In vivo effect of GZD824 in Ba/F3‐FGFR1, Ba/F3‐FGFR1‐V561M, and Ba/F3‐FGFR1‐V561F xenograft model. (A) Antitumor efficacy of GZD824 in Ba/F3‐FGFR1 xenograft mouse model. (B) Antitumor efficacy of GZD824 in Ba/F3‐FGFR1‐V561F xenograft mouse model. (C) Antitumor efficacy of GZD824 in Ba/F3‐FGFR1‐V561M xenograft mouse model. (D) pFGFR1, Ki67, and TUNEL staining of Ba/F3‐FGFR1 tumors harvested from mice treated with GZD824, BGJ398, or vehicle for 12 days. (E) pFGFR1, Ki67, and TUNEL staining of Ba/F3‐FGFR1‐V561F tumors harvested from mice treated with GZD824, BGJ398, or vehicle for 12 days. Tumors harvested from the mice after dosing vehicle, GZD824, or BGJ398 for 12 days. CB17‐SCID mice xenograft models were orally dosed once every 2 days (q2d) for 12 days with vehicle or GZD824, or once a day (qd) with BGJ398. Tumor volumes were measured every 2 days. Tumors were harvested from the mice at the terminal. (*p < 0.05, **p < 0.01)