2021 CMSC Annual Meeting

Comparable Ofatumumab Treatment Outcomes in Patients across Racial/Ethnic Groups in the Asclepios I/II and Apolitos Studies


Background: Ofatumumab is a fully human anti-CD20 monoclonal antibody approved by the FDA for treatment of adults with relapsing multiple sclerosis (RMS). The RMS disease course and treatment response may vary across different racial/ethnic groups. Objectives: To compare outcomes across different racial/ethnic patient groups with RMS following ofatumumab treatment. Methods: This post hoc analysis included data from patients treated with ofatumumab 20 mg subcutaneously in the Phase 3 ASCLEPIOS I/II studies (n=935; White [n=829], Black/African-American [n=28], Asian [n=36], other [n=42]) and Phase 2 APOLITOS study (n=43; White [n=22], Asian [n=21, Japanese]). We compared efficacy, pharmacokinetics (PK), pharmacodynamics (PD), and safety outcomes for ofatumumab by these patient groups. Results: In ASCLEPIOS I/II, annualized relapse rates (95%CI) were similar in White (0.13 [0.11; 0.15]), Black/African-American (0.07 [0.02; 0.22], Asian (0.08 [0.03; 0.24]), and other (0.08 [0.03; 0.18]) patients treated with ofatumumab. As per PK analysis, ofatumumab trough concentrations (median [95%CI]) were comparable in White (0.438 [0.05; 2.53] ?g/mL), Black/African-American (0.106 [0.05; 1.67] ?g/mL), Asian (0.127 [0.05; 1.20] ?g/mL) and other (0.453 [0.05; 2.25] ?g/mL) patients in ASCLEPIOS I/II, with numerically higher concentrations (0.713 [0.142; 2.00] ?g/mL) observed in Asian patients in APOLITOS. A population-PK analysis demonstrated a statistically significant difference between Japanese and Caucasian PK parameters but no clinically significant difference for maximum serum concentrations and area under the curve in these two populations. In APOLITOS, ofatumumab was associated with a consistent depletion of CD19+ B-cells and CD3+CD20+ T-cells in Asian and White patients, indicating similar PD response. No meaningful differences were observed in the incidence of adverse events (AEs) in ASCLEPIOS I/II (White [84.9%], Black/African-American [92.9%], Asian [66.7%], other [69.8%]) nor in APOLITOS. Overall pattern, incidence rate and severity of AEs across the groups was consistent with the overall population with no discernible trends/safety signals. Conclusions: Results revealed no clinically relevant differences in outcomes for RMS patients of different racial/ethnic groups treated with ofatumumab 20 mg subcutaneously, suggesting dose adjustment may not be necessary across these groups.