Resistant myasthenia gravis and rituximab

This retrospective study evaluated the efficiency and tolerance of rituximab in the management of resistant myasthenia gravis (MG). Twenty-eight patients who received rituximab for the treatment of MG between 2004 and 2015 at Pitié-Salpétrière University Hospital (Paris, France) were included.

The efficacy of rituximab was evaluated every 6 months by the myasthenic muscle score (MMS), the Myasthenia Gravis Foundation of America – Clinical Classification (MGFA-CC), the MGFA Therapy Status and the Postintervention Status (PIS). All rituximab-related side effects were noted. Twenty-one patients had anti-acetylcholine receptor antibodies, 3 had anti-muscle-specific tyrosine kinase antibodies and 4 seronegatives. The mean age at day 1 of RTX was 50.6 ± 12.0 years. Patients previously received 1-4 immunosuppressants. The mean follow-up was 27.2 months (range: 6-60 months). The mean total dose of rituximab was 4.8 ± 2.5 g. The initial median MMS (58.8 points) improved significantly at M6 (74.5 ± 15.0 points; p < 0.0001) and remained stable thereafter: at M12: 75.9 ± 14.0 points (p = 0.00014), at M36: 72.5 ± 13.1 points (p = 0.0013). Among 16 patients with initial severe symptoms (MGFA-CC class IV), 14 improved. The PIS showed efficacy in about 50% of patients: at M6, 12/28 (43%) patients were considered improved. This benefit remained stable thereafter: at M12: 12/24, at M24: 7/17, at M36: 6/12. One patient developed a delayed progressive multifocal leukoencephalopathy.

Based on the PIS, rituximab may be efficient in 50% of patients with MG resistant to immunosuppressants.

Afanasiev V, Demeret S, Bolgert F, Eymard B, Laforêt P, Benveniste O. Resistant myasthenia gravis and rituximab: A monocentric retrospective study of 28 patients. Neuromuscul Disord. 2016 Dec 14. [Epub ahead of print]