Real-world safety and effectiveness of ofatumumab in multiple sclerosis: A clinic-based study in Australia.

Background: Monoclonal antibodies that target the CD20 antigen and cause B-cell depletion have proven to be a highly effective treatment strategy in relapsing-remitting MS (RRMS). Ofatumumab, the first fully human anti-CD20 monoclonal antibody, was approved for RRMS treatment in 2021 following successful phase III clinical trials. Real-world patient populations are inherently heterogeneous and offer further insights into the impact of therapies on disease activity, adverse events and immunological parameters. Objective: To evaluate the safety and effectiveness of ofatumumab in a clinic-based MS population. Methods: Adult RRMS patients attending a clinic in Sydney, Australia, treated with ofatumumab were included. A retrospective review of medical records was undertaken. Results: A total of 170 patients were enrolled. Mean age was 46.2 years (±11.0). Median duration of treatment with ofatumumab was 18.1 months (11.0-26.0). 96.5% of patients met three-parameter criteria for no evidence of disease activity (NEDA-3) during treatment. No relapses occurred. Eighteen patients had progression independent of relapse activity (PIRA) in the 12 months before ofatumumab, 12 of whom stabilised. Serious infections occurred in 2.9%, and 6.4% stopped treatment due to adverse events. Immunoglobulin levels decreased on treatment, though this was only significant for IgM ( Conclusion: This study demonstrates high effectiveness of ofatumumab in an older RRMS population with longer disease duration than pivotal trials. A positive effect on PIRA was observed in 66.7% of those experiencing it in the year prior. Discontinuation due to adverse events was rare.