Abstract LB530: A potent and selective small molecule antagonist of PD-L1 ABSK043 demonstrates significant anti-tumor efficacy in combination with other agents in preclinical models

Abstract

Abstract Immunotherapy has revolutionized cancer treatment in the last decade. Several monoclonal PD-1 and PD-L1 antibodies have been approved for various cancers. Unlike antibodies, small molecule inhibitors may offer potential advantages in oral dosing, adjustable control of drug exposure, improved tumor penetration and many other aspects. Therefore, small molecule antagonist which can efficiently abolish interaction of PD-1 and PD-L1 may render a novel alternative treatment approach with potentially improved clinical benefits. ABSK043, an oral small molecule inhibitor of PD-L1 discovered by us, has entered into clinical Phase I in 2021. Preclinically, ABSK043 has shown significant tumor growth inhibition as a single agent in multiple models. To explore potential synergy of ABSK043 with other therapeutic agents, in vivo combination experiments were conducted. In this work, we present in vivo combination results for ABSK043 with several therapeutic agents such as a VEGFR inhibitor axitinib, or carboplatin, a key component of the widely used CRC standard-of care chemotherapy treatment regimen, as well as other immune-oncology agents. These combinations demonstrated strong in vivo synergy in tumor mouse syngeneic models. Taken together, these data for the first time demonstrated combination synergy of a small molecule PD-L1 inhibitor with other agents and pave the road for potential clinical evaluation of combination treatment of ABSK043 with these agents in patients. Citation Format: Haiyan Ying, Yongxian Zhang, Fei Yang, Wenqun Xin, Jiaqi Song, Zhui Chen. A potent and selective small molecule antagonist of PD-L1 ABSK043 demonstrates significant anti-tumor efficacy in combination with other agents in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB530.