BANGALORE (Reuters) - Progenics Pharmaceuticals Inc (PGNX.O: Quote, Profile, Research) and partner Wyeth (WYE.N: Quote, Profile, Research) said their bowel drug, Relistor, received marketing clearance from Canadian authorities, sending Progenics' shares up as much as 18 percent.

The news comes as a relief to the companies that last month said the drug, chemically called methylnaltrexone, failed a late-stage U.S. trial in post-operative ileus (POI), a gastrointestinal disorder.

The companies said Health Canada, a regulatory body, approved the subcutaneous form of the drug to treat patients with another bowel malaise -- constipation caused by use of opioid painkillers, or opioid-induced constipation (OIC).

The drug had faced severe criticism from analysts, who said it may not succeed in another POI study.

POI is common after bowel resection surgery, and is marked by stomach bloating and pain, nausea, and constipation. No drugs are approved to treat POI.

RAY OF HOPE

"This is the first approval of Relistor and may indicate a higher likelihood of approval for Relistor in the U.S. and E.U. where applications are under review," Lazard Capital Markets analyst Joel Sendek said in a note.

Sendek said there is a 50-50 chance of the drug getting U.S. Food and Drug Administration's marketing approval on the due date of April 30. The agency may want to review safety data from previous trials, which could delay approval, he said.

Sendek, who kept a "hold" rating on the stock, projected $35 million sales for the drug in 2008 for opioid-induced constipation.