ocrelizumab
Ocrevus (ocrelizumab) is a CD20-directed monoclonal antibody from Genentech for relapsing forms of multiple sclerosis in adults and children aged 10 years and older, and for primary progressive MS in adults. It depletes the B cells that contribute to inflammatory damage in the brain and spinal cord.
This page is based on FDA prescribing information and the EMA medicine record for ocrelizumab, cross-checked with DailyMed and the National Cancer Institute dictionary; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
In multiple sclerosis, immune cells called B cells help misdirect the attack on the insulation around nerve fibers. Ocrelizumab acts like a homing tag that sticks to CD20, a marker covering the surface of most B cells. Once tagged, the body's cleanup crews break those B cells down, and the mistaken attack on the brain and spinal cord calms.
In simple terms
Ocrelizumab is given by intravenous infusion and binds CD20, a protein on the surface of most B cells. Marking the cells this way triggers the body's own defences to destroy them, through complement-dependent cell lysis and antibody-dependent cell-mediated cytotoxicity. Depleting B cells dampens the inflammatory activity that damages the brain and spinal cord in multiple sclerosis, which is why relapses and disability progression slow during treatment.
In depth
Ocrelizumab is an Fc-modified, humanized monoclonal antibody directed against the B-cell CD20 cell surface antigen. Binding CD20, a non-glycosylated cell surface phosphoprotein present on more than 90 percent of B cells, triggers complement-dependent cell lysis and antibody-dependent cell-mediated cytotoxicity of CD20-expressing B cells. The resulting B-cell depletion reduces the inflammatory cascade that drives demyelination in multiple sclerosis, supporting its use across relapsing forms of the disease and in early primary progressive disease with imaging features of inflammatory activity.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
How ocrelizumab depletes CD20 B cells to calm MS demyelination
- Ocrelizumab is given by intravenous infusion and binds CD20, a protein on the surface of most B cells.
- Ocrelizumab is an Fc-modified, humanized monoclonal antibody directed against the B-cell CD20 cell surface antigen.
- Binding CD20, a non-glycosylated cell surface phosphoprotein present on more than 90 percent of B cells, triggers complement-dependent cell lysis and antibody-dependent cell-mediated cytotoxicity of CD20-expressing B cells.
- The resulting B-cell depletion reduces the inflammatory cascade that drives demyelination in multiple sclerosis, supporting its use across relapsing forms of the disease and in early primary progressive disease with imaging features of inflammatory activity.
Target: CD20 antigen on B cells
A surface phosphoprotein found on more than 90 percent of B cells; tagging it marks B cells for destruction, reducing the B-cell-driven inflammation that damages nerve insulation in multiple sclerosis.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in United States
FDA- For the treatment of relapsing forms of multiple sclerosis, to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults
- For the treatment of primary progressive multiple sclerosis in adults
- For the treatment of relapsing-remitting multiple sclerosis in pediatric patients 10 years of age and older who weigh 25 kg or more
Approved uses in European Union
EMA- For the treatment of adults with relapsing forms of multiple sclerosis with active disease defined by clinical or imaging features
- For the treatment of adults with early primary progressive multiple sclerosis in terms of disease duration and level of disability, and with imaging features characteristic of inflammatory activity
Official sources
The statements on this page trace back to these records.
- Ocrevus (ocrelizumab) — Summary of product characteristics and package leaflet, English version
European Medicines Agency
- DailyMed: OCREVUS (ocrelizumab) official US label
U.S. National Library of Medicine, DailyMed
- U.S. Food and Drug Administration: ocrelizumab prescribing information
U.S. Food and Drug Administration
- National Cancer Institute: ocrelizumab
National Cancer Institute
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.