American College of Medical Genetics responds to new FDA labeling decision fo...( BETHESDA MD August 23 2007 On Augus...)

BETHESDA, MD August 23, 2007 On August 16, the Food and Drug Administration approved new labeling information for the blood-thinner warfarin, sold under the brand name Coumadin. The new label suggests that one can prescribe higher or lower doses that may be safer for patients with variations in two genes, CYP2C9 or VKORC1. These variations can be learned through genetic testing, which may be a useful tool in determining appropriate dosing levels for individual patients and lower risks of bleeding complications.

The FDA labeling change for warfarin is the next step in the pathway toward incorporating genetics into the care of patients who need anticoagulation. The FDA has said that physicians should be aware of the role of genetics in warfarin dosing, but now the hard part is doing the necessary groundwork to determine how best to use genetic testing to improve care, said Marc S. Williams, MD, FACMG, ACMG Board Member and a co-chair of the expert group on Pharmacogenetic Testing of CYP2C9 and VKORC1 Alleles for Warfarin Use. This group is completing a report on the use of pharmacogenomic testing for warfarin and is based on a rapid-ACCE (Analytic validity, Clinical validity, Clinical utility and Ethical, legal and social implications) Review on Genetic Testing and Warfarin Dosing.

Available online at www.acmg.net, this 74-page report is the most thorough review of the scientific and clinical evidence surrounding the use of genetic testing to guide dosing of warfarin and was undertaken by a multidisciplinary group convened in 2006 of clinical pharmacologists, doctors of pharmacy, clinical geneticists, physicians with expertise in the use of warfarin, pharmacoeconomists, and experts in evidence-based medicine. The purpose of the rapid-ACCE review was to provide an independent, systematic review of the evidence and to develop recommendations based on this evidence. The review indicated that the test itself i
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