Abstract A78: Preclinical evaluation of 3D185, a novel potent inhibitor of FGFR1/2/3 and CSF-1R, in FGFR-dependent and macrophage-dominant cancer models

The interaction between tumor cells and their immunosuppressive microenvironment promotes tumor progression and drug resistance. Thus, simultaneously targeting tumor cells and stromal cells is expected to have synergistic antitumor effects. Herein, we present the preclinical antitumor investigation of 3D185, a novel dual inhibitor targeting FGFRs, which are oncogenic drivers, and CSF-1R, which is the major survival factor for protumor macrophages. The antitumor characteristics of 3D185 were assessed by a range of assays, including kinase profiling, cell viability, cell migration, immunoblotting, CD8+ T-cell suppression, and in vivo antitumor efficacy, followed by flow cytometric and immunohistochemical analyses of tumor-infiltrating immune cells and endothelial cells in nude mice and immune-competent mice. We found that 3D185 significantly inhibited the kinase activity of FGFR1/2/3 and CSF-1R, with equal potency and high selectivity over other kinases. 3D185 suppressed FGFR signaling and tumor cell growth in FGFR-driven models both in vitro and in vivo. In addition, 3D185 could inhibit the survival and M2-like polarization of protumor macrophages, reversing the immunosuppressive effect of macrophages on CD8+ T cells as well as CSF1-differentiated macrophage induced-FGFR3-aberrant cancer cell migration. Furthermore, 3D185 inhibited tumor growth via remodeling the tumor microenvironment in TAM-dominated tumor models. In summary, 3D185 is a dual inhibitor against FGFR1/2/3 and CSF-1R that exhibits potent antitumor activities. This compound is promising because it simultaneously targets tumor cells per se and the immunosuppressive tumor microenvironment to synergistically antagonize tumors. Our study provides a solid foundation for the investigation of 3D185 in cancer patients, particularly in patients with aberrant FGFR and abundant macrophages, who respond poorly to classic pan-FGFRi treatment. Now 3D185 is in phase I clinical trials. Citation Format: Yang Dai, Yichun Ji, Yanyan Shen, Yi Su, Bo Liu, Yueliang Wang, Deqiao Sun, Yuchen Jiang, Chuantao Zha, Zuoquan Xie, Jian Ding, Meiyu Geng, Jing Ai, Xia Peng, Pengcong Hou, Yi Chen. Preclinical evaluation of 3D185, a novel potent inhibitor of FGFR1/2/3 and CSF-1R, in FGFR-dependent and macrophage-dominant cancer models [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A78.