Astellas shelves PhIII clot drug as rival blockbusters crowd market

Just weeks after unveiling some troubling mid-stage data on the risk of bleeding among patients with acute coronary syndrome, Astellas has decided to kill off its late-stage program for the anti-clotting drug darexaban. While researchers had continued to hold out hope for the drug as a new treatment for patients suffering from atrial fibrillation, the Japanese Big Pharma company had to consider the potential payback for an expensive late-stage program as major league competition in the field continues to grow.

Darexaban (YM150) is in a new class of Factor Xa inhibitor drugs angling for a share of a multibillion-dollar market for blood thinners. But Pradaxa and Xarelto are already on the market and Eliquis, from Pfizer ($PFE) and Bristol-Myers Squibb ($BMY), has produced promising data in the atrial fibrillation group as it prepares to challenge rival drugs for the lead in a market that could soon grow from $7 billion to $9 billion a year. Daiichi-Sankyo has another program underway for edoxaban.

Astellas also noted that finding a partner for the treatment has become increasingly problematic.

"Astellas had been considering the appointment of a partner for the Phase III clinical development and commercialization of darexaban for these indications rather than developing and commercializing it alone," the company said in a brief statement. "However, Astellas concluded that finding a suitable partner has been difficult and considering intensified competition for this product and the order of priority in its pipeline, Astellas has decided to discontinue development of darexaban for all indications."

In Phase II darexaban appeared to double if not quadruple the risk of bleeding among ACS patients. Some researchers in the field, though, had held out hope for a lower dose of the drug as a potential winner.

- here's the Astellas release