If you look at biotech stock's reactions to positive Adcomm votes, you'll see that there is usually a large increase in the pps, (but not always). Unlike FDA approval at PDUFA date, subsequent to the Adcomm, the price tends to build a base after Adcomm, then increase into PDUFA. Two recent examples are VVUS and ARNA. While the market cap is unlikely to ever get to $2B, like the companies I mention, it now sits at $460M with upside to over $1B. Much of the appreciation could happen in the coming 2 days based on the Adcomm vote for AEGR, then followed on Thursday by the (now) potential negative vote for ISIS. One reason is that the market had always expected better than 50% market share, if approved, due to efficacy versus ISIS, but that may now change to much higher if ISIS gets a negative vote. The negative briefing docs for ISIS, especially the 7 questions the Adcomm have to consider, were not expected and give more potential upside to AEGR. As well, if you look at the last two years of AEGR charts, combined with the low market cap, it would be hard to argue that a positive Adcomm and eventual approval are priced in. There are lots of safety concerns for Lomitapide as well, so an overwhelmingly positive Adcomm is no slam dunk, even after the positive briefing docs. More reason to believe it's not completely priced in and a pop could occur.
VVUS and ARNA both increased 75%+ at Adcomm, then another 50% leading to PDUFA date. While there were reasons for this, (low market caps, prior negative Adcomm's, larger market for the drugs in question, etc), there is at least a chance AEGR sees $25 when it re-opens after the Adcomm (it will likely be halted throughout the meeting), then maybe even $30 if ISIS gets a negative vote on Thursday. Even at $30, the market cap would still only be $800M.