Phase III trial of tenapanor in patients with IBS-C achieves endpoints

Positive top-line results from the T3MPO-1 trial, the first of two Phase III trials evaluating tenapanor for the treatment of patients with irritable bowel syndrome with constipation (IBS-C) have been reported.

Tenapanor is Ardelyx' (Nasdaq: ARDX) investigational, minimally systemic, small-molecule NHE3 inhibitor. Notwithstanding the positive elements, Ardelyx’ shares cratered, falling 39.2% to $7.48 by close of trading on Friday, after a Wedbush analyst said the drug was not likely to be a top performer.

The T3MPO-1 trial achieved statistical significance for the primary endpoint and seven of eight secondary endpoints. The primary endpoint, the combined responder rate for six of 12 weeks, showed that a greater proportion of tenapanor-treated patients compared to placebo-treated patients (27.0% versus 18.7%, p=0.02) had at least a 30% reduction in abdominal pain and an increase of one or more complete spontaneous bowel movements (CSBM) in the same week for at least six of the 12 weeks of the treatment period. Tenapanor was well-tolerated, consistent with the experience across previous clinical trials.