Ofatumumab and Early Immunological Cells Subset Characterization in Naïve Relapsing Multiple Sclerosis Patients: A Real-World Study

Background: Ofatumumab (OFA) is a fully human anti-CD20 monoclonal antibody administered with a 20 mg subcutaneous monthly dosing regimen. Methods: Inclusion criteria were patients: 1) aged 18-55; 2) with a confirmed diagnosis of relapsing Multiple Sclerosis (RMS), per the revised 2010 McDonald criteria; 2) who started OFA according to Italian Medicines Agency prescription rules and within 12 months from the RMS diagnosis; 3) naïve to any disease-modifying therapy. The primary outcome was to offer an overview of cellular subsets of RMS naïve patients (time 0) and then after 4 weeks (time 1) and 12 weeks (time 2) on therapy with OFA in a real-world setting. Results: Fifteen patients were enrolled. CD3+ T cell frequencies were higher at time 1 (%80.4, SD 7.7) and time 2 (%82.6, SD 5.8) when compared to time 0 (%72.4, SD 9.8), p = .013. B naïve cells were barely detectable in the OFA group at time 1 (%0.4, SD 0.5) and 2 (%1.4, SD 2.9) when compared to time 0 (%11.5, SD 3.8), p < .001. Conclusion: The progressive and increasing use of anti-CD20 drugs imposes the need for larger, prospective, real-world, long-term studies to characterize further immunophenotypes of patients with RMS treated with OFA.