Merck and Neuromed Pharmaceuticals have discontinued development of NMED-160 (also known as MK-6721), a Phase II compound for the treatment of chronic pain. Their joint research collaboration will continue to evaluate other therapeutic candidates.

While no serious adverse events with the drug were observed in clinical trials, it was determined that MK-6721 does not demonstrate the “ideal pharmaceutical characteristics considered necessary to advance the compound further in development,” according to a press statement.

“We are encouraged by what we’ve learned from MK-6721 and are continuing our productive collaboration with Merck with a focus on improving the pharmaceutical properties of our compounds to produce a best-in-class pain treatment,” said Dr. Christopher Gallen, president and chief executive officer of Neuromed.

“Merck and Neuromed are committed to the further research and development of oral N-type calcium channel blockers for pain,” said Dr. Darryle Schoepp, senior vice president, franchise head, Neuroscience at Merck. “Neuromed is a leader in the field of oral N-type calcium channel blockers and we are pleased with the results of our ongoing collaboration.”

N-type calcium channel blockers represent a class of analgesics that are selective for calcium channels involved in pain signal transmission.