Plavix biomarker test can improve patient outcomes

Key Points

Editor's note: Scientific information from studies released since this article was written have raised more questions about the Plavix CYP2C19 genome connection as it affects some people. Watch for updates in future issues of Drug Topics.

In January, the Agency for Healthcare Research and Quality (AHRQ) released "Outpatient Prescription Anticoagulants Utilization and Expenditures for the U.S. Civilian Noninstitutionalized Population Age 18 and Older 2007," a study from its October 2009 Medical Expenditure Panel Survey (MEPS). This report found that anticoagulant drugs were prescribed to more than 4.2 million Americans at a cost of $900 million and were paid for by patients and/or third-party payers.

Achieving correct therapeutic levels of the drugs most often used - warfarin (Coumadin, Bristol-Myers Squibb) and clopidogrel bisulfate (Plavix, Sanofi Aventis/Bristol-Myers Squibb) - is typically described as a challenging trial-and-error process. The discovery that the genetic biomarker CYP2C19 affects an individual's ability to properly metabolize these agents allows a more personalized approach, but this requires a test ordered by a physician and payor reimbursement.

On March 12, FDA added a boxed warning to the clopidogrel label, highlighting "reduced effectiveness in patients who are poor metabolizers of Plavix" and encouraging physicians to consider another product and/or to test their patients for the biomarker before prescribing the drug.

In a novel collaboration with PBM giant CVS Caremark and its specialty pharmacy Generation Health, PGXL Laboratories will use its expertise in anticoagulants to improve the quality of patient care through pharmacogenetic testing, physician education, and drug-specific software programs.

The program, launched July 1, "will be a dramatic forward step in personalized medicine" for patients who may receive the anticoagulant Plavix, Valdes said.

"The goals of our company include providing the highest level of testing and to support the tests with follow-up interpretation at the physician level," Valdes said, adding that his laboratory was the first to be certified as an exclusive pharmacogenomic testing facility according to the federal Clinical Laboratory Improvement Amendments of 1988.

Physician participation