A Synthetic Biology Rheoswitch Therapeutic System® for the Controlled Local Expression of IL-12 as an Immunotherapy for the Treatment of Cancer

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Tumors escape the immune system through the process of immunoediting. Restoration of the immune system’s ability to detect the tumor should result in improved therapeutic outcome. A gene delivery platform technology, RheoSwitch Therapeutic System® (RTS®), has been developed to enable the controlled, regulated expression of a target gene which locally delivers the desired therapy to patients. A replication-incompetent adenoviral vector, administered intratumoral, is engineered to express IL‑12 (Ad-RTS-IL-12) under control of the RheoSwitch Therapeutic System, where IL-12 expression is controlled via the administration of an oral activator ligand (veledimex). In the presented preclinical studies we have demonstrated that the oral administration of veledimex resulted in a dose-related increase in tumor veledimex levels. The increase in tumor veledimex levels in combination with Ad-RTS-mIL-12 resulted in a dose-related increase in the IL-12 mRNA (switch on) leading to dose-related increases in IL-12p70 in the tumor with minimal increase in serum IL-12. The increase in tumor IL-12 correlated with an increase in tumor CD8+ cytotoxic T cells and a concomitant decrease in regulatory T cells (Tregs) in the tumor microenvironment. Importantly, Ad-RTS-mIL-12 + veledimex elicited dose-related decreases in tumor growth rate with no significant change in body weight in both breast and melanoma syngeneic mouse models. When veledimex was discontinued, expression of IL-12 mRNA returned to baseline concomitant with tumor IL-12 levels. In summary, these results highlight the potential of a synthetic biology-based approach for cancer treatment, safely leveraging the full anticancer potential of some immunomodulators without the serious side-effects associated with systemic injection.

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