Efficacy and safety of ocrelizumab vs interferon beta-1a in participants of African descent with relapsing multiple sclerosis in the Phase III OPERA I and OPERA II studies

Background: People of African descent with multiple sclerosis (MS) appear to have a more severe disease course and may have an attenuated response to some medications compared with people of European descent.

Methods: This is a post hoc subgroup analysis of participants of African descent with relapsing forms of MS who were enrolled in the Phase III OPERA I or OPERA II clinical trials and treated with ocrelizumab (OCR) 600 mg every 6 months or interferon beta-1a (IFN β-1a) 44 μg 3 times per week.

Results: Among the 1,656 participants enrolled in OPERA I and II, 72 (4.3%) were of African descent (OCR, 40; IFN β-1a, 32). A trend for reduction in annualized relapse rate (ARR) was observed in participants of African descent, with an ≈50% reduction with OCR vs IFN β-1a. The relative rate of the mean number of gadolinium-enhancing lesions on magnetic resonance imaging (MRI) was 0.04 (95% CI, 0.01-0.22; p=0.001) in participants of African descent treated with OCR compared with IFN β-1a. Similarly, the relative rate of the number of new or enlarging T2 lesions on MRI was 0.14 (95% CI, 0.06-0.32; p<0.001). In participants of African descent, those treated with OCR were 2.61 times more likely than those who received IFN β-1a to be classified as having no evidence of disease activity (95% CI, 1.24-5.49; p=0.003) and 4.17 times more likely to be classified as having no evidence of disease activity or progression (95% CI, 1.27-13.65; p=0.006). African-descent participants tended to have a greater radiographic burden of disease at baseline, develop more brain lesions when treated with IFN β-1a, and be at greater risk of disability progression than non-African-descent participants. Participants of African descent experienced slightly more adverse events, serious adverse events, and hypersensitivity reactions than non-African-descent participants.

Conclusion: In this small sample of participants of African descent with relapsing MS from the OPERA studies, OCR demonstrated treatment benefits in clinical, MRI, and composite efficacy outcomes vs IFN β-1a, consistent with what was observed in the complete OPERA intention-to-treat cohorts.