Efficacy and Safety of 5-HT4 Receptor Agonist Minesapride for Irritable Bowel Syndrome with Constipation in a Randomized Controlled Trial

Background & Aims: Treatment options for irritable bowel syndrome with constipation (IBS-C) are limited—new prokinetic drugs are needed. We evaluated the efficacy and safety of minesapride (DSP-6952), a partial agonist with high affinity for 5-HT4 receptors, in patients with IBS-C in Japan. Methods: We performed a double-blind phase 2 study of 171 patients with Rome III-defined IBS-C at 33 centers in Japan, from December 2012 through August 2013. Patients were randomly assigned to groups given minesapride (1, 4, 12, or 40 mg) or placebo once daily for 4 weeks. The primary outcome was efficacy, defined as improvement in the weekly frequency of complete spontaneous bowel movements (CSBMs), abdominal symptoms, and IBS-C symptoms (according to the Japanese version of the IBS severity index score). For evaluation of safety, adverse events (AEs) were recorded. Results: The least squares mean change from baseline in the weekly frequency of CSBMs was greater in all minesapride groups than in the placebo group at week 4 (40 mg vs placebo, P = .040). The abdominal symptoms score improved in minesapride 40 mg group. The overall IBS severity index score decreased from baseline to week 4 in all treatment groups—especially in the 12 mg and 40 mg groups (P = .048 and <.001 vs placebo, respectively). The proportions of patients with treatment-emergent AEs in the pooled minesapride and placebo groups were 55.0% and 60.0%, respectively. The most common treatment-emergent AE was diarrhea (in 42.9% and 37.1% of patients in the pooled minesapride and placebo groups, respectively). Conclusions: In a phase 2 trial of patients with IBS-C in Japan, minesapride increased stool frequency (measured by CSBMs), reduced abdominal and overall IBS-C symptoms, and was well tolerated. Japan Pharmaceutical Information Center trial no: JapicCTI-122041.