Rituxan, a drug currently used to treat a certain type of cancer and rheumatoid arthritis showed promise in treating patients with the most common form of multiple sclerosis, according to two small studies presented Tuesday involving the drug.

Rituxan, co-marketed by Genentech Inc. and Biogen Idec Inc. was originally approved to treat non-Hodgkin's lymphoma, a cancer of the lymphatic system. It kills B cells or a type of white blood cell.
The studies suggest that targeting such B cells might also be a new way to treat MS, a progressive disease that involves damage to nerves controlling muscles and vision. More specifically, the body attacks myelin, a fatty substance that surrounds the nerve fibers of the brain, spinal cord and optic nerves. Scar tissue, or brain lesions are left behind from the attacks, which can be detected with an MRI scan.

The studies, presented Tuesday at the American Academy of Neurology's annual meeting on Boston, looked at using Rituxan in patients with the relapsing-remitting form of MS, where symptoms flare up and then subside. Overall, the studies showed Rituxan reduced the number of brain lesions and cut the number of relapses.

One of the studies involved 104 patients, 69 of whom received a single course of Rituxan and 35 were given a placebo, or fake treatment. The patients are being followed for 48 weeks, but data from the 24 week mark was released. Rituxan is an infusion and was administered in two courses, two weeks apart.

The number of lesions per patient were reduced by 91% among the Rituxan patients compared to those in the placebo group. About 14.5% of patients receiving Rituxan relapsed compared to 34.3% in the placebo group.

The study's lead researcher Dr. Stephen Hauser, the chair of the neurology department at the University of California, San Francisco, said the data suggests a new pathway to treat MS by targeting B-cells. Other treatments like Tysabri target infection-fighting T-cells in the body to keep them from attacking myelin.

Hauser told Dow Jones Newswires the study results were very encouraging but that larger studies are needed to verify whether Rituxan would be a viable MS treatment. Genentech and Biogen are also studying it a treatment for another form of MS but the results are not yet available. Hauser also said his study wasn't long enough or large enough to address long-term safety questions.
His study showed that more patients receiving Rituxan, or 78.3%, suffered an infusion reaction compared to 40% in the placebo group. Such reactions included flu-like illness, fever and low blood pressure.

In December, Genentech and Biogen Idec warned that two patients being treated for lupus with Rituxan contracted a viral brain infection known as progressive multifocal leukoencephalopathy, or PML. Rituxan is not approved as a lupus treatment but the companies are also studying the drug for that use.
Hauser said the results from his study involving Rituxan as an MS treatment look as encouraging as the early clinical data for did for Tysabri, another MS treatment.

Tysabri, also by Biogen Idec and Elan Corp. (ELN), was taken off the market in 2005 after three patients developed PML but was allowed to return last year with strict warnings and a restricted distribution plan.

A second study involved 26 people who received Rituxan at the study start and then six months later. It also showed brain lesions were reduced by more than 90% and that the expected relapse rate was cut in the patients who were followed for at least a year. The study did not involve a placebo group and was partly designed to look at whether it was safe to use Rituxan in MS patients. CLICK FOR MORE