Here is My Question:
What are the risks and benefits of rituximab vs Ocrevus?
Both rituximab and Ocrelizumab bind to circulating CD20 B Cells and destroy them. Although they bind to different portions of the CD20 protein on the surface of the B cells, the end result of this binding is identical.
Rituximab is a Chimeric antibody; this means it is a fusion protein containing both human and mouse protein components. Because your immune system may view the mouse protein as foreign, it is possible for people to develop human anti-chimeric antibodies (HACA). In the phase II HERMES trial of rituximab for relapsing MS, approximately 25 % of treated patients developed HACA, but there was no relationship between the development of HACA and either treatment efficacy or infusion related reactions (IRR). Nevertheless, there are case reports of patients with other conditions (i.e. rheumatoid arthritis or SLE) losing benefit from Rituximab after the development of HACA, and some believe that HACA can lead to persistent, more severe IRRs with subsequent infusions. This issue is controversial since IRRs are very common in all patients administered either rituximab or orelizumab (see below), a humanized anti-CD20 monoclonal antibody that does not lead to the development of HACA.
Ocrelizumab is one of the currently approved entire human anti-CD20 monoclonal antibodies. Human anti human antibodies (HAHA) develop in very few individuals and do not seem to be related to be related to efficacy or infusion related reactions (IRR). Ocrelizumab is also associated with a high rate of infusion related reactions.
Other humanized anti-CD20 monoclonal antibodies include obinutuzumab, eltuzumab, and the fully human, ofatumumab. None are currently approved for multiple sclerosis but this is likely to occur in the future.
Revere (Rip) Kinkel MD
Professor of Clinical Neurosciences
Director of the Multiple Sclerosis Program
Clinical Neurosciences Director
University of California San Diego
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