...• Diagnostic criteria for refractory AML: Treatment-naïve patients refractory to 2 courses of standard regimen; patients who relapse within 12 months after consolidation and intensive treatment after CR; patients who relapse after 12 months but fail to respond to conventional chemotherapy; patients who relapse twice or more; and patients with persistent extramedullary leukemia; 3) Aged ≥ 14 years old (body surface area ≥ 1.2 m2 for patients aged 14 years), male or female (including 14 years old); 4) Patients with C-KIT D816 or C-KIT N822 mutation detected by bone marrow molecular biology, and with CBFB::MYH11 gene, or with RUNX1::RUNX1T1 fusion gene detected; 5) Performance status (ECOG PS) 0-2; 6) Adequate organ and bone marrow function, defined as follows: • Serum total bilirubin ≤ 1.5 × upper limit of normal (ULN), unless it is considered to be due to Gilbert’s syndrome or leukemia; • Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) ≤ 3.0 × ULN, unless considered to be due to leukemia; • Platelet count ≥ 20 × 109/L; • Serum creatinine ≤ 2.0 × ULN • Creatinine clearance rate > 40 mL/min based on estimated Cockcroft-Gault glomerular filtration rate (GFR); Note: Estimated glomerular filtration rate (eGFR, Cockcroft-Gault formula): Ccr = (140 - age) × weight (kg)/(72 × Scr (mg/dl)), calculated as × 0.85 for female; 7) Subjects must undergo bone marrow aspiration and/or biopsy to confirm diagnosis and evaluate AML; 8) Females of childbearing potential must agree to use contraception (e.g., intrauterine device, contraceptive pill, or condom) during the study and for 3 months after the end of the study; must have a negative serum pregnancy test within 7 days before study enrollment and must be non-lactating; male subjects must agree to use contraception during the study and for 3 months after the end of the study period....

...Accompanied by KIT mutation 3....

Avapritinib is safe and effective in the prophylactic and preemptive treatment of AML with KIT mutation after allo-HSCT in children, which provides a clinical drug for the prevention of relapse after transplantation.