Tenapanor improved symptoms in patients with IBS-C

Patients with constipation-predominant irritable bowel syndrome treated with tenapanor experienced improved symptoms compared with patients who received placebo in a phase 2b clinical trial, according to a press release.

Tenapanor (Ardelyx, AstraZeneca) is “a minimally absorbed inhibitor of the intestinal sodium transporter NHE3” that reduces dietary sodium and phosphate absorption, the release said.

Researchers assessed the safety and efficacy of tenapanor in 371 participants with IBS-C who were randomly assigned 5 mg, 20 mg or 50 mg tenapanor or placebo twice daily for 12 weeks and followed for an additional 4 weeks. Of patients assigned 50 mg tenapanor, 60.7% achieved increased complete spontaneous bowel movement (≥1 CSBM from baseline during 6 out of 12 weeks) compared with 33.7% with placebo (P<.001). In the same dose group, 50% had CSBM response plus ≥30% decrease in abdominal pain in the same week for 6 of 12 weeks compared with 23.6% with placebo. Other secondary endpoint symptoms also improved, and tenapanor was well tolerated. Its safety profile was consistent with past observations; common adverse events included diarrhea and urinary tract infections, the release said.

“The magnitude of the response to tenapanor in this trial, combined with the fact that the drug was well tolerated, with only a modest incidence of diarrhea is remarkable,” David Rosenbaum, PhD, vice president of drug development at Ardelyx, said in the release. “In addition, of those subjects who were administered 50 mg of tenapanor twice a day, over 65% responded that they were ‘quite satisfied’ or ‘very satisfied’ with tenapanor vs. about 38% with placebo, a result that was also statistically significant.”

The study results will be presented in a peer-reviewed forum, the release said.