Plecanatide Improves Symptoms of Irritable Bowel Syndrome with Constipation: Results of an Integrated Efficacy and Safety Analysis of Two Phase 3 Trials.

Purpose: Patients with irritable bowel syndrome with constipation (IBS-C) experience abdominal pain with altered bowel movements. Plecanatide is indicated as IBS-C treatment in adults. This integrated analysis further characterizes plecanatide efficacy and safety in IBS-C.
Patients and Methods: Data pooled from 2 identically designed phase 3 trials included adults with IBS-C randomized to plecanatide 3 mg or 6 mg, or placebo once daily for 12 weeks. A daily diary recorded stool frequency/symptoms, with abdominal pain, bloating, cramping, discomfort, fullness, and straining intensity individually rated. Overall response (primary endpoint) was defined as ≥30% improvement from baseline in average worst abdominal pain severity and increase of ≥1 complete spontaneous bowel movement, during same week (composite), for ≥6 of 12 weeks. Secondary endpoints included sustained response (overall response, plus meeting weekly composite criteria during ≥2 of last 4 treatment weeks) and changes from baseline in individual symptoms. Safety assessments included adverse event monitoring.
Results: Overall, 2176 patients (74.0% female; mean [SD] age, 43.5 [14.1] years) were included in efficacy analyses (plecanatide 3 mg [n = 724], 6 mg [n = 723], placebo [n = 729]). A significantly greater percentage of patients achieved overall response with plecanatide 3 mg (25.6%) and 6 mg (26.7%) versus placebo (16.0%; both P < 0.001 vs placebo). A significantly greater percentage of patients were sustained responders with plecanatide 3 mg (24.3%) and 6 mg (25.6%) versus placebo (15.6%; both P < 0.001 vs placebo). Significant improvements from baseline in abdominal discomfort, abdominal fullness, abdominal pain, bloating, and cramping occurred as early as Week 1 (Week 2 for abdominal pain) with plecanatide and were maintained through Week 12 versus placebo. Diarrhea, the most common adverse event, occurred in 4.3% (3 mg), 4.0% (6 mg) and 1.0% (placebo) of patients, leading to study discontinuation in 1.2%, 1.4%, and 0 patients, respectively.
Conclusion: Plecanatide is safe and effective for treating global and individual IBS-C symptoms.
Competing Interests: Darren M. Brenner is a consultant and speaker for Salix Pharmaceuticals and is supported in research by an unrestricted gift from the IDP Foundation. Jennifer Christie reports being an advisory board member for Evoke Pharma, Takeda Pharmaceuticals, USA, Inc., and Grail, LLC, as well as grants from Syneos Pharmaceuticals. Adam P. Laitman is an employee of Salix Pharmaceuticals. Jonathan Rosenberg reports serving on speakers bureaus for AbbVie (Allergan), Salix Pharmaceuticals, and Takeda Pharmaceuticals USA, Inc. The authors report no other conflicts of interest in this work.
(© 2023 Brenner et al.)