A Study to Investigate the Safety and Preliminary Efficacy of ALLO-329, an Allogeneic CAR T-cell Therapy, in Adults With Autoimmune Disease

Inclusion Criteria:

1. Adults ≥ 18 to < 70 years of age.

2. Adequate hematological function and liver, cardiac, and pulmonary function.

3. A highly sensitive urine pregnancy test or serum pregnancy test (for females ofchildbearing potential) negative at screening. All participants of childbearingpotential must be willing to use a highly effective method of contraception for atleast 12 months (6 months for males) after LD chemotherapy or ALLO-329administration, whichever is later.

4. Signed and dated informed consent form.

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

6. Confirmed active disease (SLE, IIM, or SSc) as defined by the appropriateclassification criteria for each respective disease, clinical evidence, and/orlaboratory testing.

7. Disease activity as above despite prior treatment with standard of care therapyincluding at least one immunosuppressive agent for at least 3 months (in addition tohydroxychloroquine [HCQ]).

Exclusion Criteria:

1. Participants with active systemic bacterial, fungal, or viral infection requiringsystemic treatment or a clinically significant active, opportunistic, chronic orrecurrent infection.

2. Any active malignancy within 3 years prior to enrollment, except for adequatelytreated localized basal cell or squamous cell skin cancer, carcinoma in situ or lowrisk prostate cancer (Gleason score ≤ 6).

3. Prior treatment with CD19 or CD70 targeted therapy or any prior engineered celltherapy (e.g., CAR T therapy).

4. Clinically significant or unstable or uncontrolled acute or chronic disease (e.g.,hypothyroidism and diabetes) not due to SLE/IIM/SSc.

5. Symptomatic cardiac or vascular disease requiring medical intervention within 6months prior to screening, hemodynamically symptomatic pericardial effusion, orsymptomatic electrocardiogram abnormality requiring medical intervention.

6. Child-Pugh Class B or C cirrhosis.

7. Symptomatic airway disease requiring medical intervention, pleural effusion ≥ Grade 2, or history of pulmonary embolism requiring anticoagulant therapy within 6 monthsof enrollment.

8. Participants known to be refractory to platelet or red blood cell transfusions orwho will refuse indicated transfusion support to manage cell counts followingtreatment.

9. Any form of primary, inherited immunodeficiency.

10. Unwilling to participate in an extended safety monitoring period.

11. For participants with SLE: Active disease involving CNS within the last 6 months orSLE that is drug-induced. For those with lupus nephritis, history of dialysis within 12 months or expected need for renal replacement therapy within the next 12 months,or National Institutes of Health (NIH) chronicity score of 3+ in any of thefollowing domains: glomerular sclerosis, glomerular fibrous crescents, tubularatrophy, and/or interstitial fibrosis.

12. Participants with IIM: A myositis other than IIM classification, non-reversible,unrelated or weakness not amenable to assessment, or dermatomyositis with presenceof anti-TIF1 gamma antibody.

13. Participants with SSc: Pulmonary arterial hypertension requiring treatment, rapidlyprogressive or severe SSc gastrointestinal involvement, or prior scleroderma renalcrisis.