Phase 3 open-label study of RELISTOR presented at American Pain Society meeting

May 21 2011

Salix Pharmaceuticals, Ltd. (NASDAQ:SLXP) today announced findings from two analyses of a Phase 3 open-label study of RELISTOR^® (methylnaltrexone bromide) presented at the 30^th Annual Scientific Meeting of the American Pain Society. The meeting is being held in Austin, TX, on May 19-21, 2011.

RELISTOR is a peripherally acting mu-opioid receptor antagonist that counteracts the constipating effects of opioid pain medications in the gastrointestinal tract without affecting their ability to relieve pain. The FDA approved RELISTOR Subcutaneous Injection in 2008 for the treatment of opioid-induced constipation (OIC) in patients with advanced illness who are receiving palliative care, when response to laxative therapy has not been sufficient. Use of RELISTOR beyond 4 months has not been studied. Currently we are developing RELISTOR for the potential treatment of OIC in patients with chronic nonmalignant pain. Salix intends to submit a supplemental New Drug Application (sNDA) for this indication in mid-2011.

The purpose of the Phase 3, multicenter, open-label study was to determine the long-term safety, tolerability and efficacy of subcutaneous methylnaltrexone in patients with chronic nonmalignant pain. The study included 1,034 patients on stable doses of opioids (equal to or greater than one month) who demonstrated constipation over the month prior to screening. Patients underwent a 14-day screening period. Eligible patients received methylnaltrexone bromide subcutaneous injection (12 mg) at least once weekly and up to once daily for 48 weeks. Use of routine laxatives was permitted for the duration of the study. Efficacy end points included: 1) weekly bowel movement (BM) frequency compared with baseline, 2) percentage of injections resulting in a BM within 4 hours and 3) BM scales, including Bristol Stool Form, Straining and Complete Evacuation Scales.

RELISTOR Presentations

Poster #376: L. Webster et al. The Long-Term Efficacy of Subcutaneous Methylnaltrexone for the Treatment of Opioid-Induced Constipation in Patients with Chronic Nonmalignant Pain

Poster#378: L. Webster et al. Long-Term Safety of Subcutaneous Methylnaltrexone for the Treatment of Opioid-Induced Constipation in Patients with Chronic Nonmalignant Pain

SOURCE Salix Pharmaceuticals, Ltd.