A Randomized, Double-Blind, Placebo-Controlled, Multicenter Phase IIb Study to Evaluate the Efficacy and Safety of Multiple Alvimopan Dosage Regimens for the Treatment of Opioid-Induced Bowel Dysfunction in Subjects with Chronic Pain of Non-Malignant Origin

Primary objectives: To identify at least one orally-dosed alvimopan treatment regimen that improves spontaneous bowel movement (SBM) frequency compared to placebo while maintaining an acceptable tolerability profile. Primary endpoints: The primary endpoint is the changes in weekly spontaneous bowel movement frequency during the first 3 weeks of the 6-week Treatment Period