Tuesday marks a significant stage for hundreds of British people seeking compensation over health problems which they say were caused by the painkiller Vioxx.
Merck is facing thousands of lawsuits related to Vioxx
Legal arguments are being heard in the US to see whether hundreds of British claims can be considered by the American courts.
BBC health correspondent Jane Dreaper has been finding out more.
Fred Myers, who is 68 and from Mattishall in Norfolk, is practising his golf swing - but the effort is leaving him breathless.
Mr Myers, who has always prided himself on his fitness, took Vioxx for more than two years for his arthritis.
Like many sufferers, he found that traditional drugs for treating arthritis left him with side-effects and stomach problems.
"Then the doctor told me they had a new drug - Vioxx - and lo and behold, it was good," said Mr Myers.
But 19 months after beginning on Vioxx, Fred had a heart attack, which has had a big effect on his life.
"I've kept fit all my life - and done all the things doctors tell you you should do - don't smoke, don't drink too heavy, don't eat fatty food.
"The heart attack has altered my life so much in the things I can do. If the wind is blowing hard, I get breathless and I can't enjoy my golf.
"I go to heart rehabilitation classes in the village. You have to cope with it and live life as best you can. But you haven't got that energy behind you."
Almost 500,000 people in the UK were on Vioxx when its makers Merck took it off the market in 2004 after a long-term study found that the risk of heart attacks and strokes was doubled if patients took the drug for 18 months.
And then last August a jury in Texas awarded a multi-million settlement to the widow of a man who died suddenly after using Vioxx.
The court heard claims that Merck had played down safety fears about the drug for a decade.
Lawyers in this country had been watching the case closely - they are now representing at least 400 claimants, though there've been lots of inquiries and that number could go up.
Success for Mr Myers and the other British claimants is by no means certain.
There have already been cases relating to six people who took Vioxx heard in the US so far - and Merck has been found not liable in three of them.
The company has argued each time that its doctors and scientists acted in good faith - and they did not hide data on the drug.
And on Tuesday afternoon a jury awarded £5m in damages to a man who had a heart attack after four years on Vioxx.
Lawyers for the British claimants said they cannot get the cases heard here. They have been refused legal aid and insurers will not fund no-win, no-fee cases.
All the cases are taking place in New Jersey because that is where Merck's headquarters are.
Merck wants the foreign cases dismissed, arguing that they should be heard in their own countries.
Because of the publicity that there has been over Vioxx, lawyers have huge numbers of people calling about it.
Ann Alexander is a solicitor who represents Mr Myers and dozens of others. She said it is important to test the cases where people have had the more serious injuries.
"I think there's no doubt that something like this can lead to tenuous claims.
"We had an incredible number of phone calls from people who had taken Vioxx - some of whom had just severe headache, for example, and wanted to know whether or not this was an easy way for them to claim compensation.
"And I also know there are lawyers in the US who are pursuing claims which have had a far less serious effect of injury on their clients."
The judge in New Jersey is considering what should happen to the British cases - and that decision may not come for weeks, maybe even months - and if the cases are heardin America, they'll each be considered individually.
Overall, Merck is facing 9,500 cases. We will be hearing about this story for some time to come.