Clinical studies with AZD4547 (SWOG S1400D, NCT02965378, NCT00979134) revealed Sq-NSCLC patients with FGFR3 p.(Ser249Cys) who achieved partial response (1.5 months with ~32% tumor shrinkage) [9] or stable disease (2.6-month progression-free survival and 12% tumor shrinkage) [10], while no significant benefit of AZD4547 [9] or BGJ398 (NCT01004224) [8] was shown in two other patients (2–4% tumor size decrease). Here, FGFR3 is linked to non-small cell lung carcinoma.