It's really good news if you know how to play the market. Unlike Merck, Pfizer has a very successful drug line, so Pfizer still remains a very profitable company. Also, since Pfizer let the news slip in mid december, it means investors can sell their stock at a loss at the end of the year to garner a tax loss. This means that the stock will most likely be cheapest in January after the flaky investors pull out.
Since Pfizer makes up a huge percentage of pharmaceutical mutual funds and indexes, this makes financial institutions sell these stocks and depress (I think unfairly) the stock price of other drug companies that don't even have cox-2 inhibitors in their drug line. This makes the other drug companies look more attractive and we should see their stock price increse shortly.