A Study of ADCLEC.syn1 in People With Acute Myeloid Leukemia

Inclusion Criteria:

1. Age ≥18 years of age at the time of signing informed consent.

2. Patients must have R/R AML. The following disease status will be eligible for thestudy: a. Refractory AML is defined as failure to achieve a CR, CRh or CRi after one of thefollowing regimens: i. At least one course of standard intensive inductionchemotherapy (e.g., 7+3, MEC, HiDAC, etc.) or hypomethylating agent (HMA) or lowdose cytarabine-based combination regimen including but not limited to venetoclax (e.g. venetoclax in combination with azacytidine, decitabine or cytarabine) ii. Fourcycles of HMA monotherapy b. Relapsed AML is defined the appearance of ≥5% blasts inthe bone marrow or peripheral blood at any time after achieving a CR, CRh, or CRi.

3. ECOG performance status 0 or 1.

4. Subjects must have a suitable stem cell donor identified who may donate cells in theevent that the subject needs to undergo an allogeneic HSCT for rescue from prolongedmarrow aplasia. Donor may be from related or unrelated matched source, haplo or cord, and must befound to be suitable according to the institution's standard criteria.

5. Adequate organ function defined as:

6. Serum creatinine <2.0 mg/100 mL.

7. Total bilirubin <2.0 mg/100 mL, unless benign congenital hyperbilirubinemia ordue to leukemia organ involvement

8. AST and/or ALT ≤5 × ULN, unless considered due to leukemic organ involvement.

Exclusion Criteria:

1. Diagnosis of acute promyelocytic leukemia.

2. Radiologically-detected or symptomatic CNS disease or CNS 3 disease (i.e., presenceof ≥5/µL WBCs in CSF). Subjects with adequately treated CNS leukemia are eligible.

3. Oxygen saturation <90% on room air.

4. Patients with prior allogeneic HSCT are allowed as long as HSCT occurred > 3 monthsof signing ICF and without ongoing requirement for systemic graft-versus-hosttherapy.

5. Treatment with clofarabine or cladribine within 3 months prior to leukapheresis

6. The following medications are excluded:

7. Steroids: Therapeutic doses of corticosteroids (greater than 10mg daily ofprednisone or its equivalent) within 7 days of leukapheresis or 72 hours priorto CAR T cell infusion.

8. Chemotherapy: Should be stopped one week prior to leukapheresis or startingconditioning chemotherapy. Hydroxyurea for cytoreduction can be administered upto 72 hours before leukapheresis or CAR T cell infusion.

9. Clinically significant cardiovascular disease, including stroke or myocardialinfarction within 6 months prior to first study medication; or the presence ofunstable angina or congestive heart failure of New York Heart Association Grade 2 orhigher; or cardiac ejection fraction <40%.

10. Uncontrolled clinically significant infections such as ongoing fever for 48 hours,persistent bacteremia or requiring new supplemental oxygen.

11. Previous treatment with CAR therapy

12. Positive serologic test results for HIV.

13. Acute or chronic HBV infection as assessed by serologic (HBVsAg) or PCR results,defined as HBVsAg+, HBVcAb+, HBV PCR+. 12. Acute or chronic HCV infection asassessed by serologic (HCV ab) or PCR results, defined as HCV Ab+ with reflex topositive HCV PCR.

14. Active second malignancy that requires systemic treatments, with the exception ofmalignancy treated with curative intent and without evidence of disease for >2 yearsbefore screening.

15. Live vaccine within 4 weeks prior to leukapheresis 15. Pregnant orlactating/breastfeeding women 16. Any prior or ongoing condition/issue that in theopinion of the investigator would make the patient ineligible for study