Five-Year Safety and Efficacy Outcomes with Ofatumumab in Patients with Relapsing Multiple Sclerosis

Introduction: Ofatumumab demonstrated superior efficacy and similar safety versus teriflunomide in ASCLEPIOS I/II in people with relapsing multiple sclerosis; no new safety concerns and sustained efficacy were observed up to 4 years in the open-label extension study ALITHIOS. Here, we further characterise the safety and efficacy of ofatumumab up to 5 years by discussing infection outcomes in the COVID-19 era and providing a comprehensive overview of participant disability outcomes. Methods: Safety (N = 1969; participants who received ≥ 1 dose of ofatumumab in ASCLEPIOS I/II, APLIOS, APOLITOS, or ALITHIOS) and efficacy sets (N = 1882; participants randomised to ofatumumab [OMB-OMB] or teriflunomide [TER-OMB] in ASCLEPIOS I/II, regardless of whether they entered ALITHIOS) were analysed. Data cutoff: 25 September 2022. Results: The exposure-adjusted incidence rates (per 100 patient-years) of adverse events (AEs, 124.65), serious AEs (4.68), serious infections (1.63), and malignancies (0.32) remained consistent with previous findings up to 5 years of follow-up, with no new safety signals identified. With ofatumumab treatment up to 5 years, > 80% of patients remained free of 6-month confirmed disability worsening (6mCDW). Annualised relapse rates (ARR) remained low, and magnetic resonance imaging (MRI) activity was almost completely suppressed with OMB-OMB through years 1–5; after switching from teriflunomide (years 2–3), pronounced reductions in ARR/MRI activity were observed with low rates sustained through years 3–5. During year 5, 9 of 10 participants in both groups were free of disease activity (NEDA-3). Conclusion: Ofatumumab has a favourable benefit-risk profile that is sustained up to 5 years. Trial registration: ALITHIOS (NCT03650114): https://clinicaltrials.gov/ct2/show/NCT03650114