Forest diabetes drug study fails

Radiprodil (RGH-896), in development by Forest Laboratories for the treatment of neuropathic pain associated with diabetic peripheral neuropathy missed its primary endpoint in a phase II study compared to placebo.

Forest and its partner on the drug, Gedeon Richter, said that they have not yet made a determination about whether to continue development of the product, but will do so in the coming weeks after reviewing the complete study database.

The drug is part of a wider development partnership signed between Forest and Budapest, Hungary-based Richter in 2005. The agreement gave Forest exclusive rights to the product in the US and Canada in return for undisclosed upfront and milestone payments, research funding and royalties.

Radiprodil targets a specific portion of the NMDA receptor that may be involved in the transmission of pain, an approach that the companies hoped would yield improvements in efficacy and the side effect profile compared to currently available treatments.

However, top-line results from the phase II dose-response trial failed to show statistically significant or clinically meaningful reductions in mean daily pain scores compared to placebo, which was the study's primary endpoint. The 14-week study enrolled about 450 patients.

Forest and Richter are also developing radiprodil for other chronic neuropathic pain conditions.