Effects of rituximab on prognosis in myasthenia gravis: A single-center experience from Turkey

Abstract

Management of treatment-resistant patients with myasthenia gravis (MG) remains an important issue. This study aimed to evaluate the effects of rituximab (RTX) treatment on the prognosis of patients with acetylcholine receptor autoantibody-positive (AChR-Ab+), muscle-specific kinase autoantibody-positive (MuSK-Ab+), or seronegative or double seropositive MG. Nineteen patients treated with RTX between 2015 and 2020 were included in this study. Demographic and clinical characteristics, prognosis, and prognostic predictors of MG were evaluated retrospectively. The Myas-thenia Gravis Foundation of America Post-Inter-vention Status (MGFA-PIS) before RTX treatment (pre-RTX) and after RTX treatment (post-RTX) were recorded. A total of 10 patients (52.6%) were AchR Ab+, 6 patients (31.6%) were MuSK Ab+, 1 patient (5.3%) was seronegative, and 2 patients (10.5%) were double seropositive. Steroid dose was pre-RTX 38.9±5.7 (25-45), it was post-RTX 10.5±10.3 (0-30) (p<0.001). Post-RTX steroid treatment was discontinued in 6 of 19 patients (p=0.041). Only three patients received intravenous immunoglobulin at the post-RTX follow-up (p<0.001). In post-RTX 12th month, the MGFA-PIS score was as minimally manifestation or better in 9 patients (47.3%) and improved or was better in 18 patients (94.7%) (p-value 0.004; <0.001, respectively). The improvement in MGFA-PIS scores post-RTX was similar in MuSK-Ab+ and AChR-Ab+ patients. The data are insufficient in seronegative and double seropositive patients and RTX must be considered in the treatment of suitable patients with MuSK-Ab+ and AChR-Ab+ refractory MG.