Biogen Idec, Inc. and Genentech, Inc. submitted a supplemental Biologics License Application (sBLA) with the US FDA for a new indication for Rituxan (Rituximab) in patients with active rheumatoid arthritis (RA) who inadequately respond to an anti-TNF therapy.

The sBLA submission is based primarily on the 24-week results of a multi-centre, randomized, double-blind, placebo-controlled Phase III study known as Reflex. In the trial, patients who received a single course of two infusions of Rituxan with a stable dose of methotrexate (MTX) displayed a statistically significant improvement in symptoms measured at 24 weeks, compared to those receiving placebo and MTX.

"Rituxan may provide a potential new treatment approach for the RA patient population with the greatest unmet medical need," Hal Barron, Genentech's senior vice president, development and chief medical officer said adding, "This submission marks an important milestone in our ongoing efforts to develop novel therapies for B-cell-mediated diseases."

RA is a debilitating autoimmune disease that affects more than two million Americans and hinders the daily activities of sufferers. RA occurs when the immune system inappropriately attacks joint tissue, causing painful chronic inflammation and irreversible destruction of cartilage, tendons and bones, often resulting in disability.

Rituxan is a therapeutic antibody that targets and selectively depletes CD-20-positive B- cells without targeting stem cells or existing plasma cells. Rituxan is also being investigated in other autoimmune diseases, including lupus, multiple sclerosis and ANCA-associated vasculitis.