Retrospective analysis of children with high-risk acute myeloid leukemia who underwent allogeneic hematopoietic stem cell transplantation following complete remission with initial induction chemotherapy in the AML-05 clinical trial

A Retrospective Study of Pediatric Patients With Low- or Intermediate-Risk Acute Myeloid Leukemia Who Underwent Allogeneic Hematopoietic Cell Transplantation for the AML-05 Study Conducted by the Japanese Pediatric Leukemia/Lymphoma Study Group

The AML-05 study aimed to examine the efficacy and safety of a therapeutic strategy based on risk stratification for low-, intermediate-, or high-risk acute myeloid leukemia (AML) pediatric patients. Allogeneic hematopoietic cell transplantation (allo-HCT) was not indicated for low- or intermediate-risk AML patients in first complete remission. The present retrospective study for the AML-05 study aimed to identify prognostic factors for survival and to determine optimal allo-HCT according to multivariate analysis on overall survival (OS), event-free survival (EFS), cumulative incidence of relapse (CIR), and cumulative incidence of nonrelapse mortality for and between low- and intermediate-risk AML group patients in the AML-05 study who had undergone allo-HCT after its completion and relapse. The unique patient numbers (UPNs) of the AML-05 study were matched with the Transplant Registry Unified Management Program (TRUMP)-registered numbers, and the tied data on the AML-05 study's UPNs and the TRUMP-registered numbers were analyzed. The primary endpoint was 3-yr OS. Among 443 AML patients in the AML-05 study, 79 (32 low-risk AML and 47 intermediate-risk AML) were analyzed. The following statistically favorable prognostic factors were identified by multivariate analysis on the low- and intermediate-risk AML groups, respectively: UCB (OS-hazard ratio [HR], 0.105; 95% CI, 0.011 to 0.941; P = .004 and EFS-HR, 0.065, 95% CI, 0.007 to 0.577, P = .014) and late relapse (OS-HR, 0.212; 95% CI, 0.072 to 0.626; P = .005 and EFS-HR, 0.236; 95% CI, 0.088 to 0.630; P = .004). Three-year OS, 3-yr EFS, and 3-yr CIR were significantly different between the low- and intermediate-risk AML groups. UCB may be a safe and beneficial donor source for low-risk AML patients, while late relapse was a favorable prognostic factor for intermediate-risk AML patients. Intermediate-risk AML patients with late relapse and low-risk AML patients may benefit from allo-HCT after relapse.

Risk factors for post-transplant relapse and survival in younger adult patients with t(8;21)(q22;q22) acute myeloid leukemia undergoing allogeneic hematopoietic stem cell transplantation: A multicenter retrospective study

Background

Outcomes of patients with t(8;21)(q22;q22) acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remain heterogeneous.

Methods

To identify the risk factors for relapse and survival after allo-HSCT in t(8;21) AML patients, we retrospectively evaluated the clinical and prognostic information of 142 patients with t(8;21) AML undergoing allo-HSCT between January 2002 and September 2018 at 15 hematology research centers in China.

Results

Twenty-nine patients (20%) relapsed after undergoing allo-HSCT. A > 1-log reduction in RUNX1/RUNX1T1-based minimal residual disease (MRD) directly before allo-HSCT and a > 3-log reduction within the first 3 months after allo-HSCT were associated with a significantly lower post-transplant 3-year cumulative incidence of relapse (CIR, 9% vs. 62% and 10% vs. 47%,all P < 0.001), whereas transplantation during the second complete remission (CR2, 39% vs. 17% during CR1, P = 0.022), during relapse (62% vs. 17% during CR1, P < 0.001) and KIT D816 mutations at diagnosis (49% vs. 18%, P = 0.039) were related to a significantly higher 3-year CIR. Multivariate analysis demonstrated that a > 1-log reduction in MRD directly before transplantation (CIR: hazard ratio(HR), 0.21 [0.03-0.71], P = 0.029; overall survival (OS): HR = 0.27 [0.08-0.93], P = 0.038) and a > 3-log reduction in post-transplant MRD within the first 3 months (CIR: HR = 0.25 [0.07-0.89], P = 0.019; OS: HR = 0.38 [0.15-0.96], P = 0.040) were independent favorable prognostic factors, and transplantation during relapse (CIR: HR = 5.55 [1.23-11.56], P = 0.041; OS: HR = 4.07 [1.82-20.12], P = 0.045) were independent adverse prognostic factors for post-transplant relapse and survival in patients with t(8;21) AML.

Conclusion

Our study suggests that for patients with t(8;21) AML undergoing allo-HSCT, it would be better to receive transplantation during CR1 with a MRD directly before transplantation achieving at least 1-log reduction. MRD monitoring in the first 3 months after allo-HSCT might be robust in predicting relapse and adverse survival after allo-HSCT.

[Unrelated cord blood stem cell transplantation for high-risk/refractory childhood acute myeloid leukemia: a clinical analysis of 160 cases]

Objective: To retrospectively analyze the clinical outcomes of single unrelated cord blood transplantation (UCBT) in children with high risk and refractory acute myeloid leukemia (AML) . Methods: Between June 2008 and December 2018, a total of 160 consecutive pediatric patients with AML received single UCBT (excluding acute promyelocytic leukemia) . Myeloablative conditioning (MAC) regimen were applied. All patients received a combination of cyclosporine A (CsA) and mycophenolate mofetil (MMF) for the prophylaxis of graft -versus- host disease (GVHD) . Results: The cumulative incidence of neutrophil cells engraftment at day +42 and platelet recovery at day +120 was 95.0% (95% CI 90.0%-97.5%) at a median of 16 days after transplantation (range, 11-38 days) and 85.5% (95%CI 83.3%-93.4%) with a median time to recovery of 35 days (range, 13-158) , respectively. Incidence of grades Ⅱ-Ⅳ and Ⅲ-Ⅳ acute GVHD and chronic GVHD were 37.3% (95%CI 29.3%-45.2%) , 27.3% (95%CI 20.0%-35.0%) and 22.4% (95%CI 15.5%-28.7%) , respectively. The transplant-related mortality (TRM) at 360 day was 13.1% (95%CI 8.4%-18.9%) . The 5-year cumulative incidence of relapse was 13.8% (95%CI 8.5%-20.3%) . The 5-year disease-free survival (DFS) and overall survival (OS) were 71.7% (95%CI 62.7%-77.8%) and 72.2% (95%CI 64.1%-78.7%) , respectively. The 5-year GVHD and relapse free survival (GRFS) was 56.1% (95%CI 46.1%-64.9%) . The 5-year cumulative recurrence rates of CR1, CR2, and NR groups were 5.3%, 19.9%, and 30.9% (P=0.001) , and the 5-year OS rates were 79.9% (95%CI 70.3%-86.7%) , 71.1% (95%CI 50.4%-84.4%) and 52.9% (95%CI 33.0%-69.3%) (χ(2)=7.552, P=0.020) , respectively. Conclusions: For pediatric patients with high risk and refractory AML, UCBT is a safe and effective treatment option, and it is favorable to improve the survival rate in CR1 stage.

Droplet digital polymerase chain reaction assay for the detection of the minor clone of KIT D816V in paediatric acute myeloid leukaemia especially showing RUNX1-RUNX1T1 transcripts

KIT D816V mutation within exon 17 has been particularly reported as one of the poor prognostic factors in pediatric acute myeloid leukemia (AML) with RUNX1-RUNX1T1. The exact frequency and the prognostic impact of KIT D816V minor clones at diagnosis were not examined. In this study, the minor clones were examined and the prognostic significance of KIT D816V mutation in pediatric patients was investigated. Consequently, 24 KIT D816V mutations (7.2%) in 335 pediatric patients were identified, and 12 of 24 were only detected via the digital droplet polymerase chain reaction method. All 12 patients were confined in core binding factor (CBF)-AML patients. The 5 year event-free survival of the patients with KIT D816V mutation was significantly inferior to those without KIT D816V mutation (44.1% [95% confidence interval (CI), 16.0%-69.4%] vs. 74.7% [95% CI, 63.0%-83.2%] P-value = 0.02, respectively). The 5 year overall survival was not different between the two groups (92.9% [95% CI, 59.0%-NA vs. 89.7% [95% CI, 69.6%-96.8%] P-value = 0.607, respectively). In this study, KIT D816V minor clones in patients with CBF-AML were confirmed and KIT D816V was considered as a risk factor for relapse in patients with RUNX1-RUNX1T1-positive AML.

Aberrantly low STAT3 and STAT5 responses are associated with poor outcome and an inflammatory gene expression signature in pediatric acute myeloid leukemia

The relapse rate for children with acute myeloid leukemia is nearly 40% despite aggressive chemotherapy and often stem cell transplant. We sought to understand how environment-induced signaling responses are associated with clinical response to treatment. We previously reported that patients whose AML cells showed low G-CSF-induced STAT3 activation had inferior event-free survival compared to patients with stronger STAT3 responses. Here, we expanded the paradigm to evaluate multiple signaling parameters induced by a more physiological stimulus. We measured STAT3, STAT5 and ERK1/2 responses to G-CSF and to stromal cell-conditioned medium for 113 patients enrolled on COG trials AAML03P1 and AAML0531. Low inducible STAT3 activity was independently associated with inferior event-free survival in multivariate analyses. For inducible STAT5 activity, those with the lowest and highest responses had inferior event-free survival, compared to patients with intermediate STAT5 responses. Using existing RNA-sequencing data, we compared gene expression profiles for patients with low inducible STAT3/5 activation with those for patients with higher inducible STAT3/5 signaling. Genes encoding hematopoietic factors and mitochondrial respiratory chain subunits were overexpressed in the low STAT3/5 response groups, implicating inflammatory and metabolic pathways as potential mechanisms of chemotherapy resistance. We validated the prognostic relevance of individual genes from the low STAT3/5 response signature in a large independent cohort of pediatric AML patients. These findings provide novel insights into interactions between AML cells and the microenvironment that are associated with treatment failure and could be targeted for therapeutic interventions.

Tandem high-dose chemotherapy with autologous stem cell rescue for stage M high-risk neuroblastoma: Experience using melphalan/etoposide/carboplatin and busulfan/melphalan regimens

The efficacy of tandem HDCT against high-risk neuroblastoma has been reported; however, an optimal regimen remains to be established. In this paper, we report our experience using tandem HDCT comprising the MEC and BuMel regimens in patients with high-risk neuroblastoma. We retrospectively analyzed four patients with stage M high-risk neuroblastoma who received HDCT with MEC followed by BuMel combined with autologous stem cell rescue. Although none of their metastatic lesions had disappeared after induction chemotherapy, three patients showed a CR after tandem HDCT. Gastrointestinal mucosal injuries and renal dysfunction were observed as non-hematologic adverse events of grade 3 or higher. Gastrointestinal mucosal injuries were observed in all four patients following the first HDCT and in one patient following the second HDCT and were treated with parenteral nutrition and analgesics. One patient experienced renal dysfunction during the first HDCT, which was alleviated by sufficient hydration and diuretics and resulted in the reduction of melphalan dosage for the second HDCT. SOS was not observed in any patient. The HDCT regimens examined in this study were observed to be feasible and did not result in any life-threatening adverse events. Our findings indicate that tandem HDCT comprising MEC and BuMel is a potentially effective regimen for patients with high-risk neuroblastoma, including for those who respond poorly to induction chemotherapy, although additional studies in a larger population should be conducted to verify any long-term outcomes and toxicity.

Alternative donor peripheral blood stem cell transplantation for the treatment of high-risk refractory and/or relapsed childhood acute leukemia: a randomized trial

Background

The high-risk refractory and/or relapsed (R/R) childhood acute leukemia prognosis is poor, and allogeneic stem cell transplantation (allo-HSCT) is the most prudent treatment modality. However, there are limited matched sibling donors (MSDs), and alternative donors (ADs) are the main source for allo-HSCT. Thus, we evaluated the clinical efficacy of AD peripheral allo-HSCT for treating high-risk R/R childhood acute leukemia.

Methods

We assessed 111 children who underwent allo-HSCT at the Affiliated Cancer Hospital of Zhengzhou University between October 2006 and July 2019. The patients were divided in the MSD and AD groups, and their clinical characteristics, complications, and survival rates were compared.

Results

The cumulative incidences of Epstein–Barr virus and cytomegalovirus infections were significantly higher in the AD than in the MSD group (P < 0.001); however, the recurrence and mortality rates were significantly higher in the MSD than in the AD group (P < 0.05). Furthermore, the 5-year disease-free (DFS) (65.2% vs. 43.3%, P = 0.033) and overall survival (OS) rates (71.6% vs. 53.8%, P = 0.053) were significantly higher in the AD than in the MSD group. In the AD group, the grade II–IV acute graft-versus-host disease (aGVHD), donor-recipient ABO compatibility, conditioning regimen, and CMV infection affected the 5-year OS. The grade II–IV aGVHD also affected the 5-year DFS; however, only the donor-recipient ABO compatibility affected the 5-year DFS. The donor MSD (HR: 2.035, 95% confidence interval [CI] 1.057–3.920, P = 0.034) and the grade II–IV aGVHD (HR: 2.914, 95% CI 1.261–6.736, P = 0.012) affected the 5-year DFS of childhood acute leukemia after allo-HSCT, and the grade II–IV aGVHD (HR: 3.016, 95% CI 1.217–7.473, P = 0.017) affected the 5-year OS. Moreover, the donor source (HR: 2.836, 95% CI 1.179–6.823, P = 0.020) and grade II–IV aGVHD (HR: 3.731, 95% CI 1.332–10.454, P = 0.012) were independent predictors of the 5-year DFS, while the latter (HR: 3.524, 95% CI 1.310–10.988, P = 0.030) was an independent predictor of the 5-year OS.

Conclusions

AD-PBSCT was effective for high-risk R/R childhood leukemia and may have better clinical outcomes than MSD-PBSCT; thus, it can be used as first-line treatment for high-risk R/R childhood leukemia.