Icahn boosts stake in Amylin

Guess who's knocking at Amylin Pharmaceuticals' door? None other than activist investor Carl Icahn, who boosted his stake in the company to 10.1 million shares, or 7.3 percent. Known for rattling the doors of executive suites--and pushing for M&A deals--Icahn could already be eyeing his next biopharma project.

Icahn owns a chunk of Biogen Idec, the company he pushed onto the sales block last year. Though that bidding process failed to turn up a buyer, Icahn is still pressing Biogen to make a deal, saying it didn't try hard enough the first time around. Meanwhile, as chairman of ImClone, Icahn is in a contest of wills with Bristol-Myers Squibb CEO Jim Cornelius, who offered $60 a share for the company. Icahn says he has a $70-per-share buyer in the wings, but with that bid contingent on due diligence, he and Cornelius have been trading accusations via letter.

What's Icahn's interest in Amylin? The company sells the diabetes med Byetta in partnership with Eli Lilly, and as you know, the drug came in for some controversy last week when the FDA announced several severe cases of pancreatitis among Byetta patients. But its follow-up med, a once-weekly version, won some research kudos for controlling blood sugar better than Merck's Januvia.

And that controversy may be the simple reason: Amylin stock plummeted on the news, so Icahn had a chance to buy low. Still, the move shows a confidence in Amylin that investors haven't exactly shared recently. Will the market now follow Icahn? We'll have to wait and see.

- read the CNBC story