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University of Groningen Better prediction of drug response in diabetic kidney disease Idzerda, Nienke DOI: 10.33612/diss.113117223 IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2020 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Idzerda, N. (2020). Better prediction of drug response in diabetic kidney disease: a biomarker approach to personalize therapy. Rijksuniversiteit Groningen. https://doi.org/10.33612/diss.113117223 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license. More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne- amendment. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 06-02-2022

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University of Groningen

Better prediction of drug response in diabetic kidney diseaseIdzerda, Nienke

DOI:10.33612/diss.113117223

IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.

Document VersionPublisher's PDF, also known as Version of record

Publication date:2020

Link to publication in University of Groningen/UMCG research database

Citation for published version (APA):Idzerda, N. (2020). Better prediction of drug response in diabetic kidney disease: a biomarker approach topersonalize therapy. Rijksuniversiteit Groningen. https://doi.org/10.33612/diss.113117223

CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).

The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.

Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.

Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.

Download date: 06-02-2022

5Prediction and validation of the  effects of exenatide on progression of kidney  disease in type 2 diabetes

NMA IdzerdaLE CleggAF HernandezG BakrisRC PenlandDW BoultonMA BethelRR HolmanHJL Heerspink

Submitted

Abstract

Objective: Glucagon-like peptide-1 receptor agonists (GLP-1 RA) may

slow progression of renal disease in patients with type 2 diabetes (T2D).

We previously developed the PRE score that translates multiple short-

term drug effects into a predicted effect on long-term outcomes. We

assessed the short-term effects of the GLP-1 RA exenatide on multiple

cardio-renal risk markers, and aimed to determine whether the PRE

score could predict the renal effects observed in the EXSCEL cardio-

vascular outcomes trial.

Research Design and Methods: Changes from baseline to six months

in multiple risk markers were evaluated for glycated hemoglobin

(HbA1c), systolic blood pressure (SBP), urine albumin:creatinine ratio

(UACR), body mass index (BMI), hemoglobin and total cholesterol.

The renal outcome was defined as a composite of a sustained 30% de-

cline in estimated glomerular filtration rate (eGFR) or end-stage renal

disease. The effect of exenatide on the composite of 40% eGFR decline

or ESRD was also assessed. Relationships between multiple risk mark-

ers and long-term renal outcomes were determined in patients with

T2D from the ALTITUDE study using multivariable Cox regression

analysis. These relationships were applied to short-term changes in risk

markers observed in EXSCEL to predict the likely drug induced impact

on renal outcomes.

Results: Compared with placebo, mean HbA1c, BMI, SBP, and total

cholesterol were lower at six months with exenatide, as was the in-

cidence of micro- or macroalbuminuria. The PRE score predicted a

relative risk reduction for the 30% eGFR decline / ESRD endpoint of

11.3% (HR 0.89; 95%CI 0.83 to 0.94), compared with 12.7% (HR

0.87; 95%CI 0.77 to 0.99) observed risk reduction. For the 40% eGFR

/ ESRD endpoint, the predicted and observed risk reductions were

11.0% (HR 0.89; 95%CI 0.82 to 0.97) and 13.7% (HR 0.86, 95%CI

0.72 to 1.04), respectively.

Conclusions: Integrating short-term risk marker changes into a mul-

tivariable risk score predicted the observed renal risk reduction seen in

EXSCEL.

83

5

Prediction and validation of the  effects of exenatide on progression of kidney  disease in type 2 diabetes

Introduction

Recent cardiovascular outcome trials in patients with type 2 diabetes

(T2D) have characterized the cardiovascular safety of glucagon-like

peptide-1 receptor agonists (GLP-1 RA) [1–3], with some trials also

showing cardiovascular protective effects.[2,3] The Exenatide Study of

Cardiovascular Event Lowering (EXSCEL) assessed the cardiovascular

safety of the GLP-1 RA exenatide in a broad range of patients with T2D,

with or without atherosclerotic cardiovascular disease (ASCVD), and

confirmed that exenatide did not increase cardiovascular risk.[1] Sec-

ondary analyses of some of the cardiovascular safety trials with GLP-1

RAs have suggested that this drug class may also delay the progression

of diabetic kidney disease (DKD).[4,5] This benefit likely results in part

from improvement in glycemic control but may also be mediated by

other effects such as reductions in blood pressure, body weight, albu-

minuria, and inhibition of pro-inflammatory mediators.[6,7]

We previously developed and validated a multivariable risk score (PRE

score), that uses multiple short-term drug effects to predict the longer-

term drug impact on renal and/or cardiovascular outcomes.[8] The

PRE score was developed and validated in trials with renin-angiotensin-

aldosterone-system inhibitors and subsequently applied to trials with

endothelin receptor antagonists and sodium glucose co-transporter 2

inhibitors.[9–12] To date, the PRE score has not been applied to a

GLP-1 RA and it is not known whether it can predict renal outcomes

for this class of glucose-lowering agents.

We performed a post-hoc analysis of EXSCEL to determine the short-

term effects of exenatide on multiple cardio-renal risk markers and ap-

plied the PRE score to predict the longer-term impact of exenatide on

renal disease progression. We then compared the predicted impact with

that observed in EXSCEL.

Methods

Patient populationEXSCEL included patients with T2D with or without prior ASCVD. Par-

ticipants were assigned to receive subcutaneous injections of once- weekly

84

Chapter 5

exenatide (EQW) at a dose of 2 mg or matching placebo, and were fol-

lowed for a median of 3.2 years. The EXSCEL design and primary re-

sults have been previously published.[1,13]

The PRE score was used to predict the effect of exenatide on renal

outcomes in the EXSCEL trial. The relationships between short-term

risk marker changes and renal outcomes were established in a back-

ground population derived from the ALTITUDE trial, a study in pa-

tients with T2D at high cardiovascular and renal risk.[14] A subgroup

of patients with urine albumin:creatinine ratio (UACR) < 400 mg/g and

estimated glomerular filtration rate (eGFR) > 55 ml/min/1.73 m2 was

included in the analysis in order to calculate risk marker-outcome re-

lationships that are representative of patients included in the EXSCEL

trial. The baseline characteristics of the ALTITUDE population are

presented in Supplementary Appendix Table S1.

Cardio-renal risk markersParameters measured in the EXSCEL intention-to-treat population,

and which have previously been identified as risk markers for progres-

sion of renal disease, included: glycated hemoglobin (HbA1c), systolic

blood pressure (SBP), UACR, body mass index (BMI), hemoglobin

(Hb) and total cholesterol (TC). Due to a lack of continuous data for

UACR in EXSCEL, categorical information on new micro- or mac-

roalbuminuria was used to reflect short-term UACR changes. Data on

UACR levels in the ALTITUDE population used were similarly catego-

rized into normo-, micro- or macroalbuminuria.

Outcome definitionseGFR was derived from locally-measured serum creatinine values using

the Modification of Diet in Renal Disease equation. The renal outcome

was defined as a composite of a sustained 30% decline in eGFR or end

stage renal disease (ESRD: chronic dialysis or renal transplantation). A

sustained 30% eGFR decline was used as component of the composite

outcome because it reflects a large decline in eGFR in patients with pre-

served renal function such as those included in EXSCEL and has been

proposed as alternative renal endpoint for drugs without acute eGFR

effects such as GLP1 RAs. We also assessed the effect of exenatide on

the composite of 40% eGFR decline or ESRD since in certain settings

85

5

Prediction and validation of the  effects of exenatide on progression of kidney  disease in type 2 diabetes

this may be a more robust endpoint than 30% eGFR decline.[15] In

the ALTITUDE population, the composite renal outcome with 30%

eGFR decline and the outcome with 40% eGFR decline occurred in

292 (17.4%) and 153 (9.1%) patients during a median follow-up of

2.8 years, respectively.

Statistical analysisThe observed drug-induced reduction in risk of the composite renal out-

come was calculated using a Cox proportional hazards model with ex-

enatide treatment as explanatory variable. Relative risk reductions were

calculated by (1 − hazard ratio) × 100%.

A Cox proportional hazards model was used to estimate the coefficients

associated with each risk marker for the first recorded renal event in the

background population derived from the ALTITUDE placebo arm

among subjects with all required covariates measured at baseline. These

coefficients were then applied to the baseline and 6- month cardio-renal

risk factor measurements of patients in the EXSCEL trial to estimate risk

of renal outcomes at both time points. The mean difference in the pre-

dicted risk in the exenatide arm, adjusted for the mean difference in the

predicted risk in the placebo arm, represents the PRE score and reflects

an estimation of the expected renal risk reduction conferred by exenatide

treatment. To generate 95% confidence intervals on the predicted risk re-

duction, 1000 sets of coefficients were generated from independent nor-

mal distributions based on the estimated regression coefficients and their

standard error from the Cox proportional hazards model.

Before applying the PRE score, multiple imputations were performed

on the baseline and month 6 EXSCEL data using the ‘mice’ package

in R. Imputation for numeric covariates was done by predictive mean

matching, a semi-parametric imputation method that replaces missing

variables based on a multivariable regression model.[16,17] An impu-

tation method based on logistic regression was used to impute missing

values of categorical albuminuria. Imputations were performed with 10

iterations, and all metrics included in the PRE score at baseline and

month 6 were used as predictors. Covariate distributions were checked

visually to ensure reasonably imputed values. In the main analysis, the

predictions were generated using all EXSCEL participants missing one

or fewer of the required covariates at baseline and/or month 6.

86

Chapter 5

Mean and standard deviation (SD) are provided for variables with

a normal distribution, whereas median (25th and 75th percentiles) are

provided for those with a skewed distribution. Categorical variables

are reported as frequencies and percentages. As UACR is not normally

distributed, a natural log transformation was applied before analysis.

Two-sided p-values < 0.05 indicated statistical significance. All statisti-

cal analyses were conducted with R version 3.0.1 or 3.4.0 (R Project for

Statistical Computing, http://www.r-project.org).

Results

A total of 14,752 patients were randomly assigned to receive placebo

(N = 7396) or EQW (N = 7356) and were included in the EXSCEL

intention-to-treat population. Demographic and clinical characteristics

of these patients were well-balanced between the treatment groups (Ta-

ble  1), with 10,782 (73.1%) having prior ASCVD. EXSCEL partici-

pants were generally characterized by a low risk of complications due

to renal disease. Approximately 30% had a normal renal function, with

50% and 20% having mild and moderate renal impairment, respec-

tively. The prevalence of micro- and macroalbuminuria was 12.7% and

3.3%, respectively.

Effects of exenatide on cardio-renal risk markersA total of 3,395 participants in the placebo group and 3,523 in the

exenatide group had ≤ 1 risk marker missing at baseline or 6 months,

and were included in these analyses after imputation of missing values.

Their baseline characteristics were similar to those of the total popula-

tion (Supplementary Appendix Table S2).

Changes in cardio-renal risk markers from baseline to 6-months

after treatment with EQW or placebo are shown in Figure 1. Com-

pared with placebo, greater reductions were seen with EQW in HbA1c

(−0.79%. 95%CI −0.84 to −0.74, P < 0.001), BMI (−0.50 kg/m2, 95%CI

−0.57 to −0.43, P < 0.001), blood pressure (−1.7 mmHg, 95%CI −2.5 to

−0.9, P < 0.001) and total cholesterol (−0.14 mmol/L, 95%CI −0.19

to −0.09, P < 0.001). During the first six months of placebo treatment

136 (4.0%) participants with normoalbuminuria at baseline progressed

87

5

Prediction and validation of the  effects of exenatide on progression of kidney  disease in type 2 diabetes

to microalbuminuria or macroalbuminuria versus 106 (3.0%) in the

EQW arm (P for difference 0.03). Progression to microalbuminuria oc-

curred in 97 (2.0%) of the participants on placebo versus 69 (2.9%) pa-

tients on EQW (P for difference 0.02). Progression to macroalbuminuria

occurred in 39 (1.1%) and 37 (1.0%) of participants in the placebo and

EQW groups, respectively (P for difference 0.79).

Predicted longer term effect of EQW on renal outcomesThe predicted risk change for the composite renal endpoint of ≥ 30%

eGFR decline or ESRD based on the observed placebo corrected

change in HbA1c alone was −9.9% (95%CI −14.7 to −4.9) with EQW

(Figure 2A). The PRE score predicted effect of EQW on the composite

renal endpoint was −11.3% (95%CI −16.7 to −5.9). The predicted risk

change for the composite endpoint of ≥ 40% eGFR decline or ESRD

was −11.0% (95%CI −18.5 to −3.2) (Figure 2B).

Table 1. Baseline characteristics of the placebo and exenatide arms of the EXSCEL population.[1]

Placebo (n = 7396) Exenatide (n = 7356)Age (years) 61.9 (9.4) 61.8 (9.4)Female, n (%) 2809 (38) 2794 (38)Race, n (%) Caucasian 5621 (76.0) 5554 (75.5) Black 436 (5.9) 442 (6.0) Asian 727 (9.8) 725 (9.9) Other 612 (8.3) 635 (8.6)Glycated hemoglobin (%) 8.1 (1.0) 8.1 (1.0)Systolic BP (mmHg) 135.5 (16.9) 135.4 (16.9)Diastolic BP (mmHg) 78.0 (10.2) 78.2 (10.3)UACR (mg/g) 23.8 [13.5, 35.1] 22.9 [11.6, 34.1]Body mass index (kg/m2) 32.7 (6.4) 32.6 (6.3)Hemoglobin (g/L) 138.3 (15.8) 138.4 (15.6)Cholesterol (mmol/L) 4.5 (1.3) 4.5 (1.3)eGFR (ml/min/1.73m2)* 76.6 (24.0) 77.1 (23.5)UACR category, n (%) UACR < 30 mg/g 6245 (84.4) 6151 (83.6) UACR 30–300 mg/g 892 (12.1) 981 (13.3) UACR > 300 mg/g 259 (3.5) 224 (3.0)

Numeric variables are presented as mean (SD) if normally distributed. UACR is presented as median [IQR]. Categorical variables are presented as frequency (%). BP, blood pressure; UACR, urine protein: urine creatinine ratio; eGFR, estimated glomerular filtration rate. *Calculated with the Modification of Diet in Renal Disease study equation (MDRD).

88

Chapter 5

Impact of EQW on renal outcomes In the overall EXSCEL population, the composite renal outcome of

≥ 30% eGFR decline or ESRD occurred in 546 (7.4%) participants in

the placebo group compared with 489 (6.7%) in the EQW group (HR

0.87, 95%CI 0.73 to 0.99, p = 0.03; Figure 3A). A ≥ 30% eGFR de-

cline occurred in 533 (8.3%) participants in the placebo group versus

482 (7.5%) in the EQW group (HR 0.88, 95% CI 0.78 to 1.00, P = 0.10).

The composite renal outcome of ≥ 40% eGFR decline or ESRD oc-

curred in 241 (3.3%) participants in the placebo group and 213 (2.9%)

in the EQW group during a median follow-up of 2.6 years (Figure 3B), a

relative risk reduction with EQW of 14% (HR 0.86, 95%CI 0.72 to 1.04;

P = 0.12). ESRD was a relatively infrequent event during the trial, with

an ESRD HR of 0.65 (95%CI 0.39 to 1.08; P = 0.10).

Among the population used for the PRE score analysis with

≤ 1  cardio- renal risk factor missing (N = 6,918), the observed relative

risk reduction of 11.6% for the composite outcome of 30% eGFR de-

cline and ESRD was consistent with that the overall population (HR

0.88; 95%CI 0.74 to 1.05, P = 0.16) although the confidence intervals

were wider, reflecting the smaller number of patients. Similarly, the

observed relative risk reduction of 14.2% for the composite outcome

Figure 1. Mean changes in risk markers from baseline to month 6 in the included population of the EXSCEL trial. Changes are represented as mean (±95% CI) and are given for placebo and exenatide 2 mg.

Figure 1 – Short term changes (imputed)

Placebo (n=3395)

Exenatide (n=3523)

SBP (mmHg) Cholesterol (mmol/L)HbA1c (%)

-0.75

-0.50

-0.25

0.00

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

-3

-2

-1

0

-1.00 -4

Hemoglobin (g/L)

*** *** ***

BMI (kg/m2)

-0.6

-0.4

-0.2

0.0

-0.8***

New macroalbuminuria (%)

New microalbuminuria (%)

*p<0.05**p<0.01***p<0.001

-1.00

-0.75

-0.50

-0.25

0.00

-1.25

0.25

1.1% 1.0%

2.9%

2.0%

*

8.1 8.1 Baseline value 135.9 135.8 138.2 138.6 4.5 4.5 32.7 32.7

89

5

Prediction and validation of the  effects of exenatide on progression of kidney  disease in type 2 diabetes

Figure 2. Predicted risk change for the composite renal outcome of ≥ 30% eGFR de-cline or ESRD (A) and for the composite renal outcome of ≥ 40% eGFR decline or ESRD (B) in the EXSCEL population based on changes in single risk markers and the integrated effects of all risk markers. Circles indicate point estimates of the per-centage mean change in relative risks with EQW compared with placebo, with their 95% confidence intervals.

* Due to a lack of continuous data for albuminuria in the EXSCEL trial, categori-cal information on new micro- or macroalbuminuria was used to reflect short-term changes in albuminuria.

Figure 2 – PRE score for kidney outcomes (imputed, 30% eGFR decl)

-15 -10 -5 0

Renal risk change (%)

Systolic BP (mmHg)

HbA1c (%)

BMI (kg/m2)

Hemoglobin (mg/L)

Macroalbuminuria (mg/g)*

PRE score

Microalbuminuria (mg/g)*

Cholesterol (mmol/L)

-11.3 (-16.7,-5.9)

-9.9 (-14.7,-4.9)-0.88

-0.4 (-0.6,-0.2)

-0.06 (-0.09,-0.03)

-2.5 (-4.0,-1.5)

0.1 (-0.9,1.1)

0.8 (-0.6,2.1)

Change in risk marker at month 6

Exenatide 2 mgPlaceboPredicted renal risk change (%)

Favors Exenatide

Favors Placebo

5

Observed (analysis pop) -11.6 (-25.7,5.2)

-20-25

Observed (full pop) -12.7 (-22.7,-1.3)

-3.16

-0.29

-0.64

-0.21

-0.10

-1.46

-0.69

-0.14

-0.07

-2.2 (-3.9,-0.8)

A

-30 -20 -10 0 10

Renal risk change (%)

Systolic BP (mmHg)

HbA1c (%)

BMI (kg/m2)

Hemoglobin (mg/L)

Macroalbuminuria (mg/g)*

PRE score

Microalbuminuria (mg/g)*

Cholesterol (mmol/L)

-11.0 (-18.5, -3.2)

-12.6 (-18.9,-5.9)-0.88

-0.6 (-1.0, -0.3)

-0.1 (-0.15, -0.05)

-2.8 (-5.1,-1.4)

1.2 (-0.2, 2.6)

1.1 (-0.7, 2.9)

Change in risk marker at month 6

Exenatide 2 mgPlaceboPredicted renal risk change (%)

Favors Exenatide

Favors Placebo

Observed (analysis pop) -14.2 (-34.1, 11.7)Observed (full pop) -13.7 (-28.2, 3.8)

-3.16

-0.29

-0.64

-0.21

-0.10

-1.46

-0.69

-0.14

-0.07

-1.3 (-3.3, 0.5)

Supp Fig 1 – PRE score for kidney outcomes (imputed, 40% eGFR decl)

B

90

Chapter 5

of 40% eGFR decline and ESRD did not differ from that in the overall

population (hazard ratio 0.86; 95%CI 0.66 to 1.12, P = 0.26).

Conclusions

In this post-hoc analysis of the EXSCEL, we demonstrated that EQW

2 mg reduced multiple cardio-renal risk markers after 6 months treat-

ment in a broad population of patients with T2D. Integrating these

short-term changes in multiple risk markers resulted in a predicted

renal risk reduction of 11%, which was of similar magnitude to the rel-

ative risk reduction observed in the trial. These results support further

clinical trials to prospectively assess the renal efficacy of EQW.

Prior studies have suggested that GLP-1 RAs may slow renal dis-

ease progression in patients with T2D. A pre-specified analysis from

The Evaluation of Cardiovascular Outcomes in Patients With Type

2 Diabetes After Acute Coronary Syndrome During Treatment With

Lixisenatide (ELIXA) trial reported that patients treated with the

short-acting GLP-1 RA lixisenatide showed a smaller increase in al-

buminuria from baseline to 108 weeks compared to placebo-treated

patients (24% versus 34%; P = 0.004).[18] No effect was observed on

eGFR decline in that study. In the LEADER and SUSTAIN−6 trials,

Figure 3. Rates of the composite outcome of 30% eGFR decline and ESRD (A) and the composite outcome of 40% eGFR decline and ESRD (B) in the exenatide and placebo groups among the total EXSCEL population.

7368 6722 5216 3192 1714 464 957331 6751 5273 3260 1885 535 116

0

0 1 2 3 4 5 6

5

10

0 1 2 3 4 5 6Time (years)

0

5

10

15

20

% P

atie

nts

with

eve

nt

73687331

66486665

50575133

30223135

15961789

429508

90109

Number at riskPlaceboExenatide

PlaceboEQW 2 mg

A

Number at riskPlaceboExenatide

Time (years)

PlaceboEQW 2 mg

% P

atie

nts

with

eve

nt

B

Figure 3

Hazard ratio 0.87 (95%CI 0.77,0.99; P=0.03)

Hazard ratio 0.86 (95%CI 0.72,1.04; P=0.12)15

20

91

5

Prediction and validation of the  effects of exenatide on progression of kidney  disease in type 2 diabetes

liraglutide and semaglutide reduced the composite renal outcome of

new onset of persistent macroalbuminuria, persistent doubling of se-

rum creatinine level and ESRD by 22% and 36%, respectively.[3,5]

These favourable effects were predominantly driven by reductions in

the risk for macroalbuminuria. The benefits on a clinically meaning-

ful endpoint of doubling of serum creatinine or ESRD were less clear.

In this analysis we demonstrated that treatment with exenatide signifi-

cantly lowered the risk of a composite endpoint −30% eGFR decline or

ESRD- that did not include the surrogate albuminuria. Replacing the

30% eGFR decline by a more robust endpoint of 40% eGFR decline

yielded similar estimates of the treatment effect size although it did

not reach statistical significance possibly due to the smaller number of

events. Dedicated outcome trials with GLP-1 RAs are needed to more

definitively assess the renoprotective potential of these compounds.

In concordance with the results of prior studies with GLP-1 RAs, treat-

ment with EQW had multiple effects beyond improvement in glycemic

control that also associate with improved renal outcomes. Although the

mechanisms underlying the effects of incretin-based therapies are not

completely understood, there is growing evidence that several non-gly-

cemic mechanisms substantially mediate the renoprotective effects of

incretin-based therapies. Firstly, GLP-1 RA have been suggested to en-

hance sodium excretion by inhibition of the sodium-hydrogen exchange

3 transporter.[19–21] Enhanced sodium excretion may result in blood

pressure and body weight reductions. Secondly, GLP-1 RA appear to

exert direct effects on the renal vascular endothelium which may be

involved in their albuminuria lowering effect and stabilization of renal

function decline.[22–24] Moreover, preclinical and clinical studies have

suggested thatGLP-1 RA therapy may attenuate inflammation and oxi-

dative stress thereby reducing renal tissue injury.[25–29]

The longer term effects of EQW on renal outcomes were accurately

predicted by the PRE score algorithm. The PRE score has previously

been used to predict the long-term renal effects of renin angiotensin

aldosterone system (RAAS) inhibitors, endothelin receptor antagonists

and sodium glucose co-transporter 2 inhibitors.[8–12] These results ap-

pear to extend to the GLP-1 RA exenatide, thereby extending the ap-

plicability of the algorithm. The reduction in HbA1c appeared to be the

driving parameter for the observed renal risk reduction. This contrasts

92

Chapter 5

with previous studies where reductions in albuminuria were the driving

parameter for the observed renal risk reduction.[30–32] Differences in

the measurement and registration between prior trials and the EXS-

CEL trial (transition in albuminuria stage in EXSCEL versus percent-

age change in UACR in other trials) may explain this.

What is the applicability of the PRE score in future clinical trials?

Surrogate endpoints based on a single risk marker may not capture the

overall drug effect. Indeed, multiple examples exists where drug effects

on single surrogates insufficiently predict the drug effect on long-term

clinical outcomes.[14,33–35] Apparently, additional drug effects be-

yond the single surrogate substantially influenced long-term outcome.

Integrating multiple effects of a drug assists in better long-term drug

efficacy prediction. As such, the PRE score can be applied during

early clinical trials and provide information as to whether (or in which

patients) the drug is likely to be effective and may inform power and

sample size calculations.

This analysis has limitations. The analyses were exploratory and post-

hoc in nature and therefore the results should be interpreted as hy-

pothesis generating. The majority of participants in the EXSCEL trial

had only mild-to moderate chronic kidney disease, and therefore the

number of ESRD events during the trial was low. Determining whether

EQW genuinely slows progression of renal function decline would re-

quire a dedicated hard outcome trial in a population at risk of renal dis-

ease progression to capture a sufficient number of clinically meaningful

ESRD events. Furthermore, despite the use of multiple imputation in

participants missing ≤ 1 of the required risk marker data at baseline

and/or month 6, a small proportion of participants in the EXSCEL trial

had complete risk marker data available. As a result, our predictions

are based on a subset of patients in the EXSCEL trial with most risk

marker data available, possibly inducing bias.

In conclusion, among patients with T2D at cardiovascular risk, EQW

compared with placebo decreased multiple cardio-renal risk markers

and reduced the risk for progression of renal disease. Integration of the

short-term risk marker changes resulted in a predicted risk reduction

of similar magnitude as the actual observed risk reduction for renal

outcomes.

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Prediction and validation of the  effects of exenatide on progression of kidney  disease in type 2 diabetes

Acknowledgements

The EXSCEL trial was conducted jointly by the Duke Clinical Research

Institute and the University of Oxford Diabetes Trial Unit, in collabora-

tion with the sponsor Amylin Pharmaceuticals, a wholly owned subsidi-

ary of AstraZeneca. LEC is a fellow of the AstraZeneca IMED Postdoc-

toral programme. NMAI is supported by a grant from the Innovative

Medicines Initiative BEAt-DKD programme. The BEAt-DKD project

has received funding from the IMI2 Joint Undertaking under grant

agreement 115974. This joint undertaking receives support from the

European Union’s Horizon 2020 research and innovation programme

and European Federation of Pharmaceutical Industries and

Associations. HJLH is supported by a VIDI grant from the Nether-

lands Organisation for Scientific Research (917.15.306). RRH is an

Emeritus NIHR Senior Investigator.

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28. Rizzo M, Abate N, Chandalia M, Rizvi AA, Giglio RV, Nikolic D et al. Liraglutide reduces oxidative stress and restores heme oxygenase-1 and ghrelin levels in patients with type 2 diabetes: a prospective pilot study. J Clin Endocrinol Metab 2015; 100: 603–606.

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30. Heerspink HJ, Kropelin TF, Hoek-man J, de Zeeuw D, Reducing Al-buminuria as Surrogate Endpoint (REASSURE) Consortium. Drug-In-duced Reduction in Albuminuria Is Associated with Subsequent Reno-protection: A Meta-Analysis. J Am Soc Nephrol 2015; 26: 2055–2064.

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32. Eijkelkamp WB, Zhang Z, Remuzzi G, Parving HH, Cooper ME, Keane WF et al. Albuminuria is a target for reno-protective therapy independent from blood pressure in patients with type 2

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Supplementary files

Supplementary Table 1. Baseline characteristics of the background population from the ALTITUDE trial.

Number of patients 1675Age (years) 62.1 (10.0)Female, n (%) 518 (31.3)Race, n (%) Caucasian 868 (52.5) Black 62 (3.7) Asian 584 (35.3) Other 140 (8.5)Glycated hemoglobin (%) 8.0 (1.7)Systolic BP (mmHg) 137.8 (16.6)Diastolic BP (mmHg) 75.6 (9.8)UACR (mg/g) 46.7 [23.1, 99.6]Body mass index (kg/m2) 29.8 (5.9)Hemoglobin (g/L) 135.1 (16.6)Cholesterol (mmol/L) 4.6 (1.2)Potassium (mmol/L) 4.4 (0.4)eGFR (ml/min/1.73m2)* 77.5 (22.3)UACR category, n (%) UACR < 30 mg/g 578 (34.9) UACR 30–300 mg/g 1017 (61.5) UACR > 300 mg/g 59 (3.6)

Numeric variables are presented as mean (SD) if normally distributed. UACR is pre-sented as median [IQR]. Categorical variables are presented as frequency (%). BP, blood pressure; UACR, urine protein: urine creatinine ratio; eGFR, estimated glomerular fil-tration rate. *Calculated with the Modification of Diet in Renal Disease study equation (MDRD).

97

5

Prediction and validation of the  effects of exenatide on progression of kidney  disease in type 2 diabetes

Sup

plem

enta

ry T

able

2.

Bas

elin

e ch

arac

teri

stic

s of

the

pla

cebo

and

EQ

W a

rms

from

the

EX

SC

EL

stu

dy p

opul

atio

n w

ith

≤ 1

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sing

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tire

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pop

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are

also

list

ed.

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lysi

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n (n

= 1

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lace

bo (

n =

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5)E

xena

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(n

= 3

523)

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alue

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cebo

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396)

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nati

de (

n =

735

6)P

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ueA

ge (

year

s)62

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9.2)

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61.8

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(%

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54 (

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ace,

n (

%)

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casi

an26

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78.8

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49 B

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206

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ther

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(5.5

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5 (8

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Gly

cate

d he

mog

lobi

n (%

)8.

1 (0

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328.

1 (1

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8.1

(1.0

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34S

ysto

lic B

P (

mm

Hg)

135.

9 (1

6.6)

135.

8 (1

6.7)

0.69

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5 (1

6.9)

135.

4 (1

6.9)

0.72

Dia

stol

ic B

P (

mm

Hg)

78.0

(10

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78.0

(10

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0.97

78.0

(10

.2)

78.2

(10

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0.19

UA

CR

(m

g/g)

24.8

[14

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6.3]

24.0

[14

.2, 3

5.3]

0.60

23.8

[13

.5, 3

5.1]

22.9

[11

.6, 3

4.1]

0.14

Bod

y m

ass

inde

x (k

g/m

2 )32

.7 (

6.3)

32.7

(6.

2)0.

6032

.7 (

6.4)

32.6

(6.

3)0.

55H

emog

lobi

n (g

/L)

138.

2 (1

5.0)

138.

6 (1

5.2)

0.65

138.

3 (1

5.8)

138.

4 (1

5.6)

0.69

Cho

lest

erol

(m

mol

/L)

4.5

(1.3

)4.

5 (1

.3)

0.71

4.5

(1.3

)4.

5 (1

.3)

0.73

eGF

R (

ml/m

in/1

.73m

2 )*

76.4

(22

.9)

77.3

(23

.2)

0.11

76.6

(24

.0)

77.1

(23

.5)

0.18

UA

CR

cat

egor

y, n

(%

) U

AC

R <

30

mg/

g26

70 (

78.6

)25

82 (

73.3

)<

0.0

162

45 (

84.4

)61

51 (

83.6

)0.

18 U

AC

R 3

0–30

0 m

g/g

569

(16.

8)66

2 (1

8.8)

0.03

892

(12.

1)98

1 (1

3.3)

0.02

UA

CR

> 3

00 m

g/g

156

(4.6

)15

1 (4

.3)

0.57

259

(3.5

)22

4 (3

.0)

0.13

Num

eric

var

iabl

es a

re p

rese

nted

as

mea

n (S

D)

if n

orm

ally

dis

trib

uted

. UA

CR

is p

rese

nted

as

med

ian

[IQ

R].

Cat

egor

ical

var

iabl

es a

re p

rese

nted

as

fre-

quen

cy (

%).

BP,

blo

od p

ress

ure;

UA

CR

, uri

ne p

rote

in: u

rine

cre

atin

ine

rati

o; e

GF

R, e

stim

ated

glo

mer

ular

filt

rati

on r

ate.

*C

alcu

late

d w

ith

the

Mod

ifica

tion

of

Die

t in

Ren

al D

isea

se s

tudy

equ

atio

n (M

DR

D).