RGH-896 (radiprodi) is orally active and selective NMDA NR2B antagonist, a potential therapeutic agent in treatment of neuropathic pain and possibly other chronic pain conditions. It blocks pain signaling without interacting with other NMDA receptor subtypes thus potentially improving therapeutic index and side effect profile. RGH-896 is the first of this group and is currently in early clinical development. Forest and Richter initiated a Phase IIb study in neuropathic pain in the United Stated in the second half of 2006. The drug did not produce significant reductions in patient-reported pain scores for all the dosages tested. Forest says that it and Gedeon Richter will review the findings before making a decision about the further development of radiprodil. In addition to neuropathic pain, the companies intend to investigate various other pain conditions and possibly CNS indications not related to pain. Forest will pay Richter undisclosed upfront and milestone payments in addition to royalties and will have exclusive rights in the U.S. and Canada. The two companies will jointly fund the development program. RGH-896 has patent applications that provide patent protection until at least 2022.