68 dotatate production with automated pet synthesis system

* Corresponding author: Alireza Aslani, Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia. Tel: +61 2 99264440; Email: [email protected] © 2014 mums.ac.ir All rights reserved. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Gallium‐68 DOTATATE Production with Automated PETRadiopharmaceutical Synthesis System: A Three YearExperienceAlireza Aslani1,2*, Graeme M Snowdon1, Dale L Bailey1,2,3, Geoffrey PSchembri1,2,ElizabethABailey1,PaulJRoach1,21 DepartmentofNuclearMedicine,RoyalNorthShoreHospital,Sydney,Australia2 SydneyMedicalSchool,UniversityofSydney,Sydney,Australia3 FacultyofHealthSciences,UniversityofSydney,Sydney,Australia

ARTICLEINFO ABSTRACT

Articletype:Originalarticle

Objective(s): Gallium‐68 (Ga‐68) is an ideal research and hospital‐based PETradioisotope. Currently, the main form of Ga‐68 radiopharmaceutical that is beingsynthesised in‐house is Ga‐68 conjugated with DOTA based derivatives. Thedevelopment of automated synthesis systems has increased the reliability,reproducibility and safety of radiopharmaceutical productions.Herewe report on ourthreeyear,500synthesesexperiencewithanautomatedsystemforGa‐68DOTATATE.Methods: The automated synthesis system we use is divided into three parts of a)servomotor modules, b) single use sterile synthesis cassettes and, c) a computerisedsystemthatrunsthemodules.AnaudittrailisproducedbythesystemasarequirementforGMPproduction.Therequiredreagentsandchemicalsaremadein‐.TheGermaniumbreakthroughisdeterminedonaweeklybasis.Productionyieldsforeachsynthesisarecalculatedtomonitortheperformanceandefficiencyofthesynthesis.ThequalityofthefinalproductisassessedaftereachsynthesisbyITLC‐SGandHPLCmethods.Results: A total of 500 Ga‐68 DOTATATE syntheses (>800 patient doses) wereperformedbetweenMarch2011 andFebruary2014.Theaverage generator yieldwas81.3±0.2% for 2011, 76.7±0.4% for 2012 and 75.0±0.3% for 2013. Ga‐68 DOTATATEyields for 2011, 2012, and 2013 were 81.8±0.4%, 82.2±0.4% and 87.9±0.4%,respectively. These exceed the manufacturer’s expected value of approximately 70%.Germaniumbreakthroughaveraged8.6×10‐6%of totalactivitywhich iswellbelowtherecommended level of 0.001%. The average ITLC‐measured radiochemical purity wasabove98.5%and the averageHPLC‐measured radiochemical puritywas above99.5%.Although there were some system failures during synthesis, there were only eightoccasionswherethepatientscansneededtoberescheduled.Conclusion:Inourexperiencetheautomatedsynthesissystemperformsreliablywitharelatively low incident of failures. Our system had a consistent and reliable Ga‐68DOTATATEoutputwithhigh labellingefficiencyandpurity.There isminimaloperatorintervention and radiation exposure. The system is GMP‐compliant and has lowmaintenanceandacceptablerunningcosts.Thissystemtogetherwiththerecommended68Ge/68Gageneratoriswellsuitedforuseinahospital‐basedradiopharmacy.

Articlehistory:Received:4Feb2014Revised:7Mar2014Accepted:23Mar2014

Keywords:DOTATATEAutomatedsynthesissystemsGallium‐68Neuro‐endocrinetumoursPetradiopharmaceuticals

►Pleasecitethispaperas:AslaniA,SnowdonGM,BaileyDL,SchembriGP,BaileyEA,RoachPJ.Gallium‐68DOTATATEProductionwithAutomatedPETRadiopharmaceuticalSynthesisSystem:AThreeYearExperience.AsiaOceaniaJNuclMedBiol.2014;2(2):75‐86.

IntroductionToday, the majority of Positron Emission

Tomography (PET) studies are performedwith

Fluorine‐18 (F‐18) labelled radiophar‐maceuticals and, in particular, fluoro‐

Aslani A et al Gallium-68 DOTATATE

76 Asia Oceania J Nucl Med Biol. 2014; 2(2):75-86.

Figure1.Theimagesshowtwopatientswhounderwentcontemporaneous[F‐18]‐FDGand[Ga‐68]‐DOTATATEimaging.(A)Thisisa72yearoldfemalepatientdiagnosedwithcarcinoidandknownmetastaticdiseaseintheliverandabdominallymphnodes.Theliver lesion (closedwhite arrow)was identified on FDG imaging alone. Lymph nodes (openwhite arrows)with increased focaluptakewereonlydemonstratedonDOTATATE imaging.FDGpositive/DOTATATEnegative lesionsaremore likely tobepoorlydifferentiatedandhighergradewhereasDOTATATEpositive/FDGnegativeareusuallywelldifferentiatedandlowergrade.(B)A73yearoldfemalepatientwithmetastaticsmallbowelcarcinoid,currentlybeingtreatedwith[Lu‐177]‐DOTATATEtherapy.Theknown small bowel lesion can be seen on both the FDG and DOTATATE images (pink arrows). Used in combination, FDG andDOTATATEimagingallowsthedegreeofdifferentiationofthelesionstobeassessedwhichisaguidetothemostappropriateformoftherapy(PeptideReceptorRadionuclideTherapy(PRRT)orconventionalchemotherapy).AllpatientscanswereperformedintheDepartmentofNuclearMedicine,RoyalNorthShoreHospital,SydneyusingaSiemensBiographmCTTime‐of‐FlightPETscanner(BiographmCT.s/x64,SiemensHealthcare,IL,USA)

deoxyglucose (FDG). F‐18 is a cyclotron‐produced radioisotope and, as a result, itrequires an on‐site cyclotron or access to anearby cyclotron and subsequent delivery,costing both time and money. Generator‐produced radioisotopes, such as Ga‐68, have anumber of advantages that makes themattractiveashospital‐basedPETradioisotopes.

Ga‐68hasrapidlygainedattentionasoneofthe ideal research and hospital‐based PETradioisotopes. It has the advantage of beingproduced on‐site from a small wet‐bed68Ge/68Gagenerator,soitcanbemadeavailablewithin minutes as well as at much lower costthan other similar radioisotopes. It has a shorthalf‐life (67.7 minutes) making it suitable forhuman studies and low radiation dose to thepatients.ThetrivalentnatureofGallium‐68alsomakes it well suited for radiolabelling the1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) compounds as well aslabellingproteinsandpeptides(1).

Currently a general review of the reportspublished in the literature suggests that the

main non‐cyclotron produced PET radiophar‐maceuticalthat isbeingsynthesisedin‐houseisGa‐68conjugatedwithDOTAbasedderivatives,specifically for imaging over‐expression ofvarious subtypes of somatostatin receptorsexpressed by neuroendocrine tumours (NETs).The main radiopharmaceuticals being used forthis application are DOTATATE, DOTATOC andDOTANOC, all of which are labelled via theDOTA chelator to Ga‐68. Figure 1 showsexamples of patient scans from our institutionusingbothFDGandDOTATATE,demonstratingthat these tumours can be either FDG orDOTATATE positive or negative in variouscombinations. Although the synthesis andpurification of these radiopharmaceuticals cansuccessfully be carried out manually in thelaboratory, the use of automated synthesissystems (2), (3) is on the increase. Theseautomated systemshave clear advantages overthe manual methods which have resulted intheirincreasinginstallationanduseinhospital‐based radiopharmacies.Herewe report on ourthree year experience of over 500 syntheses

A FDGPET DOTATATEPET

B FDGPET DOTATATEPET

Gallium-68 DOTATATE Aslani A et al

Asia Oceania J Nucl Med Biol. 2014; 2(2):75-86. 77

with an automated synthesis system for Ga‐68DOTATATE.

MethodsThere are a number of reports in the

literatureusinganddetailingvariousautomatedsynthesis systems. One of the automatedsystems thatclosely,butnotexactly, resemblesour systemwas reported by Decristoforo et al(4).Automatedsynthesissystemsaregenerallyset‐upandadjustedto thespecificneedsof theinstitution. As a result over time, these setupsevolveandaretweakedtoimproveproductivityand become unique to the institution. Thesystem used here was the Eckert & ZieglerEurotope’s Modular‐Lab Pharm Tracer®automatedsynthesissystem.

All materials and methods used werefollowed as instructed or later modified byEckert & Ziegler Eurotope (Berlin, Germany)fromwhomtheautomatedsynthesissystemandsynthesiscassetteswereobtained.

Reagents

As recommended by the manufacturer ofthe automated synthesis system, Eckert &ZieglerEurotope(Berlin,Germany),allreagentswere high purity pharmaceutical grade, unlessstatedotherwise.Theexactgradeaswellasthesource of the reagents used was theirrecommendation.

Water puriss p.a (FLUKA Trace SELECT®95305)used in thepreparationof themajorityof reagents was obtained from Sigma‐Aldrich,Australia. Hydrochloric acid (Ultrapure 30%HCl, 0.1 M), was obtained from Merck kGaA(64271 Darmstadt, Germany). In addition, the>99.5% pure acetone (puriss p.a 32201), 200proof ethanol (HPLC / spectrophotometricgrade, 459828‐1L), glacial acetic acid solution(>99.99% purity; 338826) and sodium acetatetrihydrate (BioUltra® >99.5% purity; 71188)were obtained from Sigma‐Aldrich, Australia.Sodium chloride 0.9% for injection in 50mLglass bottles (INJ089) were obtained fromPhebra(LaneCove,NSW,Australia).

The reagents used for the High PressureLiquid Chromatography (HPLC) phase of theautomated system were of HPLC grade. Thetrifluoroaceticacid(HPLCgradeFLUKA;91707),acetonitrile (CHROMASOLV®, HPLC grade,>99.9% purity; 34998), ammonium acetate(17836), and HPLC grade water(CHROMASOLV®;270733)wereobtained fromSigma‐Aldrich, Australia. The sodium citratedihydrate p.a was obtained from Bacto

Laboratories (Liverpool, NSW, Australia;#1.06448)

TheDOTATATE, orDOTA‐(Tyr3)‐octreotate(where DOTA=1, 4, 7, 10 ‐ tetraazacyclo‐dodecane – 1, 4, 7, 10‐tetraacetic acid) wasobtained from Auspep, Victoria, Australia. Thepeptide is obtainedasa1mgpowderwhich issubsequently dissolved in 1 mL of water andused in 40 µl aliquots. Up till recently theDOTATATE was only available as a researchgradepeptide.However,sincemid‐2013aGoodManufacturingProcess(GMP)gradeproducthasalsobeenavailablewhichwenowutilise.

The preparation of the required Ga‐68DOTATATE reagents and chemicals are shownin Table 1. This table is used as a quickinstruction guide for the daily preparation ofchemicalsatourcentre.

SynthesisCassettesandAutomation

The synthesis of DOTATATE is performedusing theEckert&ZieglerEurotope’sModular‐Lab Pharm Tracer® automated synthesissystemdesignedspecificallyforthesynthesisofradiopharmaceuticals. It can be separated intothree parts. These are: a) the modulesassembled according to the specificradiopharmaceutical being synthesised; b) thesynthesis cassettes on which the appropriatechemicals, reagents, filters, columns, etc areattached; and c) the computerised system thatruns themoduleswhich in turn run the valvesand syringes on the cassettes producing therequiredradiopharmaceutical.Sincethesystemis computer‐controlled, an audit trail is alwaysmaintained which is a requirement for GMPproductionruns.

Thereisaspecificsynthesiscassettefortheproductionof Ga‐68DOTATATEaswell as oneforasimpleelutionoftheGa‐68generator.Thesystem is also currently being used for theproductionofother radiopharmaceuticals, suchasLu‐177DOTATATE,usingaspecificsynthesiscassette.TheproductioncassettesareobtainedfromEckert&ZieglerEurotope.Thesecassettesaresterileandsingle‐use.

As with the cassettes, there is a specifictemplate computer program for each specificradiopharmaceutical synthesis process. ThesesynthesistemplatesarealsoprovidedbyEckert& Ziegler Eurotope. These are subdivided intotemplate programs for the cassette’s pressuretesting, terminal sterilisation filter testing,running the HPLC analysis and eluting thegenerator. The Modular‐Lab software alsoallows programming and modifications to the



Table1.PreparationmethodsforGa‐68DOTATATEchemicalsNameofSolution Preparation ProductCodeHCl(0.1M) 1.06mL30%HCl

Fillupto100mLwithH2O

30%,HClUltrapure,Merck1.01514.0500WaterPuriss.p.a.,SigmaAldrichFLUKA95305

Eluent(0.02MHCl,98%acetone)

52.5LHCl557µLH2OVolumetricallyfillupto25mLwithacetoneStoreinfreezer.ReplaceeachMondaymorningDonotusebeyond5days.

30%,HClUltrapure,Merck1.01514.0500WaterPuriss.p.a.,SigmaAldrichFLUKA9530599.5%Acetone,puriss.p.a.,SigmaAldrich32201

Bufferstocksolution(Sodiumacetatebuffer0.2M)

Prepare2solutionsA.0.2MNaOAc:2.721gNaOAcx3H2OFillupto100mLwithH2OB.0.2MAcOH:1.145mLAcOHFillupto100mLwithH2OMixthe2solutions:82mL0.2MAcOH+18mL0.2MNaOAcCheckthepH=4.0±0.2.IfpHisnotinrangedonotusethesolution.Storeinfridge.

Sodiumacetatetrihydrate,SigmaAldrich71188[250g]Puriss.p.a.,SigmaAldrichFLUKA95305Aceticacidsolution,glacial99.99+%,SigmaAldrich338826100mLWaterPuriss.p.a.,SigmaAldrichFLUKA95305

Ethanolsolution 10mLethanol10mLH2O

Ethanol200proofHPLC/SpectrophotometricgradeSigmaAldrich459828‐1LWaterPuriss.p.a.,SigmaAldrichFLUKA95305

NaCl(saline) 50mLsterilesaline SodiumChloride0.9%Injection900mgin50mLPhebraINJ072

DOTATATE StockDOTATATE1mgpeptidein1mLH2O.StoreinfreezerDispense40Lintoeppendorfvials.Storeinfreezer

DOTA‐(TYR3)Octreotateacetatesalt25004371mgCAS‐No177943‐89‐4WaterPuriss.p.a.,SigmaAldrichFLUKA95305

HPLCFor68Ga‐DOTATATE22%Acetonitrile

Fill385mLofwaterina1000mLcylinder.Add0.5mLTFAbypipetteFillto500mLwithacetonitrile

WATER,CHROMASOLV,FORHPLCSigmaAldrich#270733‐4LTFA(trifluoroaceticacid,HPLCGrade,SigmaAldrichFLUKA,91707)Acetonitrile(HPLCGrade,ChromosolvRPlusSigmaAldrich#34998)

PreparationofHPLCcolumncleaningsolution

Fill700mLofacetonitrileina1000mLcylinder.Fillto1000mLwithwater

Acetonitrile(HPLCGrade,ROTH,8825.2)WATER,CHROMASOLV,FORHPLCSigmaAldrich#270733‐4L

68Ga‐DotatateITLCQC

0.1MNaCitratepH=5.0(2.94gin100mL)1Mammoniumacetateinwater/methanol,1:1*1Mammoniumacetate7.704gin100mLwater

Sodiumcitratedehydratep.aBactoLaboratories#1.06448AmmoniumAcetateSigmaAldrich#17836

templatesviaagraphicaluserinterface(GUI).

Generators

So far, on average one generator per yearhas been used during the three years of usingthe automated system. All three 68Ge/68GageneratorswereobtainedfromEckert&ZieglerEurotope(Berlin,Germany).Thefirstgenerator(IGG100‐30M)usedwasa1.11GBqwhereasthesubsequenttwo(IGG100‐50M)generatorswere1.85GBq.Thelattertwogeneratorsallowedforlarger number of patient doses per synthesisandalonger“useful”life.

Due to the build‐up of metal ions on thecolumn,thegeneratorsarerequiredtobeeluted

onadailybasisandwithin24hourspriortoanyDOTATATE synthesis. Therefore, the generatorwaselutedon the firstdayof theweekandonnon‐synthesis days. The elution processinvolved using an elution cassette, 0.1 M HClsolution driven by the Modular‐Lab system inapproximatelyfiveminutes.Theelutionvolumewas8mL.

AutomatedRadiolabellingProcess

Theradiolabellingprocessisexplainedfullyand in details in the instructionmanual that issuppliedwith theModularLabPharmTracer®automated system. Briefly the process issummarisedhere.

Gallium-68

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Aslani A et al

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phase isb Pharmprocessishe entireis drivensyringe‐umberoff variouse Watersdge (alsoSepPak®ed) withgeneratorndpassedcartridgeexcess0.1ottle. Therom the eluenttion vialn acetatefor 400



Figure3.ModularLabPharmTracer®Ga‐68DOTATATEsynthesisschematic.ImagedcapturedfromEckert&ZieglerEurotope’sModular‐LabPharmTracer®automatedsynthesissystemandusedwithpermissionseconds at 95ºC to bind the DOTATATE withgallium‐68chlorideandtoevaporatetheeluent(acetone/HCL).Thecontentsofthereactionvialare then removed and passed through the C18ion exchange cartridge where the Ga‐68DOTATATE is trapped and the unbound Ga‐68andDOTATATEaresenttothewastebottle.Thetrapped Ga‐68 DOTATATE is eluted from theC18 ion exchange by ethanol and then 0.9%saline into theproductvialviaa0.22µmfilter.The total volume of the final product is 8 mL.The Modular Lab Pharm Tracer® softwareprovided a graphical display of each step andprogress of the synthesis (Figure 3). Oncompletion, the synthesis process is saved onthecomputerforaudittrailpurposes(Figure4).

The third phase of the synthesis involvestestingoftheintegrityofthe0.22µmfilter.Thisis known as the Filter Pressure Test and is,again, driven by the Modular Lab PharmTracer® software. The only operatorinterventionrequiredistheremovalofthe0.22µm filter and needle from the product vial andputtingitintothewastebottlepriortothetest.Thetestisperformedbysubjectingthefilterto200 kPa of pressure. If pressure ismaintainedabove 100 kPa, the test is considered to havebeen successful and the product is sterile forpatientuse.However,ifthepressurefallsbelow100 kPa, the test is considered to have beenunsuccessful and there is a chance of the

product being unsterile. To rectify this, theproductneedstobedrawn‐upmanuallyina10mLsyringeandpassed throughanew0.22µmfilter into another sterile vial. To date, this hasneveroccurredatourcentre.Oncompletion,thefilter pressure test process log is saved on thecomputer for audit trail purposes. The traceproducedbythesoftwareisidenticaltotheonesproducedfortheCassettePressureTest(Figure2). After removing a 0.2 mL sample from theproduct for quality control purposes, theproduct is ready to be administered to thepatient.

AnalysisandQualityControl

Thequalitycontroloftheresultingproductis done by twomethods of Instant Thin LayerChromatography (ITLC) as well as HighPressureLiquidChromatography(HPLC).Theseare performed using the 0.2 mL sample takendirectly from the final Ga‐68 DOTATATEproduct.

InstantThinLayerChromatography(ITLC)

The ITLC test is used to determine thepercentage of Ga‐68 DOTATATE, Ga‐68impurities, and Ga‐68 colloid in the finalproduct.TheITLCpaperstripsarecountedinalaboratory gamma‐counter (PerkinElmerWizard2® Automated Gamma Counter,PerkinElmer Downers Grove, IL USA) and

Gallium-68

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ForDOTATAcitrate bCorporatGa‐68 (andGa‐6

Forcolloid,1(1:1)/68colloi1)andfr

8 DOTATATE

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entered intoersion 2010).the determinATE and Ga‐buffer (pH=5tion,EastHilRf=0.8–1), G68colloid(Rfthe determin1mol/LammITLC‐SG(Paid(Rf=0.0‐0reeGa‐68(Rf=

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Aslani A et al

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Generator Elution Percentage Yields

Elution Period

2011 (1.11 GBq) 2012 (1.85 GBq) 2013 (1.85 GBq)

Yie

ld (

%)

52545658

62646668

72747678

82848688

92949698

50

60

70

80

90

100

Figure5.Boxandwhiskersplotofthepercentageyieldforeach generator. The generators for the second and thirdyearswereidentical

Ge‐68Breakthrough

TheGe‐68breakthrough ismeasured inaneluted sample, on a weekly basis, after acomplete Ga‐68 decay (>48 hours). Themeasurements are carried out in a laboratorygamma‐counter (PerkinElmer Wizard2®Automated Gamma Counter, PerkinElmerDowners Grove, IL USA) and the data enteredinto and calculations made using a MicrosoftExcelversion2010spreadsheet.

ResultsA total of approximately 500 Ga‐68

DOTATATEsyntheseswereperformedbetweenMarch 2011 and April 2014 in our laboratory.Allsyntheseswerecarriedoutusing theEckert& Ziegler Eurotope’s Modular Lab PharmTracer® automated synthesis system andsoftware. All syntheses were performed in theDepartment of Nuclear Medicine, Royal NorthShore Hospital in a purpose‐builtradiopharmaceuticallaboratory.Generators

Generator yields for the three years areshown in Figure 5. The percentage yield wascalculatedastheactualyieldasapercentageofcalculatedastheactualyieldasapercentageoftheexpectedyield.Theaveragegeneratoryieldfor the first year was 81.3±0.2%. The yieldswere lower for second and third years at76.7±0.4%and75.0±0.3%correspondingtothelargergenerators.Theexpectedyield,asindica‐tedbythemanufacturer,isapproximately70%.Ga‐68DOTATATESyntheses

Although the synthesis cassettes used forGa‐68 DOTATATE had the same overall design

68Ga-DOTATATE Synthesis Yields

Synthesis Period

2011 (1.11 GBq) 2012 (1.85 GBq) 2013 (1.85 GBq)

Yie

ld (

%)

60

65

70

75

80

85

90

95

100

Figure 6. Ga‐68 DOTATATE synthesis yields for theautomatedsynthesissystem

and specifications there were some minormodificationsmadebythemanufacturerduringthethreeyears.Thesemodificationsweremadeas apart of ongoing improvements andqualitycontrol in response to user comments andfeedback. Some of these modificationsaddressed the connections on the cassettes toincreasereliabilitywhereassomeaddressedtheincrease in product yield by, for example,increasing the volumeof ethanol beingused toelute the final product from the C18 cartridge.These resulted in the cassette failure ratesdropping dramatically with time and are nowveryrare.Inaddition,thesealsoresultedintheaveragesynthesisyields increasingfrom81.8±0.4% in the firstyear to82.2±0.4%(P=0.42) inthesecondyearand87.9±0.4%(P<0.001)inthethirdyear(Figure5).

Duetothenatureofthe68Ge/68Gageneratorandthehalf‐lifeof271dayswhennew,enoughactivitycanbeobtainedtosynthesisesufficientGa‐68 DOTATATE for three patients persynthesis run (150MBqto200MBqperdose).As the generator decays this is reduced to twopatients after approximately one year andeventuallytoonepatient.Thisreducesthecost‐effectivenessof the synthesisprocess requiringthe purchase of a new generator. In order topredicthowlongthegeneratorwillbeeffectivein producing enough Ga‐68, a graph of finalproduct activity against the age of generator(Figure6)wasmadeandanequationofthelineof best‐fit was obtained. This took the averagesynthesis yields into account and produced arough estimate as to when a new generatorwould be required to maintain the minimumrequirednumber of patients per synthesis run.For example, with a 1.85 GBq generator areplacement is required at approximately 14

Gallium-68 DOTATATE Aslani A et al

Asia Oceania J Nucl Med Biol. 2014; 2(2):75-86. 83

Figure7.GraphtopredicttheactivityGa‐68DOTATATEsynthesisproductwithtime(1.85GBq68Ge/68Gagenerator)

months to provide enough product for morethanonepatientperrun.Germanium‐68Breakthrough

Thegermanium‐68breakthroughmeasuredduring the three years of use was constantlywellbelowtherecommendedlevelof0.001%ofthetotalradioactivity.Theactualaveragevalueswere8.6×10‐6%ofthetotalradioactivity.RadiochemicalQualityControl

The radiochemical purity of the finalproduct was measured using ITLC as well asHPLC.Theresultsdemonstrated(Figure7)that

Radiochemical Purity By ITLC

Synthesis Period

2011 2012 2013

Ga

-DO

TA

TA

TE

(%

)

97.0

97.5

98.0

98.5

99.0

99.5

100.0

Figure8.ITLCtesttodetermineradiochemicalpurityofGa‐68DOTATATE

theaverageradiochemicalpurityasdeterminedby ITLCwas above 99% for 2011 (99.6±0.2%)and2012(99.1±0.2%)andabove98%for2013(98.7±0.4%). The average radiochemical purityas determined by HPLC technique was above99.5%forallthreeyears(Figure9).Thevaluesfor 2011 and 2012 were 99.75±0.03% and99.71±0.04%, respectively. The 2013 period’sHPLC results were marginally higher at99.87±0.01%.

Theseresultswerewellabovetheminimumrecommendedvalueof91%(5).Thereasonforthe small decline in the ITLC‐measured puritylevel during the three years has not beenidentified.

Radiochemical Purity By HPLC

Synthesis Period

2011 2012 2013

Ga

-DO

TA

TA

TE

(%

)

95

96

97

98

99

100

Figure 9. HPLC test to determine radiochemical purity ofGa‐68DOTATATE

y=833.3e‐0.00x

R²=0.809

0

100

200

300

400

500

600

700

800

900

0 50 100 150 200 250 300

Activity(MBq)

GeneratorAge(Days)

ChangeinProductActivityWithTime

Aslani A et

84

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1. Ga‐68 (left)n the same patienedwithaPET(MIP) image

he Lu‐177 imageerior whole boately four hoursE ceased. Thity at the timeous differences ies the biodistribetheheadonthenstandard

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and Lu‐177 (ent, are shown.scannerandaMfrom the antere is a geometricody planar (2Ds after the infuhe estimateof scanning isn spatial resolubution is similaeLu‐177gamma

some signiic radioisotoscanning. Dudiolabellings is requhort periodhasanapprome.Thismeahesis, the neemadeaftersre, the synthnot withoutany errors os systems ar

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(right) DOTATA The Ga‐68 imaMaximumIntensrior orientationcmean of anterD) scans acquirusion of 8 GBqof the retain6GBq.Apart frution between tar. The rectanguacameraimagei

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The automdditional bedapted to beadiopharmacne example.ynthesisingLutomated syOTATATE usynthesis casssedforneurouetothepreromLu‐177, tammacameratient’s progigure11whesingaGa‐68eceived Lu‐1mages demootential ofherapeuticOTATATE. Tcquired apprOTATATE iifferencesinET cameraistributionsaAlthough

roduction faiwith the secoverable.Tetected befoyntheses.Thedjustments twere replaceancellationw

All threeromthesameor all threeuoted estimreakthroughwithin the req.01%. The hmeasuredinth

The synthrst two yearhis was amodifying theightly higher18 cartridgemore of theartridge willroduct yieldight modificahese modific

and reprodunthesesyieldsmated synthenefit that te used for theuticals(6).We have

Lu‐177DOTAynthesis syssing a Lu‐17sette. The Loendocrinetuesenceofagathepatientca.Thisisusegress. ThiserethepatienDOTATATE177 DOTATAnstrate thediagnosticLu‐177

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ucible and cas.esis systemsthey can behe synthesisLu‐177DOTArecently comATATEusingstem as th7 DOTATATELu‐177 DOTAumour(NET)amma‐raycocanbe imageefulformonitis demonstnthasbeendandsubsequATE therapytheranosticGa‐68 (PE(gammaimage sho

four hours aased. Allowesolutionbetmma cameysimilar.ere a numst all were aassettes anofthesefailummencementtifiedeitherttes or theresulting inlyrare.used wereer.Theaverae the manuf%. The geere generatofications of lakthrough leas0.0007%.were similarsed in the thy the mansoftware toethanol thr

ffect of thisconcentratedd thus increaufacturer alse synthesis cnly involved

Aslani A et al

85

anensure

have thee readilyof otherATATEismmencedthesamehe Ga‐68E‐specificATATE is)therapy.omponentdusingatoringthetrated indiagnosedentlyhasy. Theseimaging

ET) andcamera)

own wasafter thewing fortweentheera, the

mber ofssociatednd wereuresweret of thebyminorcassettesn patient

obtainedageyieldsfacturer’srmaniumors wereless thanevel that

r for thehird year.ufacturero pass aough thewas thaton the

asing theso madecassettes.how the



tubes are connected to the cassettes. Thesereduced the rate of leaks and cartridgesdislodging.

The actual Modular Lab System, with theexception of two occasions, performedflawlessly throughout the three years withoutany maintenance. However, the synthesiscassettes had relatively much higher failurerates. As a percentage of total number ofsyntheses carried out, these failure rates werevery low (16.4%). From the total of 82equipment failure events in the three yearperiod,onlyeight (9.8%) led toa full synthesisfailureandpatientsbeingdeferred.Thisrate isalsoverylowandalloccurredininitialteethingperiod. With more operator experience duringthesecondandthirdyears,someofthefailuresthat could have led to full synthesis failuresweresuccessfullyaverted.Inaddition,feedbacktothemanufacturerledtoanumberofareasofconcern being addressed – particularly thoserelatingtothecassettes.

The Ga‐68 DOTATATE productradiochemical purity was measured using theITLC as well as the HPLC techniques. Resultsshowed that not only was the synthesisedproduct above the minimum recommendedlevel, but also was of high purity. There was,however,amarginalandgradualdeclineinITLCvalues. We could not explain this decline. Theverylowvariationintheproductquality(Figure8, 9) demonstrated a consistent‐qualityproductionsystemthatcouldreliablyproduceaveryhighqualityproduct.

ConclusionTheautomatedsynthesissystemprovidesa

reliable and straightforward approach tosynthesising one particular short‐lived PET

radiopharmaceutical. Eckert & ZieglerEurotope’s Modular‐Lab Pharm Tracer® is aninnovative automated synthesis system thatperformsreliablywitharelatively low incidentof failures. Our system had a consistent andreliable Ga‐68 DOTATATE output with highpurity exceeding the minimum recommendedrequirements.ThesystemisGMP‐compliantandhas low maintenance and acceptable runningcosts.

References1. WanglerC,WanglerB,LehnerS,ElsnerA,Todica

A, Bartenstein P, et al. A universally applicable68Ga‐labelingtechniqueforproteins.JNuclMed.2011;52(4):586‐91.

2. OcakM,AntretterM,KnoppR, Kunkel F, PetrikM, Bergisadi N, et al. Full automation of (68)Galabelling of DOTA‐peptides including cationexchange prepurification. Appl Radiat Isot.2010;68(2):297‐302.

3. PetrikM,KnetschPA,KnoppR,ImperatoG,OcakM, von Guggenberg E, et al. Radiolabelling ofpeptides for PET, SPECT and therapeuticapplications using a fully automated disposablecassette system. Nucl Med Commun.2011;32(10):887‐95.

4. Decristoforo C, Knopp R, von GE, Rupprich M,Dreger T, Hess A, et al. A fully automatedsynthesis for the preparation of 68Ga‐labelledpeptides. Nucl Med Commun. 2007;28(11):870‐75.

5. European Association of Nuclear Medicine.Gallium Edotreotide Injection Draft Monograph.Pharmeuropa.2011;23(2):310‐313.

6. PetrikM,KnetschPA,KnoppR,ImperatoG,OcakM, von Guggenberg E, et al. Radiolabelling ofpeptides for PET, SPECT and therapeuticapplications using a fully automated disposablecassette system. Nucl Med Commun.2011;32(10):887‐95.

68 dotatate production with automated pet synthesis system

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