Description The 2nd generation anti-CD20 (ocrelizumab) is a humanized monoclonal antibody directed against the CD20 surface antigen on human B-cells. Anti-CD20 antibodies work by binding to a particular protein (the CD20 antigen) on the surface of normal and malignant B-cells. From there, they recruit the body's natural defenses to attack and kill the marked B-cells.

Development Status Phase III clinical trials are ongoing evaluating ocrelizumab for rheumatoid arthritis and lupus nephritis; and a Phase II clinical trial for relapsing remitting multiple sclerosis is ongoing.

This molecule is being developed in collaboration with F. Hoffmann-La Roche and Biogen Idec Inc.

Our collaborator Biogen Idec disagrees with certain of our development decisions under our 2003 collaboration agreement related to humanized anti-CD20 products. We continue to pursue a resolution of our differences with Biogen Idec. The disputed issues were submitted to arbitration in San Francisco, California. Resolution of the arbitration could require that both parties agree to certain development decisions before moving forward with humanized anti-CD20 antibody clinical trials, and possibly clinical trials of other collaboration products, including Rituxan, in which case we may have to alter or cancel planned trials in order to obtain Biogen Idec's approval.

Additional Information on Clinical Trials For inquiries about our clinical trials, please submit a request through our information request form or call (888) 662-6728.

National Institutes of Health Website: www.clinicaltrials.gov

August 2008