An open-label study to assess safety, efficacy, and cellular kinetics of YTB323 in treatment resistant generalized myasthenia gravis (CYTB323O12101)

Recruitment & Eligibility

Inclusion Criteria

Confirmed gMG diagnosis supported by the following: -Documented report of positive serology testing for either AChR antibodies or MuSK antibodies at screening AND at least one of the following: -History of abnormal neuromuscular transmission test demonstrated by repetitive nerve stimulation or single-fiber electromyography -History of positive acetylcholinesterase inhibitor test -Improvement in MG signs on an oral acetylcholinesterase inhibitor as assessed by the treating physician
MGFA Class III-IVa (gMG) at screening
Treatment-resistant gMG as defined by: MG-ADL score >= 6 at screening despite adequate treatment trials with at least two different non-steroidal immunosuppressive drugs given at adequate doses and duration of therapy.
If on chronic corticosteroids, the ability and willingness to taper to a maximum dose of 10 mg prednisolone daily or equivalent at least one week before leukapheresis
If treated with cholinesterase inhibitors, patients must be on a stable dose for at least two weeks prior to screening

Exclusion Criteria

Exclusively ocular myasthenia gravis (MGFA I), mild symptoms (MGFA II), or severe bulbar disease or MG crisis, MGFA Class IVb or V at screening
History of bone marrow/hematopoietic stem cell or solid organ transplantation.
Clinically significant active, opportunistic, chronic or recurrent infection (including positive for hepatitis B or hepatitis C) confirmed by clinical evidence, imaging, or positive laboratory tests one month prior to leukapheresis
Other uncontrolled disease states, such as asthma, or inflammatory bowel disease, where flares are commonly treated with oral or parenteral corticosteroids, at screening
Participants with a known immunodeficiency syndrome (AIDS, hereditary immune deficiency, drug induced immune deficiency), or tested positive for HIV antibody, at screening
Prior treatment with anti-CD19 therapy, adoptive T cell therapy or any prior gene therapy product (e.g. CAR-T cell therapy).

Study & Design

Primary Outcome Measures

Name	Time	Method
Frequency of Adverse Events (AEs)		Frequency of Adverse Events (AEs) (including CRS and ICANs)
Occurrence of Adverse Events (AEs)		Occurrence of Adverse Events (AEs) (including CRS and ICANs)
Severity of Adverse Events (AEs)		Severity of Adverse Events (AEs) (including CRS and ICANs)
Change from baseline in safety parameters		Change from baseline in safety parameters including, but not limited to: Vital signs, laboratory parameters, ECG, and neurological status

Secondary Outcome Measures

Name	Time	Method

Recruitment & Eligibility