ET140203 T Cells in Pediatric Subjects With Hepatoblastoma, HCN-NOS, or Hepatocellular Carcinoma

Inclusion Criteria:

1. Histologically confirmed HB, HCN-NOS, or HCC with serum AFP >100ng/mL at the time ofscreening and following the most recent line of therapy.

2. Disease reoccurrence after remission following initial standard-of care (SOC)treatment (i.e., relapse) or failure of response to SOC treatment (i.e.,refractory).

3. Age ≥ 1 year and ≤ 21 years.

4. Molecular Human Leukocyte Antigen (HLA) class I allele typing that confirms subjectcarries at least one HLA-A2 allele.

5. Life expectancy of > 4 months per the Investigator's opinion.

6. Lansky or Karnofsky Performance Scale ≥ 70.

7. For enrollment to the dose-finding cohort, subjects must have at least one (1)lesion ≥ 5 mm in diameter or two (2) or more lesions ≥ 3 mm in diameter. For thedose-expansion cohort, subjects must have measurable disease by Response EvaluationCriteria in Solid Tumors (RECIST) version 1.1.

8. Child-Pugh score of A6 or better.

9. Adequate organ function.

Exclusion Criteria:

1. Recurrent HB who are candidates for complete surgical resection (e.g., isolatedpulmonary relapse amendable to pulmonary metastasectomy).

2. Pre-existing illness including heart failure, uncontrolled pulmonary disease notcancer-related, or psychiatric illness/social situation that would limit compliancewith study requirements.

3. Active, uncontrolled systemic bacterial, fungal, or viral infection. Subjects withHuman Immunodeficiency Virus (HIV), hepatitis B, or hepatitis C are eligibleprovided their infection is being treated and the viral load is controlled.

4. Any known active malignancy (other than HB, HCN-NOS, or HCC).

5. Pregnant or lactating women.

6. Received the following within two (2) weeks of leukapheresis or within two (2) weeksof conditioning chemotherapy: cytotoxic chemotherapy, radiation, other anti-cancertherapies (including immunotherapeutic agents), immunosuppressive therapy, orsystemic corticosteroids at doses greater than 5 mg/day of prednisone or equivalentdoses of other corticosteroids. (Note: Topical and inhaled corticosteroids instandard doses and physiological replacement doses of corticosteroids for adrenalinsufficiency are allowed).

7. Concurrently receiving other investigational agents, biological, chemical, orradiation therapies, while participating in the study.

8. Contraindication for receipt of conditioning chemotherapeutic agents includingFludarabine and Cyclophosphamide.

9. Active autoimmune disease requiring systemic immunosuppressive therapy.

10. Compromised circulation in the main portal vein, hepatic vein, or vena cava due topartial or complete obstruction which, in the opinion of the Investigator, wouldmake the subject unsuitable for the study.

11. History of organ transplant.

12. HB, HCN-NOS, or HCC involving greater than 50% of the liver (volumetric).