Early research partly funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases shows that the cancer medication rituximab may someday be effective against another devastating disease: systemic lupus erythematosus (lupus).

In a study of 17 adults with lupus that was clinically active despite treatment, just one injection of rituximab eased symptoms for up to a year or more. Several participants were able to reduce or completely stop their regular lupus medications.

Rituximab, which is FDA-approved for a type of cancer called lymphoma, works by lowering the number of B cells in the body. B cells are white blood cells that produce proteins called antibodies that kill viruses, bacteria and other invaders. In lymphoma, the body makes too many B cells. In lupus, there are usually lower-than-normal levels of B cells, but the B cells that do exist overreact or react inappropriately toward the body's own tissues. As a result, the disease can damage many body organs and systems including the joints, skin, blood and blood vessels, kidney, lungs and brain.

Study scientists Jennifer Anolik, M.D., Ph.D., R. John Looney, M.D., Inaki Sanz, M.D. and their colleagues at the University of Rochester suspected that using rituxumab to rid the body of some of these errant B cells might bring improvement in lupus. Their results proved them right. All of the participants in whom rituxmiab reduced B cell levels experienced significant reduction in symptoms.

Furthermore, the side effects from rituximab were minimal and even reactions to the infusion - a side effect of the drug seen in lymphoma- were not seen in the lupus patients.

While current lupus treatments work by suppressing the entire immune system, rituximab selectively targets the B cells that are at the root of the problem. In doing so, it may not only be more effective than other medications, it may also be less toxic. But more studies are needed to better understand its effectiveness and safety and to better determine its role in lupus treatment. The researchers are currently planning another multicenter study to begin later this year that will help address those issues.

The National Institute of Allergy and Infectious Diseases, Genentech, IDEC Pharmaceuticals and the Lupus Foundation of America also provided support for the study.

The mission of NIAMS, a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at www.niams.nih.gov.

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Looney RJ, et al. B cell depletion as a novel treatment for systemic lupus erythematosus. Arthritis Rheum 2004;50(8): 2580-2589.

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