Clopidogrel Pharmacogenetics: Ready for Prime-Time? Stephen D Wiviott MD Brigham and Women’s Hospital TIMI Study Group Harvard Medical School

Conflicts of Interest Research Funding: Eli Lilly, Daiichi Sankyo, Merck/Schering Plough Consulting, CME Speaking Honoraria: Eli Lilly, Daiichi Sankyo, sanofi-aventis, Schering Plough, Astra Zeneca, ARENA, Novartis, Bayer

Why do we give patients clopidogrel? It’s NOT MAGIC, It’s drug effect: Clopidogrel is metabolized to an active metabolite The active metabolite binds to platelets and inhibits platelet activation/aggregation Inhibition of platelet aggregation results in less platelet mediated thrombosis Less platelet mediated thrombosis results in fewer clinical ischemic events in patients

Why Genetics Matters When Choosing Antiplatelet Therapy Reduced Function Alleles of CYP 2C19 Associated with less efficient metabolism of clopidogrel Associated with less platelet inhibition on clopidogrel Associated with worse ischemic outcomes in ACS with PCI Less effect in conditions with less clopidogrel effect (AF, Chronic CAD) Not associated with worse outcomes with more potent agents

Clopidogrel → Active Metabolite N S O Cl CH3 C Compliance Pro-drug Clopidogrel Environmental Drug-Drug Genetics Hydrolysis (Esterases) 85% Inactive Metabolites hCE1 Active Metabolite HOOC * HS N O Cl OCH3 Oxidation (Cytochrome P450) CYPs: 1A2 2B6 2C19 CYPs: 3A 2B6 2C9 2C19 S CH3 C Kurihara A. et al. Drug Metab. Rev. 37(S2): 99 (2005) Tang M. et al. JPET 319: 1467-1476 (2006) 5 5

GWAS of Platelet Aggregation in Response to Clopidogrel 14 1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 18 20 22 CYP2C18-CYP2C19-CYP2C9-CYP2C8 Cluster Chromosome -log10 (P Value) GWAS = genome-wide association study. Shuldiner A, et al. JAMA. 2009;302:849-857. 6

GRAVITAS: Pharmacodynamic Outcomes Effect of study drug in patients with high OTR Events in Patients Treated with 75 mg However, it appeared that high-dose clopidogrel provided a variable and modest reduction in on-treatment reactivity compared with standard dose therapy. High-dose provided variable and modest reduction in on-treatment reactivity (OTR) Post-hoc: “responders” with events had OTR clustered just below 230 PRU Price MJ, AHA 2010

Predicted CYP2C19 Metabolic Phenotype Is A Major, Independent Predictor of High OTR Post-PCI Ultra, Ultra-rapid; Ext, Extensive; Int, Intermediate Adjusted for BMI, gender, age, current smoking, CrCl<60 ml/min, DM, CHF, HTN, hyperlipidemia

Results: Influence of PON1, CYP2C19, and ABCB1 on the Primary Endpoint P < 0.0013 for statistical significance On-Treatment Reactivity at Screening (12-24 hrs post-PCI) N=1013 SNP R2 PON1 Q192R 0.2% P = 0.42 CYP2C19*2 6.5% P = 2.2 x 10-15 CYP2C19*17 0.5% P = 0.08 ABCB1 3435 CT 0.1% P = 0.61 Change in On-Treatment Reactivity at 30 days N=714 SNP R2 PON1 Q192R 0% P = 0.71 CYP2C19*2 5.1% P = 1.4 x 10-5 CYP2C19*17 1.2% P = 0.02 ABCB1 3435 CT P = 0.40 Co-dominant model, adjusted for tx and characteristics associated with OTR.

Effects of CYP2C19*2 and *17 Combined ACC 2010 Montalescot FINAL_030810 Effects of CYP2C19*2 and *17 Combined N=445 patients; 24 hours post 600-mg clopidogrel loading dose Slow Normal Fast Frequency 3% 3.5% PRI=platelet reactivity index; VASP=vasodilator-stimulated phosphoprotein. Frére C, et al. J Thromb Haemost. 2009;7(8):1409-1411. 10 10

CYP2C19*2 and Clinical Outcomes With Clopidogrel ACC 2010 Montalescot FINAL_030810 ACC 2010 Montalescot CE Approved_030210 CYP2C19*2 and Clinical Outcomes With Clopidogrel Mega/p 359/Figure 3A Collet/p 314/Figure 3A Simon/p 372/Figure 2B 3 Collet JP, Hulot JS, Pena A, et al. Cytochrome P450 2C19 polymorphism in young patients treated with clopidogrel after myocardial infarction: a cohort study. Lancet. 2009;373(9660):309-317. Simon T, Verstuyft C, Mary-Krause M, et al; French Registry of Acute ST-Elevation and Non-ST-Elevation Myocardial Infarction (FAST-MI) Investigators. Genetic determinants of response to clopidogrel and cardiovascular events. N Engl J Med. 2009;360(4):363-375. *Death, nonfatal myocardial infarction, or urgent revascularization. †Composite of death from cardiovascular causes, myocardial infarction, or stroke. 1Reprinted with permission from Collet JP, et al. 2009;373(9660):309-317. 2Reprinted with permission from Mega JL, et al. N Engl J Med. 2009;360(4):354-362. 3Reprinted with permission from Simon T, et al. N Engl J Med. 2009;360(4):363-375. 11 11

CYP2C19 and Treatment with Clopidogrel Predominantly for PCI Hazard Ratio (95% CI) P Value N=9,685 91.5% PCI CVD, MI, or Stroke 1 or 2 CYP2C19 RFA vs Non-Carriers 1.57 (1.13-2.16) 0.006 1 CYP2C19 RFA vs Non-Carriers 1.55 (1.11-2.17) 0.01 2 CYP2C19 RFA vs Non-Carriers 1.76 (1.24-2.50) 0.002 1 CYP2C19 RFA vs Non-Carriers 2 CYP2C19 RFA vs Non-Carriers 2.67 (1.69-4.22) 3.97 (1.75-9.02) <0.001 0.001 Stent Thrombosis 1 or 2 CYP2C19 RFA vs Non-carriers 2.81 (1.81-4.37) <0.0001 N=5,894 1.0 2 5 10 Risk Lower with CYP2C19 Variant Risk Higher with CYP2C19 Variant Mega JL, Simon T, Collet JP et al. JAMA 2010;304(16):1821-30 . RFA=reduced-function allele

http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm203888.htm#ds

CURE Genetics Substudy No association seen between CYP2C19 and outcomes in clopidogrel arm. BUT, patients treated conservatively (only ~15% rate of PCI). Pare et al. NEJM 2010; 363(18):1704-14. 14

CYP2C19 and Treatment with Clopidogrel CVD, MI, or Stroke: Carriers of 1 or 2 CYP2C19 Variants vs Non-Carriers Est. Hazard Ratio (95% CI) Meta-Analysis (91.5% PCI) 1.57 (1.13-2.16) PLATO (66% planned PCI) Meta-Analysis + PLATO 1.43 (1.11-1.84) CHARISMA (stable CAD or risk factors) CURE (15.5% PCI) Meta-Analysis + PLATO + CURE + CHARISMA 1.32 (1.07-1.63) 0.5 1.0 1.5 3.0 Risk Lower with CYP2C19 Variant Risk Higher with CYP2C19 Variant Mega JL, Simon T, Collet JP et al. JAMA 2010;304(16):1821-30 .

Clopidogrel Reloading Among Genetic Carriers Bonello et al JACC 2010

Study Design R Clopidogrel Dose A Clopidogrel Dose B Clopidogrel Schedule 0 weeks 2 weeks 4 weeks 6 weeks 8 weeks Visit 1 Visit 2 Visit 3 Visit 4 Visit 5 Stable CAD Patients on Clopidogrel 75 mg per day (>4 Weeks and <6 Months Post-ACS or PCI) Resume Pre-study Antiplatelet Medication R Clopidogrel Dose A Clopidogrel Dose B Clopidogrel Dose C Clopidogrel Dose D Genetic Sample Platelet Function Testing (VASP & VerifyNow) Platelet Function Testing (VASP & VerifyNow) Platelet Function Testing (VASP & VerifyNow) Platelet Function Testing (VASP & VerifyNow) Platelet Function Testing (VASP & VerifyNow) 17

 Clopidogrel in CYP2C19*2 Heterozygotes vs. 75 mg in Non-Carriers Non- Carriers CYP2C19*2 Heterozygotes PRUdiff +61 P<0.001 PRUdiff +24 P=0.02 PRUdiff -10 P=0.31 PRU PRUdiff -37 P<0.001 Clopidogrel Daily Dose (mg) Squares represent the means and vertical lines the 95% confidence intervals. Differences are reported as least squares differences.

Platelet Reactivity with  Clopidogrel Non- Carriers CYP2C19*2 Heterozygotes CYP2C19*2 Homozygotes PRU Clopidogrel Daily Dose (mg) Squares represent the means and vertical lines the 95% confidence intervals.

Alternative Treatments: Pharmacodynamics Clopidogrel Prasugrel 100 Storey RF, et al. JACC 2010; 122(11):1056-67. Clopidogrel Ticagrelor 100 200 300 400 500 Peak 235 PRU 80 60 IPA (%) 40 20 Clopidogrel Responder Clopidogrel Non-responder *Responder = 25% IPA at 4 and 24 h -20 Brandt JT et al., Am Heart J 2007;153:e9-e16.

TRITON-TIMI 38 Genetic Substudy 1477 Pts w/ ACS and Planned PCI Clopidogrel 1466 Pts w/ ACS and Planned PCI Prasugrel CYP2C19 Reduced-Function Allele Carriers Non-carriers of a CYP2C19 reduced function allele Non-carriers Carriers CV Death, MI, or Stroke (%) CV Death, MI, or Stroke (%) HR 1.53 (95% CI 1.07-2.19) P=0.014 P=0.046 for interaction between benefit of prasugrel vs. clopidogrel and CYP2C19 genotype Mega JL, Close SL, Wiviott SD et al. Circulation 2009; 119:2553-2560. Matetzky S, Shenkman B, Guetta V, et al. Clopidogrel resistance is associated with increased risk of recurrent atherothrombotic events in patients with acute myocardial infarction. Circulation. 2004;109:3171-3175.

PLATO Genetic Substudy: Ticagrelor vs Clopidogrel CYP2C19 non-carriers 14% RRR, P=NS 1.2% abs Δ, NNT 84 CYP2C19 LOF Carriers 23% RRR, P=0.038 2.6% abs Δ, NNT 39 Pinteraction=0.46 At 30 days: 4% RRR in non-carriers vs. 27% RRR in CYP2C19 LOF carriers Wallentin L, et al. Lancet 2010; 376(9749):1320-8

Clopidogrel Label Tests are available to identify a patient's CYP2C19 genotype and can be used as an aid in determining therapeutic strategy. Consider alternative treatment or treatment strategies in patients identified as CYP2C19 poor metabolizers. Note increase or alternative agents

ACCF/AHA Clinical Alert Approaches to the FDA Boxed Warning Recommendations Follow existing ACCF/AHA guidelines for antiplatelet therapy Use clinical judgment to assess importance of clopidogrel response variability for the individual patient Be aware that genetic variability in CYP enzyme alters clopidogrel metabolism Areas of uncertainty Information regarding predictive value of pharmacogenomic testing is limited Evidence base is insufficient to recommend routine genetic or platelet function testing PPI = proton pump inhibitor Holmes DR Jr, et al. Circulation. 2010;122:537-557.

Nissen, S JAMA 2011 “Overall, no significant association between genotype and cardiovascular events.” --Holmes, MV et al JAMA 2011

Conservatively managed Magnitude of PGx Interaction Will Depend on Relative Benefit of Clopidogrel 85% Risk Reduction Conservatively managed Invasively managed 0.14 Placebo HR 1.25 HR 0.80 Aspirin Monotherapy 0.12 HR 6.67 HR 0.15 0.10 0.08 Clopidogrel CV Death, MI, Stroke 0.06 0.04 Dual Antiplatelet Therapy 0.02 0.0 3 6 9 12 Months of follow-up CURE. NEJM 2001;345:494-502 STARS. NEJM 1998; 339: 1665.

CYP2C19 and Treatment with Clopidogrel Mega JL et al. & Sabatine MS. CVD, MI, or Stroke: Carriers of 1 or 2 CYP2C19 Variants vs Non-Carriers Est. Hazard Ratio (95% CI) Meta-Analysis (91.5% PCI) 1.57 (1.13-2.16) PLATO Invasive Strategy (77% PCI) PREDOMINANTLY INVASIVE 1.48 (1.14-1.91) P heterogeneity = 0.013 CURE (15.5% PCI) CHARISMA (stable CAD or risk factors) PLATO Conservative Strategy (21% PCI) PREDOMINANTLY CONSERVATIVE 0.98 (0.80-1.19) 0.5 1.0 1.5 3.0 Mega JL et al. & Sabatine MS. JAMA 2010;304:1821 Risk Lower with CYP2C19 Variant Risk Higher with CYP2C19 Variant Wallentin. Lancet 2011; 377:637

Ready for Prime Time? Little value for PON-1 or ABCB1 at this time CYP 2C19 Testing Associated with less metabolism of clopidogrel Associated with less platelet inhibition Associated with worse clinical outcomes in ACS with PCI on clopidogrel Not associated with worse outcomes on prasugrel or ticagrelor Major outcomes trials missing, but strong associative evidence suggests value to use