P-NJ006. Rituximab in myasthenia gravis: Experience from a low – and middle – income country

Introduction. Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction with 10% being refractory to conventional immunosuppressants. Rituximab is a potential therapeutic option for these patients. We aim to describe the response to rituximab and safety profile in MG. Methods. Retrospective chart review of 12 patients (M:F = 5:7, mean age: 41.08 ± 10.96 years) with MG treated with rituximab and followed up in a single neurology unit at the National Institute of Mental Health and Neurosciences, Bangalore, between 2017 and 2020. Results. Mean duration of MG was 105.16 ± 71.8 months (range 6–260 months). Pre-rituximab treatment included steroids, azathioprine, methotrexate, mycophenolate, cyclophosphamide, and thymectomy. Pre-rituximab MGFA grading included: IIa (n = 1), IIb (n = 1), IIIa (n = 2), IIIb (n = 5), IVb (n = 1), and V (n = 2). Reasons for initiation of rituximab included poor response to steroids (n=10), comorbid illnesses limiting the use of other drugs (n = 4), and drug-induced side effects (n = 2). The mean duration of follow-up was 20.33 ± 13.64 months (range 3-37 months). Two patients developed myasthenic crisis after the induction phase of rituximab and one patient died. Another patient died after 25 months of rituximab therapy due to an unrelated cause. The rest improved, pyridostigmine dose was reduced in four and was stopped in six patients. Other immunosuppressants were continued in all but one patient. Complete stable remission and pharmacological remission were achieved in one and four patients respectively while five patients had minimal manifestations. No infusion-related adverse events were noted. One patient developed transient asymptomatic neutropenia three weeks after rituximab infusion. Conclusion. Rituximab appears to be a safe and effective therapeutic option for patients with refractory MG. however, a proportion does develop worsening similar to steroid-induced exacerbation. Most of the patients in our cohort had a good response with infrequent side effects.