Evaluation of the Condition of Patients Receiving EARLY Ravulizumab and Admitted in ICU for gMG Crisis

Inclusion Criteria: * Male or female aged ≥18 years. * Diagnosed with gMG with confirmed documentation and supported by a physical exam and confirmed seropositivity for AChR-Abs. * Patients having received more than 1 cycle of PLEX or IVIg 1-2 g/kg (max 50g/day), according to clinical practice. * Meets the clinical criteria as defined by the Myasthenia Gravis Foundation of America (MFGA) for generalized MG class V - IV, at ICU admission. * Patients treated with at least one standard MG-targeted therapy. * Patients receiving Ravulizumab following PLEX of IVIg during their stay in the ICU, as per local label and reimbursement conditions. The prescription must be validated by experts from the French Health Care Network for rare neuromuscular diseases FILNEMUS. * Patients capable of understanding written informed consent and providing signed, dated, and witnessed written informed consent. If unable to sign the consent due to muscular weakness, a dedicated informed consent can be signed by a trusted witness. * Patients willing and able to comply with scheduled visits, treatment plan, study restrictions and other study procedures. * Patients affiliated to a European social security system. * Patients agree to comply with the prevention of meningococcal infections by vaccination and/or antibiotic prophylaxis in accordance with the current local vaccination/antibiotic prophylaxis recommendations. * Patients with no contraindication to anti-C5 treatment. * Patients with no contraindication to antibiotic therapy. Exclusion Criteria: * Active infection or other disorders causing weakness, known immunoglobulin A deficiency, active renal or hepatic disease, clinically significant cardiac disease, known hyperviscosity, or hypercoagulable state. * Any active malignancy. * Presence of antibodies other than anti-AChR-Ab+ (anti-titin-Ab+ were permitted as these are considered complementary markers to anti-AChR-Ab+). * Patient with a diagnosed thymoma. * Patient with a pathology judged by the investigator to interfere with the proper conduct of the study. * Positive pregnancy test. A urine pregnancy test will be carried out for women of childbearing age. * Any current mental condition (psychiatric disorder, senility, or dementia) that, in the opinion of the investigator, may affect study compliance or prevent understanding of the aims, investigational procedures, or possible consequences of the study. * Vaccination with live or live-attenuated vaccines within the 6 weeks. * Refusal of the subject to participate in the study. * Patient protected by law, under guardianship or curator ship, or not able to participate in a clinical study according to the article L.1121-16 of the French Public Health Code. * Known hypersensitivity to the active substance or to any of the excipients.