Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of drug maker Amylin Pharmaceuticals (Nasdaq: AMLN) jumped 13% today after the company released a positive drug announcement.

So what: Diabetes treatment Bydureon has been recommended for approval by Europe's Committee for Medicinal Products for Human Use. The drug is being developed with Alkermes (Nasdaq: ALKS) and Eli Lilly (NYSE: LLY) in a partnership that has had a rocky road to say the least.

Now what: After being pummeled when Bydureon failed to meet primary endpoints in a study last month, this is certainly good news for shareholders. Considering the volatile nature of the stock and constant surprises one way or the other, it's still a risky proposition to buy on this news. I'm going to stick firmly on the sidelines, considering the stock has let investors down more than once before.

Interested in more info on Amylin Pharmaceuticals? Add it to your watchlist.