Background: Compared with HLA-matched sibling donor (MSD) transplant, the outcomes of haploidentical donor (HID) transplant for refractory acute leukemia need to be further explored. In this study, we compared the outcomes of HID with MSD for refractory acute leukemia. Patients and methods: This study population came from two prospective multicenter trials (NCT01883180, NCT02673008). Two hundred and seventy-eight patients with refractory acute leukemia were enrolled in this study, including 119 in HID group and 132 in MSD group. Sequential intensified conditioning was employed in all patients, and donor lymphocyte infusion (DLI) was administered in patients in the absence of active GVHD and according to minimal residual disease (MRD) from day + 60 post-transplantation for preventing relapse. Results: The complete remission of leukemia by day + 30 post-transplant were 94% and 93%, respectively, in HID and MSD groups (p = .802). The 1-year incidence of grades II–IV acute GVHD was 62% and 54% (p = .025), and 3-year incidence of chronic GVHD was 55% and 55% (p = .789), respectively, in two groups. HID transplant had lower incidence of first episode of MRD positivity and relapse than MSD transplant (28% vs 45%, p = .006; 26% vs 38%, p = .034). There was higher infection-related mortality in HID than MSD (8% vs 2%, p = .049) within the first 100 days’ post-transplant. The 5-year overall survival was 46% and 42% (p = .832), respectively; the 5-year disease-free survival was 43% and 39% (p = .665), in HID and MSD groups, respectively. Conclusions: HID transplant has lower relapse, but higher infection-related mortality and similar survival rates in refractory acute leukemia by the strategy of sequential intensified conditioning followed by DLI compared with MSD transplant.

The clinical significance of cyclin-dependent kinase inhibitor 2 (CDKN2) deletion in adult T-lineage acute lymphoblastic leukemia (T-ALL) is still a matter of debate. This study aimed to investigate the prognostic value of CDKN2 deletion and impact of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in adult T-ALL. A total of 241 T-ALL patients were enrolled in this single-center retrospective study: 57 with CDKN2 deletion and 184 with CDKN2 wild-type (WT). CDKN2 deletion was associated with a higher white blood cell (WBC) count (P = 0.013), a greater proportion of high-risk disease (P = 0.004), and a complex karyotype (P = 0.004) than CDKN2 WT. The 5-year cumulative incidence of relapse (CIR) was 30.9% (95% CI 17.5-45.3) and 17.5% (95% CI 11.2-25.1) (P = 0.004), disease-free survival (DFS) was 39.7% (95% CI 25.6-53.4) and 53.8% (95% CI 45.1-61.7) (P = 0.002), and overall survival (OS) was 36.8% (95% CI 23.2-50.5) and 58.2% (95% CI 49.1-66.2) (P < 0.001) in patients with CDKN2 deletion and CDKN2 WT, respectively. In the multivariable analysis of the entire population, CDKN2 deletion was found to be an independent adverse prognostic factor for CIR (HR 2.79 (95% CI 1.3-6), P = 0.009), DFS (HR 1.76 (95% CI 1.1-2.79), P = 0.018), and OS (HR 1.91 (95% CI 1.19-3.07), P = 0.008). In the CDKN2 deletion subgroup, the 5-year CIR was 15.8% (95% CI 4.8-32.6) and 53.9% (95% CI 26.3-75.1) (P = 0.005), DFS was 51.8% (95% CI 30.9-69.1) and 21.1% (95% CI 7.2-39.8) (P < 0.001), and OS was 51.2% (95% CI 30.4-68.7) and 17.4% (95% CI 4.8-36.5) (P < 0.001) in patients with and without allo-HSCT, respectively. Conclusion: CDKN2 deletion is associated with poor prognosis in adult patients with T-ALL. Patients with T-ALL and CDKN2 deletions may benefit from allo-HSCT.