Doesn't look like billionaire Carl Icahn is worried about the recently reported pancreatitis cases from Amylin Pharmaceuticals' (NASDAQ:AMLN) Byetta. The investor upped his stake in the drug company by almost 50% and now owns 7.3% of the company.

Icahn obviously sees value in the company at these fire-sale prices and realizes that when investors panic is often the best time to invest.

We haven't heard much from Icahn about what his plans are for Amylin since he took a stake in the company back in May. Then again, the Investor of the Year nominee has been a little busy between failing to get Yahoo! (NASDAQ:YHOO) and Biogen Idec (NASDAQ:BIIB) sold off and now having to deal with ImClone Systems (NASDAQ:IMCL) being bid on by Bristol-Myers Squibb (NYSE:BMY). It's understandable that Icahn might not want to get into a fight with management at this point.

When he does finally get around to dealing with Amylin, I think it's more likely that Icahn will try and shake up management rather than trying to get Amylin sold. With Amylin's major drug Byetta and its once-weekly successor already partnered up with Eli Lilly (NYSE:LLY), it could be hard to get a bidding war going. Then again, ImClone is partnered with Bristol-Myers and Icahn was able to find a mystery bidder to stir the pot, so maybe he can pull another rabbit out of the hat for Amylin as well.

Investors seem to be following Icahn's lead today and have sent the stock up more than 5% on a day when almost everything else is tanking. Call me the eternal optimist, but now may be the perfect time to be greedy.

Biogen Idec is a Stock Advisor recommendation. Eli Lilly is an Income Investor pick. Try any of our Foolish newsletters today, free for 30 days.

Fool contributor Brian Orelli, Ph.D., likes it when billionaires agree with him. He doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.