RUBY-1 trial shows Astellas' blood thinner darexaban increases bleeding

A Phase II dose-finding study has found that the new oral Factor Xa inhibitor darexaban, under development by Japanese drug major Astellas Pharma (TYO:4503) was associated with a two to four-fold increase in bleeding when added to dual antiplatelet therapy in patients following an acute coronary syndrome.

In February, Astellas announced that it withdrew a market authorization application for darexaban maleate (YM150), which had been submitted to the Ministry of Health, Labor and Welfare in Japan. The application was for the indication of the prevention of venous thromboembolism in patients at risk, such as those undertaking orthopedic surgical procedures in the lower limbs. The decision to shelve the approval filing followed a request from Japanese regulator for additional clinical studies. At the time, Astellas said it is considering partnering the product and that future plans are contingent on the outcome of this process.

Gabriel Steg, a professor at France’s Hopital Bichat in Paris, presenting results from the RUBY-1 trial in a Hot Line session of the European Society of Cardiology (ESC) Congress in Paris this week, said the study produced no other safety concerns and that "establishing the role of low-dose darexaban in preventing major cardiac events after ACS now requires a large Phase III trial."