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
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
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
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
The study is published in the May issue of the journal Arthritis and
Rheumatism. It was funded by drug makers Genentech, Biogen, and
Hoffmann-La Roche, which market the drug jointly. Genentech and Biogen are
There were nine different treatment groups, designed to better understand
which doses of drugs were most effective and whether adding steroids improved
A total of 55% of the patients treated with the higher-dose Rituxan regimen
showed a 20% or better improvement after six months, compared with 54% of
patients on the low-dose regimen and 28% of patients taking a placebo.
Steroids, whether given in the vein or by mouth, didn't add any further
improvement than Rituxan and methotrexate alone. But intravenous steroids given
prior to Rituxan made the drug more tolerable.