A Safety and Efficacy Study Evaluating CTX112 in Adult Subjects With Refractory Autoimmune Disease

Key Inclusion Criteria:

1. Age ≥18 years and < 70 years of age.

2. Subjects must voluntarily sign a written informed consent and be willing and able tocomply with all study requirements.

3. Adequate hematologic, renal, liver, cardiac and pulmonary organ function.

4. Subjects must agree to use acceptable methods of contraception.

5. Willing and able to comply with scheduled visits, treatment plan, laboratory tests,contraceptive guidelines, and other study procedures.

6. Diagnosis of systemic lupus erythematosus (SLE), systemic sclerosis (SSc) oridiopathic inflammatory myopathy (IIM).

For systemic lupus erythematosus (SLE) subjects:

• Diagnosis of SLE by a board-certified rheumatologist that conforms with 2019ACR/EULAR criteria. For lupus nephritis subjects, active, biopsy-provenproliferative lupus nephritis Class III or IV, either with or without the presenceof Class V, and appropriate National Institutes of Health index activity score usingthe 2018 International Society of Nephrology/Renal Pathology Society criteria.

For Systemic Sclerosis (SSc) subjects:

• Diagnosis of diffuse cutaneous systemic sclerosis (dcSSC) or SSc-ILD that conformswith 2013 ACR/EULAR criteria. Subjects should meet active skin or lung diseasecriteria.

For Idiopathic Inflammatory Myopathy (IIM) subjects:

• Diagnosis with dermatomyositis (DM), polymyositis (PM) or myositis as part ofrheumatologic overlap syndrome, antisynthetase (ASyS), or immune-mediatednecrotizing myopathy (IMNM) that conforms with 2017 ACR/EULAR criteria forinflammatory myopathies. Subjects must meet moderate severe, skin, or lunginvolvement criteria.

Key Exclusion Criteria:

1. Prior anti-CD19 therapy or any gene therapy/genetically modified cell therapy.

2. Prior solid organ (heart, liver, kidney, lung) transplant or hematopoietic celltransplant.

3. Severe active or history of central nervous (CNS) involvement.

4. History of a seizure disorder, cerebrovascular ischemia/hemorrhage, dementia,cerebellar disease or any autoimmune disease with CNS involvement other than SLE,SSc or IIM.

5. Mixed connective tissue disease with no clear predominant disease.

6. Presence of study disease manifestations or other conditions that are likely to poseincrease safety risks and/or confound disease assessments, or pose significant riskto those receiving CAR T cell therapy.

7. History of primary or secondary immunodeficiency.

8. Presence or history of certain bacterial, viral or fungal infection.

9. Malignancy in the last 5 years (with the exception of cancers deemed to be lowlikelihood for recurrence).

10. Diagnosis of a genetic disorder associated with bone marrow failure ormyelodysplastic syndrome.

11. History or current diagnosis of catastrophic anti-phospholipid syndrome or antiphospholipid syndrome that requires ongoing anticoagulation.

12. Pregnant or lactating.

13. Presence or history of disease requiring treatment that is not compatible with thestudy protocol; presence or history of other conditions that are not compatible withthe study protocol.