The FDA has informed Salix Pharmaceuticals (SLXP) that Relistor (methylnaltrexone bromide) can be approved for the treatment of constipation in patients taking opioids for chronic non-cancer pain (OIC) based on data submitted in the current New Drug Application, though the drug is not yet approved. Relistor is currently limited to a small fraction of the OIC market: patients with advanced illness receiving palliative care when laxatives have been insufficient. SLXP was unmoved in morning trading, though small-cap drug partner Progenics Pharmaceuticals (PGNX) climbed 13% on the news; if Relistor is approved in the expanded indication, PGNX will receive a $40 million milestone payment from Salix.
The FDA rejected the same supplemental New Drug Application in mid-2012.
In accordance with recommendations from the June meeting of the Anesthetic and Analgesic Drug Product Advisory Committee, FDA will not require long-term cardiovascular outcomes studies for Peripherally Acting Mu-Opioid Receptor Antagonists, like Relistor, before approval. FDA is, however, requiring a post-marketing observational study of Relistor to assess the relative incidence of Major Adverse Cardiovascular Events (MACE) when compared to another approved OIX product. Salix will submit proposals for the planned MACE study within the next few weeks, as well as proposed product labeling.
Progenics receives a 15-19% teired royalty on US sales of Relistor and splits revenue with Salix on ex-US sales. The companies are also developing a fully oral version of Relistor, and Progenics will receive a $50M milestone on its approval. Monday’s press release includes no details on oral Relistor.
