A randomized comparison of platelet reactivity in patients after treatment with various commercial clopidogrel preparations: The CLO-CLO trial = Étude randomisée comparant la réactivité plaquettaire des patients traités par diverses prépa

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A

randomized

comparison

of

platelet

reactivity

in

patients

after

treatment

with

various

commercial

clopidogrel

preparations:

The

CLO-CLO

trial

Étude

randomisée

comparant

la

réactivité

plaquettaire

des

patients

traités

par

diverses

préparations

commerciales

de

clopidogrel.

Étude

CLO-CLO

Markus

Oberhänsli ,

Cédric

Lehner ,

Serban

Puricel ,

Sonja

Lehmann ,

Mario

Togni ,

Jean-Christophe

Stauffer ,

Gérard

Baeriswyl ,

Jean-Jacques

Goy

∗

,

Stéphane

Cook

ServicedeCardiologie,HôpitalCantonal,1700Fribourg,Switzerland

KEYWORDS Antiplatelet; Aspirin; Clopidogrel; Percutaneous coronaryintervention Summary

Background.—Thesaltlinkedtotheclopidogrelmoleculeingenericpreparationsissuspected

toaffectitsclinicalefﬁcacy.Thereisalackofinformationaboutinhibitionofplateletreactivity bygenericpreparations.

Aims.—Tocomparetheeffectoforiginalclopidogrel(clopidogrelbisulphate[Plavix®_]),_generic

clopidogrelpreparations(clopidogrelhydrochloride[Clopidogrel-Mepha®_];_clopidogrel_besylate [ClopidogrelSandoz®_])_and_prasugrel_(Eﬁent®₎_on_platelet_reactivity_in_patients_with_coronary arterydisease.

Methods.—Patientswith coronaryarterydiseasetreatedwithstents received,inarandom

sequence,originalclopidogrelbisulphate,clopidogrelhydrochlorideandclopidogrelbesylate. PlateletfunctionwasassessedwiththeMultiplateanalyserafteraninitialloadingdose(600mg) andatday10aftereachtreatmentperiod.Prasugrelwasgivenforanother10days.Anadenosine diphosphate(ADP)testvalue<46antiaggregationunits(U)wasdeﬁnedastherapeuticplatelet inhibition.

Results.—Sixtypatients(meanage69±10years;50men)wererandomized.Original

clopido-grelbisulphate,clopidogrelhydrochlorideandclopidogrelbesylateprovidedsimilarinhibition

Abbreviations: ADP,adenosinediphosphate;PCI,percutaneouscoronaryintervention;U,antiaggregationunits. ∗_{Corresponding}_author.

E-mailaddress:jjgoy@goyman.com(J.-J.Goy).

Published in "$UFKLYHVRI&DUGLRYDVFXODU'LVHDVHV±" which should be cited to refer to this work.

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ofplateletreactivitywith valuesof31±25,33±28and28±23 U,respectively(Pnot sig-niﬁcant).Prasugrel providedbetterinhibitionofplatelet function(10±11 vs.31±25U for clopidogrelbisulphate;P<0.001).AnADPtestvalue>46Uwasmeasuredin11patients(18%) withclopidogrelbisulphate,13(22%)withclopidogrelbesylateand13(22%)withclopidogrel hydrochloridecomparedwithonlyone(2%)withprasugrel.Conclusion Genericclopidogrel preparationsprovidedsimilarinhibitionofplateletreactivitytooriginalclopidogrelbisulphate, althoughprasugrelwasmoreefﬁcient.

MOTSCLÉS Clopidogrel; Aspirine; Angioplastie coronaire; Thrombosedestent Résumé

Objectifs.—Lebutdecetteétudeestdecomparerl’effetsurl’agrégationplaquettairedela

moléculeoriginaledeclopidogrel (clopidogrelbisulfate[Plavix®_]) _aux_molécules_génériques (clopidogrelbesylate[clopidogrelSandoz®_]_et_clopidogrel_{hydrochloride}_{[clopidogrel-Mepha}®_]) etauprasugrel(Eﬁent®_).

Historique.—Onsuspectequeleselutilisépourlierlamoléculedeclopidogrelpourraitchanger

l’efﬁcacité dumédicamentetpar làmême avoir unimpact sursonactivité d’antiagrégant plaquettaires.Aucuneinformationn’estactuellementdisponible.

Méthode.—Despatientsavecmaladiecoronairetraitésparangioplastieetmiseenplacede

stentontétéinclusdanscetteétude.Ilsontrec¸udemanièrerandomiséelestroismoléculesde clopidogrel,àsavoirleclopidogrelbisulfate(Plavix®_),_le_clopidogrel_{hydrochloride} (Clopidogrel-Mepha®₎_et_le_clopidogrel_besylate_(Clopidogrel_Sandoz®₎_pour_une_durée_de_dix_jours_chacune. Aprèscettepériode de30jourslesmaladesétaientplacéssousprasugrelpourunenouvelle périodededixjours.L’agrégationplaquettaireaétémesuréeaprèsladosedecharge(600mg) etaprèschaqueintervalledetraitementdedixjours.UnappareildetypeMultiplateAnalyzera étéutilisépourévaluerlafonctionplaquettaire.Unevaleurd’ADPinférieureà46Ureprésentait uneantiagrégationplaquettaireefﬁcace.

Résultats.—Soixantepatients(50hommes)avecunâgemoyende69±10ansontétéinclus.Il

n’yavaitpasdedifférencesignificativedel’activitéantiagréganteentrelestroispréparations declopidogrel,leclopidogrelbisulfate,leclopidogrelhydrochlorideetleclopidogrelbesylate avecdesvaleursd’ADPde,respectivement,31±25U,33±28et28±23U(p=NS).Leprasugrel estsignificativementplusefficacequel’ensembledesclopidogrel;10±11Uvs.31±25U.Une valeurd’ADPsupérieureà46Uaétéobservéechez11maladesavecleclopidogrelbisulfate (19,6%),12malades(21,1%)avecleclopidogrelbesylateet13malades(23,2%)avecle clopid-ogrelhydrochloride.Seulunpatient(2,3%)avecleprasugrelavaitunevaleurd’ADPsupérieure à46U.

Conclusion.— Leniveaud’antiagrégationplaquettaireobtenuaveclespréparationsgénériques

declopidogrelestcomparableàceluiobtenuaveclaformeoriginalealorsqueleprasugrelest plusefﬁcace.

Background

Dualantiplatelettherapywithaspirinandthienopyridineis essentialafter coronaryinterventionand stentplacement

[1—3].Thelevelofon-treatmentplateletreactivityis asso-ciatedwithlong-termadversecardiovascular events after percutaneouscoronaryintervention (PCI)[4].Theefﬁcacy of such treatment is largely inﬂuenced by interindividual variabilityinthepharmacodynamicresponsetoclopidogrel

[5,6].Inaddition,clopidogrelrecentlybecamegeneric; sev-eralcommercial preparations are now available in which clopidogrelis linked toa saltthat might change its clini-calefﬁcacy. Noneof thesegeneric preparationshas been validated other then by pharmacodynamic tests. In this prospectivetrial,weuseaplateletfunctiontest[7]to com-pare,in routineclinical practice,plateletreactivity after randomizedadministrationoftwonewgenericclopidogrel preparations (clopidogrel besylate [Clopidogrel Sandoz®_]

and clopidogrel hydrochloride [Clopidogrel-Mepha®_]) _and

theoriginalpreparation(clopidogrelbisulphate[Plavix®_]).

Methods

Patient

selection

and

study

design

Consecutive patients withischaemic heart disease under-going PCI with stent implantation were considered for enrolment in this trial. PCIwasperformed usingstandard techniquesbythefemoralor radialroute.Exclusion crite-ria were: cardiogenic shock; pregnancy; intolerance to aspirin, thienopyridine or contrast media; poor compli-ance; active bleeding;inability togiveinformed consent; anaemia;thrombocytopenia;moderate-to-severerenal fail-ure (deﬁned as creatinine clearance of 30 to 60mL/min and<30mL/min, respectively);plannedsurgery;or inabil-itytohavefollow-upinformation.Patientsalreadytreated

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Figure1. Trialdesign.ADP:adenosinediphosphate;PCI:percutaneouscoronaryintervention.

with thienopyridines were equally excluded. All patients gavetheirwritten informedconsentand theprotocolwas approved by the hospital’s ethical committee. The con-trol group was composed of 50 healthy medication-free adults.Thesubjectsinthecontrolgroupdidnotreceiveany antiplatelettherapy.Therationalebehindhavingacontrol groupwastoconﬁrmthevalidityoftheplateletaggregation test.

This wasasingle-blind randomizedtrialwithcomplete crossover (Fig. 1). The primaryendpoint was therapeutic antiaggregation deﬁned asa value of<46 antiaggregation units(U)onwholebloodplateletfunctiontesting. Random-ization was achieved with envelopes, the patients being assignedtooneofthethreeclopidogrelgroupsfor10days, thencrossedovertoanotherclopidogrelmolecule,asshown inFig.1.

Percutaneous

coronary

intervention

and

antiplatelet

therapy

management

AtthetimeofPCI,allpatientsreceived500mgofaspirinin additiontoeitherunfractionatedor low-molecular-weight heparin.Aloading dose(600mg)of clopidogrel wasgiven at the end of the procedure. The clopidogrel molecule waschosen at randombetween original clopidogrel bisul-phate, clopidogrel hydrochloride or clopidogrel besylate. Aftertreatmentinitiation,theclopidogrelpreparationwas givenfor10daysatadoseof75mg/day.Atdays10and20, theclopidogrelmoleculewaschangedtoanewmolecule,so thatafter30daysallpatientshadreceivedallclopidogrel preparations for 10 days.After this initial 30-day period, aloadingdose(60mg)ofprasugrelwasgiven,followedby amaintenancedoseof 10mg/dayfor 10days.Afterthese 40 days,the patientwasleft for 1year on thedrug that providedthelowestplateletreactivity.

Platelet

reactivity

assessment

Plateletreactivitytestingofclopidogrelandprasugrelwas performedusingtheMultiplateanalyser(Dynabyte,Munich, Germany).Thismethod hasbeenapprovedfor human use by the United States Food and Drug Administration. The assayis made upof two distinct silver electrodesensors. The changes in the electrodes’ impedance after platelet adhesionisdetectedbythesensorandallowsaggregation unitstobecalculated.Thevariablesevaluatedare: maxi-malaggregation,velocity(steepnessofthecurve)andarea underthecurve(AUC,AUmin),calculatedfromthemean valuesof thetwo curves.The final result is expressed in units(U),with1Udefinedas10AUmin.Plateletreactivity wasassessed6hoursafter theloadingdoseof clopidogrel andevery10daysatthetimeoftheswitchofthe clopido-grelpreparation.Efficientplateletinhibitionwasdefinedas anadenosinediphosphate(ADP)testvalue<46U.Patients withvalues>46Ureceivedaloadingdoseofanother clopid-ogrelpreparationonthesameday,withrepeatedplatelet functionmeasurementafter6hours.

Forthetrial,theoperatordeterminingplateletreactivity wasblindedtothetreatment arm,patientcharacteristics andbiomarkers.

Statistical

analyses

We performeda poweranalysis that concludedthe inclu-sionof 60 patients at resistance rates of 15% for original clopidogreland40%forthegenericclopidogrelpreparations wouldyieldastatisticalpowerof88%atasigniﬁcancelevel ofalphaequalto0.05foratwo-tailedanalysis.Thepower analysiswasperformedforproportionsofpairedsamples.

Continuousvariables arepresentedasmean±standard deviation and after conﬁrmation of a normal distribution (QQplot).Tocompareantiaggregationunitsachievedwith

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Table1 Patientcharacteristics.

Studycohort Controlgroup (n=60) (n=50) Men 50(83) 12(24) Age(years) 68±9 39±10 Bodymassindex(kg/m2₎ ₂₇_±₅ ₂₂_±₄

Diabetes 20(33) 0 Hypertension 18(30) 2(4) Currentsmoker 14(23) 14(28) Formersmoker 24(40) 3(6) Dyslipidaemia 42(70) 5(10) Familyhistory 22(37) 13(26) Renalfailure 4(7) 0 Heartfailure 6(10) 0 STEMI 0 0

Acutecoronarysyndrome 17(28) 0 Stableangina 28(47) 0 Silentischaemia 15(25) 0

Data are mean±standard deviation or number (%). STEMI: ST-segmentelevationmyocardialinfarction.

thedifferentclopidogrelpreparations,thepairedttestwas employed.Categoricalvariablesarepresentedasnumbers andpercentages.Weconsidered aPvalue<0.05as signiﬁ-cant.SPSSsoftware,version18(SPSSInc.,Chicago,IL,USA) wasusedforstatisticalanalyses.

Results

Sixtypatients(50menand10women)withameanageof 69±10years wereincluded. Thecontrol groupwas com-posedof50healthyadults(22%men)whowerenottaking anymedicationandhadameanageof39±10years.

PatientcharacteristicsareshowninTable1.Brieﬂy,the patientshadtheusualriskfactorsexpectedinpatientswith ischaemicheartdisease.Baselinecoagulationvariablesand platelet reactivity were normal for all patients (platelet count 225±57g/L, prothrombin time 92±13%, activated partialthromboplastintime33±4seconds).

After the loading dose, platelet reactivity was the same for all clopidogrel preparations, witha mean value of 17±15 U for clopidogrel bisulphate, 23±16 U for clopidogrelhydrochlorideand21±16Uforclopidogrel besy-late (P=0.43; Fig. 2). After 10 days of treatment, there were no signiﬁcant differences between the clopidogrel preparations, with a mean value of 31±25 U for clopid-ogrel bisulphate, 33±28 U for clopidogrel hydrochloride and 28±23 U for clopidogrel besylate (P=0.69; Table 2;

Fig. 3). There were no statistical differences between thegroups:clopidogrelbisulphatevs.clopidogrelbesylate (P=0.58);clopidogrelbisulphatevs.clopidogrel hydrochlo-ride(P=0.34);andclopidogrelhydrochloridevs.clopidogrel besylate(P=0.14)(Fig.3).Forallclopidogrelpreparations, thehigherplateletreactivityinhibitionwasobtainedafter theloadingdose,asshowninTable2.Eleven(18%)patients showedvalues>46Uforclopidogrelbisulphate,13patients

Figure2. Distributionofplateletreactivityafterloadingdose.

Figure3. Distributionofplateletreactivityafter10daysof

treat-ment.

(22%)forclopidogrelhydrochlorideand13patients(22%)for clopidogrelbesylate(Table2).

Prasugrelwassigniﬁcantlymoreefﬁcientthanany prepa-ration of clopidogrel, with a mean value of 10±11 U (P<0.001);onlyonepatient(2%)exhibitedavalue>46U.

Discussion

Stent thrombosis remains a partially unsolved problem, associated with a high rate of morbidity and mortality afterPCI.Asigniﬁcantlyhigherrateofstentthrombosisin patients with higher on-treatment platelet reactivity has been reported, with an incidence of up to 3% [8]. Also, usingthe P2Y12point-of-careassay, highplatelet reactiv-ity(P2Y12reactivityunits>230)wasassociatedwithhigher rates of death, myocardial infarction or stent thrombo-sis.Thus,asclopidogrelhasbecomegeneric, withseveral commercial preparations now available, it is of critical importancetodemonstratethatsimilarinhibitionofplatelet reactivitycanbeachievedwiththesepreparations.

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Table2 Meanantiaggregationvaluesforthetreatedpopulationandcontrols(adenosinediphosphatetest).

n MeanU±standarddeviation %ofpatientswith ADPtestvalue<46U Notreatment Loadingdose Maintenancedose

Clopidogrelbisulphate (Plavix®₎ 60 17±15 31±25 82 Clopidogrelbesylate (Clopidogrel Sandoz®₎ 60 21±16 28±23 78 Clopidogrel hydrochloride (Clopidogrel-Mepha®₎ 60 23±16 33±28 78 Prasugrel(Eﬁent®₎ ₆₀ ₆_±₁₆ ₁₀_±₁₁ ₉₈

Controlgroup(no treatment)

50 61±17

ADP:adenosinediphosphate;U:antiaggregationunits.

Inthisprospectivetrial,weshowedthatallpreparations of clopidogreltested provide similarinhibitionof platelet reactivityandthatgenericpreparationscanbeusedsafely afterPCI.Wefound 36patients(21.9%)takingany clopid-ogrelwho had an ADP test value>46 U;they have to be consideredasclopidogrelresistant.Thisisinlinewith pre-viousreportsshowingclopidogrelresistancein23to40%of patients[9].Ourresults showawideresponsevariability; thus aclear cut-offvalue todeﬁne trueclopidogrel resis-tancehasstilltobedetermined,asinotherreportedtrials

[10].Furthermore,plateletreactivityis nottheonly vari-ableinvolved in stent thrombosis-implantationtechnique, angiographicresultandclinicalstatus(suchasacute coro-narysyndromeorcomorbiditiessuchasdiabetes)alsoaffect therateofstentthrombosisandmorbidity[11].

It has also beenrecently shown that the incidence of majoradverseclinical events, includingstentthrombosis, ishigherwhen plateletreactivityisstillpresentata high value(>46U)whentheMultiplateanalyserisused[4,8].

Our data conﬁrm the results of two previous trials comparing original clopidogrel with generic clopidogrel preparations in healthy subjects [12,13]. These trials showedsimilarsafetyproﬁlesandmetthecriteriafor phar-macokineticbioequivalence.Onlyhealthyvolunteerswere included in these studies, which is a limitation because patientswithatheroscleroticdiseasehaveahigherdegreeof variabilityintheirresponsetoclopidogreldueto comorbidi-tiesandmultiplecomedications.Ourtrial,bycomparison, wasconductedinareal-lifesetting,withpatientswhohad aclinicalindicationforantiplatelettherapy.

In addition, our data conﬁrm the value of prasugrel asapotentantiplatelet agent.Prasugrel,likeclopidogrel, requires conversion to an active metabolite before bind-ing to the platelet P2Y12 receptor toconfer antiplatelet activity.PrasugrelinhibitsADP-inducedplateletaggregation more rapidly, more consistently and to a greater extent than standard and higher doses of clopidogrel in healthy volunteers and in patients with coronary artery disease undergoingPCI [14—16].When antiaggregation is of criti-calimportance(patientswithmultiplestenting,multivessel

diseaseorleftmainPCI,diabeticpatients,etc.),clopidogrel resistance can be avoided with prescription of prasugrel, alongwithveryefﬁcientinhibitionofplateletreactivity.

Study

limitations

The main limitation of this trial was the small number of patients. However, it seems obvious that a signiﬁcant difference between the original and generic clopidogrel preparations would require a considerable number of patientstoshowverylittledifference.Moreover,any bene-ﬁtfavouringoneofthepreparationswouldnotnecessarily becorrelatedwithbetterclinicaloutcome.Astheplatelet reactivitytesthaslimitations,itsroutineuseinclinicsalso haslimitationsandresultsshouldbeinterpretedinthe set-tingoftheclinicalsituation.Finally,therearenolarge-scale trialsthatshowclinicaloutcomeimprovementafter adap-tationofantiplatelet therapy usingtheplateletreactivity test[8].

Disclosure

of

interest

Theauthorsdeclarethattheyhavenoconﬂictsofinterest concerningthisarticle.

Acknowledgements

This trialwassupported bythe FondsScientiﬁque Cardio-vasculaire,Fribourg.

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