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 biotech firm Idenix Pharmaceuticals (Nasdaq: IDIX) jumped as much as 11.9% on higher-than-average trading volume.

So what: Bristol-Myers Squibb (NYSE: BMY) and Johnson & Johnson (NYSE: JNJ) just partnered up to study a two-company drug cocktail to treat chronic hepatitis C. The giants hope to find an effective hep-C treatment that doesn't rely on interferons and other injections with severe side effects -- and Idenix's IDX184 happens to target exactly that market.

Now what: Already in phase 2b FDA trials, IDX184 is Idenix's greatest hope for a future blockbuster at the moment. The oral drug is designed to enhance the efficiency of other medications, which is why the stock jumped on today's news -- Idenix doesn't have a big-name partner for the endgame yet and might end up arm-in-arm with J&J or Bristol-Myers. The firm is no stranger to big-name collaborations, having licensed hepatitis B medication Tyzeka to Novartis (NYSE: NVS) for worldwide marketing.

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Fool contributor Anders Bylund holds no position in any of the companies mentioned. The Motley Fool owns shares of Johnson & Johnson. Motley Fool newsletter services have recommended buying shares of Johnson & Johnson and Novartis. We have also recommended creating a diagonal call position in Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinion, but we all believe that considering a diverse range of insights makes us better investors. Check out Anders' holdings and bio, or follow him on Twitter and Google+. We have a disclosure policy.