Real-world experience of ocrelizumab initiation in a diverse multiple sclerosis population

Ocrelizumab (OCR) is a humanized monoclonal antibody directed against CD20 positive B-lymphocytes. It was approved for use in 2017 by the U.S. Food and Drug Administration (FDA) for both the relapsing-remitting and primary progressive forms of multiple sclerosis (MS).

To provide real-world data for patients with MS treated with OCR in our center and evaluate both the safety and efficacy across different ethnic groups not studied in previous clinical trials.

We performed a retrospective observational analysis of MS patients who were treated with OCR from March 31, 2017 to April 30, 2020. We collected data on patients who had received at least a one dose infusion of OCR at our MS center. Patient characteristics, including demographics, clinical disease course, and documented side effects, were collected and analyzed.

A total of 82 patients were eligible for this study, of which 72% had relapsing-remitting MS (RRMS), 14% had primary progressive MS (PPMS), and 11% active/relapsing secondary progressive MS (SPMS). 22% of our patients were of African American descent, 61% Caucasian, and 17% of Hispanic descent. The mean age of starting OCR was 41 ± 11 years. 47% were treatment naïve when started on OCR, 24% were previously treated with one disease-modifying therapy (DMT), 14% were treated with two DMTs, and 15% were treated with more than two DMTs prior to OCR. 50% of patients had at least one adverse event while on OCR; 4.8% had adverse events requiring to OCR discontinuation, 36% had infusion-related reactions, and 7.3% had viral infections. We found two cases of severe babesiosis along with index cases of re-activation of lichen planus, agranulocytosis, severe lymphopenia, and ectopic pregnancy. There were no cases of malignancy, progressive multifocal leukoencephalopathy, or death within our cohort. The mean time after OCR initiation was 17.3 months in the RRMS group, 22.2 months in the PPMS group, and 28.2 months in SPMS group. The annualized relapse rate reduced from 1.33 to 0.15 in the RRMS group. The mean extended disability status scale (EDSS) scores did not worsen across MS phenotypes and ethnic groups while being treated with OCR.

In a diverse patient population, OCR was well-tolerated without significant adverse events. There were novel cases of severe babesiosis, re-activation of lichen planus, lymphopenia, agranulocytosis, and ectopic pregnancy. It is vital to consider geographic risk factors that may expose patients to Babesia microti (B. microti) when either considering or initiating OCR therapy. There were an additional six cases of severe B. microti cases associated with OCR that were reported to the FDA adverse event reporting system (FAERS) along with multiple babesiosis cases associated with other DMTs, including rituximab. OCR was found in our cohort to be effective by decreasing relapse rates and maintaining EDSS scores. Our study extends the generalizability of OCR from clinical trials to a real-world setting consisting of a diverse population.