By Sophie Hutchinson
BBC News, Health correspondent
Hundreds of British patients who claim they had heart attacks after taking the drug Vioxx have lost the right to fight for compensation in the US.
Merck is facing thousands of lawsuits related to Vioxx
A New Jersey court ruled the patients must challenge the US pharmaceutical company Merck in the UK courts.
Vioxx, an anti-inflammatory drug, used to treat arthritis pain, was withdrawn from the market in 2004.
A long-term study had found the risk of heart attacks and strokes was doubled if patients took it for 18 months.
Almost 500,000 people in the UK were taking Vioxx when its US producers Merck removed it from sale.
Lawyers representing some of the British patients have stressed their disappointment at the news.
They insist this was their clients last chance to have their cases heard.
They say they have been refused legal aid and insurers will not fund a no-win, no-fee cases in the UK.
Sallie Booth, from Irwin Mitchell solicitors, which represents nearly 100 claimants in the UK, said "This is hugely disappointing for UK victims of this drug.
"Whilst they should not be forced to look to a foreign jurisdiction to determine their cases, the restricted availability of funding for claimants in group actions in this country, especially public funding is having the effect of denying these people proper access to justice.
"However we will now carefully review all alternative options for our clients."
"Drug companies must realise the huge responsibility they have to produce safe and reliable drugs.
"Profit cannot come before safety, their very business is to produce the solution they must not become the problem."
It is understood Merck, which was this week suspended from the Association of the British Pharmaceutical Industry for an unrelated matter, is facing more than 21,000 claims worldwide from people claiming Vioxx made them sick.
The company's lawyers stress that there is no proven link between heart problems and the use of the drug for less than 18-months.
They also argue other risk factors such as high cholesterol, clogged arteries, old age and smoking may have caused the heart attacks.
So far the company has won five cases but lost four.
In August a widow in Texas won $253.4m (£141.07m) damages after a jury accepted that her husband had been killed by the drug.
During the court cases lawyers have argued that Merck cut corners when developing Vioxx and rushed it through the approval process in half the time normally taken.
The company vigorously denied these claims, stressing that the drug was thoroughly tested before it went on sale.