Medicare Opening National Coverage Analysis to Review Pharmacogenomic Testing for Warfarin Use
Pharmacogenomics is the study of how an individual’s genetic makeup (genotype) affects how the body responds to medication. Everyone is different. Pharmacogenomics looks at the ways these variations can be used to determine if a patient will or will not respond to a drug.
Considerable public interest has been shown in the use of pharmacogenomic testing to predict a patient’s response to warfarin, most commonly marketed as Coumadin and used as an anticoagulant. The anticoagulant effect of coumadin is measured by the use of prothrombin time (PT) and the International Normalized Ratio (INR). Using these methods the ratio of the patient’s PT to the mean PT for a group of normal individuals is calculated.
Coumadin is most commonly used in patients with mechanical heart valves, post- cerebrovascular events and other indications as determined by the health care provider.
Since October 4, 2006, there has been a boxed warning on coumadin which will not be repeated here, but is of considerable concern to those who use coumadin on their patients. The FDA approval label notes several factors that can influence the effect of coumadin such as dietary intake of green leafy vegetables, alcohol consumptions, age, Asian ethnicity and liver function. Other factors include analgesics, antibiotics, anticonvulsants, antineoplastics, beta adrenergic blockers, antifungals, vitamins and about 130 other factors.
Trial investigators have noted that pharmacogenomic testing may contribute to the identification of over- and under- responders to this somewhat dangerous, but highly useful medication. The dosing information in the label does not require or recommend at this point pharmacogenomic testing.
The Centers for Medicare and Medicaid (CMS) has recently released intent to internally open a National Coverage Analysis (NCA) to complete a much needed thorough review of the evidence to determine if the use of pharmacogenomic testing for warfarin is reasonable and necessary under the Medicare program. They are opening a public comment period from 8/4/08 – 9/3/08 for this decision. Comments should be made through the CMS website.
CMS considers all public comments and is particularly interested in clinical studies and other technological information. Instructions for submitting these comments are on the CMS website linked to this news piece.
Contact person: Maria Ciccanti
Maria.ciccanti@cms.hhs.gov
1-410-786-3107
About the author
Kathy Shattler received her Master of Science degree from Michigan State University in E. Lansing Michigan in Human Nutrition. Her twenty-two years of practice includes holding positions as a Lecturer, Chief Clinical Dietitian and Program Manager. Kathy is the Founder of Nutri-Care Consulting and is currently the Nutrition Director of www.CEU4U.COM, an online continuing education management company for Registered Dietitians and Dietetic Technicians.
