Several retrospective case series have suggested rituximab (RTX) might improve patients with refractory Myasthenia Gravis (MG). This study evaluated prospectively the efficacy of RTX on muscle function in patients with severe, refractory generalized anti-acetylcholine receptor (AChR) MG. Enrolled patients received 1 g of RTX at day 0, day 14, and 6-month follow-up (M6). The primary endpoint was improvement of muscle function at 12-month (M12) based on myasthenic muscle score (MMS). Secondary endpoints were an improvement of the MG Foundation of America Postintervention Status (MGFA-PIS), respiratory forced vital capacity, occurrences of acute MG exacerbation and requirement of associated immunosuppressants and immunomodulatory agents. Of the 11 patients that completed the study, only a single patient presented an improvement of at least 20 points on MMS at M12, although 2 patients displayed an increase of at least 18 points at M12. MGFA-PIS had improved in 55% of patients by M12. The clinical improvement was not associated with a reduction of immunosuppressant burden. Even though the primary outcome was only reached in a single patient at M12, a beneficial effect of RTX on muscle function was seen in half of the patients at M12 and persisted in a third of patients at M18.
