Patients with migraine may not get access to Botox on the National Health Service in England and Wales as cost regulators say they are currently minded not to back funding for the drug.

The National Institute for Health and Clinical Excellence has this morning (Feb 16) published draft guidance rejecting the use of Botox (botulinum toxin type A) to prevent headaches in adult patients experiencing chronic migraines.

The Institute's committee of experts has concluded that there is not enough evidence to recommend the drug, and so has asked that its manufacturer Allergan stump up some additional information in support of its use on the NHS.

In July 2010, the Medicines and Healthcare products Regulatory Authority licensed Botox as the first preventative treatment for chronic migraine in adults, after studies (PREEMPT 1 and 2) showed it to be effective in this indication.

However, in April last year the Scottish Medicines Consortium refused to recommend the use of Botox for migraine prevention on the NHS in Scotland, referring to "weaknesses in the clinical data that limit the ability to assess its likely clinical effectiveness in the target treatment population".

Small benefit?

Along similar lines, NICE says clinical data shows the benefit to be small and that the results were confounded by a large placebo effect, because patients may have been aware they were receiving Botox due to its "widely-recognised" side effect of muscle paralysis.

In addition, the committee noted uncertainties surrounding the long-term effectiveness of Botox and its cost-effectiveness model.

Professor Carole Longson, Director of the Health Technology Evaluation Centre at NICE, said without additional information from Allergan to clarify these issues "potentially we will be unable to advise the NHS that this drug is good value for money".

The drugmaker now has until March 8 to respond to the Institute's request.