* Co seeks OK for Vivitrol to treat painkiller addicts
* Alkermes drug already cleared for alcoholics
* Sales could reach $125 million with wider use - analyst
* Shares down 1.4 percent
* FDA panel to review Vivitrol on Thursday (Adds detail from documents, analyst comment, byline, updates shares)
By Susan Heavey
WASHINGTON, Sept 14 Alkermes Inc's (ALKS.O) drug to help wean alcoholics from drinking appears to also help treat people addicted to certain painkillers based on a small, limited study, U.S. regulatory staff said in documents released on Tuesday.
But the Food and Drug Administration staff said the data was based on a single study in patients who were somewhat different than the target ones and the agency would ask its panel of outside experts on Thursday whether it was enough to back wider use of the drug called Vivitrol.
Sales could reach $125 million by 2015 if it wins the additional approval, said Steve Yoo, an analyst for Leerink Swann Research.
Although several analysts saw little harm in the FDA's comments and expected a positive review by the agency's advisers, Alkermes shares were down 20 cents, or 1.4 percent, at $14.10 in early afternoon trading on the Nasdaq.
The once-monthly injection of the drug was approved in 2006 to treat alcohol dependency, but the biotechnology company is now seeking clearance to market it for patients addicted to opioid painkillers.
On Thursday, an FDA panel of outside experts will recommend whether to approve the new use and the FDA is expected to make the final decision by Oct. 12.
Such an expansion could be a boost for Alkermes, which has just one other product on the U.S. market.
Net sales from Vivitrol were $20.2 million for fiscal 2010, compared with $16.9 million for 2009 for Alkermes and its then-partner Cephalon Inc CEPH.O, according to Alkermes.
But it costs the company roughly $40 million to make and sell the drug, said Leerink's Yoo.
"Therefore, the opioid dependence indication is critical for commercial success," he added.
The Cambridge, Massachusetts biotech has seen its shares rise more than 50 percent so far this year ahead of the anticipated expansion. It is also awaiting an FDA decision on its diabetes drug Bydureon.
Alkermes, in a separate document also released on Tuesday, said approval of the drug was key to getting more opioid drug addicts to receive treatment. Data showed the drug was effective and well tolerated "with broad and substantial impact on a devastating disorder," it wrote.
"We agree with Alkermes that the efficacy study provides convincing evidence that Vivitrol prevents relapse to opioid use in recently-detoxified opioid-dependent patients," FDA staff wrote in documents released ahead of the meeting.
However, agency reviewers also noted the study was done in people with "demographic, cultural, and societal differences from the target population."
FDA staff also said that, while no new safety issues were found with the drug, the company's most recent Russian-based study turned up fewer reported problems than a U.S. study done for the company's first approval, "perhaps due to cultural factors."
Pricing and other issues have kept the drug from taking hold so far among alcoholics, according to some analysts who see a potentially better market with opioid addiction.
"We do not think investors are placing much weight in the expansion of Vivitrol into opioid dependence and think a positive panel recommendation could give a positive boost," said Jon LeCroy, a senior analyst for Hapoalim Securities USA Inc, in a research note earlier this month.
While doctors are already free to prescribe FDA-approved medications as they see fit, formal FDA approval allows the drugmaker to legally market the new use to physicians and patients without risking fines or other legal action.
Still, even if the company wins FDA approval, there are risks. The drug is the first one the drugmaker has had to market and sell by itself, having ended its partnership with Cephalon in December 2008.
"We have very little sales and marketing experience," the company wrote in its annual report filed in May. (Reporting by Susan Heavey; editing by Dave Zimmerman and Andre Grenon)