Retrospective evaluation of the efficiency and safety of okrelizumab treatment on clinical and mr imaging in relapsing-remitting and progressive multiple sclerosis cases

As the importance of B cells in MS immunopathogenesis is understood, the use of disease-modifying drugs targeting B cells is increasing. Okrelizumab, a recombinant humanized monoclonal IgG1 antibody targeting CD20-positive B cells was approved by the FDA in 2017 and by the EMA in 2018. Okrelizumab is the first drug approved for PPMS patients. The efficacy and safety of ocrelizumab has been demonstrated in phase 2 and phase 3 studies, but there are not enough real-word data yet. In our study, a total of 49 RRMS and PMS patients who received at least 2 doses of ocrelizumab were retrospectively analyzed. The effects of the drug on the annual number of attacks, MRI lesion, disability progression and NEDA-3 were investigated, and the reasons for switching to ocrelizumab, side effects, reasons for discontinuation and retention rates were discussed. The experience of the use of ocrelizumab in our clinic has been tried to be conveyed. In our study, it was found that ocrelizumab had positive effects on attacks, disability and lesions in MRI, regardless of age and gender, in line with the literature data. After the treatment, 1 patient had a relaps in the sixth month, and then no relaps was observed in our patients in the subsequent follow-ups. No increase in disability was observed in the patients for the first 6 months. Among the patients who completed the twelfth month of treatment, the rate of patients without disability progression was 91.7%, while at the 24th month it was 70%. NEDA-3 was achieved in 81.8% of patients at 6 months, 83.3% at 1 year, and 72.7% at 2 years of ocrelizumab treatment. When the disease characteristics of the patients who could continue NEDA-3 for 2 years were examined, no significant relationship was found. Infusion-related reactions were observed in 32.7% of patients during the first dose of ocrelizumab. Urinary tract infection was observed in 8.2% of the patients during the follow-up, and upper respiratory tract infection was observed in 4.1% of the patients. In our study, although we did not have a patient who discontinued treatment due to side effects, ineffectiveness or pregnancy, 4 patients were out of follow-up and 2 patients left the treatment voluntarily because they did not want to come to the hospital due to COVID-19. The rate of staying in treatment in the first year was 89.7%, and the rate of staying in the treatment in the second year was 97.1%. Due to the small number of patients and the lack of a homogeneous patient group in our study, it is thought that statistically significant results could not be obtained in the subgroup analyzes related to the sustainability of EDSS, NEDA-3 of patients receiving ocrelizumab. In conclusion, in this single-center retrospective study, it can be said that ocrelizumab has positive effects on clinical and MRI findings in the majority of patients and is a safe drug. Keywords: Relapsing and Remitting Multiple Sclerosis, Progressive Multipl Skleroz, Ocrelizumab, Efficacy, Disability, Side Effects