Amylin Pharmaceuticals Inc.'s (AMLN) stock is getting a boost Friday after a published analysis that downplays the pancreatic risks of its diabetes drug Byetta, but investors will likely need more insight before regaining confidence in the battered drug maker.

Shares of the San Diego-based Amylin recently rose 7.4% to $10.80, but it remains down 70% from its August high of $34.80.

The data, found in a journal called Current Medical Research and Opinion, provide some reassurance to investors concerned about looming label revisions and slowing drug sales, both of which were prompted by reports about deaths of patients on Byetta.

Amylin has previously alluded to the findings of the analysis, which was funded by the company and its marketing partner Eli Lilly & Co. (LLY). It uses an insurance company database to show that neither Byetta nor Merck & Co.'s (MRK) Januvia increased the risk for pancreatitis, an inflammation of the pancreas.

In August, news about the deaths led the FDA to start working with the companies to add stronger warnings about severe pancreatitis to the drug's label. The label revision is expected soon, but its delay also has put off FDA approval for Byetta's use as a monotherapy.

Because diabetes patients have a higher incidence of pancreatitis than the general population, Amylin has stressed that Byetta's use doesn't statistically increase the likelihood of pancreatitis complications or death.

The pending label changes show that FDA seems to differ in that opinion.

The regulatory uncertainty has raised worries that the FDA will want more studies on a longer-acting version of Byetta, in development with Alkermes Inc. (ALKS) and expected to launch in 2010.

The launch and timing of that new drug, which Lazard Capital Markets expects to have $1.8 billion in sales as soon as 2012, is seen as vital to the unprofitable Amylin as sales growth of Byetta rapidly decelerate.

U.S. sales of Byetta grew almost 50% in 2007 to $636 million, but they only rose 6% in 2008 to $679 million.

Those sales could come under greater pressure in mid-2009 when Novo Nordisk A/S (NVO) is expected to launch liraglutide, which works in a similar manner but is taken daily, compared to Byetta's twice a day.

-Thomas Gryta; Dow Jones Newswires; 201-938-2053; thomas.gryta@dowjones.com