Study 314 is the fifth Entereg Phase 3 trial conducted in POI. Previous studies gave confounding results with some (studies 302 and 308) missing the primary endpoint. The mixed Phase 3 results prompted the FDA to issue an approvable letter in July 2005. According to Adolor’s website:
“In the Letter, the FDA indicated that, before the application may be approved, it will be necessary to provide additional proof of efficacy to support use of Entereg following bowel resection surgery. The FDA indicated that this may be achieved by demonstrating statistically significant results in at least one additional clinical study, and indicated that this could be addressed with positive results from Adolor's ongoing Study 314. The FDA also indicated that the company must provide justification that the median reduction in time to gastrointestinal (GI) recovery seen in bowel resection patients treated with Entereg is clinically meaningful.