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Purpose: To explore the outcome and prognostic factors between inv(16) and t(8;21) disrupt core binding factor (CBF) in acute myeloid leukemia (AML). Methods: The clinical characteristic, probability of achieving complete remission (CR), overall survival (OS) and cumulative incidence of relapse (CIR) were compared between inv(16) and (8;21). Results: The CR rate was 95.2%, 10-year OS was 84.4% and CIR was 29.4%. Subgroup analysis showed that patients with t(8;21) had significant lower 10-year OS and CIR than patients with inv(16). Unexpectedly, there was a trend for pediatric AML receiving five courses cytarabine to have a lower CIR than four courses cytarabine (19.8% vs 29.3%, P = 0.06). Among the cohort of no-gemtuzumab ozogamicin(GO) treatment, inv (16) patients showed a similar 10-year OS (78.9% vs 83.5%; P = 0.69) and an inferior outcome on 10-year CIR (58.6% vs 28.9%, P = 0.01) than those patients with t(8;21). In contrast, inv (16) and t(8;21) patients receiving GO treatment had comparable OS (OS: 90.5% vs. 86.5%, P = 0.66) as well as CIR (40.4% vs. 21.4%, P = 0.13). Conclusion: Our data demonstrated that more cumulative cytarabine exposure could improve the outcome of childhood patients with t(8;21), while GO treatment was beneficial to the pediatric patients with inv(16). [ABSTRACT FROM AUTHOR]

Background: Alterations of 11q23/KMT2A are the most prevalent cytogenetic abnormalities in acute myeloid leukemia (AML) and the prognostic significance of 11q23/KMT2A‐rearranged AML based on various translocation partners varies among different studies. However, few studies evaluated the molecular characteristics of 11q23/KMT2A‐rearranged pediatric AML. We aim to analyze the mutational landscape of 11q23/KMT2A‐rearranged AML and assess their prognostic value in outcomes. Methods: The mutational landscape and clinical prognosis of 105 children with 11q23/KMT2A‐rearranged AML in comparison with 277 children with non‐11q23/KMT2A‐rearranged AML were analyzed using publicly accessible next‐generation sequencing data from Therapeutically Applicable Research to Generate Effective Treatments (TARGET) dataset. Results: Pediatric AML patients with 11q23/KMT2A‐rearrangements harbored a low number of mutations (Median, 1 mutation/patient, range, 1‐22), 58% of which involved in RAS pathway mutations (KRAS, NRAS, and PTPN11) and 10.5% of which comprised of SETD2 mutations. Compared with non‐11q23/KMT2A‐rearranged AML, the incidence of KRAS (32.4% vs. 10.1%, P〈0.001) and SETD2 (10.5% vs. 1.4%, P=0.001) gene mutations in 11q23/KMT2A‐rearranged AML was significantly higher. Both KRAS and SETD2 mutations occurred more often in t(10;11)(p12;q23). KRAS mutations were correlated with worse 5‐year event‐free survival [EFS] (Plog‐rank = 0.001) and 5‐year overall survival [OS] (Plog‐rank = 0.009) and the presence of SETD2 mutations increases the 5‐year relapse rate (PGray = 0.004). Multivariate analyses confirmed KRAS mutations in 11q23/KMT2A‐rearranged AML as an independent predictor for poor EFS (hazard ratio [HR] = 2.10, P=0.05) and OS (HR = 2.39, P=0.054). Conclusion: Our findings show that pediatric patients with 11q23/KMT2A rearrangements have characteristic mutation patterns and varying clinical outcomes depending on different translocation partners, which could be utilized to develop more accurate risk stratification and tailored therapies. [ABSTRACT FROM AUTHOR]

Activating FLT3 mutations are the most common mutations in acute myeloid leukemia (AML), but the optimal threshold of FLT3/ITD allelic ratio (AR) among pediatric AML patients remains controversial. Here, we present the outcome and prognostic significance of FLT3/ITD AR analysis among pediatric patients with AML from the TARGET dataset. Applying fitting curve models and threshold effect analysis using the restrictive cubic spline function following Cox proportional hazards models identifies the cut-off value of 0.5 on FLT3/ITD AR. Moreover, we observe that high FLT3/ITD AR patients have an inferior outcome when compared to low AR patients. Our study also demonstrates that stem cell transplantation may improve the outcome in pediatric AML patients with high FLT3/ITD AR and may be further improved when combined with additional therapies such as Gemtuzumab Ozogamicin. These findings underline the importance of individualized treatment of pediatric AML. Activating FLT3 mutations are the most common mutations in AML. Here, the authors explore the relationship between the FLT3/ITD allelic ratio and prognosis in pediatric AML patients and identify an optimal threshold to stratify patients. [ABSTRACT FROM AUTHOR]

To evaluate the outcome and prognostic significance of CEBPA mutations among pediatric acute myeloid leukemia (AML) from TARGET dataset. A total of 1803 pediatric patients who were diagnosed with AML were classified into two groups based on the CEBPA status by using a retrospective cohort study method from September 1996 to December 2016. The incidence of CEBPA mutations was 18%. CEBPA mutations were significantly associated with elder age (p < 0.001), higher WBC (p = 0.004), higher proportion of peripheral blood blast (p < 0.001), normal karyotype (p < 0.001), low risk (p < 0.001) and higher complete remission induction rates (p < 0.05). Overall, CEBPA mutations patients had a significantly better 5‐year EFS (p < 0.001) and OS (p < 0.001) compared to CEBPA wild‐type patients, and this favorable impact was maintained even in the presence of FLT3/ITD mutations. Stem cell transplantation had no significant impact on the survival of patients with coexistence of CEBPA and FLT3/ITD mutations. Multivariate analysis demonstrated that mutated CEBPA were an independent favorable indicators of better outcome in terms of EFS (p = 0.007) and OS (p = 0.039). Our study demonstrate mutated CEBPA have an excellent outcome in pediatric AML patients. Furthermore, pediatric AML patients with coexistence of CEBPA and FLT3/ITD mutation appear to have favorable prognoses and might not required stem cell transplantation. [ABSTRACT FROM AUTHOR]

Our aim is to evaluate initial efficacy, safety, and durable response of eltrombopag in the treatment of Chinese children with chronic immune thrombocytopenia (cITP). This was a retrospective, single-center cohort study including 30 pediatric patients with cITP administered eltrombopag between 1 July 2017 and 1 January 2019. Patients with at least 12 weeks of eltrombopag treatment and available follow-up data were included. Initial response rate, durable response rate, bleeding events, and adverse events were assessed during the follow-up period. The median duration of eltrombopag administration was 6 months (range 3–8 months). The initial response rate was 73.3%. Patients with megakaryocyte count ≥100/slide or Treg <4.5% were more likely to achieve initial response. The median follow-up period was 10 months (range 6–20 months). A total of 53.2% of pediatric patients had a durable response of up to 20 months. Patients with megakaryocyte count ≥100/slide and Treg<4.5% had more than 60% durable response rates compared with individuals with megakaryocyte count<100/slide and Treg≥4.5%, respectively. No serious bleeding events or serious adverse events occurred during the study period. Eltrombopag not only shows excellent initial response but also has continued efficacy and safety. Patients with megakaryocyte count ≥100/slide and Treg<4.5% achieve increased initial response and more frequent durable response. [ABSTRACT FROM AUTHOR]

Background: This study was aimed to evaluate the value of DNA index(DI) among pediatric acute lymphoblastic leukemia (ALL) treated on Children's Oncology Group (COG) protocols between 2000 and 2015.Methods: Retrospective study were analysis among pediatric ALL patients from the TARGET dataset.Result: Totally, 1668 eligible pediatric patients were enrolled in this study. Of them, 993 are male and 675 are female with a median age of 7.6 years old. The median follow-up for those patients was 7.7 years (range 0.1-15.7 years). The probability of 15-year EFS and OS were reported to be 67.5 ± 3.1% and 78.3 ± 2.5%, respectively. BCR/ABL1 fusion gene affected the early treatment response and the survival of childhood ALL. Moreover, those patients with ETV6/RUNX1 fusion gene were also significantly associated with better EFS (HR = 0.6, 95% CI 0.4-0.8, P = 0.003) and OS (HR = 0.3, 95%CI 0.2-0.5, P < 0.001) compared to patients with no ETV6/RUNX1. On the contrary, BM NR on Day+ 29 showed a significant decrease in EFS (HR = 3.1, 95%CI 2.1-4.5, P < 0.001) and OS (HR = 1.7, 95%CI 1.1-2.8, P = 0.026). Multivariate analysis showed that DI was significantly associated with better EFS and OS. The threshold effect of DI on poor outcome was significant after adjusting for potential confounders. The adjusted regression coefficient (Log RR) was 0.7 (95%CI 0.1-3.2, P = 0.597) for DI < 1.1 while 8.8 (95%CI 1.4-56.0, P = 0.021) for DI ≥ 1.2 and 0.0 (95%CI 0.0-0.8, P = 0.041) for 1.1 ≤ DI < 1.2. Generalized additive models revealed that the lowest rates of the adverse outcomes estimated to occur among DI between 1.1 and 1.2.Conclusion: For those childhood ALL treated on COG protocols between 2000 and 2015, ETV6/RUNX1 and BM NR were closely related to the prognosis. Moreover, the DI between 1.1 and 1.2 can serve as a significant cut-point discriminating the risk group, which indicated a favourable prognostic factor. [ABSTRACT FROM AUTHOR]

The prognostic impact of Wilms tumor 1 (WT1) mutations remains controversial for patients with acute myeloid leukemia (AML). Here, we aimed to determine the clinical implication of WT1 mutations in a large cohort of pediatric AML. The clinical data of 870 pediatric patients with AML were downloaded from the therapeutically applicable research to generate effective treatment (TARGET) dataset. We analyzed the prevalence, clinical profile, and prognosis of AML patients with WT1 mutations in this cohort. Our results showed that 6.7% of total patients harbored WT1 mutations. These WT1 mutations were closely associated with normal cytogenetics (P <0.001), FMS-like tyrosine kinase 3/internal tandem duplication (FLT3 /ITD) mutations (P <0.001), and low complete remission induction rates (P <0.01). Compared to the patients without WT1 mutations, patients with WT1 mutations had a worse 5-year event-free survival (21.7 ± 5.5% vs 48.9 ± 1.8%, P <0.001) and a worse overall survival (41.4 ± 6.6% vs 64.3 ± 1.7%, P <0.001). Moreover, patients with both WT1 and FLT3 /ITD mutations had a dismal prognosis. Compared to chemotherapy alone, hematopoietic stem cell transplantation tended to improve the prognoses of WT1 -mutated patients. Multivariate analysis demonstrated that WT1 mutations conferred an independent adverse impact on event-free survival (hazard ratio 1.910, P = 0.001) and overall survival (hazard ratio 1.709, P = 0.020). In conclusion, our findings have demonstrated that WT1 mutations are independent poor prognostic factors in pediatric AML. [ABSTRACT FROM AUTHOR]

Aims: The purpose of this study is to examine the safety and efficacy of eltrombopag as first‐line treatment for thrombocytopenia among paediatric patients after haematopoietic stem cell transplantation (HSCT). Methods: Forty‐three childhood patients with thrombocytopenia after HSCT who received eltrombopag were retrospectively analysed. Result: Eltrombopag was began at the median of 27 days after HSCT and lasted for 24 days. Thirty‐five children responded to eltrombopag therapy, and the cumulative platelet recovery rate was 88.9%. The cumulative incidence of platelet recovery was lower (83.9 vs 100%; P =.035) in patients with decreased numbers of megakaryocytes before starting eltrombopag than in those with normal. Factors associated with a significantly elevated response to eltrobopag from univariate analysis were donor type. Results from the multiple regression analysis found that weight (hazard ratio [HR] = 0.7, 95% confidence interval [CI] 0.5–0.9, P =.022), platelet engraftment time (HR = 1.0, 95%CI 1.0–1.0, P =.012) and bone marrow megakaryocytes (HR = 8.0, 95%CI 1.5–43.3, P =.016) before starting eltrombopag were the independent risk factors. Based on Youden's index algorithm in the receiver‐operating characteristic curve, the optimal cut‐off value of the maintenance dose of eltrombopag in predicting nonresponders was 4 mg/kg. The area under the receiver‐operating characteristic curve was 0.923 with sensitivity of 97.8%, specificity of 87.9%, positive predictive value of 72.3%, and negative predictive value of 92%. None of the paediatric patients stopped using eltrombopag due to side effect or intolerability. Conclusion: Eltrombopag is effective and safe in paediatric patients with thrombocytopenia after HSCT. The number of megakaryocytes in bone marrow before eltrombopag treatment may serve as a predictor of the response to eltrombopag. We recommend that the maintenance dose of eltrombopag should not exceed 4 mg/kg/d. [ABSTRACT FROM AUTHOR]

Background: Early‐onset mixed chimerism (MC) with a high proportion of residual host cells is considered a signal of graft rejection in patients undergoing allogenic hematopoietic stem cell transplantation for transfusion‐dependent thalassemia. In order to prevent graft rejection and minimize the risk of treatment‐related graft‐versus‐host disease (GVHD), we established a hierarchical management system based on chimerism analysis. Method: This retrospective study provides a comprehensive review of the characteristics, interventions, and outcomes of the 38 patients who developed MC after transplantation among the 144 pediatric thalassemia patients between July 2007 and January 2019 at our center. Results: A sibling donor, a blood type‐matched donor, conditioning regimens without fludarabine, and transplants containing <10 × 108 total nucleated cells/kg were identified to be associated with the development of MC. Among the 38 patients developing MC, only four patients rejected the grafts. The response rate to donor lymphocyte infusion (DLI, only for patients receiving sibling donor transplantation) and cytokine immunomodulation without DLI was 70.6% and 42.9%, respectively. Patients that developed GVHD after DLI or cytokine therapy had a more significant increase in donor cell chimerism (16%, range 0%‐35%) than those without (8.5%, range −21% to 40%, P =.049). However, even when treatment‐related GVHD was included, patients with MC had a lower cumulative incidence of total acute GVHD than patients with complete donor chimerism (29.2% vs 48.0%, P =.030). Conclusions: Interventions based on chimerism analysis were effective in preventing graft rejection and did not increase treatment‐related GVHD in thalassemia patients with MC. [ABSTRACT FROM AUTHOR]

Studies on the clinical significance of Nucleophosmin (NPM1) mutations in pediatric AML in a large cohort are lacking. Moreover, the prognosis of patients with co-occurring NPM1 and FLT3/ITD mutations is controversial. Here, we analyzed the impact of NPM1 mutations on prognoses of 869 pediatric AML patients from the TAGET dataset. The frequency of NPM1 mutations was 7.6%. NPM1 mutations were significantly associated with older age (P < 0.001), normal cytogenetics (P < 0.001), FLT3/ITD mutations (P < 0.001), and high complete remission induction rates (P < 0.05). Overall, NPM1-mutated patients had a significantly better 5-year EFS (P = 0.001) and OS (P = 0.016) compared to NPM1 wild-type patients, and this favorable impact was maintained even in the presence of FLT3/ITD mutations. Stem cell transplantation had no significant effect on the survival of patients with both NPM1 and FLT3/ITD mutations. Multivariate analysis revealed that NPM1 mutations were independent predictors of better outcome in terms of EFS (P = 0.004) and OS (P = 0.012). Our findings showed that NPM1 mutations confer an independent favorable prognostic impact in pediatric AML despite of FLT3/ITD mutations. In addition, pediatric AML patients with both NPM1 and FLT3/ITD mutations appear to have favorable prognoses and may not need hematopoietic stem cell transplantations. [ABSTRACT FROM AUTHOR]