KYSA-6: A Study of Anti-CD19 Chimeric Antigen Receptor T-Cell Therapy, in Patients With Generalized Myasthenia Gravis

Myasthenia gravis (MG) is a chronic autoimmune disease that affects the neuromuscular junction and is characterized by muscle weakness. B cells play a role in MG, and the disease is characterized by the presence of autoantibodies such as anti-AChR and anti-MuSK antibodies. CD-19 target chimeric antigen receptor (CAR) T cells harness the ability of cytotoxic T cells to directly and specifically lyse target cells to effectively deplete both normal and autoreactive B cells in the circulation as well as impacted lymphoid and potentially non-lymphoid tissues. KYV-101 (mivocabtagene autoleucel [miv-cel])), a fully human anti-CD19 CAR T-cell therapy, will be investigated in adult subjects with myasthenia gravis (MG).

Key Inclusion Criteria

• Presence of autoantibodies to AChR or MuSK
• Myasthenia Gravis Foundation of America (MGFA) Class II-IV
• MG-Activities of Daily Living (MG-ADL) total score of ≥6 at screening and confirmed at baseline visit
• QMG total score of ≥11 at screening an confirmed at baseline visit
• Failed treatment with 2 or more immunosuppressive/immunomodulatory therapies, or failed at least 1 immunosuppressive therapy and required chronic plasmapheresis, or IVIG (or subcutaneous or intramuscular Ig) to control symptoms
• On a stable dose of glucocorticoids and/or other immunotherapies for ≥1 month prior to screening. For patients treated with azathioprine, a stable dose for ≥2 months prior to screening is required
• No change in dose of acetylcholinesterase inhibitors for ≥2 weeks prior to screening
• No use of intravenous immune globulin (IVIG) or plasmapheresis (PLEX) within 4 weeks of screening or pre-dose baseline (unless this is part of their SOC treatment regimen)
• No use of rituximab (or any other anti-CD20 or CD19 monoclonal antibody) within 12 weeks prior to screening
• Able and willing to attend the necessary visits to the study site

Key Exclusion Criteria

• Unable to washout or interrupt autoimmune disease therapy prior to apheresis and/or baseline if required
• Co-occurring neurological autoimmune disease (ie, Lambert-Eaton Myasthenic Syndrome) or any disease affecting the neuromuscular junction or muscle causing weakness (eg, myositis, myopathy, motor neuropathy)
• History of stroke (with residual sequalae and/or risk for recurrence), seizure (even if well controlled on antiepileptics), neurodegenerative disease, altered mental status (unexplained and/or recent/current), or uncontrolled/severe psychiatric disease
• Any serious and/or uncontrolled medical condition that, in the investigator's judgment, would cause unacceptable safety risk, interfere with study procedures or results, or compromise compliance with the protocol, including but not limited to, clinically significant cardiac or pulmonary disease
• History of primary immunodeficiency, organ or allogeneic bone marrow transplant, or splenectomy
• Active, uncontrolled, viral, bacterial, or systemic fungal infection or recent history of repeated infections
• Thymectomy <12 months of screening or planned during the study
• Prior treatment with gene therapy product or cellular immunotherapy (eg, CAR T) requiring vector integration and directed at any target
• Patients requiring chronic anticoagulation therapy that cannot be discontinued for medical procedures