A Clinical Study to Evaluate the Safety and Efficacy of GT802 Injection in the Treatment of Refractory Generalized Myasthenia Gravis

Prior treatment

• 1. Contraindication or hypersensitivity to any component of the investigational product.
• 2. Presence of conditions specified in the protocol within 6 months prior to signing the informed consent form.[沈9.1]
• 3. History of active malignancy or any malignancy within 5 years prior to screening.
• 6. Requirement for long-term administration of medications affecting coagulation function.
• 7. Participants with clinically obvious bleeding symptoms or definite bleeding tendency within 6 months before screening.
• 11. Active tuberculosis prior to screening.
• 12. Received any other investigational medicinal product within 4 weeks before signing the informed consent form (ICF).
• 13. Received intravenous immunoglobulin, plasma exchange or immunoadsorption therapy within 4 weeks prior to study treatment.
• 14. Received B-cell targeted therapy within 1 month prior to study treatment.
• 15. Received tacrolimus, cyclosporine, azathioprine, mycophenolate mofetil, mycophenolic acid, methotrexate, etc., within 2 weeks prior to study treatment.
• 16. Received neonatal Fc receptor (FcRn) antagonist therapy within 2 weeks prior to study treatment.
• 17. Received complement inhibition therapy within 2 weeks prior to study treatment.
• 18. Received systemic glucocorticoids at a dose >10 mg/day prednisone equivalent within 7 days prior to study treatment.
• 19. Received live attenuated vaccines or mRNA vaccines within 8 weeks before enrollment, or inactivated vaccines within 4 weeks before enrollment.
• 20. Underwent major surgery within 8 weeks before screening, or planned to undergo surgery during the study period.
• 24. Prior receipt of CAR-T products targeting any antigen or other gene-edited cell biotherapies.

Other illness

• 4. Presence of any active or untreated thymoma, or history of thymic carcinoma or other early pseudotumors of thymic malignancy.
• 5. Autoimmune diseases other than the study disease that require systemic glucocorticoids or immunosuppressants.
• 8. Presence of severe underlying medical conditions at screening.
• 9. Positive result for any of the following tests: a) Positive human immunodeficiency virus (HIV) antibody; b) Positive hepatitis B surface antigen (HBsAg) and/or positive hepatitis B core antibody (HBcAb), with HBV-DNA above the lower limit of quantitation of the assay; c) Positive hepatitis C virus (HCV) antibody, with HCV-RNA above the lower limit of quantitation of the assay; d) Positive syphilis antibody (excluding false-positive results caused by underlying diseases).
• 21. History of organ transplantation, splenectomy, allogeneic or autologous stem cell transplantation.
• 25. The investigator judges that any condition exists that would prevent the participant from completing the entire trial, confound the trial results, or make trial participation not in the participant's best interest.

Other

• 10. Positive cytomegalovirus (CMV)-DNA and Epstein Barr virus (EBV)-DNA in peripheral blood.
• 22. Presence of non-removable, clinically significant long-term indwelling catheters or drainage devices.
• 23. Uncontrolled large-volume serous cavity effusion despite treatment.

• 1. The participant or their legally authorized representative voluntarily signs the written informed consent form and is willing and able to comply with the study procedures.
• 2. Aged 18-65 years (inclusive) at the time of informed consent, without gender restriction.
• 3. Expected survival > 12 weeks.
• 4. Any prior systemic therapy for the indication must have a washout period of at least 4 weeks or 5 half-lives, whichever is shorter, before the participant is scheduled to receive study treatment.
• 5. Toxicities attributable to prior treatment must have stabilized and recovered to Grade ≤1.
• 6. Refractory generalized myasthenia gravis, as defined in the protocol.
• 7. Screening laboratory results meet the criteria specified in the protocol.
• 8. Pregnancy requirements:
  • At screening, serum beta human chorionic gonadotropin (β-hCG) pregnancy test is negative as confirmed by the investigator.
  • Agrees to refrain from breastfeeding during study participation until at least 1 year after infusion of GT802 Injection or until GT802 cells are no longer detectable by 2 consecutive flow cytometry assays, whichever occurs later.
  • Male participants with female partners and female participants of childbearing potential agree to use highly effective contraception (e.g., oral contraceptives, intrauterine device or condoms) starting at screening and continuing until at least 1 year after infusion of GT802 Injection or until GT802 cells are no longer detectable by 2 consecutive flow cytometry assays, whichever occurs later. Male participants must agree to use condoms during sexual contact with pregnant females or females of childbearing potential for at least 1 year after GT802 Injection infusion, even after successful vasectomy.