Ardelyx launches Phase 3 trial for tenapanor in chronic constipation treatment

Ardelyx, Inc. has launched a Phase 3 clinical trial for its drug IBSRELA® (tenapanor) to treat chronic idiopathic constipation (CIC) in adults. The study, named ACCEL, will involve around 700 patients across multiple research sites. Leading investigators from top universities are overseeing the trial, which aims to assess patient-reported improvements in constipation symptoms.

The ACCEL trial is a large, randomised, double-blind, and placebo-controlled study. It will track how effectively tenapanor relieves constipation in adults, with the primary focus on patient feedback. Enrolment is set to continue throughout 2026, and the first key results are expected in the second half of 2027.

Among the researchers involved are William D. Chey, MD, from the University of Michigan, Lin Chang, MD, from UCLA, and Christopher L. Johanson, MD, from the University of Illinois College of Medicine at Rockford. Other sites, including the University of Virginia and the University of Kansas, are also participating. Dr. Laura Williams, Ardelyx's chief patient officer and interim chief medical officer, has highlighted the significance of starting this trial.

IBSRELA is already approved in the US for treating irritable bowel syndrome with constipation (IBS-C) in adults. However, it is not suitable for children under six due to the risk of severe dehydration. The drug is also contraindicated for patients with suspected or confirmed gastrointestinal blockages. In earlier trials, the most frequently reported side effect among IBSRELA users was diarrhoea.

Ardelyx currently markets two products in the US: IBSRELA and XPHOZAH® (tenapanor). Both are part of the company's focus on gastrointestinal treatments.

The ACCEL trial will provide further data on tenapanor's effectiveness in managing chronic idiopathic constipation. Results from the study, due in late 2027, could expand the drug's approved uses. For now, IBSRELA remains a treatment option for adults with IBS-C, subject to its existing safety guidelines.