Rituxan Treats Rheumatoid Arthritis
Study Shows Low Doses of Rituxan as Effective as Higher Doses
April 28, 2006 -- A cancerdrug that has a unique mode of action is showing promise in the treatment of rheumatoid arthritis.
Rituxan is the first drug to target a specific B immune cell, believed to play a role in inflammation in rheumatoid arthritis (RA) patients. It was approved two months ago by the FDA for use by rheumatoid arthritis patients who have failed other biologic treatments. Rituxan is administered as an infusion into a vein.
Just over half of the RA patients in a new study saw their symptoms improve when treated with Rituxan in combination with the disease-modifying antirheumatic drug (DMARD) methotrexate.
Patients taking low doses of Rituxan responded as well as those given higher doses, and the addition of steroids during treatment did not appear to improve outcomes.
All of the patients in the study had previously failed treatment with methotrexate or other DMARDs. About a third had been treated with biologic agents that work via a different pathway, such as the drugs Enbrel, Humira, and Remicade.
The findings suggest that patients may do equally as well on low doses of the drug as on high doses. But researcher Roy Fleischmann, MD, of the University of Texas Southwest Medical Center, says it is still too early to say this for sure.
"We don't yet know if responses last longer with higher doses or if the depth of response is better with different dosing," Fleischmann tells WebMD. "Studies involving larger numbers of patients are being done to answer these questions."
An estimated 3 million adults in the U.S. have rheumatoid arthritis, a progressive autoimmune disease that involves inflammation of the joints and surrounding tissues. Over the years, RA can destroy joints, ligaments, tendons, and even bone.
Biologic drugs that suppress inflammation-causing immune system cells, or cytokines, are new to the treatment of rheumatoid arthritis. While very expensive -- costing between $16,000 and $20,000 a year, according to one cost analysis -- they hold the promise of eliciting better outcomes than traditional RA treatments with fewer side effects.
The study of Rituxan included 465 patients with moderate to severe RA treated with Rituxan or placebo plus methotrexate -- with and without steroids.