Efficacy of Tenapanor in Treating Patients With Irritable Bowel Syndrome With Constipation: A 12-Week, Placebo-Controlled Phase 3 Trial (T3MPO-1)

Am J Gastroenterol. 2020 Feb;115(2):281-293. doi: 10.14309/ajg.0000000000000516.


Objectives: Tenapanor is a first-in-class, minimally absorbed, small-molecule inhibitor of the gastrointestinal sodium/hydrogen exchanger isoform 3. This phase 3 trial assessed the efficacy and safety of tenapanor 50 mg b.i.d. for the treatment of patients with constipation-predominant irritable bowel syndrome (IBS-C).

Methods: In this phase 3, double-blind study (ClinicalTrials.gov identifier NCT02621892), patients with IBS-C were randomized to tenapanor 50 mg b.i.d. or placebo b.i.d. for 12 weeks followed by a 4-week randomized withdrawal period. The primary efficacy variable was the proportion of patients who reported a reduction in average weekly worst abdominal pain of ≥30.0% and an increase of ≥1 complete spontaneous bowel movement from baseline, both in the same week, for ≥6 weeks of the 12-week treatment period.

Results: Of the 629 randomized patients with IBS-C, 606 (96.3%) were included in the intention-to-treat analysis set (tenapanor: n = 307; placebo: n = 299) and 533 (84.7%) completed the 12-week treatment period. In the intention-to-treat analysis set (mean age 45 years, 81.4% women), a significantly greater proportion of patients treated with tenapanor met the primary endpoint than patients treated with placebo (27.0% vs 18.7%, P = 0.020). Abdominal symptoms and global symptoms of IBS also improved with tenapanor (P < 0.05 vs placebo). Diarrhea was the most commonly reported adverse event, resulting in study drug discontinuation in 6.5% and 0.7% of patients receiving tenapanor and placebo, respectively, during the 12-week treatment period.

Discussion: Tenapanor 50 mg b.i.d. improved IBS-C symptoms and was generally well tolerated, offering a potential new treatment option for patients with IBS-C.

Publication types

  • Clinical Trial, Phase III
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abdominal Pain / etiology
  • Abdominal Pain / physiopathology
  • Adult
  • Constipation / drug therapy*
  • Constipation / etiology
  • Constipation / physiopathology
  • Deprescriptions
  • Diarrhea / chemically induced
  • Double-Blind Method
  • Female
  • Humans
  • Irritable Bowel Syndrome / complications
  • Irritable Bowel Syndrome / drug therapy*
  • Irritable Bowel Syndrome / physiopathology
  • Isoquinolines / therapeutic use*
  • Male
  • Middle Aged
  • Sodium-Hydrogen Exchanger 3 / antagonists & inhibitors
  • Sulfonamides / therapeutic use*
  • Treatment Outcome


  • Isoquinolines
  • Sodium-Hydrogen Exchanger 3
  • Sulfonamides
  • tenapanor

Associated data

  • ClinicalTrials.gov/NCT02621892