Ocrelizumab is effective in reducing multiple sclerosis (MS) relapses, according to a new comparative study published in the journal Multiple Sclerosis and Related Disorders. The treatment also slows down the progression of the disease, especially in people with relapsing-remitting MS (RRMS).

To compare the effectiveness of ocrelizumab in primary progressive MS (PPMS) and RRMS and assess its tolerability, a team of researchers from Spain led by Celia Oreja-Guevara, MD, PhD, of the Neurology Department, Hospital Clínico San Carlos in Madrid, conducted a retrospective observational cohort study in which they compared clinical and magnetic resonance imaging (MRI) data of 13 patients with PPMS and 30 patients with RRMS, who were treated with at least 1 cycle of ocrelizumab and who were followed for at least 1 year.

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The results showed that the majority (69.2%) of patients with RRMS treated with ocrelizumab showed no evidence of disease activity in the first year of treatment. This proportion was even higher in the second year at 80%. 

Moreover, radiological evidence showed that in the first year disease activity was reduced by 80% in patients with RRMS treated with ocrelizumab and by 91.7% in those with PPMS who received the treatment. The treatment completely abolished disease activity in patients with both types of disease in the second year. 

There was also a statistically significant difference in the rate of progression of disability before ocrelizumab treatment started and 1 year after in patients with both types of disease. However, the rate of disease progression increased again in patients with PPMS in the second year of ocrelizumab treatment. 

“Ocrelizumab was mostly well tolerated and some adverse effects were reported,” the researchers wrote. These included infections, hematological side effects, and infusion-related reactions. Some patients discontinued the treatment and the most common cause for this was infections, hematological complications, and perception of ineffectiveness.

Ocrelizumab, marketed under the brand name Ocrevus, is a humanized monoclonal antibody that targets CD20-positive B cells, which are involved in the immune attack against the myelin sheath in MS.


Rodriguez de Antonio LA, Cuberta-Gonzalez I, Garcia-Castañon I, Oreja-Guevara C. Relapsing-remitting and primary progressive multiple sclerosis treated with ocrelizumab: a comparative study. Mult Scler Relat Disord. Published online December 5, 2022. doi:10.1016/j.msard.2022.104441