Abstract- CONFIDENTIAL To provide a means for quantitative control of CAR T cell activity, our team first created universal immune receptors (UnivIRs), a versatile platform for the de novo generation and quantitative control of tumor antigen- specific T cells where human T cells are genetically engineered with novel docking immune receptors and can be conferred with highly personalized tumor specificity through the subsequent loading/re-targeting with “tagged” antigen-specific antibodies, scFvs or other receptor ligands. Building upon these principles, we have created an orthogonal image-guided T cell delivery (IGTD) method where localization of the targeting ligand and delivery of CAR T cells with tailored payloads are guided and monitored through noninvasive imaging in order to facilitate safe and effective targeted therapy for cancer. Our theranostic IGTD platform utilizes novel targeting biologics with covalent binding tags that can be imaged, or engaged by CAR T cells to activate their antigen-specific anti-tumor response. These targeting biologics can be used for diagnostic imaging prior to CAR T cell delivery, to assess localization of the agent to the tumor, predict response to therapy, and evaluate for potential on-target off-tumor toxicity. In addition, our IGTD method will permit in vivo cell tracking via direct radiolabeling of CAR T cells prior to infusion, or via a small molecule PET imaging probe that binds the CAR construct on the T cells. Our multidisciplinary team's goal is to optimize this IGTD method to allow local, image- guided delivery of the therapeutic T cell product to the target tissue, to allow localized and controlled delivery of immunomodulatory agents for maximal activity and safety, and to provide functional imaging readouts on the therapeutic process(es) that occur during treatment. We build upon strong preliminary results to test the central hypothesis that CAR therapy can be improved by targeting multiple and diverse antigens either simultaneously or sequentially and safely applied through integrated pre-therapeutic diagnostic imaging and innovative CAR platform re-development. By uniting diverse scientific expertise in advanced T cell gene-engineering with molecular imaging and chemistry, we propose to 1) develop, test and optimize novel universal immune receptors that uniquely and covalently bind tagged and image-labeled TAA-specific antibodies to recapitulate CAR architecture and activity in vivo; 2) evaluate their potential to simultaneously attack multiple TAAs on tumor cells as well as suppressive cells in the microenvironment to maximize outcome, 3) develop radiolabeled antibody-based diagnostic PET/CT imaging to measure antibody localization to tumor and TAA biodistribution prior to universal CAR T cell administration and test for its ability to predict safety and response; and 4) serially monitor and understand universal CAR T cell distribution in tumor and healthy organs using PET-based “live” in vivo ...