Progenics Pharmaceuticals, Inc. (NASDAQ:PGNX) and Salix Pharmaceuticals, Ltd. (NASDAQ:SLXP) today announced that the U.S. Food and Drug Administration (FDA) has accepted for filing a supplemental New Drug Application (sNDA) for RELISTOR (methylnaltrexone bromide) Subcutaneous Injection to treat opioid-induced constipation (OIC) in patients with non-cancer pain. The FDA has issued an action date of April 27, 2012 under the Prescription Drug User Fee Act (PDUFA). 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. RELISTOR Subcutaneous Injection has been FDA approved since 2008 to treat OIC in patients with advanced illness who are receiving palliative care, when response to laxative therapy has not been sufficient. Use of RELISTOR beyond four months has not been studied. Bill Forbes, Pharm.D., executive vice president, research and development, and chief development officer at Salix said, “Acceptance of this filing for FDA review is a significant step toward gaining approval for RELISTOR to treat the underlying cause of OIC experienced by the millions of patients taking opioids for non-cancer pain.” Robert J. Israel, senior vice president of medical affairs for Progenics, added, “This sNDA includes results from 31 studies involving more than 4,000 patients. We are pleased to have the FDA review these data in support of RELISTOR’s safety and efficacy in a new indication.” About Opioids, Constipation and RELISTOR (methylnaltrexone bromide) Opioid analgesics are frequently prescribed to manage pain in patients with advanced illness. Constipation commonly occurs in palliative-care patients receiving opioid therapy for pain. RELISTOR is the first approved medication that specifically targets the underlying cause of OIC in these patients, when response to laxatives has been insufficient. Opioids relieve pain by specifically interacting with mu-opioid receptors within the brain and spinal cord. However, opioids also interact with mu-opioid receptors found outside the central nervous system, such as those within the gastrointestinal tract, resulting in constipation that can be debilitating. RELISTOR (methylnaltrexone bromide) is a peripherally acting mu-opioid receptor antagonist that decreases the constipating effects of opioid pain medications without affecting their ability to relieve pain. RELISTOR selectively displaces opioids from the mu-opioid receptors outside the CNS, including those located in the gastrointestinal tract, thereby decreasing their constipating effects. Because of its chemical structure, RELISTOR does not affect opioid-mediated analgesic effects on the CNS.