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 viral-disease medication developer Idenix Pharmaceuticals (Nasdaq: IDIX) climbed 10.9% on vanishingly thin trading volume.

So what: Idenix specializes in drugs to treat hepatitis C, a disease that is getting some press time these days. Pharma giant Teva Pharmaceutical Industries (Nasdaq: TEVA) has shut down some drug production lines due to a hep-C incident, fellow hepatitis fighters Pharmasset (Nasdaq: VRUS) and Vertex Pharmaceuticals (Nasdaq: VRTX) are held up as stock market champions on their drug-induced mega-gains -- and last week, analyst firm Baird identified Idenix as one of "the only currently investable pure-plays" in this market alongside Inhibitex (Nasdaq: INHX).

Now what: The lack of volume shows the distance to news that mostly happened last week, though the aftermath of Hurricane Irene has limited trading volumes in even the most popular stocks on the market today. Anyhow, the size of the move illustrates the enormous market for hepatitis drugs. Indenix shares have bounced around over the last year, just about doubling in six months but also at one point falling more than 40% from recent 52-week highs. Until the company gets its first true-blue FDA stamp of approval, investing here requires a liver of steel.

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