Spearhead 1 Study in Subjects With Advanced Synovial Sarcoma or Myxoid/Round Cell Liposarcoma

Key Inclusion Criteria * Age ≥16 (10 years at selected sites) and \<=75 years * Diagnosis of advanced synovial sarcoma (Cohort 1, Cohort 2 and Cohort 3) or myxoid liposarcoma / myxoid round cell liposarcoma (Cohort 1 only) confirmed by cytogenetics. * Previously received either an anthracycline or ifosfamide containing regimen. * Measurable disease according to RECIST v1.1 prior to lymphodepletion * HLA-A\*02:01, HLA-A\*02:02, HLA-A\*02:03 or HLA-A\*02:06 positive * Tumor shows MAGE-A4 expression confirmed by central laboratory. North America Only (United States and Canada): Tumor (either an archival specimen or a fresh biopsy) shows MAGE-A4 expression of ≥1+ staining in ≥10% of the cells by immunohistochemistry. * ECOG Performance Status of 0 or1. For subjects aged ≥10 to ≥16 years old: Lansky Score ≥60%. • Left ventricular ejection fraction (LVEF) ≥50%. Note: other protocol defined Inclusion criteria may apply Key Exclusion Criteria: * HLA-A\*02:05 in either allele * Received or plans to receive the following therapy/treatment prior to leukapheresis or lymphodepleting chemotherapy: Cytotoxic chemotherapy, Tyrosine kinase inhibitor (TKI) (e.g. pazopanib), Immune therapy (including monoclonal antibody therapy, checkpoint inhibitors,), Anti-cancer Vaccine, Gene therapy using an integrating vector (subjects who have received a gene therapy using a lentiviral vector may be eligible for the study), Corticosteroids or any other immunosuppressive therapy, Investigational treatment or interventional clinical trial, Allogeneic hematopoietic stem cell transplant, Radiotherapy to the target lesions, Major surgery * History of allergic reactions attributed to compounds of similar chemical or biologic composition to fludarabine, cyclophosphamide or other agents used in the study. * History of autoimmune or immune mediated disease * Symptomatic CNS metastases including leptomeningeal disease. * Other prior malignancy that is not considered by the Investigator to be in complete remission * Clinically significant cardiovascular disease * Uncontrolled intercurrent illness * Active infection with human immunodeficiency virus, hepatitis B virus, hepatitis C virus, or human T cell leukemia virus * Pregnant or breastfeeding Note: other protocol defined Exclusion criteria may apply.