Description Ocrelizumab (2nd Generation Anti-CD20) 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. We continue to pursue a resolution of our differences with Biogen Idec. The disputed issues were submitted to arbitration in San Francisco, California and a hearing was held in September 2008 with a concluding hearing to take place in December 2008. We expect that we will receive a ruling by approximately June 2009. The arbitration proceedings with Biogen Idec are confidential and we will not provide details on the program disagreements with Biogen Idec nor the hearing discussions.

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

October 2008