Abstract 4128: Identification and characterization of LHC165, a TLR7 agonist designed for localized intratumoral therapies

Checkpoint inhibition has transformed immunotherapy by alleviating T cell exhaustion in a subset of patients. However, an important component of effective immune targeting to expand the benefit of immune response requires engagement of both innate and adaptive responses. Our understanding of safe and effective engagement of the innate immune system is evolving, with multiple preclinical and clinical agents targeting pathways such the Toll-like Receptors. Here we disclose the structure and preclinical activity of LHC165, a benzonapthyridine TLR7 agonist that is adsorbed to aluminum hydroxide. The interaction between LHC165 and aluminum hydroxide allows for a slow release from the injection site resulting in improved efficacy in mouse models compared with free LHC165. This localization allows for immune activation at the site of the tumor and also results in lower systemic exposure and cytokine induction. Intratumoral studies in syngeneic preclinical studies show single agent activity and a benefit when dosed in combination with checkpoint blockade. LHC165 as a single agent and in combination with PDR001 is currently enrolling patients with advanced malignancies in CLHC165X2101. Citation Format: Jonathan A. Deane, German A. Cortez, Chun Li, Nora Eifler, Shailaja Kasibhatla, Nehal Parikh, Shifeng Pan, Steven Bender. Identification and characterization of LHC165, a TLR7 agonist designed for localized intratumoral therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4128.