Impact of rituximab in Mexican patients with Multiple Sclerosis-A single-center retrospective study

Background: Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS). B cells have an essential role in the disease pathogenesis and therefore selective B-cell depletion are commonly used to treat the disease. Rituximab (RTX), a chimeric anti-CD20 monoclonal antibody had demonstrated reduced inflammatory activity and radiological activity in MS patients. Due to economic constrains and treatment access limitations, RTX is often used as a treatment alternative in these patients. Here, we described our center experience in RTX-treated MS patients. Methods: A single-center observational retrospective study was conducted in a Mexican cohort MS during 2010 to 2020. All patients had a confirmed MS diagnosis.All patients received fixed scheme involving induction with 1 g on day one and day 15, followed by 500 mg-1 g every six months for maintenance. Annual Relapse Rate (ARR), Progression index (PI), Expanded Disability Status Scale (EDSS) and MRI activity of the disease were evaluated. Comparison between naive and non-naive patients was also conducted. Results: A total of 85 patients were included. The mean age at diagnosis was 33.13 (+/- 8.90) years with 73 (85.9%) being RRMS. 39 (34.1%) were treatment-naive. While treated with RTX, 62(72.9%) patients reached a free-of-relapse status, with statistically significant decrease in the mean ARR from 0.82 to 0.36 [0.14 (95%CI: 0.09-0.20), p = 0.0001 and EDSS [0.25 CI 0-0.5 (p = 0.034)] and a decrease in their T1 Gd-enhancing MRI lesions (1.64 vs. 0.12 CI 0.70-2.30, p = 0.004. 29 (29.4%) patients achieved NEDA-3. Among all patients, only 2 (2.4%) experienced infusion-related mild adverse events. No serious adverse events were reported. Conclusion: We found significant clinical and radiological improvement in naive and non-naive MS patients treated with RTX.