Anticoagulation level in response to a fixed dose of warfarin is difficult to predict at the start of therapy. The CYP2C9 gene polymorphism (involved in the metabolism of warfarin) and VKORC1 (involved in the vitamin K cycle) with the age and the body surface are responsible for about 50% of the individual variability in dose.
This study was designed to test the hypothesis of a warfarin prescribing guided by genetic markers that may add therapeutic benefits. This was a multicenter, controlled study that included 455 patients with atrial fibrillation or venous thromboembolism who were randomized to warfarin prescribing according to genotype (n = 227) versus standard dose (n = 228). The primary endpoint was the percentage time in three months that patients were within a suitable range of RIN (between 2 and 3). The percentage of time within target range was 67.4 % for the adjusted group by genotype versus 60.3 % for the standard group (p < 0.001).
The administration of warfarin based on Pharmacogenetics was associated with a greater percentage of time within the target range of anticoagulation.
Original title: EU-PACT: A Randomized Trial Comparing Genotype-Guided Dosing of Warfarin to Standard Dosing: The EU Pharmacogenetics of Anticoagulant Therapy Warfarin Study