PROJECT SUMMARY/ABSTRACT In this project we will improve the outcome and the accessibility of adoptive cell therapy with engineered CD5- specific chimeric antigen receptor (CAR) T-cells in patients with refractory or relapsed T-cell lymphoma (r/r TCL). These studies build on the promising results obtained in the Phase I clinical trial funded in the previous SPORE, where autologous CD5 CAR T-cells produced robust clinical responses in 44% of patients with recalcitrant TCL, enabling three out of nine patients to proceed with allogeneic hematopoietic stem cell transplantation (HSCT). These responses were achieved by CAR T-cell products enriched for minimally differentiated T-cell subsets. We will now overcome the remaining barriers to success and accessibility identified from our previous study, namely the rapid loss of potency of ex vivo expanded CD5 CAR T-cells induced by tonic CAR signaling, low frequency and poor fitness of patient-derived T-cells, and rapid disease progression due to lengthy manufacturing of autologous cell products. We will use several complementary strategies to improve the clinical potency of CD5 CAR T-cell products and to enable patients to rapidly receive these products as banked (off the shelf) cells. In clinical studies in Aim 1, we use pharmacologic inhibitors to reversibly inhibit tonic CAR signaling and the resultant terminal differentiation of CD5 CAR T-cells during cGMP manufacturing, and evaluate CD5 CAR T- cells generated from HSCT (i.e. normal) donors for patients whose disease relapsed after allogeneic HSCT. We predict these improvements will preserve the beneficial undifferentiated T-cell subsets and thus improve expansion and anti-lymphoma activity of CD5 CAR T-cell products; this hypothesis is supported by our early clinical data. To further maximize clinical potency of CD5 CAR T-cells and expedite treatment of patients with rapidly progressing disease, in Aim 2 we will develop banked CD5 CAR T-cells for off-the-shelf therapy. Leveraging our latest preclinical findings, we will engineer these CD5 CAR T-cells to eliminate alloreactivity (using TCR gene editing) and resist host immune rejection, by arming them with a novel alloimmune defense receptor, ADR. These modifications should ensure the safety and functional persistence of allogeneic CD5 CAR T-cells in patients. We will manufacture and bank highly potent, ADR-armed TCR-edited CD5 CAR T-cells in Aim 3 and initiate a Phase I clinical trial in patients with treatment-resistant TCL. Overall, these studies should provide a safe and effective cell therapy for patients with r/r T-cell lymphoma who have few alternative options.