Officials with the FDA have approved tenapanor (Ibsrela, Ardelyx), a 50 mg, twice-daily oral medication for the treatment of irritable bowel syndrome with constipation (IBS-C) in adults, according to a press release.
Tenapanor, a novel treatment, is a minimally-absorbed small molecule that acts locally in the gastrointestinal (GI) tract to inhibit the sodium-hydrogen exchanger NHE3. Through this mechanism, treatment results in increased bowel movements and decreased abdominal pain for patients, according to Ardelyx. IBS-C, a subtype of IBS, can cause abdominal discomfort and bloating associated with constipation in patients and symptoms can be disruptive to daily life.
“Ibsrela has the potential to provide IBS-C patients and their doctors with a novel mechanism and an innovative approach to managing IBS-C, a highly burdensome and difficult-to-treat condition affecting more than 11 million people in the United States,” Mike Raab, president and chief executive officer of Ardelyx, said in a statement.
The approval is based on results from the phase 3 IBS-C program, which included 2 randomized trials: T3MPO-1 and T3MPO-2. The primary endpoint for both trials was the proportion of patients who responded during the 12-week treatment period.
Both trials met the primary endpoint compared with a placebo:
  • Trial 1: 37% versus 24%, tenapanor versus placebo, respectively.
  • Trial 2: 27% versus 19%, tenapanor versus placebo, respectively. 
According to the results, in both trials, the proportion of responders for 9 out of the first 12 weeks, including at least 3 of the last 4 weeks, was greater in patients treated with tenapanor compared with patients treated with a placebo. Additionally, in trial 1, the proportion of responders for 13 out of 26 weeks was greater in tenapanor-treated patients compared with placebo-treated patients, according to the study.
Both trials showed improvements from baseline in average weekly complete spontaneous bowel movements and abdominal pain by week 1, with improvement maintained through the end of treatment.
In addition, a long-term safety extension trial, T3MPO-3, further supported the favorable safety profile of tenapanor, according to Ardelyx.
This article was originally published by Specialty Pharmacy Times

Ardelyx Receives FDA Approval for Ibsrela (Tenapanor), an NHE3 Sodium Transport Inhibitor, for the Treatment of Irritable Bowel Syndrome with Constipatin [news release]. Ardelyx. Accessed September 13, 2019.