具有 t(8;21) (q22;q22) 的急性髓系白血病 (AML)，形成 RUNX1::RUNX1T1 融合基因，被归类为有利风险组。然而，KIT 外显子 17 突变的存在导致该组患者预后不良。 Avapritinib 是一种新型酪氨酸激酶抑制剂，旨在针对 KIT 突变。我们报告了一项对 4 名 t(8:21) 和 KIT 外显子 17 突变的 AML 儿童患者进行的回顾性研究，他们接受了 avapritinib 治疗，其中 3 名患者在同种异体造血后未能去甲基化药物和靶向 RUNX1::RUNX1T1 阳性的供体淋巴细胞输注干细胞移植（allo-HSCT）。到目前为止，所有RUNX1::RUNX1T1阳性的患者在avapritinib治疗1、9、7、2个月后均转为阴性。阿伐普替尼常见的不良反应是中性粒细胞减少症，该副作用具有良好的耐受性。该病例系列表明，avapritinib 对于 allo-HSCT 后 t(8;21) 和 KIT 突变的 AML 儿童的抢先治疗可能是有效且安全的，为预防 allo-HSCT 后复发提供了一种治疗选择。© 2024。作者（s）。

Acute myeloid leukemia (AML) with t(8;21) (q22;q22), which forms RUNX1::RUNX1T1 fusion gene, is classified as a favorable-risk group. However, the presence of mutations in KIT exon 17 results in an adverse prognosis in this group. Avapritinib, a novel tyrosine kinase inhibitor, was designed to target KIT mutation. We report a retrospective study of four pediatric patients with AML with t(8:21) and KIT exon 17 mutation who were treated with avapritinib, three of them failed to demethylate drugs and donor lymphocyte infusion targeting RUNX1::RUNX1T1-positivity after allogeneic hematopoietic stem cell transplantation (allo-HSCT). So far, all patients with RUNX1::RUNX1T1 positivity had turned negative after 1, 9, 7, 2 months of avapritinib treatment. The common adverse effect of avapritinib is neutropenia, which is well-tolerated. This case series indicates that avapritinib may be effective and safe for preemptive treatment of children with AML with t(8;21) and KIT mutation after allo-HSCT, providing a treatment option for preventing relapse after allo-HSCT.© 2024. The Author(s).