A-C, PC-9/AR xenografts were treated with vehicle control, osimertinib (Osim), VRT752271 (VRT) or their combination starting on the same day after grouping for 22 consecutive days. D-F, PC-9/AR xenografts were treated with vehicle control, trametinib (Tram), erlotinib (Erl), afatinib (Afa), trametinib combined with erlotinib or trametinib plus afatinib starting on the same day after grouping for 24 consecutive days. Tumor sizes (A, D and E) were measured as indicated. Each measurement is mean ± SE (n = 6). At the end of treatment, mice were sacrificed to remove tumors, which were weighed (B and F). Mouse body weights were also compared (C).