Effect of novel autologous immune training platform on end-stage patients with cancer.

Abstract

2546 Background: SUPLEXA therapeutic cells are the initial autologous and non-engineered candidate to emerge from the novel ENLIST cells training platform. Manufacturing is robust, reproducible and with an acceptable cost of goods. The method requires 35 days to produce multiple doses. Multiple mechanisms of SUPLEXA therapeutic cells have been delineated and all appear to complement that of immune checkpoint inhibitors (ICIs) with SUPLEXA cells serving to enhance the number of primed anti-tumor host T cells while ICIs serve to increase the durability of primed T cells by blocking their premature down-regulation. Methods: A 35 patient Phase 1 single-agent study survey study is currently ongoing in Australia to test the safety and clinical activity of SUPLEXA cells in end-stage patients with various tumor types. No chemo preconditioning or concomitant cytokine treatment was employed. CYTOF analysis of longitudinal peripheral blood is used to monitor changes to the host immune system. Results: To date, SUPLEXA therapeutic cells have demonstrated safety and significant clinical benefit with an observed CR, PR, and many durable SD in approximately half the patients. Several solid tumor patients remain on study beyond 1 year and doing well. Longitudinal analysis of PBMCs from SUPLEXA cell treated cancer patients demonstrated durable changes in the composition of myeloid immune cell subsets in SUPLEXA treated patients, impacting the anti-tumor bias of the host immune system. Specifically, we identified a dramatic decrease in the number of peripheral myeloid derived suppressor cells (MDSCs), within 3 weeks of SUPLEXA treatment. In patients with CR and PR, we also identified stable increases in activated classical CD14+ blood monocytes. Conclusions: SUPLEXA therapeutic cells are a highly differentiated approach to cellular therapy. The first-in-human experience demonstrated a pristine safety profile and strong clinical benefit as a single-agent. The pharmacodynamic decrease of in the number of MDSCs, known to suppress the anti-tumor immune response and limit immune checkpoint inhibitors (ICIs) efficacy, supports the further clinical testing to test the hypothesis that the multiple mechanisms of SUPLEXA cells will enhance the clinical activity of ICIs. Clinical trial information: NCT05237206 .