A blockbuster drug launched five years ago as
a revolutionary treatment for arthritis may have caused up to
140,000 heart attacks in US patients of whom 44 per cent died,
scientists said yesterday, making it the world's worst drug
disaster.
Vioxx, a new type of painkiller launched in
1999, was one of the most heavily promoted drugs in history,
with sales in 80 countries and a global market of 80 million
patients.
More than 400,000 patients were taking it in
Britain, where it could have caused up to 1,000 heart attacks
and deaths.
Last September, the manufacturer, Merck &
Co, withdrew the drug from the market after evidence emerged
linking it with heart problems.
Now, a study of 1.4 million people in
California shows that those taking Vioxx had a one-third higher
chance of having a heart attack than those taking other
painkillers.
David Graham, of the US Food and Drug
Administration, and colleagues concluded: "An estimated
88,000 to 140,000 excess cases of serious coronary heart disease
probably occurred in the USA over the market life of rofecoxib [Vioxx].
The US national estimate of the case-fatality rate was 44 per
cent, which suggests that many of the excess cases attributable
to rofecoxib use were fatal." The results, published online
by The Lancet, will be seized on by critics of the
pharmaceutical industry as evidence of the failure of the drug
regulatory system to protect the public. Dr Graham had earlier
estimated that Vioxx may have caused up to 27,000 heart attacks
but the new study caused him to upgrade the estimate by five
times.
Doctors on both sides of the Atlantic have
warned of a public health emergency over other painkillers in
the same class, known as Cox-2 inhibitors, which could also pose
a risk.
A report in The New England Journal of
Medicine last October said studies since 1999 had repeatedly
indicated a danger with Vioxx. Drug regulators made Merck
include a warning in the drug package but never ordered a
definitive trial.
Professor David Webb, of the clinical
pharmacology unit at the University of Edinburgh, says in The
Lancet: "It falls to the manufacturers, under the careful
review of the regulatory authorities, to provide evidence that
this class of drugs is safe."
Asked if this was the worst drugs disaster in
history, Professor Webb said: "Quite possibly because these
drugs were very widely used."
The previous worst disaster involved the drug
Tambocor (flecainide) prescribed to patients with irregular
heartbeats. It was estimated to have killed 50,000 patients in
the Seventies and Eighties.
The European Drug Safety Agency is conducting
an urgent safety review of all the Cox-2 inhibitors, which have
a combined global sale of $10bn (£6bn). Last month, the UK
Medicines and Health Care Products Regulatory Agency advised all
patients still taking Vioxx, estimated at 750,000, to review
their treatment with their doctor.
