Escalating Clopidogrel by Involving a Genetic Strategy - Thrombolysis In Myocardial Infarction 56 (ELEVATE)

To determine whether higher as compared with lower maintenance doses of clopidogrel can adequately improve the degree of platelet inhibition in carriers of a reduced-function CYP2C19 allele.

Clopidogrel blocks the P2Y12 ADP receptor on platelets and has been shown to reduce cardiovascular events in acute coronary syndrome (ACS) patients.However, inter-patient variability in the pharmacodynamic response to clopidogrel is well recognized, and patients with lesser degrees of platelet inhibition in response to clopidogrel have been shown to be at increased risk of cardiovascular events. One potential source of this variability is the metabolism of clopidogrel, which is a pro-drug requiring biotransformation to become an active antiplatelet compound. Cytochrome P-450 (CYP) enzymes play a role in the metabolism, and carriers of reduced-function genetic variants in CYP2C19 (~30% of the population) have lower active clopidogrel metabolite levels, diminished platelet inhibition, and higher rates of adverse cardiovascular events as compared with non-carriers in the setting of treatment with standard maintenance doses of clopidogrel. Aim: To determine whether higher as compared with lower maintenance doses of clopidogrel can adequately improve the degree of platelet inhibition in carriers of a reduced-function CYP2C19 allele. Hypotheses: The primary hypothesis is that subjects who carry a reduced-function CYP2C19 allele will have improvement in platelet inhibition with higher maintenance doses of clopidogrel.The secondary hypothesis is that higher maintenance doses of clopidogrel in carriers of a reduced-function CYP2C19 allele will result in similar platelet inhibition as compared to a standard maintenance dose of clopidogrel in non-carriers.

Comparisons of Vasodilator-stimulated Phosphoprotein (VASP) Phosphorylation Platelet Reactivity Index (PRI)

The outcome measurement was on-treatment PRI determined through flow cytometric assessment of phosphorylation status of VASP.

Inclusion Criteria (major): Between 18 and 75 years of age, inclusive. Have an indication for the use of clopidogrel defined as either spontaneous MI [hospitalized with final diagnosis of MI, excluding periprocedural or definite secondary MI (e.g., due to anemia or hypertensive emergency)] or PCI within the past 6 months. Clinically stable and at least 4 weeks following the MI or PCI. Exclusion Criteria (major): Conditions that alter platelet function. Conditions that increase bleeding risk.

Mega JL, Hochholzer W, Frelinger AL 3rd, Kluk MJ, Angiolillo DJ, Kereiakes DJ, Isserman S, Rogers WJ, Ruff CT, Contant C, Pencina MJ, Scirica BM, Longtine JA, Michelson AD, Sabatine MS. Dosing clopidogrel based on CYP2C19 genotype and the effect on platelet reactivity in patients with stable cardiovascular disease. JAMA. 2011 Nov 23;306(20):2221-8. doi: 10.1001/jama.2011.1703. Epub 2011 Nov 16.

Hochholzer W, Ruff CT, Mesa RA, Mattimore JF, Cyr JF, Lei L, Frelinger AL 3rd, Michelson AD, Berg DD, Angiolillo DJ, O'Donoghue ML, Sabatine MS, Mega JL. Variability of individual platelet reactivity over time in patients treated with clopidogrel: insights from the ELEVATE-TIMI 56 trial. J Am Coll Cardiol. 2014 Jul 29;64(4):361-8. doi: 10.1016/j.jacc.2014.03.051.

Carreras ET, Hochholzer W, Frelinger AL 3rd, Nordio F, O'Donoghue ML, Wiviott SD, Angiolillo DJ, Michelson AD, Sabatine MS, Mega JL. Diabetes mellitus, CYP2C19 genotype, and response to escalating doses of clopidogrel. Insights from the ELEVATE-TIMI 56 Trial. Thromb Haemost. 2016 Jul 4;116(1):69-77. doi: 10.1160/TH15-12-0981. Epub 2016 Mar 24.