2025 American Academy of Neurology Abstract Website

Nathan Chu¹, Jodie Roberts², David Hunt³, Donna Kuipers⁴, Jomana Morkous⁴, Kyra West⁴, Ana-Luiza Sayao¹, Robert Carruthers¹, Anthony Traboulsee¹, Virginia Devonshire¹, Izanne Roos⁵, Tomas Kalincik⁵, Alice Schabas¹
¹University of British Columbia; Djavad Mowafaghian Centre for Brain Health, ²University of Calgary; Clinical Outcomes Research (CORe) Unit, The University of Melbourne; Neuroimmunology Centre, Royal Melbourne Hospital, ³University of British Columbia, ⁴Djavad Mowafaghian Centre for Brain Health, ⁵Clinical Outcomes Research (CORe) Unit, The University of Melbourne; Neuroimmunology Centre, Royal Melbourne Hospital

Objective:

To compare the effectiveness of rituximab versus ocrelizumab in relapsing multiple sclerosis in a real-world setting.

Background:

Rituximab is used as an off-label first-line treatment for multiple sclerosis (MS) in British Columbia, Canada. Recent research has suggested that rituximab is not non-inferior to ocrelizumab, despite similar therapeutic mechanisms.

Design/Methods:

Medical records were manually abstracted for individuals with MS treated with rituximab or ocrelizumab at the University of British Columbia and Prince George MS Clinics in British Columbia between February 2017 and June 2024, inclusive. Individuals with ≥12 months of clinical follow up were matched 1:1 on propensity score based on age, sex, MS duration, disability, prior therapy, income quintile, treatment indication and recent relapse activity. The primary outcomes were annualized relapse rate (ARR) and cumulative hazard of relapses.

Results:

In total, 692 individuals treated with rituximab (n=283) or ocrelizumab (n=409) fulfilled inclusion criteria (mean [SD] age; 39.5 [9.91] years; 498 female [72.0%]). After matching, 532 individuals were included in the primary analysis (n=266 pairs). Similar relapse rates were observed (ARR ratio 0.9; 95% CI: 0.5-1.6), with very low ARR in both groups (rituximab 0.04 vs ocrelizumab 0.03). The cumulative hazard of relapses was numerically elevated for rituximab-treated individuals relative to ocrelizumab (hazard ratio, 1.5; 95% CI, 0.9 – 2.8), but the rarity of relapses in both groups precluded conclusive statistical comparison.

Conclusions:

Rituximab and ocrelizumab are highly effective therapies for MS with low rates of clinical disease activity among treated individuals. Low occurrence of disease activity resulted in underpowered comparisons. With this limitation, the present study did not suggest clinically meaningful differences in the effectiveness of rituximab and ocrelizumab.