Effectiveness of Ocrelizumab on Disease Progression and Disability Status in Multiple Sclerosis Patients: A Two-Year Prospective Cohort Study

<b>Background and Objectives:</b> Multiple sclerosis (MS) is a chronic autoimmune disorder characterized by inflammation and neurodegeneration. Ocrelizumab, a humanized anti-CD20 monoclonal antibody, has shown promise in reducing disease activity in MS patients. This prospective study aims to assess the effectiveness of ocrelizumab in reducing confirmed disability progression in patients with relapsing-remitting MS (RRMS) and secondary progressive MS (SPMS) over a two-year period. By evaluating clinical data, and MRI findings, this study seeks to provide comprehensive insights into ocrelizumab's impact on disease dynamics and disability. <b>Materials and Methods:</b> Ninety-eight patients aged 18 to 65 with confirmed MS were enrolled under ocrelizumab therapy at the Neurology Department of "Pius Brinzeu" Clinical Emergency Hospital in Romania between July 2020 and July 2024. Participants were assessed at baseline and every six months over two years. The key outcomes measured were changes in the Expanded Disability Status Scale (EDSS) as a measure of confirmed disability progression (CDP), annualized relapse rate (ARR), and MRI findings. <b>Results:</b> Over the two-year period, the mean EDSS score significantly decreased from 5.2 ± 1.8 to 4.6 ± 1.7 (mean change = -0.6 ± 0.9; <i>p</i> = 0.032), indicating improved neurological function. The proportion of patients experiencing relapses dropped markedly from 61.2% to 14.3% (<i>p</i> < 0.001). The MRI results showed significant reductions in patients with new or enlarging T2 lesions from 68.4% to 27.6% (<i>p</i> < 0.001) and gadolinium-enhancing lesions from 44.9% to 15.3% (<i>p</i> < 0.001). Patients previously treated with natalizumab exhibited a greater reduction in EDSS scores (-1.0 ± 0.8; <i>p</i> = 0.001) compared to other treatments. Multivariate regression identified the baseline EDSS score (β = 0.65; <i>p</i> < 0.001), previous natalizumab use (β = -0.30; <i>p</i> = 0.013), and age at diagnosis (β = 0.02; <i>p</i> = 0.048) as significant predictors of two-year EDSS scores. While markers of active inflammation decreased, the proportion of patients with brain atrophy increased from 31.6% to 43.9% (not statistically significant; <i>p</i> = 0.105). SPMS patients had higher rates of brain atrophy at baseline (61.1% vs. 25.0%; <i>p</i> = 0.007) and at two years (100.0% vs. 31.3%; <i>p</i> < 0.001) compared to RRMS patients. <b>Conclusions:</b> Ocrelizumab effectively reduced disease activity and improved neurological disability over two years in both RRMS and SPMS patients. Significant reductions in relapse rates and MRI markers of inflammation were observed. Previous natalizumab treatment was associated with greater improvements. Despite these benefits, the progression of neurodegeneration, particularly brain atrophy in SPMS patients, underscores the need for additional strategies targeting neurodegenerative aspects of MS.