Abstract 1965: Discovery of ZN-c3, a potent Wee-1 inhibitor with a differentiated pharmacologic and kinase selectivity profile

Abstract

Abstract Genome instability initiated by DNA damage or DNA replication stress is a driver of tumor development. To ensure the accuracy of DNA replication, DNA damage response (DDR) mediated by various cell cycle checkpoints activate the DNA repair system. One such checkpoint system is the G2-M checkpoint which is involved in the repair and prevention of excessive DNA damage. A key regulator of the G2-M checkpoint is the Wee1 kinase which causes cell cycle arrest to prevent damaged cells from entering mitosis. Thus, inhibition of Wee1 should prevent G2-M checkpoint activation which would lead to unscheduled mitotic entry and induction of apoptosis. Small-molecule inhibitors of Wee1 are currently being tested in several tumor types. Preliminary results show promising clinical activity of AZD-1775, a potent inhibitor of Wee1, however, achieving an optimal dose and a schedule that is well-tolerated has been a challenge. Here, we describe the characterization of ZN-c3, a potent, selective and orally bioavailable small-molecule inhibitor of Wee1. ZN-c3 exhibits potent anti-proliferative activity across multiple tumor cell lines. Compared to AZD-1775, ZN-c3 has superior selectivity profile against a panel of kinases. In vivo, ZN-c3 induced tumor regression as a single agent in several tumor models including non-small cell lung cancer, ovarian cancer, and uterine sarcoma. In combination studies, ZN-c3 potentiates the antitumor efficacies of carboplatin and gemcitabine. The pharmacokinetic and efficacy profiles of ZN-c3 and AZD-1775 were compared in tumor xenograft models. ZN-c3 showed higher plasma and tumor exposure than AZD-1775, which correlated with more potent tumor growth inhibition than AZD-1775. In summary, ZN-c3, with its key differentiated pharmacologic and kinase selectivity profile, is a promising new generation of DDR inhibitor. ZN-c3 is currently in clinical development for the treatment of advanced solid cancers. Citation Format: Jiali Li, Brant Boren, Peter Q. Huang, Kevin D. Bunker, Fernando Doñate, Ahmed A. Samatar. Discovery of ZN-c3, a potent Wee-1 inhibitor with a differentiated pharmacologic and kinase selectivity profile [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1965.