Pharmacogenomics of Anti-Platelet Intervention (PAPI) Study

CHD is the leading cause of death in the United States. One of the most common ways to prevent CHD is to take an anti-platelet agent, which lessens platelet aggregation. Two of the most common anti-platelet agents are aspirin and clopidogrel. However, up to 25% to 30% of people do not respond to these medications. Evidence indicates that treatment response may be related to genetics. The purpose of this study is to determine specific gene variants that predict response to aspirin and clopidogrel therapy.

This study is part of a larger group of studies called the Pharmacogenomics Research Network (PGRN). Participants are from the Old Order Amish of Lancaster, Pennsylvania. They are well suited for genetic studies because they are a homogenous, closed, founder population. Participants received 300 mg of clopidogrel on the first day, then 75 mg of clopidogrel per day for the next 6 days. On the last day of clopidogrel treatment, participants took a single dose of 324 mg aspirin. Participants underwent platelet function tests before and after clopidogrel alone, and then again after taking clopidogrel plus aspirin. Using the gene variation profiles across the genome, researchers analyzed which variants correspond to treatment response.