McCoull W, Boyd S, Brown MR, Coen M, Collingwood O, Davies NL, Doherty A, Fairley G, Goldberg K, Hardaker E, He G, Hennessy EJ, Hopcroft P, Hodgson G, Jackson A, Jiang X, Karmokar A, Lainé AL, Lindsay N, Mao Y, Markandu R, McMurray L, McLean N, Mooney L, Musgrove H, Nissink JWM, Pflug A, Reddy VP, Rawlins PB, Rivers E, Schimpl M, Smith GF, Tentarelli S, Travers J, Troup RI, Walton J, Wang C, Wilkinson S, Williamson B, Winter-Holt J, Yang D, Zheng Y, Zhu Q, Smith PD
J Med Chem 64 (18) 13524-13539 [2021-09-23; online 2021-09-03]
Inhibition of Mer and Axl kinases has been implicated as a potential way to improve the efficacy of current immuno-oncology therapeutics by restoring the innate immune response in the tumor microenvironment. Highly selective dual Mer/Axl kinase inhibitors are required to validate this hypothesis. Starting from hits from a DNA-encoded library screen, we optimized an imidazo[1,2-a]pyridine series using structure-based compound design to improve potency and reduce lipophilicity, resulting in a highly selective in vivo probe compound 32. We demonstrated dose-dependent in vivo efficacy and target engagement in Mer- and Axl-dependent efficacy models using two structurally differentiated and selective dual Mer/Axl inhibitors. Additionally, in vivo efficacy was observed in a preclinical MC38 immuno-oncology model in combination with anti-PD1 antibodies and ionizing radiation.