Disease course, progression and activity of neuromyelitis optica (NMOSD) in patients who were treated with Rituximab, 6 and 12 months after receiving the first dose of drug, in Isfahan city

Abstract

Introduction: Neuromyelitis optica spectrum disease (NMOSD) is a chronic inflammatory and usually relapsing demyelinating disease which mainly involves optic nerve and spinal cord and also other parts of the central nervous system. Rituximab has been used for some neurological disorders with a probable autoimmune basis. Early and aggressive immunosuppression therapy is necessary to prevent clinical relapses and permanent disability in NMOSD. Rituximab, a monoclonal antibody against B cells, has been found effective in several recent studies. The objective of this study is to evaluate the clinical efficacy of Rituximab as a newly introduced treatment to NMOSD in Iran.

Methods and materials: This is an observational cohort study carried out,on 56 patients who have been diagnosed with NMOSD. The patients' information registered in Kashani Hospital MS clinic. They received the first dose of Rituximab for approximately 6 months before the beginning of study. In the first session, every patient was interviewed and examined based on necessary information for the study. Follow up visits were done as needed in a period of 12 months after the first dose. Patient's age, sex, age of onset, presenting symptom, annual relapse rate, acute attacks, EDSS (primary, 6 and 12 months) were recorded. Comparative aims achieved by within group analysis before and after treatment. AntiAQP4 antibody had been checked before the start of study. patients divided into two groups based on the antibody test results for subgroup analysis. Data were analyzed using the IBM SPSS23 - United States software.

Results: 56 known cases of NMOSD including 17.85% male and 82.15% female were under study. The Mean disease duration was 87.60±59.65 months and mean duration of treatment was 19.56±8.26. The mean EDSS score was primarily 4.83±1.87 and after treatment it decreased significantly (p-value<0.001) to 3.38±1.57 and 2.87±1.63 (6 months and 12 months later). There was a statistical difference between the annual mean relapse rate before and after treatment (p<0.001). The above mentioned index decreased from 1.43±1.107-0.147±0.27. Also, the mean number of attacks in one year before and after treatment were 1.97±0.57 and 0.28±0.45 with significant statistical difference (p<0.001). In the patients with positive anti AQP4 antibody,the mean EDSS decreased from 4.94±1.83-3.52±1.27 and 2.92±1.54. Annual mean relapse rate also decreased significantly from 1.35±0.85-0.10±0.19. Mean number of attacks in one year before and after treatment were 2.05±0.75-0.27±0.46 (p<0.001) respectively.

Conclusion: In the current study, we found that Rituximab can significantly improve disability state and also can markedly reduce relapse rate in NMOSD patients.

Keywords: Annual relapse rate; EDSS; Monoclonal antibody; Neuromyelitis optica; Rituximab.