EPIX Pharmaceuticals, Inc., a developer of innovative pharmaceuticals for magnetic resonance imaging (MRI) which recently announced a definitive agreement to merge with Predix Pharmaceuticals Holdings, Inc., announced that Schering AG, which is undergoing a merger with Bayer AG, is not going to exercise its option for EPIX's fibrin-binding imaging agent EP-2104R. Under the terms of the agreement, EPIX will retain full rights to the EP-2104R programme.

"Although Schering has decided not to exercise its option, we intend to diligently pursue a collaboration for the continued development of EP-2104R with other potential partners," commented Andrew Uprichard, M.D., EPIX president and chief operating officer. "We found the images generated from the phase IIa feasibility studies of EP-2104R to be encouraging, and are excited about the potential role of EP-2104R in imaging medicine."

EP-2104R is EPIX's second novel imaging agent in human clinical trials. The compound is a fibrin-binding agent designed to detect blood clots using MRI. After injection the agent localizes in fibrin, a constituent of all blood clots, allowing visualization using MRI. EPIX completed two Phase IIa studies earlier this year that evaluated the performance of EP-2104R in 52 patients. The agent confirmed the presence of thrombus in all vascular beds studied across the arterial and venous circulations and including the chambers of the heart. Despite the high-risk patients enrolled in these studies, no trends or patterns were seen in the overall safety data.

Vasovist, EPIX's lead product candidate, a novel blood-pool contrast agent, is approved in the European Union and Switzerland and is currently under review at the United States Food and Drug Administration. Schering AG, EPIX's development and marketing partner for Vasovist, markets Vasovist in the European Union.