Health authorities could be under pressure to fund Betaferon treatment for thousands more patients - at a cost of millions of pounds - by the end of the year.

Pharmaceutical giant Schering has applied for European approval to extend the use of the drug after releasing data from a trial suggesting it could benefit twice as many patients as first thought. It hopes to receive a licence to extend the use of the drug to patients with 'secondary-progressive' multiple sclerosis by the end of the year.

The move has re-opened concerns about funding for beta interferon, which costs about pounds10,000 per patient per year.

Aberdeen consultant neurologist John Hern, who had 24 patients in the Schering trial, said: 'If you look at the control patients, then one year into this trial 40 per cent had deteriorated by one point on (the standard) disability scale. It took two years for the treated patients to deteriorate by the same amount. Although it is not a cure, I would expect it to be something that secondary-progressive MS patients would seek.'

He added: 'From the NHS point of view, this could cause problems. We have 1,000 patients with MS in Grampian. If only 500 of them were suitable for this treatment, it would cost pounds5m a year.

'We cover 1 per cent of the UK population, so the total cost could be pounds500m. I do not want to sound apocalyptic, but this could be a watershed for the NHS.'

NHS Confederation chief executive Stephen Thornton said the issue was 'a classic example' of why the National Institute for Clinical Excellence was needed.

But he added: 'That will not change the funding situation. HAs and primary care groups must be careful not to use effectiveness arguments to deny treatments for financial reasons.'

Schering revealed details of its trial at a meeting of the European Neurological Society in Nice last week. An abstract says Betaferon delayed the progression of MS by between nine and 12 months. Relapse rates were 'significantly reduced', and hospitalisations were cut by 10 per cent.

David Harrison of the MS Society said: 'It seems there is a strong case for the licence being extended. And the existing guidelines on giving this drug to patients with relapsing-remitting MS should be enforced.'