Real-world effectiveness and safety of Ocrelizumab in a gulf multiple sclerosis cohort: extension of the Q-OCRE study to 451 patients.

Real-world evidence on ocrelizumab in multiple sclerosis (MS) from the Middle East and North Africa (MENA) is limited. We extended our original Q-OCRE cohort (n = 60) to evaluate effectiveness and safety in an ethnically diverse Gulf population. In a single-center retrospective cohort of all patients starting ocrelizumab at Hamad General Hospital, Doha, Qatar (October 2017-May 2025), the primary outcome was No Evidence of Disease Activity (NEDA-3) at Year 1; secondary outcomes were annualized relapse rate (ARR), Expanded Disability Status Scale (EDSS) trajectory, 24-week confirmed disability worsening (CDW), persistence, and safety. A total of 451 patients were included (86.7% RRMS, 7.1% SPMS, 6.2% PPMS; 57.6% female; mean age 34.3 years; median follow-up 18.1 months; 696 person-years). The cohort was mildly affected at initiation (median EDSS 1.0; 42% with no relapse in the prior 2 years). ARR fell from 0.381 to 0.046, an 87% reduction (IRR 0.13, 95% CI 0.07-0.22, p < 0.001), preserved in patients meeting trial-like activity criteria (IRR 0.09). The EDSS slope was -0.04 points/year (p = 0.03) with a phenotype-by-time interaction (p < 0.001): RRMS improved while progressive forms worsened. NEDA-3 was 59.0% at Year 1 and 61.7% at Year 2. 24-week CDW reached 8.9% at 36 months, progressive phenotype being the only independent predictor (HR 5.02). Persistence was 90.7% at 36 months. Infusion-related reactions occurred in 18.4%, adjudicated opportunistic infections in 1.0%, IgG below 7 g/L in 6.9%, and incident malignancy in 0.4%, with no deaths and no progressive multifocal leukoencephalopathy. Ocrelizumab showed robust effectiveness and a favorable safety profile in this Gulf cohort, with disability trajectories dissociating by phenotype.