Mar 6, 2003
By Stephen Pincock
The cost-effectiveness of treating multiple sclerosis (MS) with interferon beta and glatiramer acetate is low in the short term, but improves significantly over a 20-year period, British researchers reported on Thursday.
But, they add, the real cost-benefit relationship is impossible to determine because long-term data are surprisingly unavailable.
"That 'but' is absolutely huge," said health economics lecturer Chris McCabe from the University of Sheffield, whose group modelled the benefits of the drugs for Britain's National Institute for Clinical Excellence (NICE).
"The model predicts out to 20 years, but by about 10 years the vast majority of patients will no longer be receiving therapy," McCabe explained. Patients stop for their own reasons or therapy is stopped clinically.
The researchers' assessment assumes that the clinical benefit patients receive while taking the drugs is sustained once the therapy is stopped.
"That assumption is responsible for almost all the benefits in the second 10 years that the model looks at," McCabe said. "We have absolutely no idea what happens in practice."
Using the 20-year time horizon, the cost per quality adjusted life year (QALY) gained by using any of the three available forms of interferon-beta or glatiramer acetate ranged from 42,000 pounds to 98,000 pounds, the group reports in the March 8th issue of the British Medical Journal. QALYs combine the life-enhancing and life-extending properties of medical treatments into one measurement.
"But depending upon the assumption you make, you can get a cost-effectiveness heading up to the region of half a million [pounds] or down around 31,000," McCabe said.
Beta interferon and glatiramer acetate are used in many countries to slow MS disease progression, but in Britain most patients have been denied the drugs following controversy over their long-term effectiveness and cost.
Last year, the Department of Health agreed upon a "risk-sharing" scheme with drug firms, under which the government will continue payments for the drugs if they prove effective.
If not, payments to firms such as Germany's Schering AG, Switzerland's Serono SA, Biogen Inc of the U.S. and Israel's Teva Pharmaceutical Industries Ltd will be reduced on a sliding scale.
McCabe said he and his team had been surprised the companies did not already have long-term efficacy data available. "It has to be asked, is it defensible that the companies that developed these products for what has always been known to be a long-term condition cannot provide that information?"
"The therapies have been around for a long time now and it's come down to the British taxpayer footing the bill to get that piece of information into the public domain," he said, adding that the U.K'.s risk-sharing scheme is probably the best way to collect that data.
"Only once we've got that data can we really start being more confident about the value of these drugs."
© 2003 Reuters Ltd