Adolor Corporation has begun enrollment in two additional pivotal Phase 3 clinical trials of alvimopan, the Company's first-in-class small molecule opioid receptor antagonist, for the management of post-operative ileus. The Company initiated its first Phase 3 trial of alvimopan for this indication in March 2001.

Each of the double-blind and placebo-controlled Phase 3 trials is expected to include 450 patients at approximately 30 centers nationwide. Patients will be administered twice-daily doses of 6 mg of alvimopan, 12 mg of alvimopan or placebo. All of the pivotal trials have incorporated enhancements that were established based on the recently completed Phase 2 clinical trials.

Each year, millions of patients undergo a variety of surgical procedures, such as hysterectomy, colectomy and caesarean section. These patients frequently develop a form of temporary bowel dysfunction known as post-operative ileus that prolongs recovery from surgery, extends the length of hospital stay, causes significant patient distress and adds significant cost to treating surgical patients. There are currently no approved treatments for post-operative ileus.

In three Phase 2 double-blind and placebo-controlled clinical trials, alvimopan shortened the time to recovery of bowel function following certain abdominal surgical procedures.

Alvimopan is a peripherally restricted opioid narcotic antagonist that treats or prevents the gastrointestinal side effects of opioid analgesics such as morphine and codeine without interfering with their beneficial analgesic effects. For patients who take opioid analgesics over a long period of time for chronic pain, these side effects include severe constipation, which often does not respond to laxatives or stool softeners.