Adolor Corporation has initiation of a phase-2 proof-of-concept (PoC) study of ADL5945 in patients suffering from opioid-induced constipation (OIC).

"We are pleased to announce the initiation of our phase-2 proof-of-concept study," said Michael R Dougherty, president and chief executive officer. "We begin this study having just completed a single-ascending dose (SAD) study of ADL5945 in healthy volunteers and a multiple-ascending dose (MAD) study in OIC patients with chronic non-cancer pain. The results were highly encouraging on all fronts: PK profile, tolerability and efficacy. Adolor has a wealth of expertise in this indication, and we look forward to the completion of this trial next summer."

The phase-2 PoC trial will evaluate two doses of ADL5945 (0.10mg and 0.25mg given twice daily) versus placebo in patients with OIC over a four week period. Approximately 120 patients will be enrolled. The primary endpoint of the study will be change from baseline in the weekly average of spontaneous bowel movements (SBMs) during treatment.

The recently completed SAD and MAD studies of ADL5945 and ADL7445 enrolled both healthy volunteers and non-cancer pain patients on long-term opioid therapy with OIC. Both compounds were well-tolerated and, in the patients with OIC, produced increases in weekly average SBMs compared to placebo. Notably, the 0.10mg and 0.25mg doses of ADL5945 being tested in the PoC study were successfully evaluated in extended cohorts in the MAD study against placebo. The most commonly reported side effects were dose-dependent gastrointestinal-related effects such as abdominal cramping and nausea. There were no serious adverse events reported.

"The data from this recent trial validate both ADL5945 and ADL7445 for the treatment of OIC in patients with chronic non-cancer pain," said Richard M Mangano, vice president of Clinical Research & Development at Adolor. "The safety and efficacy of these doses of ADL5945 are encouraging and clearly warrant continued clinical development."

ADL5945 is a proprietary, peripherally-acting mu opioid receptor antagonist being developed by Adolor for the treatment of OIC.

Adolor Corporation is a biopharmaceutical company specializing in the discovery, development and commercialization of novel prescription gastrointestinal and pain management products.