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What: Shares of hepatitis C drug developer Inhibitex (Nasdaq: INHX) felt ill today, with shares down as much as 17%, over continued safety concerns with its drug INX-189.

So what: Last month, rival Pharmasset (Nasdaq: VRUS) reported some safety issues with its own similar drug, crushing others in the sector and setting the stage for investor skittishness. This morning's sell-off may be attributed to cautious comments from Bank of America Merrill Lynch analyst Rachel McMinn.

Now what: McMinn said that there could be a lot of downside if safety issues arise, although she believes the risk-reward balance is still positive. Inhibitex is conducting a study to evaluate different dosages, and the interim results of the study are expected within this month or next. Shareholders are anxious that INX-189 may share too many similarities with Pharmasset's PSI-938.

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Fool contributor Evan Niu holds no position in any company mentioned. Check out his holdings and a short bio. The Motley Fool owns shares of Bank of America. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.