[The efficacy and safety of avapritinib in the treatment of molecular biologically positive core binding factor-acute myeloid leukemia with KIT mutation after allogeneic hematopoietic stem cell transplantation].

<b>Objective:</b> To investigate the efficacy and safety of avapritinib in the treatment of molecular biologically positive core binding factor-acute myeloid leukemia (CBF-AML) with KIT mutation after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . <b>Methods:</b> We retrospectively analyzed the clinical data of six patients with molecular biologically positive CBF-AML with KIT mutation after allo-HSCT, who were treated with avapritinib at Henan Cancer Hospital from December 2021 to March 2023, and evaluated the efficacy and safety of avapritinib. <b>Results:</b> After 1 month of treatment with avapritinib, the transcription level of the fusion gene decreased in six patients, and the transcription level decreased by ≥1 log in five patients. In four patients who received avapritinib for ≥3 months, the fusion gene turned negative, and the median time to turn negative was 2.0 (range: 1.0-3.0) months. Up to the end of follow-up, four patients had no recurrence. The most common adverse reaction of avapritinib was myelosuppression, including neutropenia in two cases, thrombocytopenia in two cases, and anemia in one case. The non-hematological adverse reactions were nausea in two cases, edema in one case, and memory loss in one case, all of which were grades 1-2. <b>Conclusion:</b> Avapritinib was effective for molecular biologically positive CBF-AML patients with KIT mutation after allo-HSCT. The main adverse reaction was myelosuppression, which could generally be tolerated.