FDA approves extension for Relistor in Opioid-Induced Constipation - Salix Pharma

The FDA has approved Relistor (methylnaltrexone bromide) Subcutaneous Injection, 12 mg/0.6ml, from Salix Pharma, for the treatment of Opioid-Induced Constipation (OIC) in patients taking opioids for chronic non-cancer pain. Relistor subcutaneous injection is currently the only available peripherally acting mu opioid receptor antagonist that is approved for treating OIC at the cause without interfering with the centrally acting analgesic properties of the opioid.

Approval was based on a Phase III study in which a significantly greater portion of patients taking Relistor 12mg daily reported having three or more spontaneous bowel movements (SBM) per week during the four week double blind period compared to placebo (59% vs. 38%). Following the first dose, 33% of patients in the Relistor 12 mg once daily treatment group had a SBM within 4 hours and approximately half of patients had a SBM prior to the second dose of Relistor. Relistor subcutaneous injection was well tolerated and the adverse event profile was consistent with other studies of Relistor in an advanced illness population. The most commonly reported side effects included: abdominal pain (21%), diarrhea (6%), nausea (9%) and hyperhidrosis (6%).

Relistor Subcutaneous Injection was approved in the US in 2008 for the treatment of OIC in patients with advanced illness who are receiving palliative care, when response to laxative therapy has not been sufficient.