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 Inhibitex (Nasdaq: INHX), which doubled on Friday, continued their climb Monday, after the company reported strong clinical data for its in-development hepatitis C treatment. The stock popped 24% in early trading before closing up around 14%.

So what: As my Foolish colleague David Williamson points out, Inhibitex's oral drug -- code-named INX-189 -- could threaten to displace more complex treatments from Vertex Pharmaceuticals (Nasdaq: VRTX) and Merck (NYSE: MRK). Vertex, in particular, closed off 9%.

Now what: Action in Inhibtex peer Pharmasset (Nasdaq: VRUS), which closed up more than 4%, could help explain the Vertex sell-off. At the very least, it suggests that investors believe oral treatments are the future for hepatitis C sufferers. Do you agree? Would you buy shares of Inhibitex at current prices? Please weigh in using the comments box below.

Interested in more information about Inhibitex? Add it to your watchlist.

Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn't own shares in any of the companies mentioned in this article at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Google+ or Twitter, where he goes by @milehighfool. You can also get his insights delivered directly to your RSS reader.

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