Ironwood has discontinued the clinical development program for IW-3718, a gastric-retentive investigational formulation of colesevelam, following a planned early efficacy assessment that showed the drug was not associated with statistically significant improvement in heartburn severity.

The investigational bile acid sequestrant was designed to be maintained in the stomach over an extended period of time where it was expected to intercept bile before it reached the esophagus. The phase 3 placebo-controlled study evaluated the safety and efficacy of IW-3718 administered to patients with gastroesophageal reflux disease (GERD) who continued to have persistent symptoms despite receiving a standard dose of a proton pump inhibitor (N=550).

Patients were randomized to receive 3 IW-3718 500mg tablets or 3 placebo tablets twice daily, after the morning and evening meals. The primary end point of the study was the change from baseline at week 8 in Weekly Heartburn Severity Score.

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An assessment by an independent data monitoring committee confirmed that the study did not meet the primary end point. “The outcome of this assessment is deeply disappointing for Ironwood and for patients, given the large unmet need among patients with refractory GERD for an alternative to standard treatment options,” said Mark Mallon, chief executive officer of Ironwood. “IW-3718-302 was a robust and well-conducted phase 3 trial, and while we plan to conduct a complete analysis of the data set, we believe these findings are definitive.”

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Ironwood to discontinue IW-3718 development program following results from planned efficacy assessment. Accessed September 29, 2020.