WALTHAM, Mass.--(BUSINESS WIRE)--Dynogen Pharmaceuticals, Inc. announced today that the first patients have been dosed in a Phase 2b trial of DDP733 (pumosetrag) as a treatment for irritable bowel syndrome with constipation (IBS-c). This DDP733 Phase 2b trial is a randomized, double-blind, placebo controlled study that is enrolling female patients with IBS-c at multiple centers in the U.S. and Canada. The study is assessing efficacy using the Overall Subject Global Assessment (OSGA) of relief of IBS symptoms, as well as the safety and tolerability of the drug.