To compare outcomes across different racial/ethnic patient groups with relapsing multiple sclerosis (RMS) following ofatumumab treatment.

This post hoc analysis included data from patients treated with ofatumumab 20mg subcutaneous 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.

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] µg/mL), Black/African-American (0.106 [0.05; 1.67] µg/mL), Asian (0.127 [0.05; 1.20] µg/mL) and other (0.453 [0.05; 2.25] μg/mL) patients in ASCLEPIOS I/II, with numerically higher concentrations (0.713 [0.142; 2.00] µg/mL) observed in Asian patients in APOLITOS. A population-PK analysis demonstrated no significant correlations between White, Black/African-American, Asian/others and PK parameters. 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.

Results revealed no clinically relevant differences in outcomes for RMS patients of different racial/ethnic groups treated with ofatumumab 20mg subcutaneous, suggesting dose adjustment may not be necessary across these groups.