Yes, bio stocks are always halted for Adcoms (T1 Halt - News Pending: Trading is halted pending the release of material news), and the halts are usually lifted in AH after Adcom votes, so if you want to sell or buy with anything other than a risky market order you have to have the trade placed before 4:00 - with TDA you can hide your intentions by using a Trade Trigger, with Time in Force either day + AH or GTC + AH.
You can see when the halt will be lifted by watching here, remember to refresh every hour or so:
Market Data 
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