Clinical study of single-center PDT-ALL-2016 regimen in the treatment of KMT2A-rearranged acute lymphoblastic leukemia

Abstract Objective:To investigate the efficacy and prognostic factors of single-center PDT-ALL-2016 regimen in the treatment of patients with KMT2A-rearranged acute lymphoblastic leukemia(KMT2A-r ALL). Methods：A total of 57 diagnosed patients with KMT2A-r ALL who received treatment in Nanfang Hospital Affiliated to Southern Medical University from October 2018 to November 2021 were retrospectively analyzed. Results：Among the 57 patients with KMT2A-r ALL, 25(43.9%) were males and 32(56.1%) were females;40(70.2%) aged ≤40 years old（adult and young adolescence,AYA）, and 17(29.8%) aged>40 years old（non-AYA）. The median age at diagnosis was 30.0 years old(range: 15-73 years old). There were 48(84.2%) cases of B-ALL and 9(15.8%) case of T-ALL. 27（47.3%）patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT).The median followup time was 16.6 months(range: 0.7-60.0 months).The 5-year overall survival (OS) and event-free survival(EFS) of the overall cohort were 36.4% and 38.4%,respectively.Notably,patients treated with the PDT-ALL-2016 protocol (n=42) had better survival statistic than those receiving adult regimens (n=34) (5-year OS:65.2% vs.17.6%,P=0.001;5-year EFS:64.5% vs.17.6%,P=0.001).Additionally, in our cohort,T-ALL cases exhibited worse outcomes than B-ALL cases (OS:P=0.002;EFS:P=0.026).The 5-year EFS of HSCT were improved in both treatment groups (P<0.001), however,its impact on 5-year OS was not statistically significant (P>0.05). The results of univariable analysis showed that there were significant differences in 5-year OS between HSCT and immunophenotype (B-ALL vs.T-ALL) (both P<0.05). Multivariable analysis of Cox model showed that HSCT was an independent protective prognostic factor affecting the OS in patients with KMT2A-r ALL(HR=1.445,P=0.032). Conclusions:The PDT-ALL-2016 regimen may partially overcome the poor prognosis associated with KMT2A-rearranged acute lymphoblastic leukemia.