Impact of pre-transplantation minimal residual disease determined by multiparameter flow cytometry on the outcome of AML patients with FLT3-ITD after allogeneic stem cell transplantation

Outcomes and prognosis of haploidentical haematopoietic stem cell transplantation in children with FLT3-ITD mutated acute myeloid leukaemia

The presence of internal tandem duplication mutations in the FMS-like tyrosine kinase 3 receptor (FLT3-ITD) is a poor prognostic predictor in paediatric patients with acute myeloid leukaemia (AML). We evaluated the treatment outcomes and prognostic factors of 45 paediatric patients with FLT3-ITD AML who achieved complete remission before haploidentical haematopoietic stem cell transplantation (haplo-HSCT) at our institution from 2012 to 2021. Among the 45 patients, the overall survival (OS), event‑free survival (EFS), and cumulative incidence of relapse (CIR) rates were 74.9% ± 6.6%, 64.1% ± 7.2%, and 31.4% ± 7.1%, respectively, with 48.8 months of median follow-up. Univariate and multivariate analyses associated positive minimal residual disease (MRD) at pre-HSCT and non-remission (NR) after introduce 1 with inferior long-term survival. The 100-day cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 35.6% ± 5.2%, and that of grade III-IV aGVHD was 15.6% ± 3.0% The overall 4-year cumulative incidence of chronic graft-versus-host disease after transplantation was 35.7% ± 9.8%, respectively. In conclusion, haplo-HSCT may be a feasible strategy for paediatric patients with FLT3-ITD AML, and pre-HSCT MRD status and NR after introduce 1 significantly affected the outcomes.

The FLT3-ITD allelic ratio and NPM1 mutation do not impact outcomes in AML patients with FLT3-ITD after allo-HSCT: a retrospective propensity-score matching study

BACKGROUND

FLT3-ITD mutation has consistently been correlated with poor outcomes in AML patients. Allo-HSCT (allogeneic hematopoietic stem cell transplantation) plays a major role in curing blood diseases. Whether allo-HSCT can eliminate the detrimental effects of FLT3-ITD mutation in AML patients remains debatable. In addition, studies showed that FLT3-ITD allelic ratio (AR) and NPM1 mutation appear to further influence the prognostic utility of FLT3-ITD in patients with FLT3-ITD-mutated AML. The influence of NPM1 mutation and AR on FLT3-ITDmut patients remains unclear in our database.

OBJECTIVE

To compare the survival outcomes following allo-HSCT between FLT3-ITDmut and FLT3-ITDwt patients and further analyze the influence of NPM1 and AR on outcomes.

STUDY DESIGN

118 FLT3-ITDmut patients and 497 FLT3-ITDwt patients with allo-HSCT were matched 1:3 on the propensity score using a nearest-neighbor matching with a caliper size of 0.2. 430 AML patients were considered, including 116 FLT3-ITDmut patients and 314 FLT3-ITDwt patients.

RESULTS

OS (overall survival) and LFS (leukemia-free survival) of FLT3-ITDmut patients were similar to FLT3-ITDwt (2-year OS:78.5% vs 82.6%, P=0.374; 2-year LFS: 75.1% vs 80.8%, P= 0.215). A cut-off of 0.50 was applied to define subgroups with a low or high AR of FLT3-ITD, no significant CIR (cumulative incidence of relapse) and LFS differences were observed between the low AR and high AR groups (2-year CIR: P=0.617; 2-year LFS: P=0.563). CIR and LFS were comparable when patients were grouped according to the presence or absence of NPM1 and FLT3-ITD (2-year CIR: P=0.356; 2-year LFS: P=0.159). Additionally, the CIR and LFS of FLT3-ITDmut and FLT3-ITDwt patients tended to be different after MSD-HSCT (matched-sibling donor hematopoietic stem cell transplantation) (2-year CIR: P= 0.072; 2-year LFS: P= 0.084), however, the differences were not observed in patients with haplo-HSCT (2-year CIR: P= 0.59; 2-year LFS: P= 0.794). The presence of MRD before transplantation and non-CR1 were risk factors related to inferior outcomes in a multivariate analysis, regardless of FLT3-ITD or NPM1 status.

CONCLUSION

Our results suggested that allo-HSCT, especially haplo-HSCT, may overcome the adverse effect of FLT3-ITD mutation, regardless of the NPM1 status or AR. Allo-HSCT could be an ideal option for AML patients with FLT3-ITD.

Monitoring of post-transplant MLL-PTD as minimal residual disease can predict relapse after allogeneic HSCT in patients with acute myeloid leukemia and myelodysplastic syndrome

Background

The mixed-lineage leukemia (MLL) gene is located on chromosome 11q23. The MLL gene can be rearranged to generate partial tandem duplications (MLL-PTD), which occurs in about 5-10% of acute myeloid leukemia (AML) with a normal karyotype and in 5-6% of myelodysplastic syndrome (MDS) patients. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently one of the curative therapies available for AML and MDS with excess blasts (MDS-EB). However, how the prognosis of patients with high levels of MLL-PTD after allo-HSCT, and whether MLL-PTD could be used as a reliable indicator for minimal residual disease (MRD) monitoring in transplant patients remains unknown. Our study purposed to analyze the dynamic changes of MLL-PTD peri-transplantation and the best threshold for predicting relapse after transplantation.

Methods

We retrospectively collected the clinical data of 48 patients with MLL-PTD AML or MDS-EB who underwent allo-HSCT in Peking University People’s Hospital. The MLL-PTD was examined by real-time quantitative polymerase chain reaction (RQ-PCR) at the diagnosis, before transplantation and the fixed time points after transplantation. Detectable MLL-PTD/ABL > 0.08% was defined as MLL-PTD positive in this study.

Results

The 48 patients included 33 AML patients and 15 MDS-EB patients. The median follow-up time was 26(0.7-56) months after HSCT. In AML patients, 7 patients (21.2%) died of treatment-related mortality (TRM), 6 patients (18.2%) underwent hematological relapse and died ultimately. Of the 15 patients with MDS-EB, 2 patients (13.3%) died of infection. The 3-year cumulative incidence of relapse (CIR), overall survival (OS), disease-free survival (DFS) and TRM were 13.7 ± 5.2, 67.8 ± 6.9, 68.1 ± 6.8 and 20.3% ± 6.1%, respectively. ROC curve showed that post-transplant MLL-PTD ≥ 1.0% was the optimal cut-off value for predicting hematological relapse after allo-HSCT. There was statistical difference between post-transplant MLL-PTD ≥ 1.0% and MLL-PTD < 1.0% groups (3-year CIR: 75% ± 15.3% vs. 0%, P < 0.001; 3-year OS: 25.0 ± 15.3% vs. 80.7% ± 6.6%, P < 0.001; 3-year DFS: 25.0 ± 15.3% vs. 80.7 ± 6.6%, P < 0.001; 3-year TRM: 0 vs. 19.3 ± 6.6%, P = 0.277). However, whether MLL-PTD ≥ 1% or MLL-PTD < 1% before transplantation has no significant difference on the prognosis.

Conclusions

Our study indicated that MLL-PTD had a certain stability and could effectively reflect the change of tumor burden. The expression level of MLL-PTD after transplantation can serve as an effective indicator for predicting relapse.

Haploidentical Stem Cell Transplantation for Acute Myeloid Leukemia: Current Therapies, Challenges and Future Prospective

Haploidentical stem cell transplantation (haplo-SCT), an alternative donor source, offers a curative therapy for patients with acute myeloid leukemia (AML) who are transplant candidates. Advances in transplantation techniques, such as donor selection, conditioning regimen modification, and graft-versus-host disease prophylaxis, have successfully improved the outcomes of AML patients receiving haplo-SCT and extended the haploidentical transplant indictions for AML. Presently, treating de novo AML, secondary AML, therapy-related AML and refractory and relapsed AML with haplo-SCT can achieve comparable outcomes to those of human leukocyte antigen (HLA)-matched sibling donor transplantation (MSDT), unrelated donor transplantation or umbilical cord blood transplantation. For some subgroups of AML subjects, such as patients with positive pretransplantation minimal/measurable residual disease, recent studies suggest that haplo-SCT might be superior to MSDT in decreasing relapse and improving survival. Unfortunately, for patients with AML after haplo-SCT, relapse and infections remain the causes of death that restrict further improvement in clinical outcomes. In this review, we discuss the recent advances and challenges in haplo-SCT for AML treatment, mainly focusing on unmanipulated haplo-SCT protocols. We provide an outlook on future prospects and suggest that relapse prophylaxis, intervention, and treatment, as well as infection prevention and therapy, are areas of active research in AML patients who receive haploidentical allografts.

Impact of pre-transplantation minimal residual disease (MRD) on the outcome of Allogeneic hematopoietic stem cell transplantation for acute leukemia

OBJECTIVE

To investigate the impact of minimal residual disease (MRD) before allogeneic hematopoietic stem cell transplantation (allo-HSCT) on the outcome of acute leukemia.

METHODS

Data from 114 patients who were diagnosed with acute leukemia (AL) and underwent allo-HSCT between Jan 2013 and Dec 2019 were collected and analyzed. The patients were attributed into MRD positive (MRD+) group and MRD negative (MRD-) group.

RESULTS

Among the 114 acute leukemia patients, there were 32 MRD+ patients before transplantation, and 82 MRD- patients. No significant difference was found between the MRD+ group and the MRD- group in the incidence of acute graft-versus-host disease (aGvHD) (p = 0.09). Compared with the MRD+ group, the MRD- group had a higher incidence of chronic graft-versus-host disease (cGvHD) (p = 0.008). There is no significance in relapse between the two groups (p = 0.084), while the incidence of relapse was seemingly higher in the MRD+ group: 36.9% Vs 19.7% . We attributed to the lack of sample size and NRM in MRD+ group was remarkably higher. The MRD+ group had significantly worse one-year overall survival (OS) ( , p = 0.003) and one-year progression-free survival (PFS) (, p = 0.009). In the multivariate analysis, MRD+ was an independent prognostic factor for OS (HR = 1.898; 95%CI 1.042-3.457; p = 0.036).

CONCLUSION

Pre-transplantation MRD positive status is a risk factor for survival and prognosis after HSCT. Upon this, emphasis should be put on (1) screening more efficient chemo regimen with targeted agents, to help patients reach and keep MRD- status before transplantation; (2) designing better management with different GvHD prophylaxis treatment, timely disease monitoring and preemptive intervention on relapse.

Prognostic significance of SET-NUP214 fusion gene in acute leukemia after allogeneic hematopoietic stem cell transplantation

The SET nuclear proto-oncogene (SET)-nucleoporin (NUP) 214 fusion gene (SET-NUP214) is a rare leukemia fusion gene. Due to the limited number of samples with SET-NUP214 fusion gene in previous studies, the significance of SET-NUP214 for measurable residual disease (MRD) monitoring in patients with acute leukemia (AL) is still unclear. Our study aimed to observe the dynamic changes in SET-NUP214 expression before and after allogeneic hematopoietic stem cell transplantation (allo-HSCT), and analyzed whether SET-NUP214 could be used to evaluate MRD status. Our study included 24 AL patients who were newly diagnosed with SET-NUP214 fusion gene and they all received allo-HSCT. Their MRD was evaluated by monitoring SET-NUP214 fusion gene and leukemia-associated immunophenotype (LAIP). The median follow-up time was 501 days (56-2208 days). Of the enrolled patients, 6 (25%) patients died, including 3 (12.5%) patients died of leukemia relapse. Total 5 (20.8%) patients experienced hematological relapse at a median of 225 days (56-1057 days) post-transplantation. The SET-NUP214 median expression level at diagnosis was 405.1% (14.6%-1482.4%). SET-NUP214 gene expression generally became positive prior to flow cytometry results. In addition, the Kaplan-Meier survival curves analysis showed that those who had SET-NUP214 positive (SET-NUP214+) post-transplantation had a higher 2-year cumulative incidence of leukemia relapse (CIR) of 43.7 ± 18.8% (P < .05). However, there was no significant difference between SET-NUP214 positive and SET-NUP214 negative patients with regard to their 2-year overall survival (OS) (82.5 ± 11.3 vs 64.6 ± 17.5%, respectively, P = .271). ROC curve analysis turned out that the area under the ROC curve (AUC) was 0.916 (95% CI: 0.784-1.0; P = .005). In conclusion, SET-NUP214 fusion gene determined by real-time quantitative reverse transcriptase polymerase chain reaction (RQ-PCR) could be used to evaluate MRD status after allo-HSCT. Patients with positive SET-NUP214 expression after transplantation will have a poor prognosis.

Pre-transplant FLT3/ITD status predicts outcome in FLT3-mutated acute myeloid leukemia following allogeneic stem cell transplantation

Acute myeloid leukemia (AML) with fetal liver tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) is associated with poor prognosis, and allogeneic stem cell transplantation (Allo-SCT) seems to be the preferred therapeutic approach. However, the predictors of post-transplant outcomes were not well-defined. The aim of the study was to evaluate the significance of FLT3/ITD mutation by polymerase chain reaction as minimal residual disease (MRD) marker of outcomes after transplantation. We identified 43 patients (28 females and 15 males) with FLT3-mutated AML at the median age of 45 years who were allografted between 2009 and 2019. Hematological status at transplant was as follows: the first complete remission (CR1) in 29 patients, CR2 in 5, and 9 patients were transplanted in marrow aplasia (MA). Twenty-seven patients were FLT3 MRD negative at transplant. Median time from diagnosis to transplant was 16.7 months. Post-allograft CR rate was 88%. The relapse incidence (RI) was lower for patients who were FLT3 MRD negative at transplant when compared with those with FLT3 MRD positivity (41% vs 59%; p = 0.01). The patients who eradicated FLT3/ITD at day + 30 after transplant had lower RI than those with detectable FLT3/ITD (23% vs 76%; p = <0.001). The 2-year LFS and OS were 53% and 54%, with the median OS and LFS of 28 months and 27 months, respectively. Patients with CR1/2 and FLT3 MRD(-) had a 2-year OS of 80%. The FLT3 MRD negativity at transplant prolonged LFS in multivariate analysis (HR 5.3 95%CI 1.97-14.2); p < 0.001), whereas FLT3 MRD negativity and unrelated donor predicted favorable OS.

Treatments for children and adolescents with AML

In recent decades, survival rates for childhood acute myeloid leukemia have remarkably improved, owing to chemotherapy intensification, allogeneic hematopoietic stem cell transplantation, and improved supportive care. Furthermore, treatment protocols have evolved and are currently better matched to prognostic factors and treatment responses. Recently, new molecular prognostic factors were discovered via leukemia genomic studies. Moreover, new tumor subtypes with independent gene expression profiles have been characterized. To broaden the therapeutic options for patients with poor prognoses, therapies that target specific candidate mutations are being identified. Additionally, new drugs are undergoing clinical trials, and immunotherapy is attracting significant interest as a treatment option for recurrent or refractory childhood acute myeloid leukemia.

Clinical practice recommendation on hematopoietic stem cell transplantation for acute myeloid leukemia patients with FLT3-internal tandem duplication: a position statement from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

The FMS-like tyrosine kinase 3 (FLT3) gene is mutated in 25-30% of patients with acute myeloid leukemia (AML). Because of the poor prognosis associated with FLT3-internal tandem duplication mutated AML, allogeneic hematopoietic stem-cell transplantation (SCT) was commonly performed in first complete remission. Remarkable progress has been made in frontline treatments with the incorporation of FLT3 inhibitors and the development of highly sensitive minimal/measurable residual disease assays. Similarly, recent progress in allogeneic hematopoietic SCT includes improvement of transplant techniques, the use of haploidentical donors in patients lacking an HLA matched donor, and the introduction of FLT3 inhibitors as post-transplant maintenance therapy. Nevertheless, current transplant strategies vary between centers and differ in terms of transplant indications based on the internal tandem duplication allelic ratio and concomitant nucleophos-min-1 mutation, as well as in terms of post-transplant maintenance/consolidation. This review generated by international leukemia or transplant experts, mostly from the European Society for Blood and Marrow Transplantation, attempts to develop a position statement on best approaches for allogeneic hematopoietic SCT for AML with FLT3-internal tandem duplication including indications for and modalities of such transplants and on the potential optimization of post-transplant maintenance with FLT inhibitors.

Different Effects of Pre-transplantation Measurable Residual Disease on Outcomes According to Transplant Modality in Patients With Philadelphia Chromosome Positive ALL

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. 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.

Mutation topography and risk stratification for de novo acute myeloid leukaemia with normal cytogenetics and no nucleophosmin 1 (NPM1) mutation or Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD)

About 25% of patients with newly diagnosed acute myeloid leukaemia (AML) have normal cytogenetics and no nucleophosmin 1 (NPM1) mutation or Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD). The prognosis and best therapy for these patients is controversial. We evaluated 158 newly diagnosed adults with this genotype who achieved histological complete remission within two cycles of induction therapy and were assigned to two post-remission strategies with and without an allotransplant. Targeted regional sequencing at diagnosis was performed and data were used to estimate their prognosis, including relapse and survival. In multivariable analyses, having wild-type or mono-allelic mutated CCAAT/enhancer-binding protein alpha (CEBPA) [hazard ratio (HR) 2·39, 95% confidence interval (CI) 1·08-5·30; P = 0·032), mutated NRAS (HR 2·67, 95% CI 1·36-5·25; P = 0·004), mutated colony-stimulating factor 3 receptor (CSF3R) (HR 2·85, 95% CI 1·12-7·27; P = 0·028) and a positive measurable residual disease (MRD)-test after the second consolidation cycle (HR 2·88, 95% CI 1·32-6·30; P = 0·008) were independently correlated with higher cumulative incidence of relapse (CIR). These variables were also significantly associated with worse survival (HR 3·02, 95% CI 1·17-7·78, P = 0·022; HR 3·62, 95% CI 1·51-8·68, P = 0·004; HR 3·14, 95% CI 1·06-9·31, P = 0·039; HR 4·03, 95% CI 1·64-9·89, P = 0·002; respectively). Patients with ≥1 of these adverse-risk variables benefitted from a transplant, whereas the others did not. In conclusion, we identified variables associated with CIR and survival in patients with AML and normal cytogenetics without a NPM1 mutation or FLT3-ITD.

Detection of measurable residual disease may better predict outcomes than mutations based on next-generation sequencing in acute myeloid leukaemia with biallelic mutations of CEBPA

Acute myeloid leukaemia (AML) patients with biallelic mutations of CEBPA (bi CEBPA) have a 30-50% relapse rate. This study established the value of mutations based on next-generation sequencing (NGS) and multiparameter flow cytometric measurable residual disease (MFC-MRD) detection and compared the outcomes. From 2014 to 2018, 124 newly diagnosed bi CEBPA AML patients were treated. The median age was 37·5 (16-69) years. The 3-year cumulative incidence of relapse (CIR), relapse-free survival (RFS) and overall survival (OS) were 33·0%, 64·7% and 84·3%, respectively. Patients without additional mutations and with GATA2 mutations were defined as 'NGS low risk', which was the only favourable independent factor for CIR and RFS of pretreatment parameters. Patients with sustained positive MRD after two consolidation cycles and MRD negative losses at any time were defined as 'MRD high risk', which was the only poor independent factor for CIR, RFS and OS, including pretreatment and post-treatment parameters. In CR2 and non-remission patients who underwent allo-HSCT, superior OS was achieved. We conclude that NGS low risk was a favourable factor in the analysis of pretreatment parameters. MRD risk stratification was an independent prognostic factor in pretreatment and post-treatment parameters. Relapsed patients still have a favourable outcome followed by allo-HSCT.

Granulocyte Colony-Stimulating Factor-Primed Unmanipulated Haploidentical Blood and Marrow Transplantation

Granulocyte colony-stimulating factor (G-CSF), a growth factor for neutrophils, has been successfully used for stem cell mobilization and T cell immune tolerance induction. The establishment of G-CSF-primed unmanipulated haploidentical blood and marrow transplantation (The Beijing Protocol) has achieved outcomes for the treatment of acute leukemia, myelodysplastic syndrome, and severe aplastic anemia with haploidentical allografts comparable to those of human leukocyte antigen (HLA)-matched sibling donor transplantation. Currently, G-CSF-mobilized bone marrow and/or peripheral blood stem cell sources have been widely used in unmanipulated haploidentical transplant settings. In this review, we summarize the roles of G-CSF in inducing T cell immune tolerance. We discuss the recent advances in the Beijing Protocol, mainly focusing on strategies that have been used to improve transplant outcomes in cases of poor graft function, virus infections, and relapse. The application of G-CSF-primed allografts in other haploidentical modalities is also discussed.

Association of Persistent Minimal Residual Disease with Poor Outcomes of Patients with Acute Myeloid Leukemia Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Background:

Several studies have shown that detection of minimal residual disease (MRD) in acute myeloid leukemia (AML) is an independent prognostic factor. This study aimed to evaluate the significance of dynamic MRD pretransplantation on outcome of AML patients receiving allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Methods:

We retrospectively analyzed 145 consecutive AML patients undergoing allo-HSCT in complete remission status between June 2013 and June 2016. MRD was determined with multiparameter flow cytometry after the first and second courses of chemotherapy and pre-HSCT.

Results:

In matched sibling donor transplantation (MSDT) settings, patients with positive MRD had higher cumulative incidence of relapse (CIR) than those without MRD after the first (32.3 ± 9.7% vs. 7.7 ± 3.1%, χ² = 3.661, P = 0.055) or second course of chemotherapy (57.1 ± 3.6% vs. 12.5 ± 2.7%, χ² = 8.759, P = 0.003) or pre-HSCT (50.0 ± 9.7% vs. 23.0 ± 3.2%, χ² = 5.547, P = 0.019). In haploidentical SCT (haplo-SCT) settings, the MRD status at those timepoints had no significant impact on clinical outcomes. However, patients with persistent positive MRD from chemotherapy to pre-HSCT had higher CIR than those without persistent positive MRD both in MSDT and haplo-SCT settings. Patients with persistent positive MRD underwent MSDT had the highest relapse incidence, followed by those with persistent positive MRD underwent haplo-SCT, those without persistent MRD underwent haplo-SCT, and those without persistent MRD underwent MSDT (66.7 ± 9.2% vs. 38.5 ± 6.0% vs. 18.8 ± 8.7% vs. 12.0 ± 1.0%, χ² = 20.763, P < 0.001). Multivariate analysis showed that persistent positive MRD before transplantation was associated with higher CIR (hazard ratio [HR] = 1.69, 95% confidence interval [CI]: 1.200–2.382, P = 0.003), worse leukemia-free survival (HR = 1.812, 95% CI: 1.168–2.812, P = 0.008), and overall survival (HR = 2.354, 95% CI: 1.528–3.627, P < 0.001).

Conclusion:

Our results suggest that persistent positive MRD before transplantation, rather than positive MRD at single timepoint, could predict poor outcome both in MSDT and haplo-SCT settings.

The consensus on the monitoring, treatment, and prevention of leukemia relapse after allogeneic hematopoietic stem cell transplantation in China

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important curative therapy for patients with leukemia. However, relapse remains the leading cause of death after transplantation. In recent years, substantial progress has been made by Chinese physicians in the field of establishment of novel transplant modality, patient selection, minimal residual disease (MRD) monitoring, and immunological therapies, such as modified donor lymphocyte infusion (DLI) and chimeric antigen receptor T (CART) cells, as well as MRD-directed intervention for relapse. Most of these unique systems are distinct from those in the Western world. In this consensus, we reviewed the efficacy of post-HSCT relapse management practice from available Chinese studies on behalf of the HSCT workgroup of the Chinese Society of Hematology, Chinese Medical Association, and compared these studies withthe consensus or guidelines outside China. We summarized the consensus on routine practices of post-HSCT relapse management in China and focused on the recommendations of MRD monitoring, risk stratification directed strategies, and modified DLI system. This consensus will likely contribute to the standardization of post-HSCT relapse management in China and become an inspiration for further international cooperation to refine global practices.

Is human leukocyte antigen-matched sibling donor transplant always better than haploidentical allograft?

Currently, haploidentical donor has been an alternative source of stem cell allografts for patients who have no human leukocyte antigen-matched sibling donor or unrelated donors. A number of studies indicated that treating hematological malignancy patients with haploidentical stem cell transplantation (haplo-SCT) could achieve comparable outcomes to those who underwent matched sibling donor transplantation (MSDT). In recent years, more and more evidence support the notion that haploidentical allografts may have a stronger graft-vs-leukemia (GVL) effect than MSDT. In this review, we summarized the transplant outcomes of haplo-SCT and MSDT, mainly focusing on the subgroup of patients who will benefit from the stronger GVL effects of haplo-SCT compared with MSDT. We also offered strategies of how to translate the strong antileukemia activity of haploidentical allograft into superior survival. Future directions of GVL effects in haplo-SCT settings were also discussed.