This study was terminated due to lack of funding.

Pilot open-label study to estimate the feasibility, safety and efficacy of intravenously administered, RNA electroporated autologous T cells expressing anti-CD123 chimeric antigen receptors expressing tandem TCR and 4-1BB (TCR /4-1BB) costimulatory domains (referred to as RNA CART123) in Acute Myeloid Leukemia (AML) subjects.

Inclusion Criteria:

• Male or female subjects 18 years of age or older with AML with no available curative treatment options using currently available therapies

• Subjects must have a suitable stem cell donor available who may donate cells if the subject needs to undergo allogeneic HCT. Donor may be matched or mismatched and must be found to be suitable according to the institution's standard criteria.

• Subjects with second or subsequent relapse, any relapse refractory to salvage, or with persistent disease after at least two lines of therapy.

  a. Subjects with relapsed disease after prior allogeneic HCT (myeloablative or non-myeloablative) will be eligible if they meet all other inclusion criteria and i. Have experienced graft rejection (no evidence of donor cells by STR analysis on 2 occasions separated by at least 1 month), OR: ii. Donor cells are present but there is no active GVHD, subject does not require immunosuppression and is more than 6 months from transplant

• Subjects must have evaluable disease defined as >5% blasts on marrow aspirate or biopsy, extramedullary disease (CNS involvement is prohibited), or at least 20% blasts in the peripheral blood within 2 weeks prior to enrollment. Note: subjects with second or subsequent relapse are considered to have evaluable disease even without meeting the above morphologic criteria if they are found to have persistent recurrent disease-associated molecular or cytogenetic abnormalities.

• Creatinine < 1.6 mg/dl

• ALT/AST must be < 5 x upper limit of normal unless related to disease

• Bilirubin < 2.0 mg/dl, unless subject has Gilbert's syndrome (≤3.0 mg/dL);

• ECOG Performance status 0-2.

• Left ventricular ejection fraction > 40% as confirmed by ECHO/MUGA

• Written informed consent is given.

• Subjects of reproductive potential must agree to use acceptable birth control methods.

Exclusion criteria:

• Pregnant or lactating women. The safety of this therapy on unborn children is not known. Female study participants of reproductive potential must have a negative serum pregnancy test at enrollment. A urine pregnancy test will be performed within 48 hours before infusion.
• HIV infection.
• Active hepatitis B or hepatitis C infection.
• Concurrent use of systemic steroids or immunosuppressant medications. Recent or current use of inhaled steroids or physiologic replacement with hydrocortisone is not exclusionary.
• Absolute lymphocyte count <500/uL
• Any uncontrolled active medical disorder that would preclude participation as outlined.
• Subjects with signs or symptoms indicative of CNS involvement. A CNS evaluation should be performed as clinically appropriate to rule out CNS involvement.
• Known history of allergy or hypersensitivity to study product excipients (human serum albumin, DMSO, and Dextran 40).
• Class III/IV cardiovascular disability according to the New York Heart Association Classification.
• Patients with a known history or prior diagnosis of optic neuritis or other immunologic or inflammatory disease affecting the central nervous system
• Subjects with clinically apparent arrhythmia, or arrhythmias that are not stable on medical management, within 2 weeks of the Screening/Enrollment visit.