Adolor Corporation announced topline results of a Phase 3 clinical trial (OBD 13CL304) of its investigational product candidate, alvimopan, in opioid bowel dysfunction (OBD) patients. This outpatient study enrolled 168 patients who were chronic users of opioids, such as morphine and codeine, primarily for pain relief, and whose bowel function had been impaired as a result of opioid treatment. The patients received once daily dosing for 21 days of either a 0.5 mg or 1 mg dose of alvimopan or placebo.

The primary endpoint of the study was the proportion of patients having a bowel movement within 8 hours after each dose of study medication during the 21-day treatment period. On average, the proportion of patients who had at least one bowel movement within eight hours of each dose during the 21-day treatment period was 43% (p < 0.001 vs. placebo) for alvimopan 0.5 mg, 55% (p < 0.001 vs. placebo) for alvimopan 1 mg and 29% for placebo. In this study, alvimopan was well tolerated; the most frequently occurring adverse events versus placebo, included, diarrhea, abdominal cramps, nausea and vomiting.

"Opioid bowel dysfunction is a significant problem in patients who take opioids for relief of their pain. A compound that has the potential to treat this condition would be a meaningful advance for these patients. I find the results of this first Phase 3 study of alvimopan in opioid induced bowel dysfunction to be promising. If further studies confirm these data, the compound has the potential to change the way physicians practice pain management," said Dr. Daniel Paulson, Chief Group Practice A, McGuire Veterans Administration Hospital, Richmond, Virginia and a principal investigator on the study. "Importantly, the data show that alvimopan was well tolerated in this study," he added.

"Our goals for this year included completing the OBD study and announcing its results before the end of the year. We are pleased to have fulfilled that goal and are excited about continuing to advance the development of alvimopan," said Bruce Peacock, president and chief executive officer of Adolor Corporation.

In addition to the OBD study results, which were reported today, three separate Phase 3 efficacy trials, studying the use of alvimopan for reducing the time to gastrointestinal recovery following abdominal surgery (postoperative ileus-POI) are underway. The uses of alvimopan in POI and OBD differ in the patient populations, in the duration of treatment of patients, association with surgical events and the amount of the dose administered to patients each day. Results from this study of alvimopan in the OBD indication are not necessarily indicative of the results that may be reported from the clinical studies in the POI indication.

The results of the study reported today have not been submitted to, nor reviewed by, any regulatory agency. Additional clinical studies are expected to be required before filing of any regulatory approval application for alvimopan in OBD.

Opioids are widely used and are effective for the treatment of acute and chronic pain. Inadequate treatment of nonmalignant and malignant chronic pain is often identified as a major healthcare concern. This may be due in part to the gastrointestinal side effects caused by opioid therapy. Morphine and other opioids are potent analgesics that work by stimulating mu opioid receptors in the brain. However, these receptors are also located elsewhere in the body including the wall of the gastrointestinal tract and stimulation of the gastrointestinal receptors results in the common unwanted effects of opioid bowel dysfunction including severe constipation, hard stools, straining, incomplete evacuation, bloating, abdominal distension, and increased gastroesophageal reflux. These symptoms comprise a condition recognized as opioid-induced bowel dysfunction. Alvimopan is an orally administered mu opioid antagonist, which is intended to reverse the effects of opioids in the gastrointestinal tract without affecting the central nervous system analgesic properties of the opioid.