IW-3718 + proton pump inhibitor

**IW-3718 + proton pump inhibitor** is a combination therapy evaluated as an adjunctive treatment for patients with **refractory gastroesophageal reflux disease (GERD)** who continue to experience symptoms despite ongoing standard-dose proton pump inhibitor (PPI) therapy. IW-3718 is a novel, gastric-retentive formulation of **colesevelam**, a bile acid sequestrant, designed to remain in the stomach longer and bind bile acids, which are thought to contribute to GERD symptoms unresponsive to acid suppression alone. The treatment pairing aims to address both acid and bile components of reflux[1][7][9]. Developed by Ironwood Pharmaceuticals, the combination was shown in Phase II to reduce heartburn and regurgitation compared to PPI alone, with constipation as the most frequent side effect and no serious drug-related adverse events. However, Phase III trials failed to meet primary efficacy endpoints, and the clinical development program was discontinued[3][5][6].