Sweden's Active Biotech is to pocket a 10 million euro milestone payment from partner Ipsen after reaching the halfway mark in recruiting patients for a prostate cancer study of tasquinimod.

The firms noted that 600 patients are now on board for a Phase III study of tasquinimod in patients with metastatic castrate-resistant prostate cancer. The primary goal of the study is radiological progression-free survival, with overall survival as a secondary endpoint.

The study will include about 1,200 patients in more than 250 centres and Active and Ipsen expect top-line results by the end of 2013. Marc de Garidel, chief executive of the French drugmaker said that on-schedule recruitment of the 600th patient "is a testimony of the interest of the medical community in the drug's novel and differentiated mode of action…in a crowded prostate cancer space".

Tasquinimod has a pleiotropic mode of action which includes immunomodulatory, anti-angiogenic and antimetastatic activity. Phase II results published in September 2011 revealed that median PFS for the drug of 7.6 months versus 3.3 months on placebo. Preliminary OS data was released last week which showed that median time to death was 34.2 for tasquinimod versus 30.2 months.