Clinical Data’s PGxHealth
™ division launched PGxTest:WARFARIN
™ a pharmacogenetic test that measures variation in two genes. One gene, CYP2C9
, metabolizes warfarin to an inactive metabolite. The second, VKORC1
, encodes the enzyme that is the target of warfarin. Variants in these genes have been shown in multiple studies to correlate with warfarin dose requirements.
“There is wide inter-individual variability in the warfarin dose that each patient requires,” explains Carol Reed, M.D., senior vp and CMO. “While dose requirements are influenced by fluctuations in variables, such as diet and co-prescribed therapeutics, the genetic influences are not affected by such external factors. The results of this test, when used in combination with other important clinical information, should reduce the guesswork in dose selection and enable more precise determination of the final dosing regimen.”
Warfarin is taken to prevent blood clotting after cardiovascular events, such as heart attack and stroke, for prophylaxis of clot formation in the setting of major surgery, and for the treatment of other clotting disorders.
Warfarin dosing remains challenging due to side effects, including life-threatening bleeding that may occur if the dose is too high and failure to prevent recurrent thromboembolic episodes if the dose is too low, explains Clinical Data. The company adds that the optimal maintenance dose of warfarin for each patient is difficult to predict at the beginning of treatment and it can take several weeks of frequent monitoring before a stable maintenance dose of warfarin is established.