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: Cholesterol drugmaker Esperion Therapeutics (NASDAQ:ESPR) fell by over 23% on tremendous volume today. The catalyst behind this massive downward move was the recent Food and Drug Administration's Advisory Committee meeting for Sanofi and Regeneron's injected cholesterol lowering PCSK9 inhibitor known as Praluent (alirocumab).

The committee voted thirteen to three to recommend approval of Praluent, but the consideration of a handful of different sub-populations resulted in quite a few caveats on the committee's recommendation. Specifically, nine of the sixteen experts on the panel were decidedly against approving the drug for so-called "statin intolerant" patients -- the exact patient population Esperion is targeting with its experimental cholesterol pill ETC-1002. The problem is that statin intolerance is a medically fuzzy phrase, and includes patients that experience adverse effects to statins such as Crestor, as well as individuals that simply refuse to take a statin. 

So what: ETC-1002 is a key clinical product for Esperion, given that it was believed to have blockbuster potential prior to yesterday's advisory committee meeting. But now the drug may have a hard time even gaining a regulatory approval in the U.S.

Now what: The FDA's final decision on Praluent, as well as its potential label, will undoubtedly have a major impact on how Esperion decides to move forward with ETC-1002. Right now, it's looking like ETC-1002 is going to face an uphill battle with the FDA for its current indication, and that doesn't bode well for Esperion's stock moving forward. That's why it's probably best to avoid this falling knife for the time being.