(Corrects spelling of "Movantik" throughout)
By Natalie Grover
Sept 16 (Reuters) - The U.S. Food and Drug Administration approved an oral therapy to treat opioid-induced constipation developed by Nektar Therapeutics and AstraZeneca Plc .
The decision opens the door for peripherally acting mu opioid receptor antagonists, which have been linked with cardiovascular risk in the past.
This class of opioid-induced constipation (OIC) drugs are designed to fight the effects of opioid painkillers on the gut without compromising centrally mediated pain relief.
The drug, known generically as naloxegol, will be sold under the trade name Movantik, and is indicated for patients on opioids for pain unrelated to cancer. (http://1.usa.gov/1qbvs7U)
It will benefit from a two-three year advantage over other therapies undergoing development, Roth Capital Partners analyst Debjit Chattopadhyay said.
An FDA panel had recommended in June that large cardiovascular safety trials were not needed before approval for this class of drugs.
The agency on Tuesday asked the developers to conduct a postmarketing study to further evaluate the potential risk of heart-related side-effects.
The panel had met after a late-stage study showed Cubist Pharmaceuticals Inc's OIC drug, Entereg, was associated with a greater number of heart attacks.
Constipation is the most frequent side effect associated with long-term opioid therapy.
Only 40-50 percent of patients experience effective relief from currently available over-the-counter medicines or Sucampo Pharmaceutical's stool softener Amitiza, Nektar said.
Movantik will likely compete with Salix Pharmaceuticals Ltd and Progenics Pharmaceutical's subcutaneous injection Relistor - slated for an FDA decision this month for the same patient population.
Relistor was first approved in 2008 to treat OIC in severely ill patients, receiving palliative care, who were unresponsive to laxatives.
AstraZeneca's deep pockets and the fact that Movantik is orally administered gives it the best possible market positioning, Chattopadhyay said.
"If you look at the way they structured the deal with Nektar, clearly they think this is a multi-billion dollar drug," he said.
Movantik is also being reviewed by European and Canadian regulators.
Chattopadhyay said he expects it to launch in the United States by the first quarter of 2015, and in Europe the following quarter.
Nektar discovered Movantik, using its proprietary technology, and licensed the compound to AstraZeneca in 2009.
The company is eligible to receive up to $235 million if Movantik achieves some regulatory milestones, and additional sales milestones of up to $375 million.
Tuesday's approval is crucial for Nektar, which has been unable to significantly benefit from prior deals - despite multiple successful approvals for drugs co-developed by it.
The appointment of Chief Executive Howard Robin in 2007 led to a marked shift in strategy, which evolved in order to better monetize Nektar's technology.
"Since Robin has come on board...all cases they are getting a high dollar amount up front and pretty significant milestones, with high double digit (20-30 percent) royalty streams," Chattopadhyay said.
(Reporting by Natalie Grover in Bangalore; Editing by Joyjeet Das)