Safety of B cell depleting effects of ocrelizumab in patients with multiple sclerosis in clinical practice

Document Type

Conference Proceeding

Publication Date


Publication Title

Mult Scler J


Introduction: Ocrelizumab is a humanized monoclonal antibody that targets CD20 expressing cells. It rapidly depletes circulating B-cells that express CD20. However, it has a prolonged peripheral B-cell depleting effect, relatively less well-understood effect on tissue compartment B-cell population, and complex cross-talk with T-cells. Therefore, there is considerable interest in the short and long-term safety of ocrelizumab, mainly regarding severe infections and malignancies. Objective: To investigate the safety of ocrelizumab therapy in relapsing-remitting (RRMS), secondary-progressive (SPMS) and primary progressive multiple sclerosis (PPMS) patients including the incidence of infections and malignancies. Methods: This retrospective study included MS patients receiving ocrelizumab therapy for up to 46 months. Patients' demographic, duration of disease, phenotype, expanded disability status scale(EDSS), course of treatment, number of infusions, infusion site reactions, infection, and laboratory data were recorded. Wilcoxon two-sample tests were used to compare patient with and without infections. Results: Of the 187 patients, 67% were female, 66% were White, 21% were Black, median EDSS was 6 (range 0-8.5), and the mean age was 50.7 years. RRMS(55%) was the most common type of MS with an equal number of both PPMS and SPMS(22%), and the median duration of MS was ten years. Twenty-seven(14%) patients had infusion site reactions primarily mild, with only 2 patients having an anaphylactic reaction. Fifty-two(28%) patients had an infection, the most common being recurrent UTI , 9 with URI, 7 with COVID-19 infection, and 7 with pneumonia, out of which 5 were severe. 6(3%) patients had a cancer diagnosis after the start of treatment. In contrast, 13(7%) had a cancer diagnosis before starting treatment. Infections were associated with older age(p=0.01), higher EDSS at last clinic visit(p=0.046) and more infusions(p=0.031). Conclusion: The rate of infections in clinical settings seems similar to reports from clinical trials, but cancer rates were slightly higher. Advanced age and higher disability status increased the risk of infections.

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