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 hepatitis-C-focused research company Idenix Pharmaceuticals (NASDAQ:IDIX) dipped as much as 16% after the company received an unfavorable initial ruling from the U.S. Patent and Trademark Office in regards to a patent dispute filed against Gilead Sciences (NASDAQ:GILD).

So what: The patent dispute -- which covers certain 2'-methyl-2' fluoro nucleoside compounds used in hepatitis-C treatment -- was filed by Idenix last March. Today, the U.S. Patent and Trademark Office in the first phase of its judgment determined that Gilead is the senior party and that Idenix is the junior party. In short, their determination was that Gilead was the first party to file for a patent application for the above nucleoside compounds. The next phase of the trial will determine which party is the first to invent.

Now what: I had always thought Idenix’s patent dispute with Gilead was a bit of a stretch. Now, with the company being named the junior party in the initial phase of its patent trial, there appears a much slimmer hope that it'll be declared the inventor and patent holder of these nucleoside compounds. Idenix has had a miserable past year with its previous leading compounds placed on clinical hold following the death of a patient in a Bristol-Myers Squibb (NYSE:BMY) trial for BMS-096984, which shares some nucleoside similarities to Idenix's pipeline. To add, Gilead’s Sofosbuvir is cleaned up in all four late-stage trials and looks well on its way to becoming a blockbuster. To conclude, even after today’s tumble, Idenix still has plenty of caution tape draped all over it.

Craving more input? Start by adding Idenix to your free and personalized watchlist so you can keep up on the latest news with the company.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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