New trials show that a cancer drug can be an effective treatment for multiple sclerosis (MS) by ‘rebooting’ patients’ immune systems. The results of two phase III clinical trials were published today in the journal The Lancet.

The trials, sponsored by Genzyme and Bayer Schering Pharma, found that for patients who recently relapsed, using a drug called alemtuzumab saw new episodes reduced by 49% over standard treatment and 65% of them remained relapse free compared to 47% of those on standard MS treatments. In addition, alemtuzumab was found to reduce the risk of acquiring disability by 42% over standard treatments.

“Our research shows the transformative effect that alemtuzumab can have for people with MS,” said Alastair Coompston, principal investigator on both studies and professor at the University of Cambridge. “Patients who continue to show disease activity while on their initial therapy are especially difficult to treat. Now, we have shown that alemtuzumab works where first-line drugs have already failed. It not only reduces the chances of disability associated with MS but may even result in long-term clinical improvements.”

The CARE MS II trial looked at 840 MS patients who had previously been treated but relapsed during therapy. They received either alemtuzumab or interferon beta-1a treatments. They had check-ups every three months for two years and yearly brain scans.

The CARE MS I trial looked at 581 patients who were not previously treated for MS. As in the other trial, the patients received either alemtuzumab or interferon beta-1a treatments and were monitored for two years. It found that alemtuzumab reduced MS relapses 55% over the standard treatment.

“Although alemtuzumab causes potentially serious side-effects, these can be identified and treated provided a monitoring schedule is carefully followed,” said Dr. Alasdair Coles, lead author of the study based on the trials and a clinician at the University of Cambridge. “Additionally, we think that we can identify which patients are at risk of autoimmune disease after alemtuzumab, and we are currently recruiting for a clinical trial which will explore whether we can use a drug to reduce the risk of autoimmunity in those at highest risk.”