Rituximab for RRMS

May 2, 2007 (Boston) — Results of 2 studies suggest that rituximab (Rituxan, Genentech/Biogen Idec), a chimeric antibody already approved for the treatment of several types of lymphoma and rheumatoid arthritis, may be a promising treatment for relapsing-remitting multiple sclerosis (RRMS).

Rituximab targets and selectively depletes CD20-positive B cells. "These data provide a proof of principle that B cells clearly play a central role in the pathophysiology of relapsing-remitting MS," Stephen Hauser, MD, from the University of California, San Francisco, told attendees here.

In a phase 2 placebo-controlled study, researchers showed a reduction in disease activity, as evidenced by gadolinium-enhancing lesions on magnetic resonance imaging (MRI) and in clinical relapses over a 6-month period with rituximab treatment vs placebo.

These therapies either are nonspecific immunomodulators or target T cells, but recent evidence has pointed to a pathologic role for antibodies and B lymphocytes in MS, he said. Rituximab is a therapeutic chimeric antibody that targets and selectively depletes CD20-positive B cells without affecting either stem cells or plasma cells. A single course of rituximab depletes CD20-positive B cells in the peripheral blood for about 6 months, Dr. Hauser noted.

Rituximab was developed and approved for the treatment of various lymphomas and was more recently approved for the treatment of rheumatoid arthritis.