Rituxan, the lymphoma drug developed by





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, worked better than a placebo in treating patients with rheumatoid arthritis in a phase III study, the companies said.

The study group comprised patients who had an inadequate or no response to so-called anti-TNF drugs, which generally speaking include

Abbott Labs'

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Johnson & Johnson's

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Remicaid and


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According to Genentech and Biogen, Rituxan met its primary endpoint of a greater proportion of Rituxan-treated patients achieving a response standard defined by the American College of Rheumatology in the 24th week of treatment, compared to a placebo. Both classes of patients were taking the chemotherapy methotrexate.

The Rituxan antibody targets positive B cells that are suspected of playing various roles in promulgating rheumatoid arthritis. It's been approved as a treatment for non-Hodgkins lymphoma since 1997.

"These are the first phase III Rituxan data to demonstrate clinical improvement in this difficult-to-treat RA patient population. The findings add to the growing body of evidence that selectively targeting B cells may provide an important new treatment approach for this debilitating disease," Genentech said.