more pre-disposed to develop CMV disease (Table 2). This concept was illustrated anecdotally in a report of two liver recipients who developed late-onset CMV disease, despite lacking tra-ditional risk factors17. In possibly the first co-hort study that evaluated this association, the incidence of recurrent major infections was higher in liver recipients with recurrent HCV

hepatitis compared to other patients (10/22 [45%] vs. 8/78 [10%]; p = 0.005), including a trend towards a higher incidence of CMV dis-ease (32 vs. 9%; p = 0.12)28. Three subse-quent studies, however, did not observe this association. The median peak CMV load, and the incidence of CMV infection and disease was not significantly different in HCV-infected patients who did and did not develop recur-rent hepatitis C, although a trend towards a higher incidence of CMV disease was ob-served in patients with severe recurrence of hepatitis C13. In comparing HCV-infected from non HCV-infected liver recipients, two studies found no significant differences in the inci-dence of CMV disease, viremia, and peak CMV load between the two groups13,16. Com-pared to 188 HCV-negative liver recipients, the incidence of CMV DNAemia and CMV rep-lication dynamics observed among 69 HCV-infected liver recipients was not significantly different16. These findings were reflected in a recent multicenter study wherein the inci-dence of CMV disease and CMV viremia, and the peak CMV load were not significantly dif-ferent between HCV-infected and noninfected liver recipients13.

Discussion

This comprehensive review of published clinical reports highlights the evidence for and against the bidirectional relationship between CMV and HCV after liver transplantation. On the first issue of whether CMV facilitates hepa-titis C recurrence and progression after liver transplantation, several studies have strongly argued that CMV was significantly associated with recurrent hepatitis C, time to and sever-ity of HCV-induced fibrosis and cirrhosis, and allograft failure and mortality after liver trans-plantation10,12,13,15,26,28. One study even ob-served that oral ganciclovir treatment of CMV viremia was associated with lower Knodell and fibrosis scores in HCV-infected liver re-cipients8. On the contrary, there were also


155

several studies that have refuted these findings by demonstrating the lack of significant association between CMV and hepatitis C outcomes11,14,16,24. On the second issue of whether HCV influences CMV, one study suggested that HCVinfected liver recipients are at higher risk of CMV disease28, while three other studies did not show increased risk of CMV in HCVinfected compared to non HCVinfected liver recipients16,25.

So why the conflicting data? We can surmise that this likely reflects variations in study design, patient populations, and clinical variables. It is important to emphasize that each of the studies analyzed different outcomes. Some studies focused on viral factors such as viral load, time to recurrence, and doubling time, whereas other studies focused on liver histology such as fibrosis stage or hepatitis recurrence. Depending on the study, the consideration of CMV as predictor was indicated by serology, PCR detection, antigenemia assays, culture, and clinical measures. Likewise, the outcomes of interest ranged from HCV viremia to incidence and time to onset of recurrent hepatitis, fibrosis, cirrhosis, graft failure, and death. Immunosuppression and antiviral prophylaxis also varied greatly across studies. Even within the same study, different patients received varying regi mens of medications, tailored to their specific needs as influenced by other factors such as CMV donor and recipient serostatus and immunosuppressive drugs. A patient receiving viral prophylaxis immediately after transplantation compared with a patient receiving prophylaxis once a viral reactivation was detected, could have significantly different outcomes. Patient populations varied among the different studies, introducing yet another factor that could lead to conflicting results. All these variables, together with many other confounders that may affect outcome, such as use of interferon therapy, are likely the reasons why there is such a contrast in the results.

The potential clinical relevance of the bidirectional relationship between CMV and HCV, however, should spur the conduct of large, prospective, multicenter trials that will address this issue in a standardized manner. If the association is proven, then one can provide mechanisms to prevent CMV (i.e. a correctable risk) in order to improve the outcome of liver transplantation for HCV. Undoubtedly, a thorough understanding of this relationship will not only benefit transplant recipients, but may be extrapolated to other populations including immunocompetent individuals. Indeed, in a study of 34,204 HCVinfected patients and 136,816 control subjects without HCV, CMV was observed more commonly in the HCVinfected group, even after excluding patients that were immunocompromised by AIDS and transplantation27.

Despite the contrasting findings, the clinical benefits of preventing CMV cannot be ignored. In our view, since CMV is such a preventable confounder, one can strongly argue for the aggressive prevention of CMV in all HCVinfected liver recipients29,30. In our center, we adapted the approach of antiviral prophylaxis to all HCVinfected liver recipients at risk of primary or reactivation CMV disease31. The observation that aggressive treatment of shortterm CMV viremia resulted in lower Knodell scores among HCVinfected liver recipients underscores this approach8,18.

In conclusion, a thorough understanding of the relationship between CMV and HCV is needed so that physicians will be able to better manage liver recipients and improve outcomes. Despite conflicting data from current studies, the morbidity outcomes associated with HCVCMV interaction in several studies should warrant the aggressive prevention of CMV disease in atrisk HCVinfected liver recipients. Indeed, prevention of CMV disease is standard of care in every liver transplant recipient. In this context, we strongly suggest that an aggressive implementation


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of CMV prevention strategy should be ensured for all HCV-infected patients.

References 1. (OPTN) OPTN. Transplants in the US by Region. Liver Trans-

plant Data. Vol. 2008, 2008. 2. Charlton M. Recurrence of hepatitis C infection: Where are

we now? Liver Transpl. 2005;11:S57-62. 3. Porter SB, Reddy KR. Factors that influence the severity of

recurrent HCV following liver transplantation. Clin Liver Dis. 2003;7:603-14

4. Rosen HR. Hepatitis C virus in the human liver transplanta-tion model. Clin Liver Dis. 2003;7:107-25.

5. Lauer GM, Walker BD. Hepatitis C virus infection. N Engl J Med. 2001;345:41-52

6. Belli LS, Burroughs AK, Burra P, et al. Liver transplantation for HCV cirrhosis: improved survival in recent years and increased severity of recurrent disease in female recipients: results of a long-term retrospective study. Liver Transpl. 2007;13:733-40.

7. Wright TL, Donegan E, Hsu HH, et al. Recurrent and ac-quired HCV infection in liver transplant recipients. Gastroen-terology. 1992;103:317-22.

8. Singh N, Husain S, Carrigan DR, et al. Impact of human herpesvirus-6 on the frequency and severity of recurrent HCV hepatitis in liver transplant recipients. Clin Transplant. 2002;16:92-6. *This study demonstrated that patients with CMV viremia treated preemptively with oral ganciclovir had lower Knodell scores.

9. Charlton M, Seaberg E, Wiesner R, et al. Predictors of pa-tient and graft survival following liver transplantation for hepatitis C. Hepatology. 1998;28:823-30.

10. Burak KW, Kremers WK, Batts KP, et al. Impact of CMV infection, year of transplantation, and donor age on out-comes after liver transplantation for hepatitis C. Liver Transpl. 2002;8:362-9. *This study demonstrated that donor age, MMF use, and CMV infection were independently as-sociated with allograft failure after liver transplantation for chronic hepatitis C.

11. Ceccherini-Nelli L, Giannotti A, Malizia T, et al. Recurrence of HCV infection in liver transplant patients: evaluation of IgM anti-HCV and IgM anti-CMV. Transplant Proc. 2003;35: 1030-1.

12. Razonable RR, Burak KW, van Cruijsen H, et al. The patho-genesis of HCV is influenced by CMV. Clin Infect Dis. 2002;35:974-81. *This study demonstrated the increasing risk of allograft failure and mortality among patients with CMV disease, CMV infection, and no CMV infection.

13. Humar A, Kumar D, Raboud J, et al. Interactions between CMV, human herpesvirus-6, and the recurrence of hepatitis C after liver transplantation. Am J Transplant. 2002;2:461-6. *This study showed higher degree of hepatitis C in patients with CMV infection.

14. Teixeira R, Pastacaldi S, Davies S, et al. The influence of CMV viremia on the outcome of recurrent hepatitis C after liver transplantation. Transplantation. 2000;70:1454-8.

15. Chopra KB, Demetris AJ, Blakolmer K, et al. Progression of liver fibrosis in patients with chronic hepatitis C after ortho-topic liver transplantation. Transplantation. 2003;76:1487-91.

16. Nebbia G, Mattes FM, Cholongitas E, et al. Exploring the bidirectional interactions between human CMV and HCV replication after liver transplantation. Liver Transpl. 2007;13:130-5. *This study examined the bidirectional inter-actions between HCV and CMV, and found no relationship between the two viruses.

17. Singh N, Zeevi A, Gayowski T, Marino IR. Late onset CMV disease in liver transplant recipients: de novo reactivation in recurrent HCV hepatitis. Transpl Int. 1998;11:308-11.

18. Singh N, Wannstedt C, Keyes L, Wagener MM, Gayowski T, Cacciarelli TV. Indirect outcomes associated with CMV (op-portunistic infections, HCV sequelae, and mortality) in liver transplant recipients with the use of preemptive therapy for 13 years. Transplantation. 2005;79:1428-34. *This study showed that, with preemptive therapy, the indirect effects of CMV may be eliminated.

19. Kanj SS, Sharara AI, Clavien PA, Hamilton JD. Cytomegalo-virus infection following liver transplantation: review of the literature. Clin Infect Dis. 1996;22:537-49.

20. Stratta RJ, Shaefer MS, Markin RS, et al. Clinical patterns of CMV disease after liver transplantation. Arch Surg. 1989;124: 1443-9 [discussion 1449-50].

21. Falagas ME, Snydman DR, Griffith J, Ruthazer R, Werner BG. Effect of CMV infection status on first-year mortality rates among orthotopic liver transplant recipients. The Bos-ton Center for Liver Transplantation CMVIG Study Group. Ann Intern Med. 1997;126:275-9.

22. George MJ, Snydman DR, Werner BG, et al. The indepen-dent role of CMV as a risk factor for invasive fungal disease in orthotopic liver transplant recipients. Boston Center for Liver Transplantation CMVIG-Study Group. Cytogam, Med-Immune, Inc. Gaithersburg, Maryland. Am J Med. 1997;103: 106-13.

23. Seehofer D, Rayes N, Tullius SG, et al. CMV hepatitis after liver transplantation: incidence, clinical course, and long-term follow-up. Liver Transpl. 2002;8:1138-46.

24. Firpi RJ, Abdelmalek MF, Soldevila-Pico C, et al. One-year protocol liver biopsy can stratify fibrosis progression in liver transplant recipients with recurrent HCV infection. Liver Transpl. 2004;10:1240-7. *This is the largest study to have assessed the relationship between CMV and HCV. No sig-nificant association was observed between CMV antigen-emia and cirrhosis and survival after liver transplantation for chronic hepatitis C.

25. Humar A, Washburn K, Freeman R, et al. An assessment of interactions between HCV and herpesvirus reactivation in liver transplant recipients using molecular surveillance. Liver Transpl. 2007;13:1422-7. *This is the only multicenter study that has assessed the association between HCV and CMV. HCV-infected liver recipients were not more likely to develop CMV infection and disease after liver transplantation.

26. Rosen HR, Chou S, Corless CL, et al. Cytomegalovirus vire-mia: risk factor for allograft cirrhosis after liver transplanta-tion for hepatitis C. Transplantation. 1997;64:721-6. *This is the first study to have indicated the association between CMV viremia and cirrhosis after liver transplantation for chronic hepatitis C.

27. El-Serag HB, Anand B, Richardson P, Rabeneck L. Asso-ciation between HCV infection and other infectious diseases: a case for targeted screening? Am J Gastroenterol. 2003;98:167-74. *This is the largest study describing the association between HCV and CMV, even in non-immuno-compromised patients. HCV-infected patients were more likely to develop CMV infection, even after exclusion of trans-plant patients and patients with AIDS.

28. Singh N, Gayowski T, Wagener MM, Marino IR. Increased infections in liver transplant recipients with recurrent HCV hepatitis. Transplantation. 1996;61:402-6. *This study was the first to describe the higher risk of CMV infection in HCV-infected compared to non HCV-infected liver transplant re-cipients.

29. Razonable RR. Epidemiology of CMV disease in solid organ and hematopoietic stem cell transplant recipients. Am J Health Syst Pharm. 2005;62:S7-13.

30. Razonable RR, Paya CV. Valganciclovir for the prevention and treatment of CMV disease in immunocompromised hosts. Expert Rev Anti Infect Ther. 2004;2:27-41.

31. Arthurs SK, Eid AJ, Pedersen RA, et al. Delayed-onset pri-mary CMV disease after liver transplantation. Liver Transpl. 2007;13:1703-9.

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1. NOMBRE DEL MEDICAMENTO. CellCept500 mg, comprimidos; CellCept250 mg, cápsulas; CellCept, 500 mg, polvo paraconcentrado para solución para perfusión.2. COMPOSICIÓN CUALITATIVA Y CUANTITATIVA. Cada comprimido contiene500 mg de micofenolato mofetilo. Cada cápsula contiene 250 mg de micofenolato mofetilo.Cada vial contiene el equivalentea 500 mg de micofenolato mofetilo (clorhidrato). Excipientes: Para la lista completa, ver sección 6.1. 3. FORMAFARMACÉUTICA. Comprimidos recubiertos con película. Comprimidos CellCept: oblongos, de color azul espliego, con elgrabado “CellCept 500” en una cara y el “logotipo de la Empresa” en la otra. Cápsulas duras. Cápsulas CellCept: oblongas,de color azul/marrón, con la inscripción “CellCept 250” en la mitad superior y el “logotipo de la Compañía” en la mitadinferior. Polvo para concentrado para solución para perfusión. CellCept 500 mg polvo para concentrado para solución paraperfusión debe ser reconstituido y posteriormente diluido con una solución para perfusión intravenosa de glucosa al 5 %,antes de la administración al paciente (ver sección 6.6). 4. DATOS CLÍNICOS. 4.1 Indicaciones terapéuticas. CellCept, encombinación con ciclosporina y corticosteroides, está indicado para la profilaxis del rechazo agudo de trasplante en pacientessometidos a trasplante alogénico renal, cardíaco o hepático. 4.2 Posología y forma de administración. El tratamiento conCellCept debe ser iniciado y mantenido por especialistas debidamente cualificados en trasplantes. ADVERTENCIA: LASOLUCIÓN INTRAVENOSA DE CELLCEPT NUNCA DEBE SER ADMINISTRADA MEDIANTE INYECCIÓN INTRAVENOSARÁPIDA O EN BOLUS. CellCept 500 mg polvo para concentrado para solución para perfusión es una forma farmacéuticaalternativa a las formas orales de CellCept (cápsulas, comprimidos y polvo para suspensión oral) que puede ser administradadurante 14 días. La dosis inicial de CellCept 500 mg polvo para concentrado para solución para perfusión debe administrarse,dentro de las 24 horas siguientes al trasplante.Tras la reconstitución hasta una concentración de 6 mg/mL, CellCept 500 mgpolvo para concentrado para solución para perfusión se debe administrar mediante perfusión intravenosa lenta en un períodosuperior a 2 horas, bien en vena periférica o en vena central (ver sección 6.6). Uso en trasplante renal: Adultos: el inicio dela administración de CellCept por vía oral debe realizarse en las 72 horas siguientes al trasplante. La dosis recomendada entrasplantados renales es de 1 g administrado dos veces al día (dosis diaria total = 2 g). Niños y adolescentes (entre 2 y 18años): la dosis recomendada de micofenolato mofetilo es de 600 mg/m2, administrada dos veces al día por vía oral (hastaun máximo de 2 g diarios). Los comprimidos de CellCept deben prescribirse únicamente a pacientes con una superficiecorporal mayor de 1,5 m2, deben recibir una dosis de 1 g dos veces al día (dosis diaria total = 2 g). Debido a que algunasreacciones adversas ocurren con una mayor frecuencia en este grupo de edad (ver sección 4.8), en comparación con losadultos, es posible que sea necesario efectuar reducciones de dosis temporales o interrupción del tratamiento; esto deberátener en cuenta factores clínicos relevantes incluyendo la gravedad del evento. Niños (< 2 años): existen datos limitados deseguridad y eficacia en niños con una edad inferior a los 2 años. Estos son insuficientes para realizar recomendacionesposológicas y por consiguiente, no se recomienda su uso en este grupo de edad. Uso en trasplante cardíaco: Adultos: el iniciode la administración de CellCept por vía oral debe realizarse en los 5 días siguientes al trasplante. La dosis recomendada enlos pacientes sometidos a trasplante cardíaco es de 1,5 g administrada dos veces al día (dosis diaria total = 3 g). Niños: Nohay datos disponibles en pacientes pediátricos con trasplante cardíaco. Uso en trasplante hepático: Adultos: se debeadministrar CellCept IV durante los 4 días siguientes al trasplante hepático, posteriormente se comenzará la administraciónde CellCept oral, tan pronto como ésta sea tolerada. La dosis oral recomendada en los pacientes sometidos a trasplantehepático es de 1,5 g administrados dos veces al día (dosis total diaria = 3 g). Niños: No hay datos disponibles en pacientespediátricos con trasplante hepático. Uso en ancianos ( 65 años): la dosis recomendada en ancianos es de 1 g administradodos veces al día en el trasplante renal y 1,5 g dos veces al día en los trasplantes cardíaco y hepático. Uso en pacientes coninsuficiencia renal: en pacientes sometidos a trasplante renal con insuficiencia renal crónica grave (filtración glomerular< 25 mL·min-1·1,73 m-2), deben evitarse dosis superiores a 1 g dos veces al día fuera del período inmediatamente posterioral trasplante. Se debe observar cuidadosamente a estos pacientes. No son necesarios ajustes posológicos en pacientes conretraso funcional del riñón trasplantado en el postoperatorio (ver sección 5.2).No existen datos sobre los pacientes sometidosa trasplante cardíaco o hepático con insuficiencia renal crónica grave. Uso en pacientes con insuficiencia hepática grave:los pacientes sometidos a trasplante renal con enfermedad grave del parénquima hepático, no precisan ajuste de dosis. Noexisten datos sobre los pacientes sometidos a trasplante cardíaco con enfermedad grave del parénquima hepático.Tratamiento durante episodios de rechazo: el ácido micofenólico (MPA) es el metabolito activo del micofenolato mofetilo. Elrechazo del riñón trasplantado no provoca cambios en la farmacocinética del MPA; no es necesario reducir la dosis ointerrumpir el tratamiento con CellCept. No hay fundamentos para ajustar la dosis de CellCept tras el rechazo del corazóntransplantado. No se dispone de datos farmacocinéticos durante el rechazo del hígado trasplantado.4.3 Contraindicaciones.Se han descrito reacciones de hipersensibilidad a CellCept (ver sección 4.8). Por consiguiente, este medicamento estácontraindicado en pacientes con hipersensibilidad al micofenolato mofetilo o al ácido micofenólico. CellCept estácontraindicado en mujeres en periodo de lactancia (ver el sección 4.6). Para información sobre su uso durante el embarazoasí como las medidas contraceptivas a adoptar ver sección 4.6. 4.4 Advertencias y precauciones especiales de empleo.Los pacientes que reciben CellCept como parte de un tratamiento inmunosupresor en combinación con otros medicamentos,presentan un mayor riesgo de desarrollar linfomas y otros tumores malignos, en especial de la piel (ver sección 4.8). Elriesgo parece estar relacionado con la intensidad y la duración de la inmunosupresión más que con el uso de un fármacodeterminado. Como norma general para minimizar el riesgo de cáncer de piel, se debe limitar la exposición a la luz solar ya la luz UV mediante el uso de ropa protectora y el empleo de pantalla solar con factor de protección alto. Se debe indicar alos pacientes que reciben tratamiento con CellCept que comuniquen inmediatamente cualquier evidencia de infección,contusiones no esperadas, hemorragias o cualquier otra manifestación de depresión de la médula ósea. La supresión excesivadel sistema inmunitario aumenta la vulnerabilidad a las infecciones, incluyendo infecciones oportunistas, infecciones mortalesy sepsis (ver sección 4.8). Se debe monitorizar a los pacientes en tratamiento con CellCept debido a la neutropenia, la cualpodría estar relacionada con el propio CellCept, con medicamentos concomitantes, con infecciones virales, o con lacombinación de estas causas. En los pacientes tratados con CellCept se deben realizar hemogramas completos una vez porsemana durante el primer mes, dos veces al mes durante los meses segundo y tercero de tratamiento y, a continuación, unavez al mes durante todo el resto del primer año. Se debería interrumpir o finalizar el tratamiento con CellCept si se desarrollasela neutropenia (recuento absoluto de neutrófilos < 1,3 x 10³/microlitro). Se debe informar a los pacientes que durante eltratamiento con CellCept las vacunaciones pueden ser menos eficaces y que se debe evitar el empleo de vacunas atenuadasde organismos vivos (ver sección 4.5).Se debe considerar la vacunación contra la gripe. El médico deberá observar lasdirectrices nacionales para la vacunación contra la gripe. Se ha relacionado CellCept con un aumento en la incidencia deeventos adversos en el aparato digestivo, entre los que se incluyen casos poco frecuentes de ulceraciones en el tractogastrointestinal, hemorragias y perforaciones. Por este motivo CellCept debe administrarse con precaución en pacientescon enfermedad activa grave del aparato digestivo. CellCept es un inhibidor de la inosin monofosfato deshidrogenasa (IMPDH).Por lo que, en teoría, debe evitarse su empleo en pacientes con deficiencia hereditaria rara de la hipoxantina-guaninafosforribosil transferasa (HGPRT) como es el caso de los Síndromes de Lesch-Nyhan y KelleySeegmiller. No se recomiendaadministrar CellCept al mismo tiempo que azatioprina, ya que su administración concomitante no se ha estudiado.Teniendoen cuenta la reducción significativa del AUC del MPA que produce la colestiramina, la administración concomitante deCellCept y medicamentos que interfieran en la recirculación enterohepática debe llevarse a cabo con precaución, dada laposibilidad de que disminuya la eficacia de CellCept. No se ha establecido el balance beneficio-riesgo de micofenolatomofetilo en combinación con tacrolimus o sirolimus (ver también sección 4.5). 4.5. Interacción con otros medicamentosy otras formas de interacción. Los estudios de interacciones se han realizado sólo en adultos. Aciclovir: se observaronconcentraciones plasmáticas de aciclovir más altas cuando se administra con micofenolato mofetilo que cuando se administraaciclovir solo. Los cambios en la farmacocinética del MPAG (el glucurónido fenólico del MPA) fueron mínimos (aumento delMPAG entorno al 8 %) y no se consideran clínicamente significativos. Dado que las concentraciones plasmáticas de MPAGy aciclovir aumentan cuando está deteriorada la función renal, existe la posibilidad de que micofenolato mofetilo y aciclovir,o sus profármacos, ej. valaciclovir compitan en la secreción tubular y se eleve aún más la concentración de ambas sustancias.Antiácidos con hidróxidos de magnesio y aluminio: la absorción del micofenolato mofetilo disminuyó tras su administracióncon antiácidos. Colestiramina: tras la administración de una dosis única de 1,5 g de micofenolato mofetilo a sujetos sanostratados previamente con 4 g de colestiramina, tres veces al día, durante 4 días, se observó la disminución del AUC del MPA(ver secciones 4.4, y 5.2). Se deberá tener precaución cuando se administren conjuntamente, debido a su potencial parareducir la eficacia de CellCept. Medicamentos que interfieren con la circulación enterohepática: se debe tener precaucióncuando se empleen medicamentos que interfieran con la circulación enterohepática debido a su potencial para reducir laeficacia de CellCept. Ciclosporina A: la farmacocinética de la ciclosporina A (CsA) no experimenta variaciones debidas amicofenolato mofetilo. Sin embargo, si se cesa la administración concomitante de ciclosporina, es previsible un aumento delAUC del MPA entorno al 30%. Ganciclovir: teniendo en cuenta los resultados de un estudio de administración de dosis únicaa las dosis recomendadas de micofenolato oral y ganciclovir intravenoso, así como los conocidos efectos de la insuficienciarenal en la farmacocinética del CellCept (ver sección 4.2) y del ganciclovir, se prevé que la administración conjunta de estosfármacos (que compiten por los mismos mecanismos de la secreción tubular renal) de lugar a un aumento de la concentracióndel MPAG y del ganciclovir. Como no hay indicios de que se produzca una alteración sustancial de la farmacocinética del MPAno es necesario ajustar la dosis de CellCept. Se debería considerar las recomendaciones de dosis de ganciclovir, así comollevar a cabo una estrecha vigilancia en aquellos pacientes con insuficiencia renal y que estén siendo tratados con CellCepty ganciclovir simultáneamente o sus profármacos, ej. valganciclovir. Anticonceptivos orales: la farmacocinética y lafarmacodinamia de los anticonceptivos orales no se vieron modificadas por la administración simultánea de CellCept (ver

además sección 5.2). Rifampicina: En pacientes no tratados con ciclosporina, la administración concomitante de Cellcept yrifampicina dió lugar a una disminución en la exposición al MPA del 18% al 70% (AUC 0-12h). Por lo tanto, se recomiendavigilar los niveles de exposición al MPA y ajustar las dosis de CellCept en consecuencia para mantener la eficacia clínicacuando se administra rifampicina de forma concomitante. Sirolimus: en pacientes sometidos a trasplante renal, laadministración concomitante de Cellcept con ciclosporina redujo la exposición al MPA en un 30-50% en comparación conlos pacientes que habían recibido la combinación de sirolimus y dosis similares de Cellcept (ver además sección 4.4).Sevelamer: la administración concomitante de Cellcept con sevelamer disminuyó la Cmax del MPA y del AUC 0-12 en un 30%y 25%, respectivamente, sin consecuencias clínicas (ej: rechazo del injerto). Sin embargo, se recomendó administrar Cellceptal menos una hora antes o tres horas después del uso de sevelamer para minimizar el impacto sobre la absorción del MPA.Con respecto a los ligantes de fosfasto solo existen datos de Cellcept con sevelamer. Trimetoprim/sulfametoxazol: no seobservó ningún efecto sobre la biodisponibilidad del MPA. Norfloxacino y metronidazol: no se ha observado interacciónsignificativa en la administración concomitante separada de Cellcept con norfloxacina o con metronidazol en voluntariossanos. Sin embargo, norfloxacina y metronidazol combinados redujeron la exposición al MPA en aproximadamente un 30%tras una dosis única de Cellcept. Tacrolimus: En los pacientes sometidos a trasplante hepático que comenzaron con Cellcepty tacrolimus, el AUC y la Cmáx del MPA no se vieron afectados de forma significativa por la administración conjunta contacrolimus. Por el contrario, hubo un aumento de aproximadamente un 20% en el AUC de tacrolimus cuando se administrarondosis múltiples de Cellcept (1,5 g dos veces al día) a pacientes tratados con tacrolimus. Sin embargo, en pacientes contransplante renal, la concentración de tacrolimus no pareció verse alterada por Cellcept (ver además sección 4.4). Otrasinteracciones: la administración conjunta de probenecid y micofenolato mofetilo en mono eleva al triple el valor del AUC delMPAG. En consecuencia, otras sustancias con secreción tubular renal pueden competir con el MPAG y provocar así unaumento de las concentraciones plasmáticas del MPAG o de la otra sustancia sujeta a secreción tubular. Vacunas deorganismos vivos: las vacunas de organismos vivos no deben administrarse a pacientes con una respuesta inmunedeteriorada. La respuesta de anticuerpos a otras vacunas puede verse disminuida. (ver también sección 4.4).4.6 Embarazoy lactancia. Se recomienda no iniciar tratamiento con CellCept hasta disponer de una prueba de embarazo negativa. Se debeutilizar un tratamiento anticonceptivo efectivo antes de comenzar el tratamiento, a lo largo del mismo, y durante las seissemanas siguientes a la terminación del tratamiento con CellCept (ver sección 4.5). Debe indicarse a los pacientes queconsulten inmediatamente a su médico en caso de quedar embarazadas. No se recomienda el uso de CellCept durante elembarazo, quedando reservado solo para aquellos casos en los que no haya disponible un tratamiento alternativo másadecuado. CellCept solo se debería usar durante el embarazo si el beneficio para la madre supera el riesgo potencial parael feto. Se dispone de datos limitados del uso de CellCept en mujeres embarazadas. No obstante, se han notificado casosde malformaciones congénitas en hijos de pacientes tratados durante el embarazo con Cellcept en combinación con otrosinmunosupresores, incluyendo malformaciones en oidos, p.ej. carencia del oído externo/medio o con anomalía en laformación. Los estudios en animales han mostrado toxicidad reproductiva (ver sección 5.3). Se desconoce el riesgo potencialpara humanos. En ratas lactantes se ha demostrado que el micofenolato mofetilo se elimina en la leche. No se sabe si estasustancia se elimina en la leche humana. CellCept está contraindicado en mujeres durante el periodo de lactancia, debidoal riesgo potencial de reacciones adversas graves al micofenolato mofetilo en niños lactantes (ver sección 4.3). 4.7 Efectossobre la capacidad para conducir y utilizar máquinas. No se han realizado estudios sobre la capacidad para conducir yutilizar máquinas. El perfil farmacodinámico y las reacciones adversas descritas indican que es improbable tal efecto. 4.8Reacciones adversas. Entre las siguientes reacciones adversas se incluyen las reacciones adversas ocurridas durante losensayos clínicos: Las principales reacciones adversas, asociadas a la administración de CellCept en combinación conciclosporina y corticosteroides, consisten en diarrea, leucopenia, sepsis y vómitos; se han observado, además, indicios deuna frecuencia más alta de ciertos tipos de infección (ver sección 4.4). Neoplasias malignos: Los pacientes bajo tratamientoinmunosupresor con asociaciones de medicamentos, que incluyen CellCept tienen mayor riesgo de desarrollar linfomas yotras neoplasias malignas, principalmente en la piel (ver sección 4.4). Se desarrollaron enfermedades linfoproliferativas olinfomas en el 0,6 % de los pacientes que recibían CellCept (2 g ó 3 g diarios) en combinación con otros inmunosupresores,en ensayos clínicos controlados de pacientes con transplante renal (datos con 2 g), cardíaco y hepático, a los que se les hizoseguimiento durante por lo menos 1 año. Se observó cáncer de piel, excluyendo al melanoma, en el 3,6 % de los pacientes;se observaron otros tipos de neoplasias malignas en el 1,1 % de los pacientes. Los datos de seguridad a tres años enpacientes con transplante renal y cardíaco no mostraron ningún cambio inesperado en la incidencia de neoplasias malignasen comparación con los datos a 1 año. El seguimiento de los pacientes con transplante hepático fue de al menos 1 año peroinferior a 3 años. Infecciones oportunistas: Todos los pacientes transplantados tienen mayor riesgo de padecer infeccionesoportunistas, este riesgo aumenta con la carga inmunosupresora total (ver sección 4.4). Las infecciones oportunistas máscomunes en pacientes tratados con CellCept (2 g ó 3 g diarios) juntos con otros inmunosupresores, detectadas en los ensayosclínicos controlados de pacientes con transplante renal (datos con 2 g), cardíaco y hepático, a los que se les hizo unseguimiento de al menos 1 año, fueron candida mucocutánea, viremia/síndrome por CMV y Herpes simplex. La proporciónde pacientes con viremia/síndrome por CMV fue del 13,5 %. Niños y adolescentes (entre 2 y 18 años): En un ensayo clínico,que incluía a 92 pacientes pediátricos de edades comprendidas entre los 2 y los 18 años, tratados dos veces al día con600 mg/m2 de micofenolato mofetilo administrado por vía oral, el tipo y la frecuencia de las reacciones adversas fueron, porlo general, similares a aquellas observadas en pacientes adultos tratados con 1 g de CellCept dos veces al día. No obstante,las siguientes reacciones adversas relacionadas con el tratamiento fueron más frecuentes en la población pediátrica,particularmente en niños menores de 6 años de edad, que en la de adultos: diarreas, sepsis, leucopenia, anemia e infección.Pacientes ancianos ( 65 años): Los pacientes ancianos ( 65 años) en general pueden presentar mayor riesgo de reaccionesadversas debido a la inmunosupresión. Los pacientes ancianos, que reciben CellCept como parte de un régimeninmunosupresor en combinación, podrían tener mayor riesgo de padecer ciertas infecciones (incluyendo la enfermedadhística invasiva por citomegalovirus), posibles hemorragias gastrointestinales y edema pulmonar, en comparación conindividuos jóvenes. Otras reacciones adversas: En la siguiente tabla se indican las reacciones adversas, probablemente oposiblemente relacionadas con CellCept, notificadas en 1/10 y en 1/100 a <1/10 de los pacientes tratados con CellCepten los ensayos clínicos controlados de pacientes con transplante renal (datos con 2 g), cardíaco y hepático. ReaccionesAdversas, Probablemente o Posiblemente Relacionadas con CellCept, Notificadas en Pacientes Tratados con CellCepten los Ensayos Clínicos en Transplante Renal, Cardíaco y Hepático cuando se Usa en Asociación con Ciclosporinay Corticosteroides. Dentro de la clasificación por órganos y sistemas, las reacciones adversas se presentan bajo elencabezamiento de frecuencia, usando las siguientes categorías: muy frecuentes ( 1/10); frecuentes ( 1/100 < 1/10); pocofrecuentes ( 1/1.000 < 1/100); raras ( 1/10.000 1/1.000); muy raras ( 1/10.000), no conocidas (no se puede estimara partir de los datos disponibles). Las reacciones adversas se presentan en orden decreciente de gravedad dentro de cadafrecuencia.

Muy frecuentes

Frecuentes

Muy frecuentesFrecuentes




Infecciones e infestaciones

Neoplasias benignas, malignas y no especificadas(incl quistes y pólipos)

Trastorno de la sangre y del sistema linfático

Trastornos del metabolismo y de la nutrición

Trastornos psiquiátricos

Sepsis, candidiasis gastrointestinal, infección del tracto urinario,herpes simplex, herpes zosterNeumonía, síndrome gripal, infección del tracto respiratorio, moniliasisrespiratoria, infección gastrointestinal, candidiasis, gastroenteritis,infección, bronquitis, faringitis, sinusitis, dermatitis micótica, candidiasisen piel, candidiasis vaginal, rinitis

-

Cáncer cutáneo, tumor benigno de piel

Leucopenia, trombocitopenia, anemiaPancitopenia, leucocitosis

-Acidosis, hiperpotasemia, hipopotasemia,hiperglicemia,hipomagnesemia, hipocalcemia, hipercolesterolemia,hiperlipidemia, hipofosfatemia, hiperuricemia, gota, anorexia

-

Agitación,confusión, depresión, ansiedad, alteración del pensamiento,insomnio

Clasificación por órgano y sistema Reacciones adversas al fármaco

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Los siguientes efectos adversos incluyen las reacciones adversas ocurridas durante la experiencia posterior a lacomercialización: Los tipos de reacciones adversas, notificadas tras la comercialización de CellCept, son similares a lasobservadas en los ensayos controlados en transplante renal, cardíaco y hepático. A continuación se describen reaccionesadversas al fármaco adicionales, notificadas tras la comercialización, con las correspondientes frecuencias si se conocen,dentro de paréntesis. Aparato digestivo: colitis incluyen colitis por citomegalovirus, ( 1/100 <1/10), pancreatitis ( 1/100<1/10), y atrofia de las vellosidades intestinales. Alteraciones relacionadas con la inmunosupresión: Se han comunicadoocasionalmente casos de infecciones graves con riesgo para la vida como meningitis, endocarditis infecciosa, tuberculosise infección micobacteriana atípica. Se ha comunicado agranulocitosis( 1/1000 <1/100), y neutropenia en algunospacientes, por lo que se aconseja monitorizar regularmente a los pacientes en tratamiento con CellCept (ver sección 4.4 )Se han notificado casos de anemia aplásica y depresión de médula ósea en pacientes tratados con CellCept, algunos de loscuales han provocado la muerte. Hipersensibilidad: Se han notificado reacciones de hipersensibilidad, incluyendo edemaangioneurótico y reacción anafilactica. 4.9 Sobredosis. Se han notificado casos de sobredosis con micofenolato mofetilo enensayos clínicos y durante la experiencia postcomercialización. En muchos de estos casos, no se notificaron reaccionesadversas. En los casos de sobredosis en los cuales se notificaron reacciones adversas, estas reacciones estaban dentro delperfil de seguridad conocido del medicamento. Se cree que una sobredosis de micofenolato mofetilo posiblemente podríaproducir una sobresupresión del sistema inmune y aumentar la susceptibilidad a infecciones y una supresión de la médulaósea (ver sección 4.4). Si se desarrolla neutropenia, se debería interrumpir o reducir la dosis de CellCept (ver sección 4.4).No se preveé la eliminación de cantidades clínicamente significativas de MPA o MPAG por hemodiálisis. Los secuestradoresde ácidos biliares, como la colestiramina, pueden eliminar el MPA disminuyendo la re-circulación enterohepática del fármaco(ver sección 5.2). 5. PROPIEDADES FARMACOLÓGICAS. 5.1 Propiedades farmacodinámicas. Grupo farmacoterapéutico:agentes inmunosupresores código ATC L04AA06. El micofenolato mofetilo es el éster 2-morfolinoetílico del MPA. El MPA esun inhibidor potente, selectivo, no competitivo y reversible de la inosinmonofosfato-deshidrogenasa; inhibe, por tanto, lasíntesis de novo del nucleótido guanosina, sin incorporación al ADN. El MPA tiene unos efectos citostáticos más potentes enlos linfocitos que en otras células ya que los linfocitos T y B dependen de una manera decisiva para su proliferación de lasíntesis de novo de purinas, mientras que otros tipos de células pueden utilizar mecanismos de recuperación de purinas.5.2 Propiedades farmacocinéticas. Tras la administración oral, el micofenolato mofetilo se absorbe rápida y ampliamente;a continuación se transforma en MPA, su metabolito activo, en un proceso de metabolización presistémica completa. Laactividad inmunosupresora de CellCept está correlacionada con la concentración del MPA, según ha quedado demostradopor la supresión del rechazo agudo a continuación del trasplante renal. La biodisponibilidad media del micofenolato mofetilopor vía oral, determinada mediante el AUC del MPA, es del 94 % en comparación con la del micofenolato mofetilo intravenoso.Los alimentos no tuvieron ningún efecto en el grado de absorción (AUC del MPA) del micofenolato mofetilo administrado adosis de 1,5 g, dos veces al día, a transplantados renales. Sin embargo, se produjo una disminución de aproximadamenteel 40 % en la Cmáx del MPA en presencia de alimentos. El micofenolato mofetilo no es detectable sistémicamente en elplasma tras su administración oral. El MPA, a concentraciones clínicamente relevantes, se une a la albúmina plasmática enun 97 %. Tras la administración intravenosa, el micofenolato mofetilo experimenta una metabolización rápida y completa aMPA, su metabolito activo. El MPA, a concentraciones clínicamente relevantes, se une a la albúmina plasmática en un 97 %.La sustancia de origen, el micofenolato mofetilo, puede ser detectado sistémicamente durante la perfusión intravenosa; sinembargo, tras la administración oral permanece por debajo del límite de cuantificación (0,4 microgramo/mL). Comoconsecuencia de la recirculación enterohepática, se suelen observar aumentos secundarios de la concentración plasmáticade MPA después de aproximadamente 6 - 12 horas de la administración. Con la coadministración de colestiramina (4 g tresveces al día), se produce una reducción del AUC del MPA del orden del 40 %, lo que es indicativo de una recirculaciónenterohepática importante. El MPA se metaboliza principalmente por la glucuronil-transferasa, para formar el glucurónidofenólico del MPA (MPAG), sin actividad farmacológica. La cantidad de sustancia que se excreta en forma de MPA con laorina es despreciable (< 1 % de la dosis). Tras la administración por vía oral de micofenolato mofetilo radiomarcado, larecuperación de la dosis administrada es completa. Un 93 % de la dosis se recuperó en la orina y un 6 % en las heces. Lamayor parte de la dosis administrada (alrededor del 87 %) se excreta por la orina en forma de MPAG. El MPA y el MPAG nose eliminan por hemodiálisis a las concentraciones encontradas a nivel clínico. Sin embargo, a concentraciones plasmáticaselevadas de MPAG (> 100 microgramo/mL), se eliminan pequeñas cantidades del mismo. En el postoperatorio inmediato(< 40 días posteriores al trasplante), los pacientes sometidos a trasplante renal, cardíaco y hepático tienen unos valoresmedios del AUC del MPA aproximadamente un 30 % más bajo y una Cmax aproximadamente un 40 % más baja que en elperiodo postoperatorio tardío (3-6 meses posteriores al trasplante). Insuficiencia renal: En un ensayo a dosis única (6individuos/grupo), se observó que para los individuos con insuficiencia renal crónica grave (filtración glomerular< 25 mL·min-1·1,73 m-2), el valor medio del AUC para el MPA plasmático fue de un 28 – 75 % superior que para individuossanos normales o en pacientes con menor deterioro renal. Sin embargo, el valor medio del AUC del MPAG tras una dosisúnica en los sujetos con insuficiencia renal grave, fue 3 - 6 veces superior al presentado en los pacientes con deteriororenal leve o en los voluntarios sanos, lo que concuerda con la eliminación renal conocida del MPAG. No se ha estudiado laadministración de dosis múltiples de micofenolato mofetilo en pacientes con insuficiencia renal crónica grave. No existen

datos sobre los pacientes sometidos a trasplante cardíaco o hepático con insuficiencia renal crónica grave.Retraso de lafunción renal del injerto: En pacientes con retraso funcional del riñón trasplantado, el valor medio del AUC (0-12) del MPAfue comparable al observado en los pacientes sin retraso funcional postrasplante. Asimismo, el valor medio del AUC (0-12)del MPAG fue 2 - 3 veces superior al de los pacientes trasplantados sin retraso de la función del órgano. Puede darse unaumento transitorio de la fracción libre y la concentración en plasma del MPA en pacientes con retraso de la función renaldel injerto. No se considera necesario realizar un ajuste de la dosis de CellCept. Insuficiencia hepática: En voluntarios concirrosis alcohólica se comprobó que los procesos de glucuronidación hepática del MPA estaban relativamente poco afectadospor la enfermedad del parénquima hepático. Los efectos de la hepatopatía en este proceso dependen probablemente de laenfermedad concreta de que se trate. Sin embargo, una hepatopatía con predominio de la afectación biliar, como la cirrosisbiliar primaria, puede tener un efecto diferente. Niños y adolescentes (entre 2 y 18 años): Se han evaluado los parámetrosfarmacocinéticos de 49 pacientes pediátricos con trasplante renal, tratados dos veces al día con 600 mg/m2 de micofenolatomofetilo administrado por vía oral. Con esta dosis se alcanzaron valores del AUC del MPA similares a los observados enpacientes adultos con trasplante renal, tratados con 1 g de CellCept dos veces al día, en los periodos post-trasplante inicialy tardío. Los valores del AUC del MPA en todos los grupos de edad fueron similares en los periodos post-trasplante inicial ytardío. Pacientes ancianos ( 65 años): No se ha evaluado formalmente el comportamiento farmacocinético de CellCept enpacientes ancianos. Anticonceptivos orales: La farmacocinética de los anticonceptivos orales no se vio afectada por laadministración conjunta con CellCept (ver además sección 4.5). En un ensayo realizado en 18 mujeres (que no tomaban otroinmunosupresor), durante 3 ciclos menstruales consecutivos, en el que se administraban conjuntamente CellCept (1 g, dosveces al día) y anticonceptivos orales combinados, que contenían etinilestradiol (de 0,02 mg a 0,04 mg) y levonorgestrel (de0,05 mg a 0,15 mg), desogestrel (0,15 mg) o gestodeno (de 0,05 mg a 0,10 mg), no se puso de manifiesto una influenciaclínicamente relevante de CellCept sobre la capacidad de los anticonceptivos orales para suprimir la ovulación. Los nivelesséricos de LH, FSH y progesterona no se vieron afectados significativamente.5.3 Datos preclínicos sobre seguridad. Enmodelos experimentales, el micofenolato mofetilo no fue carcinogénico. La dosis más alta ensayada en los estudios decarcinogénesis en animales resultó ser aproximadamente de 2 a 3 veces la exposición sistémica (AUC o Cmáx) observada enpacientes trasplantados renales a la dosis clínica recomendada de 2 g/ día, y de 1,3 a 2 veces la exposición sistémica (AUCo Cmáx) observada en pacientes sometidos a trasplante cardíaco con la dosis clínica recomendada de 3 g/ día. Dos estudiosde genotoxicidad (ensayo in vitro de linfoma de ratón y ensayo in vivo del test del micronúcleo en médula ósea de ratón)indicaron que el micofenolato mofetilo tenía potencial para causar aberración cromosómica. Estos efectos pueden estarrelacionados con el mecanismo de acción, p.ej. inhibición de la síntesis de nucleótidos en células sensibles. No se demostróactividad genotóxica en otros ensayos in vitro para la detección de la mutación de genes. El micofenolato mofetilo no tuvoefecto alguno en la fertilidad de las ratas macho a dosis orales de hasta 20 mg·kg-1·día-1. La exposición sistémica a esta dosisrepresenta de 2- 3 veces la exposición clínica a la dosis recomendada de 2 g/ día en los pacientes sometidos a trasplanterenal y de 1,3 a 2 veces la exposición clínica con la dosis recomendada de 3 g/ día en los pacientes sometidos a trasplantecardíaco. En un estudio de la reproducción y la fertilidad llevado a cabo en ratas hembra, dosis orales de 4,5 mg·kg-1·día-1

causaron malformaciones (incluyendo anoftalmia, agnatia, e hidrocefalia) en la primera generación de crías, sin que sedetectara toxicidad en las madres. La exposición sistémica a esta dosis fue aproximadamente 0,5 veces la exposición clínicaa la dosis recomendada de 2 g/ día en los pacientes sometidos a trasplante renal y de 0,3 veces la exposición clínica con ladosis recomendada de 3 g/ día en los pacientes sometidos a trasplante cardíaco. No se evidenció ningún efecto en la fertilidady la reproducción de las ratas madre ni en la generación siguiente. En los estudios de teratogenia se produjeron resorcionesfetales y malformaciones en ratas con dosis de 6 mg·kg-1· día-1 (incluyendo anoftalmia, agnatia, e hidrocefalia) y en conejoscon dosis de 90 mg·kg-1·día-1 (incluyendo anormalidades cardiovasculares y renales, como ectopia del corazón y riñonesectópicos, y hernia diafragmática y umbilical), sin que se registrara toxicidad materna. La exposición sistémica a estosniveles es aproximadamente equivalente o menor a 0,5 veces la exposición clínica a la dosis recomendada de 2 g/ día enlos pacientes sometidos a trasplante renal y en torno a 0,3 veces la exposición clínica con la dosis recomendada de 3 g/ díaen los pacientes sometidos a trasplante cardíaco.Ver sección 4.6. Los sistemas hematopoyético y linfoide fueron los primerosórganos afectados en los estudios toxicológicos realizados con micofenolato mofetilo en la rata, ratón, perro y mono. Estosefectos se observaron con valores de exposición sistémica equivalentes o inferiores a la exposición clínica con la dosisrecomendada de 2 g/ día en trasplantados renales. En el perro se observaron efectos gastrointestinales a niveles deexposición sistémica equivalentes o menores a la exposición clínica a las dosis recomendadas. En el mono, a la dosis másalta (niveles de exposición sistémica equivalente a o mayor que la exposición clínica), también se observaron efectosgastrointestinales y renales que concuerdan con la deshidratación. El perfil toxicológico no clínico de micofenolato mofetiloparece estar de acuerdo con los acontecimientos adversos observados en los ensayos clínicos humanos que ahoraproporcionan datos de seguridad de mas relevancia para la población de pacientes. (ver sección 4.8). 6. DATOSFARMACÉUTICOS. 6.1 Lista de excipientes. Comprimidos de CellCept: celulosa microcristalina, povidona (K-90),croscarmelosa sódica, estearato magnésico, Recubrimiento de los comprimidos: hipromellosa, hidroxipropil celulosa, dióxidode titanio (E171), polietilenglicol 400, índigo carmín en laca alumínica (E132), óxido de hierro rojo (E172). Cápsulas deCellCept: almidón de maíz pregelatinizado, croscarmelosa sódica, povidona (K-90), estearato magnésico. Envoltura de lacápsula: gelatina, índigo carmín (E132), óxido de hierro amarillo (E172), óxido de hierro rojo (E172), dióxido de titanio (E171),óxido de hierro negro (E172), hidróxido de potasio, goma laca. CellCept 500 mg polvo para concentrado para solución paraperfusión: Polisorbato 80, ácido cítrico, ácido clorhídrico, cloruro sódico, 6.2 Incompatibilidades, No procede en caso decomprimidos y cápsulas. La solución para perfusión de CellCept 500 mg polvo para concentrado para solución para perfusiónno debe ser mezclada o administrada de forma concurrente a través del mismo catéter con otros medicamentos intravenososu otras mezclas para perfusión. 6.3 Periodo de validez. 3 años para comprimidos y cápsulas. Polvo para concentrado parasolución para perfusión: 3 años. Solución reconstituida y solución para perfusión: Si la solución para perfusión no se preparainmediatamente antes de la administración, el comienzo de la administración de la solución para perfusión debe ser dentrode las 3 horas siguientes a la reconstitución y dilución del medicamento. 6.4 Precauciones especiales de conservación.No conservar a temperatura superior a 30ºC. Conservar el blister en el embalaje exterior para protegerlo de la humedad yde la luz. Polvo para concentrado para solución para perfusión: No conservar a temperatura superior a 30ºC. Soluciónreconstituida y solución de perfusión: Conservar entre 15 y 30ºC. 6.5 Naturaleza y contenido del envase. CellCept 500 mgcomprimidos: 1 estuche contiene 50 comprimidos (en blísters de 10 unidades). 1 estuche contiene 150 comprimidos (enblísters de 10 unidades). CellCept 250 mg cápsulas: 1 estuche contiene 100 cápsulas (en blísters de 10 unidades). 1 estuchecontiene 300 cápsulas (en blísters de 10 unidades).Viales de vidrio transparente tipo I de 20 mL con tapón de caucho butílicogris y precinto de aluminio con cápsulas de plástico de fácil apertura. CellCept 500 mg polvo para concentrado para soluciónpara perfusión está disponible en envases de 4 viales. 6.6 Precauciones especiales de eliminación y otrasmanipulaciones. Dado que se ha observado efecto teratogénico para el micofenolato mofetilo en la rata y el conejo, no debentriturarse los comprimidos de CellCept, no deben abrirse o triturarse las cápsulas de CellCept. Evítese la inhalación del polvocontenido en las cápsulas de CellCept, así como el contacto directo con la piel o las mucosas. En caso de contacto, lávesela parte afectada con abundante agua y jabón; los ojos deben lavarse con agua corriente.La eliminación del medicamentono utilizado y de todos los materiales que hayan estado en contacto con él se realizará de acuerdo con las normativaslocales. Preparación de la Solución de Perfusión (6 mg/mL) CellCept 500 mg polvo para concentrado para solución paraperfusión no contiene conservantes antibacterianos; por tanto, la reconstitución y dilución del producto debe realizarse bajocondiciones asépticas. CellCept 500 mg polvo para concentrado para solución para perfusión debe prepararse en dos pasos:el primer lugar reconstituir con una solución para perfusión intravenosa de glucosa al 5 % y el segundo lugar diluir con unasolución para perfusión intravenosa de glucosa al 5 %. A continuación se da una descripción detallada de la preparación:Paso 1.a. Para cada dosis de 1 g se emplean dos viales de CellCept 500 mg polvo para concentrado para solución paraperfusión. Reconstituir el contenido de cada vial mediante una inyección de 14 mL de solución para perfusión intravenosade glucosa al 5 %. b. Agitar suavemente el vial para disolver el medicamento, se produce una solución ligeramente amarilla.c.Antes de seguir diluyendo, inspeccionar la solución resultante en lo relativo a partículas y alteración del color. Descartar elvial si se observan partículas o alteración del color. Paso 2.a. Posteriormente diluir el contenido de dos viales reconstituidos(aprox. 2 x 15 mL) en 140 mL de solución para perfusión intravenosa de glucosa al 5 %. La concentración final de la soluciónes de 6 mg/mL de micofenolato mofetilo.b. Inspeccionar la solución para perfusión en lo relativo a partículas o alteracióndel color. Si se observan partículas o alteración del color desechar la solución para perfusión. Si la solución para perfusiónno se prepara inmediatamente antes de la administración, el comienzo de la administración de la solución debe efectuarsedentro de las 3 horas siguientes a la reconstitución y dilución del medicamento. Mantener las soluciones entre 15 y 30ºC.7. TITULAR DE LA AUTORIZACIÓN DE COMERCIALIZACIÓN. Roche Registration Limited. 6 Falcon Way. Shire Park. WelwynGarden City. AL7 1TW. Reino Unido. 8. NÚMERO(S) DE AUTORIZACIÓN DE COMERCIALIZACIÓN EU/1/96/005/002 CellCept(50 comprimidos). EU/1/96/005/004 CellCept (150 comprimidos). EU/1/96/005/001 CellCept (100 cápsulas). EU/1/96/005/003CellCept (300 cápsulas). EU/1/96/005/005 CellCept (4 viales). 9. FECHA DE LA PRIMERA AUTORIZACIÓN/RENOVACIÓN DELA AUTORIZACIÓN. Fecha de la primera autorización: 14 de febrero de 1996. Fecha de la última renovación: 14 de febrerode 2006. 10. FECHA DE LA REVISIÓN DEL TEXTO. 10 de agosto de 2007. La información detallada de este medicamento está disponible en la página web de la Agencia Europea del Medicamento(EMEA) http://www.emea.europa.eu/. PRECIO. CellCept 500 mg (50 comprimidos) y CellCept 250 mg (100 cápsulas): PVL99,26 euros; PVP ME/MR 144,16 euros; PVP IVA 149,93 euros.

Muy frecuentes

Frecuentes








Trastornos del sistema nervioso

Trastornos cardíacos

Trastornos vasculares

Trastornos respiratorios, torácicos y mediastínicos

Trastornos gastrointestinales

Trastornoshepatobiliares

Trastornos de la piel y del tejido subcutáneo

Trastornosmusculoesqueléticos y del tejido conjuntivo

Trastornos renales y urinarios

Trastornos generales y alteraciones en el lugarde administración

Exploraciones complementarias

-Convulsión, hipertonía, temblor, somnolencia, síndrome miasténico,mareos, dolor de cabeza, parestesia, disgeusia

-Taquicardia

-Hipotensión, hipertensión, vasodilatación

-Derrame pleural, disnea, tos

Vómitos, dolor abdominal, diarrea, náuseas

Hemorragia gastrointestinal, peritonitis, íleo, colitis, úlcera gástrica,úlcera duodenal, gastritis, esofagitis, estomatitis, estreñimiento,dispepsia, flatulencia, eructos.

-Hepatitis, ictericia, hiperbilirrubinemia

-Hipertrofia cutánea, rash, acné, alopecia

-Artralgia

-Alteración renal

-Edema, pirexia, escalofríos, dolor, malestar general, astenia

-Aumento de los niveles enzimáticos, aumento de creatinina sérica,aumento de lactato deshidrogenasa sérica, aumento de urea sérica, aumento de fosfatasa alcalina sérica, pérdida de peso

Nota: 501 (2 g diarios de CellCept), 289 (3 g diarios de CellCept) y 277 (2 g diarios de CellCept IV/3 g diarios deCellCept oral) pacientes fueron tratados en ensayos en fase III para la prevención del rechazo en trasplante renal,cardíaco y hepático respectivamente.

Clasificación por órgano y sistema Reacciones adversas al fármaco




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1. NOMBRE DEL MEDICAMENTO. Valcyte 450 mg comprimidos con cubierta pelicular. 2. COMPOSICIÓNCUALITATIVA Y CUANTITATIVA. Cada comprimido contiene 496,3 mg de hidrocloruro de valganciclovir, equiva-lente a 450 mg de valganciclovir (base libre). Para la lista completa de excipientes, ver sección 6.1. 3. FORMAFARMACÉUTICA. Comprimidos con cubierta pelicular. Comprimidos con cubierta pelicular de color rosa, conve-xo y ovalado, con el grabado “VGC” en una cara y “450” en la otra. 4. DATOS CLÍNICOS. 4.1. Indicacionesterapéuticas. Valcyte está indicado para el tratamiento de inducción y mantenimiento de la retinitis por citome-galovirus (CMV) en pacientes con síndrome de inmunodeficiencia adquirida (SIDA). Valcyte está indicado para laprevención de la enfermedad por CMV en pacientes seronegativos al CMV que han recibido un trasplante de órga-no sólido de un donante seropositivo. 4.2. Posología y forma de administración. Atención: para evitar lasobredosis, es imprescindible respetar estrictamente las recomendaciones posológicas; ver secciones4.4 y 4.9. El valganciclovir se metaboliza de manera rápida y amplia a ganciclovir después de la administraciónoral. 900 mg de valganciclovir oral, dos veces al día, equivalen terapéuticamente a 5 mg/kg de ganciclovir i.v.,dos veces al día. Posología habitual en adultos. Tratamiento de inducción de la retinitis por CMV: La dosis reco-mendada para los pacientes con retinitis activa por CMV es de 900 mg de valganciclovir (dos comprimidos de450 mg de Valcyte) dos veces al día durante 21 días y, siempre que sea posible, debe tomarse con alimentos.Un tratamiento prolongado de inducción puede incrementar el riesgo de toxicidad para la médula ósea (ver sec-ción 4.4).Tratamiento de mantenimiento de la retinitis por CMV: Después del tratamiento de inducción, o si se tratade pacientes con retinitis inactiva por CMV, se recomienda administrar una dosis de 900 mg de valganciclovir (doscomprimidos de 450 mg de Valcyte) una vez al día y, siempre que sea posible, debe tomarse con alimentos. Sepuede repetir el tratamiento de inducción en aquellos pacientes en los que la retinitis empeore; sin embargo, sedebe tener en cuenta la posibilidad de resistencia viral al fármaco. Prevención de la enfermedad por CMV en eltrasplante de órgano sólido: La dosis recomendada en pacientes que han recibido un trasplante es de 900 mg (2comprimidos de Valcyte 450 mg) una vez al día, comenzando dentro de los 10 días del trasplante hasta los 100días postrasplante. Siempre que sea posible, los comprimidos deben tomarse con alimentos. Instrucciones poso-lógicas especiales. Pacientes con insuficiencia renal: Los niveles séricos de creatinina o el aclaramiento de crea-tinina se deben vigilar cuidadosamente. Hay que ajustar la posología según el aclaramiento de creatinina, tal ycomo se indica en la siguiente tabla (ver secciones 4.4 y 5.2). El aclaramiento estimado de creatinina (ml/min) sepuede calcular según la creatinina sérica mediante estas fórmulas:

Para los varones= (140 – edad [años]) x (peso corporal [kg])(72) x (0,011 x creatinina sérica [micromoles/l])

Para las mujeres= 0,85 x valor de los varones

CrCl (ml/min) Dosis de inducción de valganciclovir Dosis de mantenimiento/Dosis de Prevención de valganciclovir

≥60 900 mg (2 comprimidos) dos veces al día 900 mg (2 comprimidos) una vez al día40 – 59 450 mg (1 comprimido) dos veces al día 450 mg (1 comprimido) una vez al día25 – 39 450 mg (1 comprimido) una vez al día 450 mg (1 comprimido) cada 2 días10 – 24 450 mg (1 comprimido) cada 2 días 450 mg (1 comprimido) dos veces por semana

Pacientes sometidos a hemodiálisis: Para pacientes en hemodiálisis (CrCl <10 ml/min) no se puede dar una reco-mendación de dosis. Por consiguiente, Valcyte no se debe emplear en estos pacientes (ver secciones 4.4 y 5.2).Pacientes con disfunción hepática. La seguridad y eficacia de Valcyte comprimidos no ha sido estudiada en pacien-tes con disfunción hepática (ver sección 5.2). Niños: Valcyte no está recomendado para uso en niños debido ainsuficientes datos sobre seguridad y eficacia (ver secciones 4.4 y 5.3). Pacientes ancianos: Se desconocen laseguridad y la eficacia del tratamiento en los ancianos. Pacientes con leucopenia, neutropenia, anemia, tromboci-topenia y pancitopenia graves; Ver sección 4.4 antes de comenzar el tratamiento. Si se produce un deterioro sig-nificativo del recuento de células sanguíneas durante el tratamiento con Valcyte, se deberá considerar el empleode factores de crecimiento hematopoyético y/o una suspensión de la medicación (ver secciones 4.4 y 4.8). Formade administración: Valcyte se administra por vía oral, y siempre que sea posible, debe tomarse con alimentos (versección 5.2). Los comprimidos no se deben romper ni triturar. Valcyte se considera potencialmente teratógeno ycarcinógeno para el ser humano, por lo que se recomienda precaución cuando se manipulen comprimidos rotos(ver sección 4.4). Evite el contacto directo de los comprimidos rotos o triturados con la piel o las mucosas. Encaso de que ocurra el contacto, lave cuidadosamente la zona con agua y jabón; lave los ojos con agua estéril, ocon agua en abundancia si el agua estéril no está disponible. 4.3. Contraindicaciones. Valcyte está contraindi-cado en pacientes con hipersensibilidad al valganciclovir, al ganciclovir o a cualquiera de los excipientes. Debidoa la semejanza en la estructura química de Valcyte y de aciclovir y valaciclovir, es posible que ocurra una reac-ción de hipersensibilidad cruzada entre estos medicamentos. Por lo tanto, Valcyte está contraindicado en pacien-tes con hipersensibilidad a aciclovir y valaciclovir. Valcyte está contraindicado durante la lactancia, ver sección4.6. 4.4. Advertencias y precauciones especiales de empleo. Antes de iniciar el tratamiento de valganciclo-vir, se debe advertir a los pacientes del riesgo potencial para el feto. En estudios con animales, se ha observadoel poder mutágeno, teratógeno, espermatogénico, carcinógeno, y supresor de la fertilidad femenina del ganciclo-vir. Por eso, Valcyte debe tratarse como teratógeno y carcinógeno potencial para el ser humano, con potencialpara ocasionar malformaciones congénitas y cáncer (ver sección 5.3 ). Además, es probable que Valcyte inhibala espermatogénesis de forma transitoria o permanente. Se debe recomendar a las mujeres en edad de procrearque empleen medidas anticonceptivas eficaces durante el tratamiento y se debe recomendar a los hombres queutilicen anticonceptivos de barrera durante y hasta, por lo menos, 90 días después del tratamiento, a menos queexista la seguridad de que la pareja femenina no corre el riesgo de quedarse embarazada. (ver secciones 4.6,4.8 y 5.3). No se recomienda el uso de Valcyte en niños y adolescentes pues no se han establecido las caracte-rísticas farmacocinéticas de Valcyte en este grupo de pacientes (ver sección 4.2). Además, valganciclovir tienepotencial de causar toxicidad reproductiva y carcinógena a largo plazo. Se han descrito casos graves de leuco-penia, neutropenia, anemia, trombocitopenia, pancitopenia, mielosupresión y anemia aplásica entre pacientes tra-tados con Valcyte (y con ganciclovir). No debe iniciarse este tratamiento si el recuento absoluto de neutrófilos esmenor de 500 células/µl, el recuento de plaquetas es menor de 25.000/µl o el nivel de hemoglobina es menorde 8 g/dl (ver secciones 4.2 y 4.8). Valcyte debe emplearse con precaución en pacientes con citopenia hemato-lógica pre-existente, o con antecedentes de citopenia relacionada con la administración de medicamentos, y enpacientes que están recibiendo radioterapia. Se recomienda vigilar el hemograma completo y las plaquetas duran-te el tratamiento. En pacientes con alteración renal se debe garantizar un aumento de la monitorización hemato-lógica. Se recomienda considerar el empleo de factores de crecimiento hematopoyético y/o una suspensión dela medicación en pacientes que desarrollen leucopenia, neutropenia, anemia y/o trombocitopenia grave (ver sec-ciones 4.2 y 4.8). La biodisponibilidad del ganciclovir tras una dosis única de 900 mg de valganciclovir es del 60%aproximadamente, en comparación con aproximadamente el 6% tras la administración de 1.000 mg de ganciclo-vir oral (como cápsulas). Una exposición excesiva a ganciclovir puede estar asociada a reacciones adversas conriesgo para la vida. Por consiguiente, se aconseja un estricto seguimiento de las recomendaciones posológicasal inicio de la terapia, cuando se cambie del tratamiento de inducción al de mantenimiento, y en pacientes quecambien de ganciclovir oral a valganciclovir, ya que no se puede reemplazar las cápsulas de ganciclovir por lasde Valcyte según una relación de uno a uno. Hay que advertir a los pacientes que tomaban con anterioridad cáp-sulas de ganciclovir del riesgo de sobredosis si ingieren un número de comprimidos de Valcyte mayor del pres-crito (ver secciones 4.2 y 4.9). El ajuste posológico para los pacientes con insuficiencia renal debe basarse en elaclaramiento de creatinina (ver secciones 4.2 y 5.2). Valcyte no debe usarse en pacientes sometidos a hemodiá-lisis (ver secciones 4.2 y 5.2). Se han descrito convulsiones entre pacientes tratados con imipenem-cilastatina yganciclovir. Valcyte no debe administrarse al mismo tiempo que imipenem-cilastatina, a menos que los posiblesbeneficios excedan los riesgos potenciales (ver sección 4.5). Los pacientes tratados con Valcyte y (a) didanosi-

na, (b) medicamentos con efecto mielosupresor conocido (ej. zidovudina) o (c) sustancias que afecten a la funciónrenal, deben vigilarse estrechamente por si aparecen signos añadidos de toxicidad (ver sección 4.5). El estudioclínico controlado con valganciclovir para el tratamiento profiláctico de la enfermedad por CMV en pacientes tras-plantados, descrito en la sección 5.1, no incluyó pacientes con trasplante de pulmón e intestino. Por ello, la expe-riencia en estos pacientes es limitada. 4.5. Interacción con otros medicamentos y otras formas de inter-acción. Interacciones farmacológicas con valganciclovir. No se han realizado estudios in vivo de interacción far-macológica con Valcyte. Debido a que valganciclovir se metaboliza a ganciclovir de manera amplia y rápida, cabeesperar para valganciclovir las mismas interacciones farmacológicas que se asocian con el ganciclovir.Interacciones farmacológicas con ganciclovir. Imipenem-cilastatina. Se han descrito convulsiones entre enfermostratados con ganciclovir e imipenem-cilastatina al mismo tiempo. Estos medicamentos no deben administrarse ala vez, a menos que los posibles beneficios excedan los riesgos potenciales (ver sección 4.4). Probenecid. El pro-benecid, administrado junto con el ganciclovir por vía oral, disminuye significativamente el aclaramiento renal delganciclovir (20%), aumentando la exposición a este medicamento de manera estadísticamente significativa (40%).Estos cambios son compatibles con un mecanismo de interacción que implica una competición por la secrecióntubular renal. Así pues, hay que vigilar con cuidado la posible toxicidad de ganciclovir entre los pacientes quetomen probenecid y Valcyte. Zidovudina. Cuando se administró zidovudina junto con ganciclovir por vía oral, elAUC de la zidovudina experimentó un incremento pequeño (17%), pero estadísticamente significativo. Asimismo,se advierte una tendencia al descenso de las concentraciones de ganciclovir, cuando se administra simultánea-mente zidovudina, aunque sin alcanzar significación estadística. De cualquier manera, puesto que tanto la zidovu-dina como el ganciclovir pueden inducir neutropenia y anemia, es posible que algunos pacientes no toleren el tra-tamiento concomitante en dosis plenas (ver sección 4.4). Didanosina. Se ha observado que las concentracionesplasmáticas de didanosina aumentan siempre que se administra ganciclovir (ya sea por vía intravenosa como oral).Se ha observado un aumento del AUC de didanosina, cuando se administran dosis orales de ganciclovir de 3 y 6g/día que varía entre 84 y 124%, y cuando se aplican dosis intravenosas de 5 y 10 mg/kg/día, el incrementoobservado del AUC de didanosina fluctúa entre 38 y 67%. No se ha observado ninguna modificación clínicamen-te significativa de las concentraciones de ganciclovir. Hay que vigilar de cerca la posible toxicidad de la didanosi-na para estos pacientes (ver sección 4.4). Micofenolato mofetilo. Considerando los resultados de un estudio deadministración de dosis orales únicas recomendadas de micofenolato mofetilo (MMF) y de ganciclovir por vía i.v.y los efectos conocidos de la insuficiencia renal en la farmacocinética de MMF y de ganciclovir, se puede preverque la administración simultánea de ambos medicamentos (que tienen potencial para competir por la secrecióntubular renal) determine aumentos del glucuronido fenólico del ácido micofenólico (MPAG) y de la concentraciónde ganciclovir. La farmacocinética del ácido micofenólico (MPA) apenas se altera y no es necesario ajustar la dosisde MMF. Sin embargo, los pacientes con insuficiencia renal que reciban al mismo tiempo MMF y ganciclovir debe-rán respetar las recomendaciones posológicas de ganciclovir y requieren una estrecha vigilancia. Ya que el MMFy el ganciclovir puede causar neutropenia, y leucopenia, se deberá vigilar a los pacientes por si presentaran toxi-cidad acumulada. Zalcitabina. No se han observado cambios farmacocinéticos clínicamente significativos despuésde la administración conjunta de ganciclovir y zalcitabina. Tanto valganciclovir como zalcitabina tienen el potencialde producir neuropatía periférica, por lo que se debe vigilar la aparición de esta clase de acontecimientos en lospacientes. Estavudina. Cuando se administran conjuntamente estavudina y ganciclovir por vía oral no se observa-ron interacciones clínicamente significativas. Trimetoprima. No se observó ninguna interacción farmacocinética clí-nicamente significativa cuando se administraron conjuntamente trimetoprima y ganciclovir oral. Sin embargo, exis-te el potencial de incremento de la toxicidad ya que los dos fármacos son mielosupresores, por lo que, ambosfármacos deben usarse de forma concomitante únicamente si los posibles beneficios superan los riesgos. Otrosantirretrovirales. No es probable que se produzca un efecto sinérgico o antagónico en la inhibición bien del VIH enpresencia de ganciclovir o de CMV en presencia de una variedad de fármacos antirretrovirales, a concentracionesclínicamente relevantes. No es probable que se produzcan interacciones metabólicas con, por ejemplo, inhibido-res de la proteasa o inhibidores de la transcriptasa inversa no nucleosídicos (ITIANNs) debido a la falta de impli-cación del P450 en el metabolismo tanto del valganciclovir como del ganciclovir. Otras interacciones farmacoló-gicas potenciales. La toxicidad puede verse aumentada cuando valganciclovir se administra junto con, o se dainmediatamente antes o después que otros fármacos que, inhiben la replicación de poblaciones celulares que sedividen rápidamente, tal y como ocurre en la médula ósea, testículos, capas germinales de la piel y mucosa gas-trointestinal. Ejemplos de estos tipos de fármacos son dapsona, pentamidina, flucitosina, vincristina, vinblastina,adriamicina, anfotericina B, trimetropima/derivados de sulfamidas, análogos de nucleósidos e hidroxiurea. Desdeque el ganciclovir es excretado a través del riñón (sección 5.2), la toxicidad puede verse aumentada cuando val-ganciclovir se administra junto con fármacos que podrían reducir el aclaramiento renal de ganciclovir y, por lotanto aumentar su exposición. El aclaramiento renal del ganciclovir puede inhibirse por dos mecanismos: (a) nefro-toxicidad, causada por fármacos como cidofovir y foscarnet, e (b) inhibición competitiva de la secreción tubularactiva en el riñón como, por ejemplo, otros análogos de nucleósidos. Por lo tanto, se debe considerar el uso con-comitante de todos estos fármacos con valganciclovir sólo si los posibles beneficios superan a los riesgos poten-ciales (ver sección 4.4). 4.6. Embarazo y lactancia. No existen datos suficientes sobre la utilización valganci-clovir en mujeres embarazadas. Su metabolito activo, ganciclovir, pasa fácilmente a través de la placenta humana.Existe un riesgo teórico de teratogenicidad en humanos, en base a su mecanismo de acción farmacológico y latoxicidad reproductiva observada en estudios animales con ganciclovir (ver sección 5.3). Valcyte no debe emplear-se en el embarazo, a menos que los beneficios para la madre superen el riesgo potencial de daño teratogénicopara el niño. Las mujeres en edad de procrear deben utilizar medidas anticonceptivas eficaces durante el tratamien-to. Se debe aconsejar a los varones que utilicen medidas anticonceptivas de barrera durante y hasta, por lo menos,90 días después del tratamiento con Valcyte, a menos que exista la seguridad de que la pareja femenina no correel riesgo de quedarse embarazada (ver sección 5.3). Se desconoce si el ganciclovir se excreta en la leche mater-na pero no se puede descartar esta posibilidad, con las reacciones adversas graves consiguientes para el bebélactante. Por eso, se debe interrumpir la lactancia. 4.7. Efectos sobre la capacidad para conducir y utilizarmáquinas. No se han realizado estudios sobre la capacidad para conducir y utilizar máquinas. El uso de Valcytey/o de ganciclovir se ha asociado con convulsiones, sedación, mareos, ataxia y/o confusión. Si aparece cualquie-ra de estas reacciones, podría alterar las tareas que exigen un estado de alerta, como la capacidad para conducirvehículos y utilizar máquinas. 4.8. Reacciones adversas. Las reacciones adversas se presentan en orden decre-ciente de gravedad dentro de cada frecuencia. El valganciclovir es un profármaco del ganciclovir, que se metaboli-za de manera rápida y extensa a ganciclovir después de su administración oral. Valganciclovir debería asociarsecon las mismas reacciones adversas conocidas para el ganciclovir. Todas las reacciones adversas observadas enlos estudios clínicos con valganciclovir se habían observado antes con ganciclovir. Las reacciones adversas máscomunes comunicadas tras la administración de valganciclovir son neutropenia, anemia y diarrea. Las formulacio-nes orales, tanto de valganciclovir como de ganciclovir, se asocian a un mayor riesgo de diarrea comparado conganciclovir i.v. Además, valganciclovir se asocia con un riesgo más alto de neutropenia y leucopenia comparadocon ganciclovir oral. Se observa con más frecuencia neutropenia grave (<500 ANC/µl) en pacientes con retinitispor CMV en tratamiento con valganciclovir que en pacientes con trasplante de órgano sólido recibiendo valganci-clovir o ganciclovir oral. En la siguiente tabla se detalla la frecuencia de las reacciones adversas notificadas en losensayos clínicos con valganciclovir, ganciclovir oral, o ganciclovir intravenoso. Las frecuencias se han definidocomo muy frecuentes, (≥1/10), frecuentes (≥1/100, <1/10), poco frecuentes (≥1/1000, <1/100), raras(≥1/10.000, <1/1.000) y muy raras (<1/10.000). Las reacciones adversas reflejadas en la tabla se comunicaronen ensayos clínicos para el tratamiento de inducción y mantenimiento de la retinitis por CMV en pacientes con SIDA,o para la profilaxis de la enfermedad por CMV en pacientes con trasplante de corazón, riñón o hígado. En la prác-tica clínica no se han observado reacciones adversas con frecuencia raras o muy raras. El término (grave) que apa-rece en paréntesis en la tabla indica que la reacción adversa se ha comunicado en pacientes tanto de intensidadleve/moderada e intensidad grave/amenazante para la vida en esa frecuencia específica.

160

Órgano - Sistema Muy frecuentes Frecuentes (≥1/100 <1/10) Poco frecuentes(≥1/10) (≥1/1000 <1/100)

Infecciones e infestaciones Candidiasis oral, sepsis(bacteriemia, viremia), celulitis, infección del tracto urinario.

Trastornos del sistema Neutropenia Anemia grave, trombocitopenia Mielosupresión.linfático y sanguíneo (grave), anemia (grave), leucopenia (grave),

pancitopenia (grave).Trastornos del sistema inmunitario Reacción anafilácticaTrastornos del metabolismo y nutrición Disminución del apetito, anorexia.Trastornos psiquiátricos Depresión, ansiedad, confusión, Agitación, alteración

pensamientos perturbados. psicótica.Trastornos del sistema nervioso Dolor de cabeza, insomnio, disgeusia Temblor

(trastorno del gusto), hipoestesia,parestesia, neuropatía periférica, mareos (sin vértigo), convulsiones.

Trastornos oculares Edema macular, desprendimiento de la Visión anormal,retina, moscas flotantes, dolor ocular. conjuntivitis.

Trastornos auditivos y laberínticos Dolor de oídos SorderaTrastornos cardíacos ArritmiasTrastornos vasculares HipotensiónTrastornos respiratorios, Disnea Tostorácicos y mediastínicosTrastornos gastrointestinales Diarrea Náuseas, vómitos, dolor abdominal, Distensión abdominal,

dolor abdominal superior, dispepsia, ulceraciones orales,estreñimiento, flatulencia, disfagia. pancreatitis.

Trastornos hepatobiliares Función hepática anormal (grave), aumento Aumento de la alaninade la fosfatasa alcalina en sangre, aminotransferasaaumento del aspartato aminotransferasa.

Trastornos del tejido Dermatitis, sudores nocturnos, prurito Alopecia, urticaria,de la piel y subcutáneos sequedad de pielTrastornos musculoesqueléticos, Dolor de espalda, mialgiadel tejido conectivo y óseo artralgia, calambres musculares.Trastornos renales y urinarios Disminución del aclaramiento de Hematuria,

creatinina renal, disfunción renal insuficiencia renalTrastornos del sistema Infertilidad masculinareproductor y de la mamaTrastornos generales y condiciones Fatiga, febrícula, escalofríos, dolor,en el punto de administración dolor torácico, malestar, astenia.Investigaciones Pérdida de peso, aumento

de creatinina en sangre.4.9. Sobredosis. Experiencia con sobredosis de Valganciclovir. Un adulto que recibió durante varios días dosis10 veces mayores de las recomendadas para su grado de insuficiencia renal (disminución del aclaramiento de crea-tinina) sufrió una mielosupresión mortal (aplasia medular). Cabe esperar que la sobredosis de valganciclovir puedaaumentar también la toxicidad renal de este compuesto (ver secciones 4.2 y 4.4). La hemodiálisis y la hidrataciónpueden resultar beneficiosos para reducir los niveles plasmáticos de los pacientes que reciben sobredosis de val-ganciclovir (ver sección 5.2). Experiencia con sobredosis de ganciclovir por vía intravenosa. Se han recibido noti-ficaciones de sobredosis de ganciclovir por vía intravenosa sucedidas en ensayos clínicos y durante la comercia-lización de este medicamento. En algunos de estos casos no se observó ningún tipo de acontecimiento adverso.La mayoría de los enfermos presentaron uno o más de estos acontecimientos adversos: • Toxicidad hematológi-ca: pancitopenia, mielosupresión, aplasia medular, leucopenia, neutropenia, granulocitopenia. • Toxicidad hepáti-ca: hepatitis, trastornos de la función hepática. • Toxicidad renal: empeoramiento de la hematuria de un pacientecon alteraciones previas de la función renal, insuficiencia renal aguda, elevación de la creatinina. • Toxicidad diges-tiva: dolor abdominal, diarrea, vómitos • Neurotoxicidad: temblor generalizado, convulsiones. 5. PROPIEDADESFARMACOLÓGICAS. 5.1. Propiedades farmacodinámicas. Grupo farmacoterapéutico: antivirales vía gene-ral, código ATC: J05A B14 (antiinfecciosos de uso sistémico, antivirales de uso sistémico, antivirales de accióndirecta). Mecanismo de acción: El valganciclovir es un éster L-valílico (profármaco) del ganciclovir. Tras su admi-nistración oral, valganciclovir se metaboliza de manera rápida y extensa a ganciclovir por las esterasas intestina-les y hepáticas. El ganciclovir es un análogo sintético de la 2’-desoxiguanosina e inhibe la replicación de los virusherpéticos in vitro e in vivo. Los virus humanos sensibles a este medicamento son el citomegalovirus humano (CMVhumano), los virus del herpes simple 1 y 2 (HSV-1 y HSV-2), el herpes virus humano 6, 7 y 8 (HHV-6, HHV-7, HHV8),el virus de Epstein-Barr (EBV), el virus de la varicela zoster (VZV) y el virus de la hepatitis B. En las células infec-tadas por CMV, el ganciclovir se fosforila en principio a monofosfato de ganciclovir por la proteinquinasa víricaUL97. La fosforilación posterior tiene lugar por quinasas celulares que producen trifosfato de ganciclovir; el cualse metaboliza lentamente dentro de la célula. Se ha demostrado que el metabolismo trifosfato ocurre en célulasinfectadas por HSV y por CMV humano, con semividas de 18 y 6-24 horas respectivamente, después de eliminarel ganciclovir extracelular. Como la fosforilación depende, fundamentalmente, de la quinasa vírica, el ganciclovirse fosforila preferentemente dentro de las células infectadas por el virus. La actividad virostática del ganciclovirse debe a la inhibición de la síntesis del DNA vírico a través de: (a) inhibición competitiva de la incorporación deltrifosfato de desoxiguanosina al DNA a través de la DNA-polimerasa vírica, y (b) incorporación del trifosfato deganciclovir al DNA vírico originando la terminación del DNA o limitando muchísimo la elongación posterior del DNAvírico. Actividad antivírica. La actividad in vitro antivírica, medida como CI50 del ganciclovir frente al CMV oscila enel intervalo de 0,08 µM (0,02 µg/ml) a 14 µM (3,5 µg/ml). El efecto antivírico clínico de Valcyte se ha demostra-do en el tratamiento de los pacientes de SIDA con retinitis por CMV recién diagnosticada (ensayo clínicoWV15376). La eliminación de CMV disminuyó en orina desde el 46% (32/69) de los pacientes al comienzo delestudio hasta el 7% (4/55) de los pacientes después de cuatro semanas de tratamiento con Valcyte. Eficacia clí-nica. Tratamiento de la retinitis por CMV: En un estudio se distribuyó aleatoriamente a pacientes recién diagnosti-cados de retinitis por CMV para recibir tratamiento de inducción con 900 mg de Valcyte, dos veces al día, o con5 mg/kg de ganciclovir intravenoso, dos veces al día. El porcentaje de pacientes con retinitis progresiva por CMVdemostrada fotográficamente a las 4 semanas fue comparable en los dos grupos tratados, 7/70 y 7/71 pacien-tes progresaron en los brazos de ganciclovir i.v. y valganciclovir respectivamente. Después del tratamiento deinducción, todos los pacientes de este estudio recibieron tratamiento de mantenimiento con Valcyte en dosis de900 mg al día. La media (mediana) del tiempo desde la aleatorización hasta la progresión de la retinitis por CMVdel grupo que recibió tratamiento de inducción y mantenimiento con Valcyte fue de 226 (160) días y la del querecibió tratamiento de inducción con ganciclovir por vía intravenosa y tratamiento de mantenimiento con Valcyte,de 219 (125) días. Prevención de la enfermedad por CMV en el trasplante: Se ha realizado un estudio clínico dobleciego, con doble enmascaramiento con comparador activo en pacientes con trasplante de corazón, hígado y riñón(no se incluyeron pacientes con trasplante pulmonar y gastro-intestinal) con alto riesgo de enfermedad por CMV(D+/R-) que recibieron bien Valcyte (900 mg al día) o ganciclovir oral (1.000 mg tres veces al día), comenzandodentro de los 10 días del trasplante hasta el día 100 postransplante. La incidencia de enfermedad por CMV (sín-drome por CMV + enfermedad tisular invasiva) durante los primeros 6 meses postransplante fue 12,1% en elbrazo de Valcyte (n= 239) comparado con 15,2% en el brazo de ganciclovir oral (n= 125). La gran mayoría delos casos ocurrieron tras el cese de la profilaxis (después del día 100) y los casos en el brazo de valganciclovirocurrieron por término medio más tarde que los aparecidos en el brazo de ganciclovir oral. La incidencia de recha-zo agudo en los primeros 6 meses fue de 29,7% en pacientes randomizados a valganciclovir comparado con36,0% en el brazo de ganciclovir oral, siendo la incidencia por pérdida de injerto equivalente, ocurriendo en cadabrazo en un 0,8% de los pacientes. Resistencia vírica. Después del tratamiento crónico con ganciclovir puedensurgir virus resistentes al valganciclovir por selección de mutaciones del gen de la quinasa vírica (UL97) respon-

sable de la monofosforilación del ganciclovir, y/o del gen de la polimerasa vírica (UL54), o de ambos. Los viruscon mutaciones del gen UL97 muestran resistencia al ganciclovir solo, mientras que aquellos con mutaciones delgen UL54 presentan resistencia a ganciclovir pudiendo mostrar resistencia cruzada a otros antivirales con unmecanismo de acción parecido. Tratamiento de la retinitis por CMV: En un estudio clínico el análisis genotípico deCMV en leucocitos polimorfonucleares (PMNL) aislados de 148 pacientes con retinitis por CMV reclutados mostróque el 2,2%, el 6,5%, el 12,8% y el 15,3% de aquellos contienen mutaciones de UL97 después del tratamientocon valganciclovir durante 3, 6, 12 y 18 meses, respectivamente. Prevención de la enfermedad por CMV en tras-plante: Se estudió la resistencia mediante el análisis genotípico de CMV en muestras de leucocitos polimorfonu-cleares (PMNL) recogidas i) el día 100 (fin de la administración del fármaco en el estudio de profilaxis) y ii) encasos de sospecha de enfermedad por CMV hasta 6 meses después del trasplante. De los 245 pacientes rando-mizados que recibieron valganciclovir, se dispuso de 198 muestras del día 100 para examen y no se observaronmutaciones de resistencia al ganciclovir. Esto puede compararse con 2 mutaciones de resistencia a ganciclovirdetectadas en 103 muestras examinadas de los pacientes en el brazo comparador de ganciclovir oral (1,9%). Delos 245 pacientes randomizados que recibieron valganciclovir, se examinaron 50 muestras de pacientes con sos-pecha de enfermedad por CMV y no se observaron mutaciones de resistencias. De los 127 pacientes randomiza-dos en el brazo comparador de ganciclovir, se examinaron muestras de 29 pacientes con sospecha de enferme-dad por CMV, observándose dos mutaciones de resistencia, lo que dio lugar a una incidencia de resistencia de6,9%. 5.2. Propiedades farmacocinéticas. Las propiedades farmacocinéticas del valganciclovir se han inves-tigado con enfermos que presentaban seropositividad para VIH y CMV, pacientes con SIDA y retinitis por CMV ypacientes con trasplante de órgano sólido. Absorción. El valganciclovir es un profármaco del ganciclovir. Se absor-be perfectamente en el tubo digestivo y se metaboliza de forma rápida y extensa en la pared intestinal y en elhígado a ganciclovir. La exposición sistémica a valganciclovir es pasajera y baja. La biodisponibilidad absoluta delganciclovir, a partir del valganciclovir, es aproximadamente del 60% y el resultado de la exposición a ganciclovires similar a la obtenida tras su administración intravenosa (véase la tabla a continuación). Por comparación, la bio-disponibilidad de ganciclovir después de la administración de 1.000 mg de ganciclovir oral (en cápsulas) es 6-8%.Valganciclovir en pacientes con seropositividad para VIH y CMV. La exposición sistémica en pacientes VIH+, CMV+después de la administración de ganciclovir y valganciclovir dos veces al día durante una semana es:

Parámetros Ganciclovir (5 mg/kg, i.v.) Valganciclovir (900 mg, v.o.)n= 18 n= 25

Ganciclovir ValganciclovirAUC (0-12 h) (µg.h/ml) 28,6 ± 9,0 32,8 ± 10,1 0,37 ± 0,22Cmax (µg/ml) 10,4 ± 4,9 6,7 ± 2,1 0,18 ± 0,06La eficacia de ganciclovir en el aumento del tiempo de progresión de la retinitis por CMV ha demostrado correla-ción con la exposición sistémica (AUC). Valganciclovir en pacientes con trasplante de órganos sólidos. Despuésde la administración oral diaria de ganciclovir y valganciclovir en pacientes con trasplante de órgano sólido, seconsiguen exposiciones sistémicas estables de:Parámetros Ganciclovir (1.000 mg tid.) Valganciclovir (900 mg, una vez al día)

n= 82 n= 161Ganciclovir

AUC (0-24 h) (µg.h/ml) 28,0 ± 10,9 46,3 ± 15,2Cmax (µg/ml) 1,4 ± 0,5 5,3 ± 1,5

De acuerdo con el algoritmo de dosificación dependiendo de la función renal, la exposición sistémica de ganciclo-vir en los receptores de trasplante hepático, renal y cardíaco fue similar a la observada tras la administración oralde valganciclovir. Efecto de la comida: La relación de proporcionalidad entre el AUC de ganciclovir y la dosis devalganciclovir, tras la administración de éste último en un rango de dosis de 450 a 2.625 mg, sólo se ha demos-trado después de la ingesta. Cuando se administró valganciclovir con alimentos a la dosis recomendada de 900mg, se observaron valores mayores que en ayunas, tanto el AUC medio (aprox. 30%) como los valores Cmaxmedios (aprox. 14%) de ganciclovir. También, la variación entre individuos en la exposición a ganciclovir descien-de cuando se toma Valcyte con alimentos. En los estudios clínicos Valcyte se ha administrado solo con comida.Así pues, se recomienda administrar Valcyte con las comidas (ver sección 4.2). Distribución: Como el valganciclo-vir se convierte enseguida en ganciclovir, no se ha determinado la unión de valganciclovir a las proteínas. El gan-ciclovir, en concentraciones de 0,5 a 51 µg/ml, se une en un 1-2% a las proteínas del plasma. El volumen de dis-tribución del ganciclovir en el equilibrio alcanza 0,680 ± 0,161 l/kg (n= 114) después de su administración intra-venosa. Metabolismo. El valganciclovir se metaboliza de manera rápida y extensa a ganciclovir; no se conoce nin-gún otro metabolito. No existe ningún metabolito del ganciclovir radiactivo administrado por vía oral (en dosisúnica de 1.000 mg) que justifique más del 1-2% de la radiactividad recuperada en las heces o en la orina.Eliminación. Después de administrar Valcyte, la vía principal de eliminación del valganciclovir consiste en la excre-ción renal de ganciclovir a través de filtración glomerular y secreción tubular activa. El aclaramiento renal da cuen-ta del 81,5% ± 22% (n=70) del aclaramiento sistémico del ganciclovir. La semivida de ganciclovir a partir de val-ganciclovir es 4,1 ± 0,9 horas en pacientes seropositivos VIH y CMV. Farmacocinética en situaciones clínicasespeciales. Pacientes con insuficiencia renal. La disminución de la función renal reduce el aclaramiento de ganci-clovir a partir de valganciclovir con el correspondiente aumento de la semivida terminal. Así pues, es necesarioajustar la dosis de los enfermos con insuficiencia renal (ver secciones 4.2 y 4.4). Pacientes sometidos a hemo-diálisis. No se puede dar la dosis recomendada de Valcyte 450 mg comprimidos con cubierta pelicular en pacien-tes que estén recibiendo hemodiálisis. Esto se debe a que la dosis individual de Valcyte que precisan estos pacien-tes es menor que la contenida en los comprimidos de 450 mg. Por lo tanto, no se debería usar Valcyte en estospacientes (ver secciones 4.2 y 4.4). Pacientes con alteraciones de la función hepática. La seguridad y la eficaciade los comprimidos de Valcyte no se han estudiado en pacientes con alteración hepática. La alteración hepáticano debería afectar a la farmacocinética de ganciclovir ya que éste se excreta por vía renal, por consiguiente, nose establecen recomendaciones posológicas específicas. 5.3. Datos preclínicos sobre seguridad.Valganciclovir es un profármaco de ganciclovir y, por consiguiente, los efectos observados con ganciclovir sonigualmente aplicables para valganciclovir. La toxicidad de valganciclovir en los estudios preclínicos de seguridadfue la misma que la observada con ganciclovir y fue inducida con niveles de exposición a ganciclovir comparablesa, o más bajos a los alcanzados en humanos a los que se administró dosis de inducción. Estos hallazgos fuerongonadotoxicidad (pérdida de células testiculares) y nefrotoxicidad (uremia, degeneración celular) que fueron irre-versibles, mielotoxicidad (anemia, neutropenia, linfocitopenia) y toxicidad gastrointestinal (necrosis de las célulasde la mucosa) que fueron reversibles. Estudios adicionales han demostrado que ganciclovir es mutagénico, carci-nogénico, teratogénico, embriotóxico y aspermatogénico (ej. alteración de la fertilidad masculina) y suprime la fer-tilidad femenina. 6. DATOS FARMACÉUTICOS. 6.1. Lista de excipientes.Núcleo de los comprimidos Recubrimiento pelicular de los comprimidos

Opadry Rosa 15B24005 que contiene:Povidona K30 HipromellosaCrospovidona Dióxido de titanio (E171)Celulosa microcristalina Macrogol 400Ácido esteárico Óxido de hierro rojo (E172)

Polisorbato 806.2. Incompatibilidades. No aplicable. 6.3. Periodo de validez. 3 años. 6.4. Precauciones especiales deconservación. No requiere condiciones especiales de conservación. 6.5. Naturaleza y contenido del enva-se. Frascos de polietileno de alta densidad (HDPE), con cierre de polipropileno a prueba de niños y algodón. 60comprimidos. 6.6. Precauciones especiales de eliminación y otras manipulaciones. La eliminación delmedicamento no utilizado y de todos los materiales que hayan estado en contacto con él, se realizará de acuer-do con las normativas locales. 7. TITULAR DE LA AUTORIZACIÓN DE COMERCIALIZACIÓN. Roche Farma,S.A. Eucalipto, nº 33. 28016 Madrid. 8. NÚMERO(S) DE AUTORIZACIÓN DE COMERCIALIZACIÓN. Nº de Reg.64.829. 9. FECHA DE LA PRIMERA AUTORIZACIÓN: 5 de marzo de 2002. RENOVACIÓN DE LAAUTORIZACIÓN: 12 de abril de 2007. 10. FECHA DE LA REVISIÓN DEL TEXTO: Julio 2007. 11. PRECIOSAUTORIZADOS: Valcyte, 450 mg (60 comprimidos) P.V.L.: 1.267,43 . P.V.P. (IVA): 1.364,82 . 12. CONDICIO-NES DE DISPENSACIÓN. Especialidad farmacéutica de uso hospitalario sin cupón precinto. Para cualquier infor-mación adicional: Roche Farma, Tel.: 91 324 81 00.

volume ii • number 3 • september-december 2008 issn: 1887-455x · and hepatitis c virus after...

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