Abstract 684: Gastrointestinal/liver-targeted TLR7 agonist for treatment of colorectal and liver cancers

Abstract

Abstract Anti-PD1/L1 has become the backbone of immune therapy for many cancer types. However, the majority of patients do not respond due to a myriad of mechanisms affecting the tumor microenvironment, including low tumor mutational burden and low immune cell infiltrate. Innate immune agonists can potentially address both issues by increasing tumor antigen presentation and tumor microenvironment inflammation, thereby turning cold tumors hot. As clinical proof-of-concept, many intratumoral TLR/STING agonists have shown promising anti-tumor responses as single agents and in combination with checkpoint inhibitors; however, successful clinical applications have been limited to cutaneous-accessible tumor types. APR003 is an orally-administered GI/liver-targeted small molecule TLR7 agonist designed for the treatment of visceral colorectal and liver cancers. Studies in mice and monkeys demonstrate robust Type-1 Interferon pathway activation with good tolerability. APR003 is efficacious in several syngeneic orthotopic models of liver and colon cancer, both as single agent and in combination with anti-PDL1. Mechanistic studies show enhancement of CD103+ dendritic cells in tumor draining lymph nodes and tumor antigen-specific T cells in the tumor microenvironment. Pre-clinical pharmacology data will be presented. Citation Format: Andrew T. Miller, Evelyn Rodrigo, Manny Corpuz, David Plouffe, Tom Y.-H. Wu. Gastrointestinal/liver-targeted TLR7 agonist for treatment of colorectal and liver cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 684.