Valeant and Progenics have filed an application in the US to market an oral form of Relistor for opioid-induced constipation in adult patients with chronic non-cancer pain.

The drug’s first approval in the US back in 2008 was as a subcutaneous injection for the treatment of OIC in patients with advanced illness receiving palliative care, and a subsequent green light came in 2014 for OIC patients with chronic non-cancer pain.

Analysts believe an oral formulation of Relistor (methylnaltrexone bromide) could bring in additional annual sales of $500-$750 million.

Around 27 million patients in the US are estimated to take opioids for chronic pain, of which are 40% develop OIC.

Relistor (methylnaltrexone bromide) is a peripherally acting mu-opioid receptor antagonist specifically designed to block the constipating effects of opioid pain medications in the gastrointestinal tract. But cecause it doesn’t cross the blood-brain barrier, the drug offers the advantage of being able to alleviate the effects of constipation without impacting the analgesic effect of the opioid.