Looks like Carl Icahn has had enough of letting Amylin Pharmaceuticals (NASDAQ:AMLN) be a free spirit.

Ever since he purchased shares last May, he seemed to be content just leaving the company alone -- the activist investor even grabbed some more shares late last year without making a stink. But it seems that he's had enough and has decided to nominate a slate of five directors for the board.

Welcome to the club, Amylin. Talk to your friends over at Biogen Idec (NASDAQ:BIIB) and ImClone to hear exactly how fun the board fight can be.

Apparently, since he owns 8.3% of the company, Amylin had been discussing placing two individuals suggested by Icahn on the company's recommended slate. I guess Icahn was either worried that he wouldn't get those seats, or he just wants more control. Even if he gets his five members on the board, Icahn can't quite take full control of the board because there are 12 seats on the board.

The big question is what Icahn plans to do with Amylin if he gets some control. Sales of diabetes drug Byetta, which it markets with Eli Lilly (NYSE:LLY), fell almost 8% year over year last quarter because of reported potential issues with pancreatitis. Unless he plans to get out and help the sales reps explain to doctors that the benefits still likely outweigh the risks, I'm not sure how Icahn could improve sales there.

He could cut costs at the unprofitable drugmaker -- research & development was 35% of revenue last year -- but R&D is pretty important at biotech firms. Amylin's long-term future is tied to its once-weekly version of Byetta, which is in head-to-head trials against Merck's (NYSE:MRK) Januvia, Takeda's Actos, and metformin, the long-genericized version of Bristol-Myers Squibb's (NYSE:BMY) Glucophage. It's going to need the trial results to win over doctors and patients once the once-weekly drug hits the market.

The last option, and perhaps the most likely given Icahn's track record, is selling the company. It's anyone's guess whether Amylin would follow the route of MedImmune (bought by AstraZeneca (NYSE:AZN) in 2007) and ImClone (bought by Lilly last year) or be stuck in limbo as Biogen and Yahoo! (NASDAQ:YHOO) have become.

I'm sure some bottom feeder would be happy to pick up Amylin on the cheap; I'm just not sure Icahn can get very much of a premium until positive head-to-head trials are released.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.