This study evaluated the effects of pretransplantation minimal residual disease (pre-MRD) on outcomes of patients with acute lymphoblastic leukemia (ALL) who underwent unmanipulated haploidentical stem cell transplantation (haplo-SCT). A retrospective study including 543 patients with ALL was performed. MRD was determined using multiparametric flow cytometry. Both in the entire cohort of patients and in subgroup cases with T-ALL or B-ALL, patients with positive pre-MRD had a higher incidence of relapse (CIR) than those with negative pre-MRD in MSDT settings (P < 0.01 for all). Landmark analysis at 6 months showed that MRD positivity was significantly and independently associated with inferior rates of relapse (HR, 1.908; P = 0.007), leukemia-free survival (LFS) (HR, 1.559; P = 0.038), and OS (HR, 1.545; P = 0.049). The levels of pre-MRD according to a logarithmic scale were also associated with leukemia relapse, LFS, and OS, except that cases with MRD <0.01% experienced comparable CIR and LFS to those with negative pre-MRD. A risk score for CIR was developed using the variables pre-MRD, disease status, and immunophenotype of ALL. The CIR was 14%, 26%, and 59% for subjects with scores of 0, 1, and 2-3, respectively (P < 0.001). Three-year LFS was 75%, 64%, and 42%, respectively (P < 0.001). Multivariate analysis confirmed the association of the risk score with CIR and LFS.The results indicate that positive pre-MRD, except for low level one (MRD < 0.01%), is associated with poor outcomes in patients with ALL who underwent unmanipulated haplo-SCT.

BackgroundThis study aimed to determine the impact of the pre‐ and post‐minimal residual disease (MRD) status as well as the peri‐transplant MRD kinetics on clinical outcomes in pediatric ALL patients who received haploidentical allografts.MethodsA retrospective study (n = 166) was performed. MRD was determined using multiparameter flow cytometry.ResultsPediatric ALL patients with pre‐MRDneg had a lower cumulative incidences of relapse (CIR) compared to those with pre‐MRDpos (19.7% vs. 41.2%, P = 0.009). Compared to post‐MRDneg group, patients with post‐MRDpos experienced higher CIR (81.0% vs. 15.9%, P < 0.001), inferior LFS (14.3% vs. 66.9%, P < 0.001) and OS (19.1% vs. 66.9%, P < 0.001). In regard to peri‐MRD kinetics, compared with the MRD‐decreasing group and MRDneg/MRDneg group, MRD‐increasing group had higher CIR, lower probabilities of LFS and OS (P < 0.001). Compared to pre‐MRDneg/post‐MRDneg group, a higher CIR was found in the pre‐MRDpos/post‐MRDpos group (66.7% vs. 12.5%, P < 0.001), pre‐MRDpos/post‐MRDneg group (32.0% vs. 12.5%, P = 0.016), and pre‐MRDneg/post‐MRDpos group (91.7% vs. 12.5%, P < 0.001). A lower incidence of LFS and OS were found in pre‐MRDpos/post‐MRDpos group and pre‐MRDneg/post‐MRDpos group than in pre‐MRDneg/post‐MRDneg group (P < 0.05). Multivariate analyses confirmed the association of pre‐MRD status, post‐MRD status, and peri‐MRD kinetics with outcomes (P < 0.05).ConclusionsThe results indicate that, in the pediatric ALL subgroup, not only pre‐MRD status or post‐MRD status but also peri‐SCT MRD dynamics, were associated with an increased CIR after haploidentical allografts. Patients are put into different risk group based on MRD kinetics versus single time MRD status. © 2019 International Clinical Cytometry Society

Background: This study compared the effects of pre-transplantation measurable residual disease (pre-MRD) on outcomes in Philadelphia chromosome (Ph)-positive ALL patients who underwent human leukocyte antigen-matched sibling donor transplantation (MSDT) or who received unmanipulated haploidentical SCT (haplo-SCT). Methods: A retrospective study (n = 202) was performed. MRD was detected by RT-PCR and multiparameter flow cytometry. Results: In the total patient group, patients with positive pre-MRD had a higher 4-year cumulative incidence of relapse (CIR) than that in patients with negative pre-MRD (26.1% vs. 12.1%, P = 0.009); however, the cumulative incidence of non-relapse mortality (NRM) (7.4% vs. 15.9%, P = 0.148), probability of leukemia-free survival (LFS) (66.3% vs. 71.4%, P = 0.480), and overall survival (OS) (68.8% vs. 76.5%, P = 0.322) were comparable. In the MSDT group, patients with positive pre-MRD had increased 4-year CIR (56.4% vs. 13.8%, P < 0.001) and decreased 4-year LFS (35.9% vs. 71.0%, P = 0.024) and OS (35.9% vs. 77.6%, P = 0.011) compared with those with negative pre-MRD. In haplo-SCT settings, the 4-year CIR (14.8% vs. 10.7%, P = 0.297), NRM (7.3% vs. 16.3%, P = 0.187) and the 4-year probability of OS (77.7% vs. 72.3%, P = 0.804) and LFS (80.5% vs. 75.7%, P = 0.660) were comparable between pre-MRD positive and negative groups. In subgroup patients with positive pre-MRD, haplo-SCT had a lower 4-year CIR (14.8% vs. 56.4%, P = 0.021) and a higher 4-year LFS (77.7% vs. 35.9%, P = 0.036) and OS (80.5% vs. 35.9%, P = 0.027) than those of MSDT. Multivariate analysis showed that haplo-SCT was associated with lower CIR (HR, 0.288; P = 0.031), superior LFS (HR, 0.283; P = 0.019) and OS (HR, 0.252; P = 0.013) in cases with a positive pre-MRD subgroup. Li et al. Pre-MRD on Ph + ALL Outcomes Conclusions: Our results indicate that the effects of positive pre-MRD on the outcomes of patients with Ph-positive ALL are different according to transplant modality. For Ph-positive cases with positive pre-MRD, haplo-SCT might have strong graft-vs.-leukemia (GVL) effects.

A retrospective study (n = 460) was performed to assess the relationship between minimal residual disease (MRD) and transplant outcomes in a haplo-stem cell transplantation (SCT) setting. Patients from the pre-MRDneg group and the pre-MRDpos group had comparable outcomes. Compared to post-MRDneg patients, post-MRDpos patients had a higher incidence of relapse (100.0% vs. 8.3%, p < 0.001), lower incidences of overall survival (OS) (16.9% vs. 78.2%, p < 0.001) and leukemia-free survival (LFS) (0% vs. 76.5%, p < 0.001), and comparable probability of NRM (13.4% vs. 16.9%, p = 0.560). In a second set of analyses, all adult AML patients undergoing haplo-SCT were classified into the MRD/MRD group, the MRD decreasing group, and the MRD increasing group according to MRD dynamics by flow cytometry peri-SCT. Compared to the other two groups, patients from the MRD increasing group had higher cumulative incidences of relapse (MRD increasing, 100.0%; MRD/MRD, 9.6%; MRD decreasing, 19.2%; p < 0.001) and worse probabilities of OS (MRD increasing, 28.5%; MRD/MRD, 76.3%; MRD decreasing, 76.0%; p < 0.001) and LFS (MRD increasing, 0.0%; MRD/MRD, 73.9%; MRD decreasing, 74.0%; p < 0.001). The results indicated that haploidentical allografts might have a beneficial anti-leukemia effect in eradicating pretransplantation MRD, and MRD assessment peri-SCT is useful for risk stratification from a practical perspective.

Prolonged isolated thrombocytopenia (PT) after allogeneic stem cell transplantation (allo-SCT) has a great impact on transplant outcome. In this study, we performed a retrospective analysis to investigate the association of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) with PT in 394 patients who underwent unmanipulated haploidentical blood and marrow transplantation (HBMT). For HLA antibody positive samples with a median fluorescent intensity (MFI) > 500, DSAs were further examined. A total of 390 patients (99.0%) achieved sustained myeloid engraftment. Of the 394 cases tested, 45 (11.4%) were DSA positive. The cumulative incidence of PT in this cohort of patients was 9.9 ± 1.5%. The incidence of PT was higher in patients with a MFI ≥ 1000 compared with those with a MFI < 1000 (16.8 ± 6.4% versus 7.4 ± 1.4%, P = 0.05). Multivariate analysis showed that the presence of DSAs (MFI ≥ 1000) was correlated to PT (hazard ratio (HR) 3.262; 95% confidence interval (CI), 1.339–7.946; P = 0.009) and transplant-related mortality (HR 2.320; 95% CI, 1.169–4.426; P = 0.044). Our results, for the first time, suggest an association of DSAs with PT after unmanipulated HBMT. It would help screen out the suitable donor and guide intervention. This indicated that DSAs should be incorporated in the algorithm for unmanipulated HBMT.