Impact of Concomitant Genetic Abnormalities on Sorafenib Therapy in FLT3-ITD Positive Acute Myeloid Leukemia Undergoing Allo-HSCT

Aim In this study, we investigated the co-occurring mutation landscape in acute myeloid leukemia (AML) patients with FLT3 internal tandem duplication (FLT3-ITD), and explored whether post-allogenic hematopoietic stem cell transplantation (allo-HSCT) sorafenib maintenance therapy could improve the outcomes of FLT3-ITD AML patients combined with other co-occurring genetic abnormalities. Methods A total of 456 FLT3-ITD AML patients receiving first allo-HSCT were included in this study. Gene mutations were detected using direct sequencing or next generation sequencing. Fusion genes were detected using a 53-gene polymerase chain reaction panel. The frequency of each genetic abnormality was investigated, and the mutation landscape was investigated. The primary outcome of this study was 3-year cumulative incidence of relapse. The secondary outcomes were 3-year overall survival (OS), disease-free survival (DFS) and non-relapse mortality (NRM). The outcomes were compared between patients who received post-HSCT sorafenib maintenance and those who did not in the whole population and in subgroups referring to co-occurring mutations. Results A total of 190 patients received post transplantation sorafenib maintenance therapy (sorafenib group) and 266 patients did not (control group). Of the patients receiving sorafenib pre-transplantation, the median duration of sorafenib therapy was 106 days (IQR 68 - 132) in the sorafenib group, and 99 days (IQR 71 - 142) in the control group (p = 0.883). Of the patients receiving post-transplantation sorafenib maintenance therapy, sorafenib was initiated at a median of 30 days (IQR, 30 - 52 days) after allo-HSCT, and continued for a median of 148 days (IQR, 112 - 150). Median follow-up time was 38.7 months (IQR, 28.1 - 47.9). Thirty-four patients in the sorafenib group and 93 patients in the control group relapsed. The 3-year cumulative incidence of relapse was 18.0% (95% CI 13.1% - 24.3%) in the sorafenib group and 36.1% (95% CI 30.5% - 42.3%) in the control group (HR 0.43, 95% CI 0.29 - 0.64; p < 0.001). A total of 126 patients died, including 39 in the sorafenib group and 87 in the control group. Three-year DFS was 75.8% in the sorafenib group and 57.5% in the control group (HR 0.47, 95% CI 0.34 - 0.66; p < 0.001). Three-year OS was 79.5% for patients in the sorafenib group and 68.4% for patients in the control group (HR 0.57, 95% CI 0.39 - 0.83, p = 0.004). Gene mutations were detected using a 12-mutation panel direct sequencing