Tenapanor proven safe, effective in treatment of IBS with constipation

Treatment with tenapanor 50 mg twice daily (bid) results in improvement of constipation-predominant irritable bowel syndrome (IBS-C) symptoms and is generally well tolerated, a phase III study has shown.

A total of 629 patients with IBS-C were randomized to receive tenapanor 50 mg bid or placebo bid for 12 weeks, followed by a 4-week randomized withdrawal period. Of these, 606 (96.3 percent; mean age, 45 years; 81.4 percent women) were included in the intention-to-treat analysis set (tenapanor: n=307; placebo: n=299) and 533 (84.7 percent) completed the 12-week treatment period.

Significantly more patients treated with tenapanor vs placebo met the primary endpoint of a reduction in average weekly worst abdominal pain of ≥30.0 percent 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 (27.0 percent vs 18.7 percent; p=0.020).

Tenapanor therapy also led to improvements in abdominal symptoms and global symptoms of IBS compared with placebo (p<0.05).

The most frequently reported adverse event was diarrhoea, which resulted in treatment cessation in 6.5 percent of patients receiving tenapanor and 0.7 percent of those treated with placebo during the 12-week treatment period.

In a previous study, tenapanor 50 mg bid was found to significantly increase stool frequency, as well as reduce abdominal symptoms in patients with IBS-C. [Am J Gastroenterol 2017;112:763-774]

 “Tenapanor is a first-in-class, minimally absorbed, small-molecule inhibitor of the gastrointestinal sodium/hydrogen exchanger isoform 3,” the investigators noted.