Efficacy of Rituximab in Refractory Generalized anti-AChR Myasthenia Gravis

Article type: Research Article

Authors: Landon-Cardinal, Océane^{a; *} | Friedman, Diane^b | Guiguet, Marguerite^c | Laforêt, Pascal^d | Heming, Nicholas^b | Salort-Campana, Emmanuelle^e | Jouen, Fabienne^f | Allenbach, Yves^a | Boyer, Olivier^f | Chatenoud, Lucienne^g | Eymard, Bruno^d | Sharshar, Tarek^b | Benveniste, Olivier^a

Affiliations: [a] AP-HP, Hôpital Pitié-Salpêtrière, Department of Internal Medicine and ClinicalImmunology, Inflammation-Immunopathology-Biotherapy Department (I2B), East Paris Neuromuscular Diseases Reference Center, Inserm U974, Sorbonne Université, Paris 6, Paris, France | [b] Department of IntensiveCare, Raymond Poincare University Hospital, Garches, France | [c] Sorbonne Université, UPMC UnivParis 06, INSERM, Institut Pierre Louis d’Epidemiologie et de Santé Publique (IPLESP UMRS 1136), F75013, Paris, France | [d] AP-HP, Hôpital Pitié-Salpêtrière, Department of Neurology, EastParis Neuromuscular Diseases Reference Center, Université Pierre et Marie Curie, Paris 6, Paris, France | [e] APHM, Hôpital la Timone, Centre de Référence des Maladies Neuromusculaires, Marseille, France | [f] Rouen University Hospital, Department of Immunology, Inserm U905, NormandieUniv, IRIB, Rouen, France | [g] Université Paris Descartes, Sorbonne Paris Cité, Paris, France, and INSERM U1151, CNRS UMR 8253, INEM Hôpital Necker-Enfants Malades, Paris, France

Correspondence: [*] Correspondence to: Océane Landon-Cardinal, Department of Internal Medicine, Pitié-Salpêtrière University Hospital, 47-83 Boulevard de l’Hôpital, 75013 Paris, France. Tel.: +33 1 42 16 10 88; Fax: +33 1 42 16 10 58; E-mail: o.landoncardinal@gmail.com.

Abstract: Background:Several retrospective case series have suggested rituximab (RTX) might improve patients with refractory Myasthenia Gravis (MG). Objective:In this study, we aimed to evaluate prospectively the efficacy of RTX on muscle function in refractory generalized anti-acetylcholine receptor (AChR) MG patients. Methods: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. Results:Twelve patients were enrolled, and 11 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. Conclusions:These results provide data on the effect of RTX in patients with severe, refractory anti-AChR Abs generalized MG. Even though 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.

Keywords: Myasthenia gravis, rituximab, refractory generalized myasthenia, anti-acetylcholine receptor antibodies, anti-AchR, anti-CD20 monoclonal antibodies

DOI: 10.3233/JND-180300

Journal: Journal of Neuromuscular Diseases, vol. 5, no. 2, pp. 241-249, 2018