Amylin shares crater after FDA rejects Bydureon app

In a stunner, Amylin, Alkermes and Eli Lilly have been handed another major setback in their long quest to get the new, once-weekly diabetes treatment Bydureon to the market. The FDA has issued a complete response letter rejecting their request for an approval and demanding a new safety study focused on its cardiovascular concerns. In premarket trading, Amylin shares (AMLN) plunged 49 percent on the news.

In a release, Amylin said that the FDA is requiring a "thorough QT (tQT) study with exposures of exenatide higher than typical therapeutic levels of Bydureon." In addition, the agency wants to see the results of the Duration-5 study "to evaluate the efficacy, and the labeling of the safety and effectiveness, of the commercial formulation of Bydureon."

The New York Times' Andrew Pollack notes that the agency, which has been highlighting stricter requirements on studying potential cardiovascular safety issues related to diabetes drug, appears to be most concerned that the drug can build up in the body if it isn't adequately flushed. The FDA's delay, its second for Bydureon, caught investors flatfooted. 

The demands add up to a substantial delay for the developers, who have been pursuing plans to make Bydureon into a blockbuster therapy in the fast-growing diabetes market. Now they say they'll need until the end of next year to hand over the new data and then face a further six months of review, putting off any market launch until at least mid-2012.

The news will hit Amylin the hardest. The biotech has been devoting much of its time and resources to gaining an approval on Bydureon, which is designed to follow in the footsteps of Byetta. Alkermes is in line for a beefy royalty stream that starts at 8 percent for the first 40 million units and then slides down to 5.5 percent. And while Lilly has plenty of Big Pharma revenue to fall back on now, CEO John Lechleiter had flagged Bydureon as an example of its commitment to bringing innovative new drugs to the marketplace. A rejection at this stage helps reinforce criticisms of Lilly's pipeline strategy.

- here's the press release

ALSO: Novo's Victoza may gain on Bydureon delay. Report