Mabthera (rituximab), a widely approved drug for treating lymphoma and/or rheumatoid arthritis, is highly effective in treating multiple sclerosis (MS), researchers reported in an observational study in Sweden, where Mabthera is increasingly being used outside of its approved indications to treat relapsing-remitting MS patients. The study, published in the journal Annals of Neurology, is titled “Rituximab versus Fingolimod after Natalizumab in Multiple Sclerosis Patients.”

Researchers also found the drug more effective than an approved MS drug, fingolimod, at reducing the risk of disease flares and with lesser side effects in patients moving off Tysabri (natalizumab). Tysabri is a highly powerful and effective MS drug, but one associated with an enhanced risk of contracting an opportunistic and potentially fatal viral brain infection through long-term use.

Rituximab is a monoclonal antibody against the protein CD20, which is primarily found on the surface of immune system B cells. Rituximab destroys B-cells, and is used to treat diseases characterized by excessive numbers of B-cells, overactive B-cells, or dysfunctional B-cells. This includes many lymphomas, leukemias, transplant rejections, and autoimmune disorders.

Fingolimod (Gilenya) is an immunomodulating drug, mostly used for treating MS, and known to reduce the rate of relapses in relapsing-remitting MS (RRMS) by approximately one-half over a two-year period.

The study was conducted in Sweden at the MS clinics at Karolinska University Hospital, Sahlgrenska University Hospital, and Umeå University Hospital. Researchers compared outcomes for all 256 RRMS patients who had switched from natalizumab to either fingolimod or rituximab.

Results revealed that, within 1.5 years of ending natalizumab treatment, 1.8 percent (rituximab) and 17.6 percent percent (fingolimod) of the patients had experienced a clinical relapse. In terms of safety, the occurrence of adverse events was lower in the rituximab group (5.3 percent) than in the fingolimod group (21.1 percent). Likewise, treatment discontinuation was reported in 1.8 percent of those taking rituximab and 28.2 percent of those on fingolimod.

Contrast-enhancing lesions, examined using magnetic resonance imaging, were also found in only 1.4 percent of rituximab-treated patients, versus 24.2 percent of those given fingolimod.

“We found that patients treated with Mabthera ran a much lower risk of their MS flaring up after the change of drugs than those treated with Gilenya,” Fredrik Piehl, professor at Karolinska Institutet’s Department of Clinical Neuroscience, a consultant at Karolinska University Hospital’s neurology clinic, and the study’s principal investigator, said in a news release. “Those who changed to Mabthera also had a lower risk of developing an adverse reaction to the new drug.”

Mabthera has not been approved for the treatment of MS, in Sweden or elsewhere. But a growing number of patients in that country are being prescribed the drug as clinicians have found it effective.

“The results we’ve seen in this study provide strong support for the genuine efficacy of Mabthera in the treatment of high-inflammatory MS and for it being a valuable alternative to approved MS drugs for this category of patients,” Professor Piehl concluded. “It would also bring considerable savings to the healthcare services as it is much cheaper than the regular MS drugs.”