OCREVUS (generic name, ocrelizumab) is a humanized monoclonal antibody under clinical investigation and development by the Swiss pharmaceutical company Roche as a potential treatment for people with multiple sclerosis (MS). The therapy targets a type of immune cells called B-lymphocytes that express a protein called CD20 on their surface, giving the drug an immunosuppressive function that might reduce the rates of immune system attacks on the body’s own myelinated neurons, the main trigger of the disease. OCREVUS is not yet an approved therapy, but it has shown promise in treating both relapsing forms of multiple sclerosis (RRMS) and primary progressive multiple sclerosis (PPMS), a disease form with no approved treatments to date.
How Ocrelizumab Works
Ocrelizumab, an anti-CD20 monoclonal antibody, targets mature B-cells. Almost 95 percent of B-cells express the CD20 protein on their surface once they mature and do not shed them, which is what makes CD20 a potent marker for therapeutic purposes. It is believed that these CD20-positive B-cells target axons and myelin sheaths of healthy neurons, initiating a cascading series of immune reactions that lead to MS and disability in patients. Preclinical studies have shown that ocrelizumab binds to specific B-cells with CD20 markers but not to stem cells and plasma cells, preserving vital immune functions within the host.
Ocrelizumab’s Clinical Trials for MS
In February 2016, Roche announced favorable results from a pivotal Phase 3 trial called ORATORIO, a randomized, double-blind, global and multi center study evaluating the efficacy and safety of ocrelizumab in 732 patients with PPMS. The drug was injected into the blood stream, as two infusions of 300 mg given two weeks apart every six months. At the end of the study period, it was seen that ocrelizumab had met the study’s primary outcome, significantly reducing clinical disease progression in PPMS patients sustained for at least 12 weeks by 24 percent (compared to placebo), as measured by the Expanded Disability Status Scale (EDSS).
In the same month, the U.S. Food and Drug Administration (FDA) designated ocrelizumab a Breakthrough Therapy as a possible PPMS treatment, a decision meant to expedite its development and review.
Data from two related Phase 3 studies, OPERA I and II, testing the efficacy of the drug in 1,656 patients with relapsing forms of MS, found that ocrelizumab was superior to interferon beta-1a, a well-established MS therapy, reducing the annualized relapse rate (the primary endpoint of both studies) by nearly 50 percent over a two-year controlled treatment period. Ocrelizumab was into the blood stream at 600 mg every six months; interferon beta-1a was given by injection under the skin at 44 mcg three times per week.
According to Roche OCREVUS is the first investigational medicine to show such positive results in patients with both primary progressive and relapsing forms of multiple sclerosis. The company submitted data from all three studies to regulatory authorities in mid-2016, potentially paving the way for FDA approval, marketing, and commercialization of ocrelizumab in the treatment of relapsing MS and PPMS. On June 28, 2016, Roche announced that the company’s Biologics License Application for OCREVUS for the treatment of relapsing multiple sclerosis and PPMS had been accepted for FDA review, and that the therapy was given Priority Review Designation, which will accelerate the review process. A targeted FDA decision date is March 28, 2017.
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