A risk-sharing scheme to supply multiple sclerosis (MS) medicines to patients has been a "costly failure", experts have said.
The NHS could have saved £250 million if the scheme had been properly assessed after two years, while the money could have been better spent on other treatments, they said.
The programme was set up between the Government and drug firms after the the National Institute for Health and Clinical Excellence deemed a set of MS medicines too expensive and questioned their effectiveness.
Other, similar types of schemes are up and running to bring more drugs to NHS patients.
Under the terms of the MS risk-sharing scheme, established in 2002, the Government agreed to pay for the drugs while research was carried out to assess their long-term cost effectiveness. The NHS would then gradually stop paying for the drugs if patients did not appear to be benefiting.
In 2009, seven years after the scheme was set up, data was published showing patients were performing less well than predicted. A total of 5,583 patients have received one or more treatments, costing in the region of £350 million.
Despite a lack of convincing evidence of benefit, a scientific advisory group reporting to the Government has said it would be premature to reduce prices without further analysis.
Writing online in the British Medical Journal (BMJ), experts led by Professor Christopher McCabe, a health economist at the University of Leeds, questioned this decision, saying none of the arguments stand up. They experts raised a series of concerns, including over the supposed "independence" of the group.
"The manufacturers, patient groups, clinicians, and the Department of Health are represented on the scientific advisory group," they wrote.
"All these bodies have a vested interest in maintaining the status quo. The budget holders, who pay for these drugs, with responsibility for the health of populations served by the NHS, are not represented on the scientific advisory group, and as a result there is no countervailing influence on the group's decision making."