Cerecor has signed a second licensing deal with Merck & Co., this time gaining global rights to Merck’s small molecule NMDA (N-methyl-D-aspartate) receptor subunit 2B (NR2B) antagonist MK-0657 (now CERC-301) for all human indications, including depression. MK-0657 was initially developed for the treatment of Parkinson’s disease, but failed to show efficacy for this indication in a Phase I study. Cerecor plans to initiate clinical trials of the drug candidate in patients with treatment-resistant depression. The deal comes a month after the company licensed global rights to Merck’s catechol-O-methyltransferase (COMT) inhibitors.