Genentech and partner Biogen Idec have reported promising data on their blockbuster cancer and rheumatoid arthritis drug Rituxan which suggests that it could be an effective treatment for relapsing remitting multiple sclerosis.

Results from a randomised, double-blind, 104-patient study, presented at the American Academy of Neurology in Boston revealed that those taking Rituxan (rituximab) showed a statistically-significant reduction in the number of brain lesions associated with MS at weeks 12, 16, 20 and 24 compared to the placebo group.

At week 24, the total number of lesions was reduced by 91% to an average of 0.5 per patient in the Rituxan-treated group, compared with 5.5 lesions in the placebo arm of the trial, and the proportion of patients with relapses over 24 weeks in the Rituxan-treated arm was 14.5% compared to 34.3% with placebo.

"There remains a great need for safe and effective treatments for patients with RRMS,” said Stephen Hauser, the study’s lead researcher from the Department of Neurology, University of California, San Francisco. "These Phase II results are very encouraging and suggest B-cells play a key role in MS. They also lend support to the concept that selective targeting of B-cells may be an important approach to treating this debilitating disease."

The study is a small one, Prof Hauser admits, but he noted that

the data suggests Rituxan is twice as effective in preventing relapses as the most widely used current treatments, Biogen Idec's Avonex (interferon beta-1a) and Copaxone (glatiramer acetate) sold by Teva Pharmaceutical Industries.

Rituxan is already a blockbuster in non-Hodgkin's lymphoma, and sales in rheumatoid arthritis are also strong. If it makes it to market for MS, the drug's already solid performance will enjoy yet another significant boost.