Study of ET140203 T Cells in Adults With Advanced Hepatocellular Carcinoma (ARYA-1)

Inclusion Criteria: * Histologically confirmed HCC with serum AFP \>100ng/ml at time of screening and following most current line of therapy OR radiographic diagnosis of HCC with serum AFP \>400ng/ml at time of screening and following most current line of therapy. * Metastatic or locally advanced, unresectable HCC * Must have failed or not tolerated at least two (2) different anti-HCC systemic agents * Molecular Human Leukocyte Antigen ("HLA") class I allele typing confirms participant carries at least one HLA-A2 allele * Life expectancy of at least 4 months * Karnofsky Performance Scale greater than or equal to 70 * At least 1 measurable lesion on imaging by RECIST * Child-Pugh A6 or better * Absolute neutrophil count greater than or equal to 1,500/mm\^3 * Platelet count greater than or equal to 75,000/mm\^3 Exclusion Criteria: * Clinically significant cardiac disease * Clinically significant pre-existing illness or active infection * Clinically significant Central Nervous System (CNS) or neural dysfunction * Active autoimmune disease requiring therapy * Active malignancy other than HCC with the exception of cholangiocarcinoma (CCA) or any malignancy with an expected survival ≥ 3 years without any treatment (exception: hormone/androgen-deprivation therapy) and without any organ involvement * History of organ transplant * Compromised circulation in portal vein, hepatic vein, or vena cava due to obstruction * Advanced HCC involving greater than 50% of the liver