Cortés Vicente, ElenaÁlvarez Velasco, RodrigoPlá-Junca, FrancescRojas García, RicardParadas, CarmenSevilla, TeresaCasasnovas, CarlosGómez Caravaca, María TeresaGutiérrez Gutiérrez, GerardoGallardo, EduardEt al.2022-07-232022-07-232022Cortés-Vicente, E., Álvarez-Velasco, R., Plá-Junca, F., Rojas-García, R., Paradas, C., Sevilla, T., Casasnovas, C., Gómez-Caravaca, M. T., Pardo, J., Ramos-Fransí, A., Pelayo-Negro, A. L., Gutiérrez-Gutiérrez, G., Turón-Sans, J., López de Munain, A., Guerrero-Sola, A., Jericó, I., Martín, M. A., Mendoza, M. D., Morís, G., Vélez-Gómez, B., … Gallardo, E. (2022). Drug-refractory myasthenia gravis: Clinical characteristics, treatments, and outcome. Annals of Clinical and Translational Neurology, 9(2), 122–131. https://doi.org/10.1002/acn3.514922328-9503http://hdl.handle.net/11268/11525Objective: To describe the clinical characteristics and outcomes in patients with refractory myasthenia gravis (MG) and to determine the effectiveness and side effects of the drugs used for their treatment. Methods: This observational retrospective cross-sectional multicenter study was based on data from the Spanish MG Registry (NMD-ES). Patients were considered refractory when their MG Foundation of America post-interventional status (MGFA-PIS) was unchanged or worse after corticosteroids and two or more other immunosuppressive agents. Clinical and immunologic characteristics of drug-refractory patients, efficiency and toxicity of drugs used, and outcome (MGFA-PIS) at end of follow-up were studied. Results: We included 990 patients from 15 hospitals. Eighty-four patients (68 of 842 anti-acetylcholine receptor [AChR], 5 of 26 anti-muscle-specific tyrosine kinase [MusK], 10 of 120 seronegative, and 1 of 2 double-seropositive patients) were drug refractory. Drug-refractory patients were more frequently women (p < 0.0001), younger at onset (p < 0.0001), and anti-MuSK positive (p = 0.037). Moreover, they more frequently presented a generalized form of the disease, bulbar symptoms, and life-threatening events (p < 0.0001; p = 0.018; and p = 0.002, respectively) than non-drug-refractory patients. Mean follow-up was 9.8 years (SD 4.5). Twenty-four (50%) refractory patients had side effects to one or more of the drugs. At the end of follow-up, 42.9% of drug-refractory patients (42.6% of anti-AChR, 100% of anti-MuSK, and 10% of seronegative patients) and 79.8% of non-drug-refractory patients (p < 0.0001) achieved remission or had minimal manifestations. Eighty percent of drug-refractory-seronegative patients did not respond to any drug tested. Interpretation: In this study, 8.5% of MG patients were drug-refractory. New more specific drugs are needed to treat drug-refractory MG patients.engAttribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)https://creativecommons.org/licenses/by-nc-nd/4.0/deed.enMiastenia gravisjournal article10.1002/acn3.51492open accessNeurologíaTratamiento médicoMedicamento