Marshfield Clinic Discovers Gene Variant Which Will Significantly Enhance the Accuracy of Molecular Tests for Warfarin Metabolis

Marshfield Clinic Discovers Gene Variant Which Will Significantly Enhance the Accuracy of Molecular Tests for Warfarin Metabolism 

Following the exclusive license of the warfarin biomarker, 4F2, by the Marshfield Clinic to Osmetech in November 2007, the Marshfield Clinic Research Foundation, led by Michael D. Caldwell, M.D., Ph.D., has an article published in the peer-reviewed journal, Blood Online, entitled “CYP4F2 genetic variant alters required warfarin dose”. This demonstrates that the biomarker will help reduce adverse reactions to the commonly-prescribed anticoagulant used to treat and prevent thrombotic events. Because of historically high rates of adverse drug-associated events, warfarin remains under-prescribed due to variability in therapeutic dose among patients which mandates frequent monitoring.

The U.S. Food and Drug Administration (FDA) mandated the re-labeling of warfarin to include genetic testing for known valid markers in two genes (CYP2C9 and VKORC1) involved in warfarin metabolism and sensitivity which impact a patient’s response to warfarin. The dosing of warfarin is complicated due to its small therapeutic window and is affected by factors including genetics, age, body mass index and gender. If a dose is too high or too low, there is a risk of serious bleeding or clotting events.

The Blood Online article describes a novel variant in a third gene cytochrome P450 4F2 (CYP4F2), discovered by the Marshfield research team, that significantly influences warfarin requirements.  The DNA variant in cytochrome CYP4F2 was found to be associated with warfarin dosage in three independent patient groups stabilized on warfarin (n=1054) recruited by the Marshfield Clinic, University of Florida and Washington University. Adjusting warfarin dosage for this variant could help reduce the serious adverse events caused by incorrect dosage and enable doctors to treat patients in a more effective and individualized manner.

James White, CEO of Osmetech said, “This article provides evidence of the value of the 4F2 marker in warfarin testing.  This marker in conjunction with variants from the two genes (CYP2C9 and VKORC1) recommended by the FDA will improve patient outcomes by reducing the overall complications of warfarin therapy, reduce costs in the health system and help provide a new standard of personalized care.  The fact that Osmetech has an exclusive license to this marker for warfarin testing, we believe will help position us as the leading diagnostic company in this area.”

About Osmetech
Osmetech plc is an AIM-listed public company on the London Stock Exchange. The company is a fast developing, international molecular diagnostics business with operations in Boston and Pasadena in the US, serving the high growth, near patient testing market targeting small to medium sized hospitals. 

In 2006 Osmetech launched the eSensor® platform, an FDA cleared electrochemistry-based array system for cystic fibrosis carrier detection, and is currently waiting FDA clearance of its next generation instrument, the eSensor® XT8 along with CYP450/VKOR, a test to determine a patient’s response to warfarin.   For more information about Osmetech, visit