New test could improve warfarin monitoring

In the secondary analysis (from day 181 to 720), Fiix-PT led to a superior long-term reduction in TE compared to conventional PT—1.1% and 2.2%, respectively (P=0.03 for superiority). But there was no significant difference in the rates of major bleeding—1.5% and 2.3%, respectively (P=0.5 for superiority).

“Compared to high-quality PT-INR monitoring, Fiix-PT increased the stability of warfarin anticoagulation,” Dr Onundarson said in closing. “Fiix-PT was clinically at least non-inferior to the INR in the primary analysis, and Fiix-PT led to superior long-term reduction in TE in the secondary analysis. Fiix-PT did not increase major bleeding, despite lowering the long-term thromboembolic rate and despite not being affected by FVII in the test sample.”

“So my overall conclusion is that a fluctuating INR during warfarin treatment is partly a confounding side effect of the PT itself. The data suggests that, if the PT is replaced with a monitoring test that is not affected by FVII, warfarin may become more stable than was previously assumed.”