Abstract 5163: Local delivery of mRNA immunotherapy encoding HPV16 antigen, IL-12, and LIGHT/TNFSF14 results in superior immunogenicity and tumor clearance in a murine model of HPV16-driven cancer

While intramuscular vaccination with HPV16 antigens has been shown to induce robust tumor-specific immune responses in the periphery, this has led to limited efficacy in the clinic. One potential explanation is the lack of sufficient infiltration of antigen-specific T cells into the tumor. The few T cells that make their way into the tumor are met with a plethora of negative signals that suppress their activity and abrogate local T cell expansion. To overcome this limitation of intramuscular cancer vaccines, we have developed an approach using in situ vaccination with a combination of immune modulators and tumor antigens, all encoded by mRNAs and delivered using nanoparticles. In this study, we show the superior efficacy and immunogenicity of a locally delivered mRNA cancer vaccine over that of an intramuscular HPV16 cancer vaccine. Both routes of administration result in robust induction of antigen-specific T cells, but local administration of mRNA-encoded antigens and immune modulators also resulted in enhanced infiltration of immune cells into the tumor, local Th1/M1 cytokine induction, and more-complete tumor clearance. Specifically, we found that the inclusion of the immunomodulators IL-12 and TNFSF14/LIGHT enabled tumor clearance in a murine tumor model. While tumors treated with mRNA-encoded HPV16 antigen alone induced robust systemic antigen-specific responses, minimal levels of local T cell expansion and infiltration, proinflammatory cytokine induction, and tumor control were observed. By contrast, tumors treated with mRNA-encoded HPV16 antigen, IL-12p70, and TNFSF14 completely cleared large established HPV16 expressing tumors with long-lasting recurrence free survival and immune memory. This observation was replicated in in a second murine tumor model, confirming the superior potency of locally delivered mRNA cancer vaccines in combination with immunomodulators. Consequently, we are developing a locally administrated mRNA therapy for the treatment of patients with cervical intraepithelial neoplasia (CIN). Citation Format: Weiqun Liu, Diane M. Da Silva, Edward E. Lemmens, Colin J. McKinlay, Sangeeta Nath, Meredith L. Leong, Samuel Deutsch, W. Martin Kast, Ole Audun W. Haabeth. Local delivery of mRNA immunotherapy encoding HPV16 antigen, IL-12, and LIGHT/TNFSF14 results in superior immunogenicity and tumor clearance in a murine model of HPV16-driven cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5163.