Primary Results From Genotype Information and Functional Testing

A Prospective Pharmacogenomic Analysis of Clopidogrel Therapy

GIFTACC/i2 2011

Matthew J. Price MD, Sarah S. Murray PhD, Dominick J. Angiolillo MD, PhD, Elizabeth Lillie PhD, Nicholas Schork PhD,

Paul S. Teirstein MD, Eric J. Topol MD

Disclosures

Consulting fees/honoraria: Bristol-Myers Squibb/sanofi-aventis, Accumetrics, DSI/Lilly & Co., Quest Diagnostics, AstraZeneca, The Medicines Company, Medicure

Speaker Honoraria: DSI/Lilly, The Medicines Company, Quest, Nanosphere

Research Support: Bristol Meyers Squibb/sanofi-aventis, Quest Diagnostics, Accumetrics,

GIFT was supported through an investigator-initiated grant from BMS/sanofi aventis

GRAVITAS was sponsored by Accumetrics.

Background

• Loss of function (LoF) alleles of the CYP2C19 gene have been shown to influence clopidogrel pharmacokinetics and pharmacodynamics.

• The Plavix® boxed warning suggests alternative dosing regimens (150 mg daily) in CYP2C19 poor metabolizers based on a small PK/PD study in healthy subjects.

• The relationship between genetics, clopidogrel dosing and platelet function over time has not been examined within a prospective, multicenter, randomized trial.

Paraoxonase 1 (PON1): A Novel Determinant of Clopidogrel PK, PD, and Outcomes After PCI?

• PON1 QQ192 homozygotes: lower activity, lower concentration of AM, lower inhibition• HR for ST = 12.92 (95% CI, 4.5-95.5)• No association between CYP2C19, platelet inhibition, and outcomes• The role of PON1 needs confirmation by external validation

Bouman HJ, Schomig E, van Werkum JW, et al. Nature Medicine 2011; 17(1):110-6

Standard-Dose Clopidogrel†

clopidogrel 75-mg/dayStandard-Dose Clopidogrel†

clopidogrel 75-mg/day

High-Dose Clopidogrel†

clopidogrel 600-mg, thenclopidogrel 150-mg/day

PRU ≥ 230

High On-treatment Reactivity

Yes No

N = 1109 N = 586

Normal On-treatment Reactivity

Random SelectionR

N = 1105

Primary Efficacy Endpoint: CV Death, Non-Fatal MI, Stent Thrombosis at 6 moKey Safety Endpoint: GUSTO Moderate or Severe Bleeding at 6 mo

Pharmacodynamics: Repeat VerifyNow P2Y12 at 1 and 6 months

†placebo-controlled All patients received aspirin (81-162mg daily)*Peri-PCI clopidogrel per protocol-mandated criteria to ensure steady-state at 12-24 hrs

Price MJ et al , JAMA 2011

Elective or Urgent PCI with DES*

N=5429 VerifyNow P2Y12 Test 12-24 hours post-PCI

GRAVITAS Study Design

Primary Endpoint: CV Death, MI, Stent Thrombosis

Observed event rates are listed; P value by log rank test.

Price MJ et al, JAMA. 2011;305(11):1097-1105

GRAVITAS: Pharmacodynamic Outcomes

Effect of study drug in patients with high OTR

• High-dose provided variable and modest reduction in on-treatment reactivity (OTR)• Post-hoc: “responders” with events had OTR clustered just below 230 PRU

Events in Patients Treated with 75 mg

Price MJ, AHA 2010

The GRAVITAS Genetic Sub-study: Objectives

To assess, in a multicenter, randomized, placebo-controlled setting:

• The genetic determinants of on-treatment reactivity (OTR) after PCI, including PON1, CYP2C19 and ABCB1

• Whether genotype influences the PD response to high-dose clopidogrel in patients with high on-treatment reactivity after PCI.

Sample Acquisition and Genotyping

• Samples (N=1,152) obtained at platelet function screening or during follow-up from patients participating in GRAVITAS at 42 participating sites

• 40 SNPs genotyped with Sequenom platform, including, but not limited to:

• CYP2C19: *2, *3, *4, *5, *6, *7, *8, *17

• PON1, ABCB1

• OTR assessed using VerifyNow P2Y12 test per GRAVITAS protocol

• Baseline: 12-24 hours post-PCI, after standard peri-procedural clopidogrel regimen

• 30±7 days

Classification of CYP2C19 Genotype and Predicted Metabolic Phenotype

Metabolic Phenotype• Ultra-rapid: *1/*17, *17/*17• Extensive: *1/*1

• Intermediate: *1/*2 thru*8, *17/*2 thru*8

• Poor: *2 thru *8/*2 thru *8

Genotype• CYP2C19 Loss-of-function allele: *2, *3, *4, *5,

*6, *7, or *8

Analyses and Endpoints

• Baseline population (12-24 hrs post-PCI) 1° endpoint: OTR (PRU)2° endpoints: Rate of OTR ≥ 230 and ≥ 208

PRU

• Response to study drug

1° endpoint: Δ OTR from baseline to 30 days 2° endpoints: Rate of OTR ≥ 230 and OTR ≥

208 PRU at 30 days

On-Treatment Reactivity at Screening (12-24 hrs post-PCI) N=1013

Co-dominant model, adjusted for tx and characteristics associated with OTR.

SNP R2

PON1 Q192R 0.2% P = 0.42CYP2C19*2 6.5% P = 2.2 x 10-15

CYP2C19*17 0.5% P = 0.08ABCB1 3435 CT 0.1% P = 0.61

Change in On-Treatment Reactivity at 30 days N=714 SNP R2

PON1 Q192R 0% P = 0.71CYP2C19*2 5.1% P = 1.4 x 10-5

CYP2C19*17 1.2% P = 0.02ABCB1 3435 CT 0% P = 0.40

Results: Influence of PON1, CYP2C19, and ABCB1 on the Primary Endpoint

P<0.0013 for statistical significance

Platelet Reactivity on Clopidogrel Post-PCI Is Associated With CYP2C19 Genotype & Phenotype

CYP2C19 genotype

Metabolic phenotype

Least squared means. P values compared to No LOF/Extensive. η2 : portion of variance explained by the genotype or phenotype in the multivariate generalized linear model

η2=6.7%

η2=6.7%

CYP2C19 LoF Allele Carriage Is A Major, Independent Predictor of High OTR Post-PCI

*Adjusted for BMI, gender, age, current smoking, CrCl<60 ml/min, DM, CHF, HTN, hyperlipidemia

N=1008

Predicted CYP2C19 Metabolic Phenotype Is A Major, Independent Predictor of High OTR Post-PCI

Ultra, Ultra-rapid; Ext, Extensive; Int, IntermediateAdjusted for BMI, gender, age, current smoking, CrCl<60 ml/min, DM, CHF, HTN, hyperlipidemia

N=1006

CYP2C19 LOF Allele Is Associated With Higher Risk of Persistently High OTR at 30 Days Regardless of Dose

Patients with OTR ≥ 230 PRU at 12-24 hours after PCI. Adjusted ORs.

N=273 N=277

ORs for PRU ≥ 208 at 30 Days

ORs for PRU ≥ 230 at 30 Days

CYP2C19 Genotype is Associated With the PD Effect of Clopidogrel at 30 Days In Patients with High OTR

Regardless of Dosing Strategy

High-dose: clopidogrel 600 re-load then 150 mg/day; Standard-dose: clopidogrel 75 mg/day. High OTR: ≥ 230 PRU at enrollment (12-24 hrs post-PCI)P values adjusted for multiple comparisons

Adjusted Hazard Ratios for CV Death, MI, or Stent Thrombosis According To CYP2C19 Genotype or

Metabolic Phenotype

Adjusted for prior MI, prior PCI, prior CABG, diabetes, CrCl < 60 ml/min, Beta-blocker use, stent length, ACS

Total # of Events= 14Interpret with caution

Summary (1)

• In the multicenter, prospective, GIFT study:

• PON1 Q192R and ABCB1 3435 CT were not associated with:

• On-clopidogrel platelet reactivity at screening after PCI or at 30-day FU

• The change in platelet reactivity with high-dose clopidogrel in patients with high OTR at baseline.

Summary (2)

• CYP2C19 genotype was significantly associated w/OTR after PCI.

• CYP2C19 genotype was an independent predictor of the antiplatelet effect of clopidogrel 150 mg/d in patients with high OTR post-PCI.

• Carriers of 1 or 2 LoF alleles substantially more likely to have persistently high OTR at 30 days

• In carriers of 2 LoF alleles, the antiplatelet effect of 150 mg MD was similar to that of 75 mg MD.

• CYP2C19*17 was not associated with significantly lower OTR after PCI, or an enhanced response to 150 mg MD

Conclusions

• GIFT does not support an effect of PON1 in clopidogrel response variability.

• GIFT confirms the importance of CYP2C19 in clopidogrel response over time, regardless of dosing strategy.

• CYP2C19 genotype may complement a platelet function-guided approach to individualized antiplatelet therapy after PCI.

FUTURE DIRECTIONS

• Whole exome sequencing of the GIFT cohort is ongoing

• allows an unbiased investigation of the complete protein-coding regions in the genome

• comprehensive strategy to define the gene variants associated with clopidogrel responsiveness (in all coding elements of the genome)

A. Abbas (Troy, MI)M. Amine (Tomball, TX)D. Angiolillo (Jacksonville, FL)R. Applegate (Winston-Salem, NC)J. Aragon (Santa Barbara, CA)H. Aronow (Ypsilanti, MI)W. Batchelor (Tallahassee, FL)M. Buchbinder (San Diego, CA)L. Cannon (Petoskey, MI )N. Chronos (Atlanta, GA)D. Cohen (Kansas City, MO)E. Fry (Indianapolis, IN)M. Fugit (Sacramento, CA)R. Gammon (Austin, TX)K. Garratt (New York, NY)P. Gordon (Providence, RI)Z. Jafar (Poughkeepsie, NY)M. Lurie (Torrance, CA)E. Mahmud (San Diego, CA)A. Malik (Fort Worth, TX )

T. Mann (Raleigh, NC)S. Manoukian (Nashville, TN)B. McLaurin (Anderson, SC)J.C. Merrit (Rome, GA)E. Nukta (Fairview Park, OH)C. O’Shaughnessy (Elyria, OH)S. Plante (Ontario, Canada)D. Purdy (Rapid City, SD) S. Puri (Moline, IL)D. Rizik (Scottsdale, AZ)M. Robbins (Nashville, TN)M. Schweiger (Springfield, MA)D. Spriggs (Clearwater, FL)R. Stoler (Dallas, TX)P. Teirstein (La Jolla, CA)R. Waksman (Washington, DC)S. Ward (Erie, PA)M. Warshofsky (Danbury, CT)G. Wong (Sacramento, CA)

Thanks to The GIFT Investigators