For investors in the biopharma arena, there's no voice more important than the Food and Drug Administration's. It's for this reason that FDA advisory committee hearings this week are keeping investors in certain stocks on the edge of their seats.

Share prices can exhibit significant volatility around these meetings and when the briefing documents are released two days prior. And while a committee's vote can conflict with the ultimate FDA decision, the two tend to have a strong correlation.

In some instances, the outcome of a committee meeting is so material that trading in shares is frozen on the day of the meeting, as is the case today as the Gastrointestinal Drugs Advisory Committee reviews NPS Pharmaceuticals' (UNKNOWN:NPSP.DL) short-bowel-syndrome drug Gattex.

On Wednesday and Thursday, the Endocrinologic and Metabolic Drugs Advisory Committee is meeting to review LDL cholesterol-lowering drugs from Aegerion (NASDAQ:AEGR) and Isis Pharmaceuticals (NASDAQ:IONS). Aegerion's briefing documents, released Monday, suggest a positive committee outcome and eventual FDA approval for its drug lomitapide, which is focused on a narrower subset of patients suffering from homozygous familial hypercholesterolemia.

While Aegerion shares are trading about 15% higher than Friday's closing price, shares of Isis are trading more than 15% lower after following today's briefing document release. The document outlines safety risks around Isis' drug mipomersen, developed in conjunction with Sanofi's (NYSE:SNY) Genzyme unit, including increased cancer risk for patients receiving the drug relative to the placebo group. The trial also exhibited a high dropout rate, a negative for any drug targeting a chronic condition such as hypercholesterolemia.

While today's news is certainly negative for Isis shareholders, it doesn't mean that the drug is a failure. After all, homozygous familial hypercholesterolemia is a deadly condition with few options for treatment. Instead, today's action reflects the increased likelihood that mipomersen won't be able to achieve more expanded approvals outside of homozygous familial hypercholesterolemia in the future.

Brenton Flynn has no positions in the stocks mentioned above. The Motley Fool has no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.