Following positive preliminary findings from a Phase IIb study that evaluated the efficacy and safety of the approved cancer drug Rituxan in rheumatoid arthritis (RA) patients, Genentech Inc, Biogen Idec and Roche Pharmaceuticals announced that a recent Phase III study has met its primary endpoint based on clinical improvement (ACR 20 responses) at week 24.

The multi-center, double-blind, placebo-controlled study included 520 patients with active RA who had an inadequate clinical response or who were intolerant to prior anti-TNF-α therapy. The patients who received a treatment course of two infusions of Rituxan along with a stable dose of methotrexate had a statistically significant improvement in clinical symptoms compared to patients who received placebo and methotrexate. Rituxan, a therapeutic antibody that targets and selectively depletes peripheral CD20⁺ B cells, has received approval in the US and European Union (where it is marketed as MabTheraR) for the treatment of relapsed or refractory, low-grade or follicular non-Hodgkin's lymphoma. Rituxan is also being investigated as a treatment for other B cell-driven autoimmune diseases