BioSpace reports that a drug under development for opioid induced bowel dysfunction (OBD) - lubiprostone - met its primary endpoint in a phase 3 clinical trial in patients with chronic, non-cancer pain, excluding those taking methadone. Lubiprostone is a chloride channel activator that is licensed in the United States for the treatment of chronic idiopathic constipation (CIC) in adults and for irritable bowel syndrome with constipation (IBS-C) in women 18 years of age and older. Patients enrolled in the phase 3, randomised, double blind, placebo controlled study received lubiprostone 24-mcg capsule or placebo capsule twice daily for 12 weeks. The primary endpoint was the overall spontaneous bowel movement (SBM) response rate. The response rate for lubiprostone-treated patients was 26.9% (n=219) versus 18.6% (n=220) for placebo-treated patients (p=0.035). There were no drug-related serious adverse events reported for patients taking lubiprostone. Overall, the percentage of patients discontinuing treatment due to adverse events was 5.9% for the lubiprostone group compared with 2.3% in the placebo group.