Merck and class action litigation are a crap shoot IMO. There is no doubt that class action lawsuits will be filed. Rumor has it the first one already has and there will be many more. Of course, they will all be consolidated in a procedure lawyers refer to "THE AWARDING OF THE PINATA" AKA as the GRANTING OF LICENSE TO STEAL.
The question is how much of a hit will they take.
1. Merck did not do anything especially wrong. The drug was approved legally, the trials were of normal power.
2. This side effect only shows up after 18 months. This is a long time.
3. The effect is slight. To definitely show it takes large numbers of patients followed for years to get the statistics.
4. People who take vioxx tend to be old, sick, and suffering from serious pre-existing conditions. Otherwise,....they wouldn't be taking it. Some of those will have heart trouble anyway. I believe it was above placebo, stat sig. The point here is that less than 1/2 of the heart attack pool can be ascribed to vioxx. People who submit medical records with a long history of heart trouble and pre-existing conditions might have a problem collecting.
5. Irregardless of whether Merck takes a hit or takes a hit and sinks, this will drag out for many, many years.
I think the lawyers can show injury. They will have a hard time proving negligence. The above being said, see my opening paragraph. It is still a crap shoot, those are some of the faces of the dice.