Efficacy and Safety of HN2302 in Refractory Myasthenia Gravis(MG)

Inclusion Criteria: * Age: 18-80 years, no gender restriction; * Confirmed diagnosis of generalized myasthenia gravis (MG) with positive AchR or MuSK antibodies, meeting at least one of the following conditions：(1) Repetitive nerve stimulation suggesting neuromuscular transmission defect; (2) Positive response to neostigmine test; (3) Clinically judged improvement of --MG symptoms after oral cholinesterase inhibitor therapy; * Clinical classification of MG according to MGFA types IIa-IVb (including IIa, IIb, IIIa, IIIb, IVa, IVb); * Baseline MG-ADL score ≥6, ocular-related score \<50%; * Poor response and/or lack of efficacy under standard therapies; * Minimum life expectancy \> 12 weeks; * Adequate bone marrow, coagulation, cardiopulmonary, liver, and renal function. Exclusion Criteria: * Subjects positive for hepatitis B surface antigen (HBsAg) and/or hepatitis B core antibody (HBcAb) with detectable or quantifiable HBV DNA, positive for hepatitis C antibody (HCV Ab) with detectable or quantifiable HCV RNA, positive for HIV antibody, positive CMV DNA, or CMV DNA above the lower limit of detection; positive for syphilis antigen or antibody; * Presence of other uncontrolled active infections; * History of major organ transplantation (e.g., heart, lung, liver, kidney) or bone marrow/hematopoietic stem cell transplantation; * Pregnant or breastfeeding women; * Receipt of any mRNA-LNP products or other LNP-based drugs within the past two years; * History of any of the following cardiovascular conditions within 6 months prior to screening: New York Heart Association (NYHA) Class III or IV heart failure, myocardial infarction, unstable angina, uncontrolled or symptomatic atrial arrhythmias, any ventricular arrhythmias, or other clinically significant cardiac disease; * History of ≥Grade 2 bleeding events within 30 days prior to screening, or requiring long-term continuous anticoagulation therapy (e.g., warfarin, low molecular weight heparin, Xa factor inhibitors); * History of live vaccination within 30 days prior to screening; * Severe central nervous system diseases or pathological changes, including but not limited to: cerebrovascular accident, aneurysm, epilepsy, seizures/convulsions, aphasia, stroke, severe brain injury, dementia, Parkinson's disease, cerebellar disorders, organic brain syndromes, or psychosis; * History of asthma or severe allergies; * Any condition that, in the investigator's opinion, may increase the patient's risk or interfere with study assessments.