A Comparison of the Effects of ORP-101 Versus Placebo in Adult Patients With Irritable Bowel Syndrome With Diarrhea (IBS-D)

The objectives of this study are to evaluate the efficacy, safety and tolerability of ORP-101 in patients with IBS-D. This is a randomized, double-blind, placebo-controlled, 3-arm, 12-week, parallel proof-of-concept study with 2 active arms (50 mg and 100 mg ORP-101, QD) and 1 matching placebo arm, using a responsive adaptive randomization approach. After screening, patients who qualify will enter the baseline symptom assessment period, during which they will be instructed on completion of an electronic diary for daily collection of data related to their IBS symptoms, bowel function and loperamide rescue usage (not allowed during baseline). Patients who meet all entry criteria will be randomized to receive one of two different doses of ORP-101 tablets or placebo for 12 weeks. The study drug will be taken once daily, approximately 30 minutes prior to breakfast. Patients will return to the clinic on Days 14, 28, 56, 84 (12 weeks) and 2 weeks after dosing has completed (Day 98) for a follow-up visit. Study subjects will include both male and female adults. Approximately 320 patients with IBS-D will be randomized to receive study drug or placebo. Randomization will be stratified by history of cholecystectomy/gallbladder agenesis.