A Phase I Feasibility And Safety Study of Fluorescein-Specific (FITC-E2) CAR T Cells In Combination With Parenterally Administered Folate-Fluorescein (UB-TT170) For Osteogenic Sarcoma

Inclusion Criteria: * Refractory or recurrent/progressive osteosarcoma that has failed first line therapy for Osteosarcoma per NCCN or upfront Children's Oncology Group clinical trial and is not amenable to surgical resection (must meet one of the following): 1. New site of measurable disease by radiographic imaging or histologic confirmation 2. New site of evaluable disease by radiographic imaging (including FDG-PET) or histologic confirmation 3. Greater than 20% increase in at least one tumor dimension documented by CT/MRI, AND a maximum absolute increase of 5 mm in longest dimension of existing lesion(s) (previously irradiated lesions may be included) 4. Persistent measurable disease or FDG-PET avid bone metastasis that has failed to achieve complete remission to upfront conventional therapy (surgery, radiotherapy and/or chemotherapy) * Able to tolerate apheresis, including placement of temporary apheresis catheter, if necessary, or already has an apheresis product available for use in manufacturing * Life expectancy ≥ 8 weeks * Lansky or Karnofsky score ≥ 50 * Anti-cancer agents, radiotherapy, cytoxic chemotherapy, biologic therapy, anti-tumor antibody therapy, genetically modified cell therapy, and, if no apheresis product available, corticosteroid therapy (excluding physiologic replacement), discontinued within protocol specified wash-out period * Adequate hematologic, renal, hepatic, cardiac, and respiratory function. * Negative HIV, hepatitis B and C test within 3 months * If of child-bearing or fathering potential, willing to use highly effective contraception through 12 months following final stud drug infusion Exclusion Criteria: * Active malignancy other than primary malignant solid tumor diagnosis (CNS intracranial metastases are allowed) * Ongoing, symptomatic CNS pathology requiring medical intervention * Receiving external beam radiotherapy * Presence of active, severe infection * Primary immunodeficiency syndrome * Pregnant or breast feeding * Unwilling to provide consent/assent for study participation, including 15 year follow up * Presence of any condition that, in the opinion of the investigator, would prohibit the subject from undergoing treatment under this protocol.