Medco Health Solutions to study genetic effect on anticlotting drugs

FRANKLIN LAKES, N.J. A pharmacy benefit manager will study how the genetic makeup of patients affects the efficacy of two anticlotting drugs.

Medco Health Solutions announced that it would examine whether the 70% to 75% of patients with a normally functioning version of the gene CYP2C19, which makes them “extensive metabolizers” of Bristol-Myers Squibb’s and Sanofi-Aventis’ drug Plavix (clopidogrel), have comparable outcomes to patients taking Eli Lilly & Co.’s Effient (prasugrel). Unlike Plavix, metabolism of Effient’s does not depend on patients’ genetic makeup because it is metabolized via a different pathway.

The implications of the study, which will enroll more than 14,000 patients with acute coronary syndrome who have recently begun using the drugs, could be huge for health plans as well as the three drug makers. Plavix will lose its patent exclusivity and come under generic competition in 2011. This means that if it proves equally effective as Effient, patients could opt for generic clopidogrel.

Lilly released Effient a few months ago, and while the drug is more expensive than Plavix and won’t become generic any time soon, it also has shown greater efficacy, but also a higher risk of bleeding. Plavix currently is the third top-selling drug in the United States, with $4.9 billion in sales, according to Medco.

The problem, Medco said, is that studies have not limited patient populations to those who extensively metabolize Plavix, which could substantially affect study results.

“This study could have a huge bearing on patient safety and the costs to treat this condition,” Medco chief medical officer Robert Epstein said in a statement. “Plavix is going generic in 2011, and if found to be equally effective as Effient for patients who have a normally functioning version of the CYP2C19 gene, the study provides the evidence that would allow these patients to opt for a lower-cost treatment.”

Enrollment of patients for the study will begin later in the fall and continue until the middle of 2011. The company will compare rates of cardiovascular deaths, nonfatal heart attacks and nonfatal strokes over a six-month period, presenting data in early 2012. Patients taking Plavix will be required to provide saliva samples to determine if their genetic makeup allows them to metabolize the drug effectively.