尽管使用米多妥林 (MIDO) 联合强化化疗 (ICT) 作为 FLT3 突变急性髓系白血病 (AML) 的一线治疗，但完全缓解率接近 60-70%，并且超过 40% 的患者出现复发。案例。在这里，我们研究了 FLT3 突变 AML 患者难治/复发 (R/R) 情况的分子机制。我们进行了一项回顾性多中心研究，纳入了 150 名在诊断时携带 FLT3-ITD (n=130) 和/或 FLT3-TKD (n=26) 的 R/R AML 患者，通过标准方法进行评估。根据诊断日期和 MIDO 标签，患者在一线接受 ICT MIDO (n=54) 或单独 ICT (n=96) 治疗。通过靶向高通量测序分析配对诊断 R/R 样本中 FLT3 克隆和共突变的进化。使用 FLT3-ITD 检测专用算法，在两个时间点均检测到 189 个 FLT3-ITD 微克隆（等位基因比率 [AR] < 0.05）和 225 个大克隆（AR ≥ 0.05）。在 R/R 疾病中，接受 ICT MIDO 治疗的患者的 FLT3-ITD 持续率低于未接受 MIDO 的患者（68% vs. 87.5%，P=0.011）。在接受 ICT MIDO 的患者中，检测到多个 FLT3-ITD 克隆（称为“克隆干扰”）与 R/R 疾病中较高的 FLT3-ITD 持续率相关（多个克隆：88% vs. 单克隆：57%） ，P=0.049）。考虑到两个治疗组，如果诊断时检测到的 FLT3-ITD 微克隆中只有 24% 在复发时保留，那么其中 43% 会变成大克隆。总之，这些结果确定了影响 FLT3-ITD 克隆适合度的参数，并强调了在临床实践中使用灵敏技术进行 FLT3-ITD 筛查的重要性。版权所有 © 2024 美国血液学会。

Despite the use of midostaurin (MIDO) with intensive chemotherapy (ICT) as the front-line treatment for FLT3-mutated acute myeloid leukemia (AML), complete remission rates are close to 60-70%, and relapses occur in over 40% of cases. Here we studied the molecular mechanisms underlying refractory/relapsed (R/R) situation in FLT3-mutated AML patients. We conducted a retrospective and multicenter study involving 150 patients with R/R AML harboring FLT3-ITD (n=130) and/or FLT3-TKD (n=26) at diagnosis assessed by standard methods. Patients were treated in front-line with ICT + MIDO (n=54) or ICT alone (n=96) according to the diagnosis date and label of MIDO. The evolution of FLT3 clones and co-mutations was analyzed in paired diagnosis-R/R samples by targeted high-throughput sequencing. Using a dedicated algorithm for FLT3-ITD detection, 189 FLT3-ITD microclones (allelic ratio [AR] < 0.05) and 225 macroclones (AR ≥ 0.05) were detected at both time points. At R/R disease, the rate of FLT3-ITD persistence was lower in patients treated with ICT + MIDO compared with patients not receiving MIDO (68% vs. 87.5%, P=0.011). In patients receiving ICT + MIDO, detection of multiple FLT3-ITD clones (referred to as "clonal interference") was associated with a higher FLT3-ITD persistence rate at R/R disease (multiple clones: 88% vs. single clones: 57%, P=0.049). Considering both treatment groups, if only 24% of FLT3-ITD microclones detected at diagnosis were retained at relapse, 43% of them became macroclones. Together, these results identify parameters influencing the fitness of FLT3-ITD clones and highlight the importance of using sensitive techniques for FLT3--ITD screening in clinical practice.Copyright © 2024 American Society of Hematology.