Summary: Investigators worldwide are recruiting 200 people with relapsing-remitting MS* for a study of intravenous ocrelizumab (Genentech, Inc., and F. Hoffman La-Roche, Ltd.). Ocrelizumab is a humanized monoclonal antibody. It targets a part of the immune system called the B cell by attaching to a specific protein on the B cell known as CD20; this attachment then leads to a removal of these cells from the blood. The experimental drug is being evaluated in two doses, and in comparison with Avonex® (interferon beta-1a, Biogen Idec) and inactive placebo. The study is funded by Genentech, inc., and F. Hoffman La-Roche, Ltd.

Rationale: Multiple sclerosis occurs when the immune system attacks the brain and spinal cord. Much of the attention in MS research in the past has focused on the part of the immune system involving the T cell which has been believed to be a major contributor to the inflammation that occurs in MS. However, increasing evidence more recently has shown that B cells, immune cells that make antibodies, may play a role in the immune attack in MS. The experimental drug, Ocrelizumab, acts by targeting B cells which contain the CD20 protein found on their surface. This interaction then leads to the removal of these cells. Initial results with another drug which also targets B cells containing the CD20 protein, called rituximab (Rituxan®, Genentech and Biogen Idec) suggested that a single intravenous course was able to reduce disease activity and relapses for 48 weeks in people with relapsing-remitting MS (The New England Journal of Medicine 2008 Feb 14;358[7]:676-88). Ocrelizumab shares a similar mechanism of action with rituximab. The efficacy of ocrelizumab in MS however, has not been established.

Eligibility and Details: People age 18 to 55 who are diagnosed with relapsing-remitting MS are eligible to participate in this study. Participants will be randomly assigned to receive one of four treatment regimens over a period of two years, which will involve either repeated intravenous infusions (ocrelizumab 2 different doses or placebo) or intramuscular injections (Avonex®). Participants who are assigned to receive placebo will switch to active ocrelizumab treatment after 24 weeks. Participants who are assigned to receive Avonex® will have the option to switch to ocrelizumab after 24 weeks.

The main objective of this study is to determine whether ocrelizumab is effective in reducing MS disease activity as observed on magnetic resonance imaging scans (MRI) compared to a placebo. This study will also evaluate any potential impact on the occurrence of MS relapses in patients receiving ocrelizumab compared to those on a placebo.

Contact: For more information on sites currently recruiting participants, please see the Ocrelizumab listing in our trials participation database.

*Relapsing-remitting MS is a course of MS characterized by clearly defined flare-ups followed by partial or complete recovery

Avonex is a registered trademark of Biogen Idec. Rituxan is a registered trademark of Genentech and Biogen Idec.