Compositions and methods for CAR T cell therapy

A method of treating a patient for cancer, the method comprising:

• i) administering to the patient an amount of a compound, or a pharmaceutically acceptable salt thereof, wherein the compound comprises a folate linked to fluorescein isothiocyanate (FITC);
• ii) administering to the patient a chimeric antigen receptor T cell (CAR T cell) composition comprising CAR T cells comprising a polypeptide having the sequence set forth in SEQ ID NO:
• 2;
• and
• iii) reducing or preventing cytokine release syndrome (CRS) or cytokine storm by administering to the patient an amount of a rescue agent comprising fluoresceinamine, FITC, or fluorescein, or a salted form thereof,
• wherein the amount of the rescue agent is in molar excess relative to the amount of the compound and the molar excess is less than 100-fold molar excess relative to the amount of the compound;
• whereupon the patient is treated for cancer.