Ocrelizumab Shows Promise for Primary Progressive MS
I have been waiting a long time for the day when I get to write about a long-overdue treatment option for primary progressive MS (PPMS). Although we aren’t quite there yet, researchers are getting closer. As a clinician I desperately need a treatment to offer to people with PPMS, and as someone living with MS I also want to see developments in research for progressive MS. Currently, I am particularly excited about a recent press release on the Phase 3 results for the drug Ocrelizumab.
Ocrelizumab is an experimental monoclonal antibody, which is a laboratory-produced molecule designed to mimic antibodies found in your immune system. They work by altering the immune response, and are used to treat autoimmune diseases. Tysabri, Lemtrada, and Rituxan are some examples of the monoclonal antibodies already used in the treatment of relapsing-remitting MS (RRMS), and researchers have recently been looking into treating secondary-progressive MS (SPMS) and PPMS with monoclonal antibodies (read more about monoclonal antibodies and ms treatment here). Ocrelizumab’s monoclonal antibodies target a protein known as CD20 on B cells, which are a type of white blood cell thought to contribute to myelin destruction in MS.
Earlier this year Genentech, a biotechnology company that is a part of the Roche group, reported positive results from two phase III clinical trials of ocrelizumab (OPERA I and OPERA II). When compared to interferon therapy ocrelizumab significantly reduced the number of relapses, disease progression, and the number of brain lesions in people with RRMS and SPMS with relapses. Researchers then went on to investigate whether ocrelizumab could be used to treat PPMS in the ORATORIO study.
Results from phase III of the ORATORIO study found that ocrelizumab significantly reduced disease progression in people with PPMS when compared to a placebo. In a press release Dr. Sandra Horning stated: “Ocrelizumab is the first investigational medicine to show a clinically meaningful and statistically significant effect on the progression of disease in primary progressive MS.”
The ORATORIO study involved 732 people with primary progressive MS from all over the globe. Participants were randomly picked to either receive ocrelizumab or a placebo via IV infusions. Researchers compared disease progression, walking ability, lesions on MRI scans, and medication tolerance between the two groups. Preliminary reports say that participants who received ocrelizumab had significantly less disease progression and more detailed trial results will be presented in a couple of weeks at the ECTRIMS (European Committee for Treatment and Research in Multiple Sclerosis) conference. I greatly look forward to seeing the detailed safety and efficacy results from the ORATORIO study. It has potential to make a big impact on those living with PPMS, who currently have no FDA approved treatment options.
Ocrelizumab is a 600mg IV infusion that is given as two 300mg infusions, 2 weeks apart. During clinical trials the rate of side effects was similar to the placebo group. The most common events that were reported were mild-to-moderate infusion reactions.
The purpose of phase III in a clinical trial is to show how effective and safe a potential new treatment is. When results are promising the next step is to present the data to the U.S. Food and Drug Administration (FDA) for approval. Genentech currently plans to submit data from the OPERA I, OPERA II, and ORATORIO studies to the FDA in early 2016.
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