NitroMed Inc announced that Merck & Co, Inc has halted the phase II trial of its lead candidate in nitric oxide-enhancing COX-2 inhibitors. The lead nitric oxide candidate is composed of a rofecoxib derivative. Rofecoxib is the primary ingredient in Vioxx, which Merck voluntarily withdrew from worldwide markets last week.

The three-year exclusive, worldwide licensing and research collaboration between NitroMed and Merck, launched in January 2003, to develop proprietary nitric oxide COX-2 inhibitors remains in effect.

NitroMed is an emerging pharmaceutical company that discovers, develops and seeks to commercialize proprietary pharmaceuticals based on the therapeutic benefits of the naturally occurring molecule nitric oxide. NitroMed has agreements with Merck to jointly develop nitric oxide COX-2 inhibitors and with Boston Scientific to jointly develop nitric oxide coated cardiovascular stents.