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 drugmaker Regeneron Pharmaceuticals (Nasdaq: REGN) popped 10% in intraday trading Friday after The New York Times reported that Roche's age-related macular degeneration treatment Avastin led to vision loss in several California patients.

So what: Given Regeneron's big jump, it's obvious that Mr. Market believes the news increases the likelihood that its own ophthalmic solution, Eylea, will eventually be approved by the FDA. Of course, biotech Fools know to judge a drug's potential on its own merits, so today's rally in Regeneron should be taken with a grain of salt.  

Now what: Even without the Times story, Regeneron's Eylea was clearly the better bet. According to analysts, efficacy data so far shows that Eylea works much faster than Avastin and only needs to be taken every-other-month (versus monthly for Avastin). Of course, Regeneron is up about 150% over the past year, so investors still need to tread cautiously. 

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Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Fool's disclosure policy always gets a perfect score.