Fast tracking new drugs could have a negative effect on patients in the longer term, a senior doctor in Britain has claimed. An article published in the British Medical Journal by consultant neurologist Abhijit Chaudhuri discusses the issues surrounding the fast tracking of new drugs.

The doctor, from the Essex centre for neurological sciences in Romford, considers fast tracking new drugs for commercial licensing. He reflects on the recent approval granted to multiple sclerosis treatment natalizumab and its subsequent withdrawal over health fears. Clinical trials of natalizumab indicated that the drug was highly effective in preventing body tissue from getting inflamed and could be used in the treatment of both multiple sclerosis and Crohn's disease.

The treatment reduced the number of relapses suffered by MS patients, but was recalled just three months after approval was granted by the US Food and Drug Administration in 2004 after three trial patients developed a life threatening rapidly progressive neurodegenerative disease (progressive multifocal leucoencephalopathy (PML)) while being treated. Dr Chaudhuri suggests: "The approval of natalizumab and its recall after three months raises questions about the fast tracking of new drugs by the FDA for commercial licensing. "It also highlights the potential risks for patients in trials of new drugs where knowledge of long term efficacy, outcome measures, and safety is lacking."

Natalizumab was licensed for use in relapsing MS patients based on short-term results from two unpublished trials, ahead of the publication of final trial and cumulative safety data. An estimated 8,000 MS sufferers in the US have been treated with the drug, which was the leading treatment for the disease before it was withdrawn on February 28th 2005. The UK National Institute for Health and Clinical Excellence was due to appraise Natalizumab this year.

The article on Natalizumab also raises questions about the breast cancer drug herceptin, which has been at the centre of a battle between breast cancer sufferers and NHS administrators over prescription of the drug to women with early stage breast cancer. Herceptin has not been licensed or approved by medical governing bodies for women in the early stages of the disease amid concerns that it can increase the threat of heart disease. However, supporters claim that it can dramatically improve the prognosis for sufferers and reduce the risk of the disease returning.

Roche, the maker of herceptin, is applying to the EU for an extended licence for the drug and the National Institute for Health and Clinical Excellence (NICE) has stated that it plans to fast track its appraisal once a licence is granted.