Somewhere, sometime, when people digest this "news" and stop being so reactionary about this label (for a drug that is best in class) there is going to be a great buying opportunity; heck, it might have even been yesterday. I'm gonna wait to see how it plays out.
But, I am not surprised about the selloff---almost every FDA approval has resulted in a "sell the news"; the black box label only accellerated it (ppl sold, without asking.....no one wants to be the last one out the door especially when institutional ownership is at 80%). Further, these same people have probably WANTED a reason to lock in their low long-term cap gains rates.....those same people can literally sell, lock in rate, and buy back immeidately (there is no wash sale rule on gains)...if they think its going up in the long term.
FWIW