The multi-kinase inhibitor sorafenib was the first-generation TKI assessed in a phase 1 study in patients with refractory or relapsed AML, which found that 10% of patients (five patients with an FLT3-ITD mutation) had complete remissions (CRs) or complete remissions with incomplete count recovery (CRi) [23]. This evidence concerns the gene FLT3 and acute myeloid leukemia.