This study demonstrated the relatively greater efficacy of rituximab for preventing relapses in neuromyelitis optica spectrum disorder patients than administering oral immunosuppressive agents.
Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory autoimmune disorder associated with high levels of disability and relapses. Despite the high disease prevalence in this population, Black patients are consistently underrepresented in NMOSD clinical trials.
This study investigated the effectiveness of oral immunosuppressive and rituximab therapies in treating NMOSD patients, the majority of whom were Black. The study concluded that rituximab was more effective compared to azathioprine (AZA) and mycophenolate (MMF) in preventing disease relapse within 3 years of the initiation of treatment. The study findings are published in the journal Multiple Sclerosis and Related Disorders.
Baseline Characteristics of the Study Participants
The study included 52 NMOSD patients with a median age of 34 years at the onset of the disease and a female-to-male ratio of 4.8:1. This cohort constituted 56% Black, 23% White, 9% Asian, and 12% Hispanic patients. Rituximab, MMF, and AZA were the first-line therapy agents in 29, 19, and 4 patients. Patients who received MMF and AZA were placed in the oral immunosuppressant category.
Rituximab and Oral Immunosuppressive Therapies in NMOSD Patients
In this study, 7 out of 29 and 13 out of 23 patients receiving rituximab and oral immunosuppressants, respectively, experienced a relapse during the initial 3 years of treatment. Two rituximab and seven immunosuppressive therapy group patients experienced a relapse during the initial 6 months of treatment.
Based on the results of the univariate analysis, patients who received MMF or AZA reported a significantly higher relapse risk compared to patients who were administered rituximab. Based on the multivariate analysis, the Black population in the study had a significantly lower relapse risk than the White population (p = 0.029).
Adverse Outcomes of Rituximab and Oral Immunosuppressive Therapies in NMOSD
In the rituximab treatment cohort, three patients discontinued the treatment due to insurance concerns, whereas one patient converted to oral immunosuppression therapy because of insurance coverage.
In the oral immunosuppressive therapy cohort, eight patients transitioned to rituximab, three converted to monoclonal antibody therapy, and two were administered combined therapy, constituting rituximab and MMF.
Positive Tolerance and Minimal Side Effects of Rituximab Therapy in NMOSD
The patients demonstrated good tolerance for rituximab therapy, and only one patient exhibited symptomatic worsening due to a urinary tract infection; however, no worsening on magnetic resonance imaging was recorded. Moreover, four oral immunosuppressive therapy cohort and six rituximab cohort patients reported infrequent UTIs.
This retrospective study concluded that rituximab was a more effective treatment for preventing relapses than immunosuppressive agents, including AZA and MMF.
Dresser, L., Chaar, W. A., Reder, A. T., Abuaf, A. F., Cipriani, V. P., & Javed, A. (2023). Effectiveness of rituximab versus oral immunosuppressive therapies in neuromyelitis optica spectrum disorder in a racially diverse cohort of subjects: A single-center retrospective study. Multiple Sclerosis and Related Disorders, 74, 104718. https://doi.org/10.1016/j.msard.2023.104718