Abstract IA011: Engineered IL-12 delivery to the tumor matrix to achieve enhanced efficacy and safety in multiple advanced tumors

Abstract

Abstract Background. Our goal is to create an effective and novel immunotherapy against multiple solid tumors with minimal toxicity. IL-12 is an “ideal” immune-activator, capable of activating both innate and acquired immune response. We tested more than 20 reported pro-inflammatory cytokines, and found IL-12 shows the most potent anti-tumor activity. Peripheral toxicity limits the use of systemic IL-12 therapy in the clinic. We have hypothesized that the tumor-specific drug delivery system would improve IL-12 immunotherapies. We took original approaches of protein engineering. Methods. We developed technologies to turn the tumor collagen into a drug reservoir after intravenous injections. The recombinant fusion of IL-12 to a collagen binding domain (CBD) derived from the VWF A3 domain allows for targeted IL-12 delivery into the tumor stroma. Here, we evaluated the pharmacology, safety, efficacy and the effects of CBD-IL-12 to the tumor microenvironment. Results. Intravenously-injected CBD proteins preferentially localized to the tumor, but not in other organs in mice. Single intravenous injection of CBD-IL-12 (recombinant fusion protein) eradicated most EMT6 breast cold tumors. CBD-IL-12-treated mice that were tumor-free developed systemic immunological memory, as 12 mice out of 13 rejected rechallenge with the breast tumor cells in their contralateral mammary fat pad. Single intravenous injection of CBD-IL-12 induced 67% complete remission of established B16F10 tumors. CBD fusion to IL-12 reduced the systemic toxicity, such as 50% reduction of hepatotoxicity markers and cytokine storm. CBD-IL-12 treatment increased intratumoral cytokine and immune cell numbers. In short, this tumor collagen-targeting approach improves both safety and efficacy of IL-12. We showed that the CBD can target multiple solid tumor types, because the CBD exploits the abnormality of tumor vasculature-specific pathological structure (e.g. leakiness and exposure of collagen to the bloodstream). So far, we have shown that CBD-IL-12 has significant anti-tumor efficacy in breast, lung, ovarian, liver, colon, prostate, melanoma, head and neck, pancreatic cancers and melanoma, sarcoma, and glioblastoma in syngeneic mouse models. CBD-IL-12 is effective in cold, advanced, spontaneous tumors, low-mutation burden tumors, and prevents metastasis and recurrence. CBD-IL-12 stimulated antigen-presenting cells and T cells. Also, humanized mice treated with humanized CBD-IL-12 show great anti-tumor effects in patient-derived lung and ovarian tumors. Humanized CBD-IL-12 was tested in dogs, and showed great tolerability at the therapeutic dose. Human CBD-IL-12 molecule was successfully manufactured in a clinical-grade. Conclusions. Intravenously injected CBD–IL-12 is effective to multiple difficult, immunologically cold tumors with low mutation burdens. Collagen is an attractive target because abnormally high expression of collagen is a shared nature of tumors, regardless of tumor types and patients. VWF A3 domain naturally exists in our body, minimizing the risk of immunogenicity. Citation Format: Jun Ishihara. Engineered IL-12 delivery to the tumor matrix to achieve enhanced efficacy and safety in multiple advanced tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr IA011.