Its a volatile stock in a volatile sector. Lots of reasons why Vertex has gone up and down and many of them have nothing to do with the drug itself, but rather the competitive environment, guesses as to when it will get FDA approval, as well as trading patterns.
In terms of relative performance, Vertex was slightly up for the past year which puts it ahead of most stocks in this recessionary market. I also believe Vertex was Nasdaq's best performer for the first quarter of 09 and possibly the only Nasdaq stock showing a gain during that period.
Here's how Vertex looked over the past year:
http://finance.yahoo.com/echarts?s=VRTX#symbol=VRTX;range=1y
From an investment standpoint I was initially long on Vertex because I believe in the drug. Later, I still believed in the drug, but short on Vertex in the market because at the time the entire sector was falling. Currently, I'm out of Vertex and the market cause things are really a mess investment wise.
As far as "good news" is concerned, remember stocks often are priced on the future and therefore frequently rise on rumored news but actually fall on the event itself, i.e. the advice "buy on the rumor, sell on the news".
-- Jim