CD19-specific CAR-T Cell Treatment of 115 Children and Young Adults with Acute B Lymphoblastic Leukemia: Long-Term Follow-up.

Purpose: Chemotherapy has been the primary treatment for patients with B-cell acute lymphoblastic leukemia (B-ALL). However, there are still patients who are not sensitive to chemotherapy, including those with refractory/relapse (R/R) disease and those experiencing minimal residual disease (MRD) re-emergence. Chimeric antigen receptor-T lymphocytes (CAR-T) therapy may provide a new treatment option for these patients. Materials and Methods: Oure institution conducted a single-arm prospective clinical trial (ChiCTR-OPN-17013507) using CAR-T-19 to treat R/R B-ALL and MRD re-emergent patients. One hundred and fifteen patients, aged 1-25 years (median age 8 years), were enrolled, including 67 R/R and 48 MRD re-emergent CD19-positive B-ALL patients. Results: All patients achieved morphologic CR, and within one month after infusion, 111 out of 115 (96.5%) patients achieved MRD-negative CR. With a median follow-up time of 48.4 months, the estimated 4-year leukemia-free survival (LFS) rate and overall survival (OS) rate were (68.7±4.5) % and (70.7±4.3) %, respectively. There were no significant differences in long-term efficacy observed among patients with different disease statuses before infusion (4-year OS: MRD re-emergence vs. R/R B-ALL, 70.6±6.6% vs. 66.5±6.1%, p=0.755; 4-year LFS: MRD re-emergence vs. R/R B-ALL, 67.3±7.0% vs. 63.8±6.2%, p=0.704). R/R B-ALL patients bridging to transplantation after CAR-T treatment had a superior OS and LFS compared to those who did not. However, for MRD re-emergent patients, there was no significant difference in OS and LFS, regardless of whether they underwent HSCT or not. Conclusion: CD19 CAR-T therapy effectively and safely cures both R/R B-ALL and MRD re-emergent patients.

[Clinical Significance of Minimal Residual Disease in Pediatric Patients with TCF3/PBX1+ B-cell Acute Lymphoblastic Leukemia].

OBJECTIVE: To explore the consistency of flow cytometry (FCM) method and polymerase chain reaction (PCR) technique in the detection of minimal residual disease (MRD) at different treatment stages in pediatric patients with TCF3/PBX1+ B-cell acute lymphoblastic leukemia (B-ALL) and the correlations between the detection results and prognosis. METHODS: The clinical data of 64 newly diagnosed pediatric patients with TCF3/PBX1+ B-ALL admitted to the Department of Pediatrics of Peking University People's Hospital from January 2005 to December 2017 were retrospectively analyzed. FCM and PCR methods were used to monitor the MRD level in bone marrow samples from 64 children during the same period of treatment on d33 and d90 respectively, and the detection results were analyzed. RESULTS: There were 37 males and 27 females in the 64 patients, with a median age of 8 years(range 0.8 to 16 years). The complete remission (CR) rate after the first cycle of induction chemotherapy was 98.4% (62/63), with overall CR rate of 100%. 12 patients experienced recurrence, with a median recurrence time of 16.9 (5.3-46.3) months. The median follow-up time of the 64 patients was 77.2 (1.0-184.8) months , and the 5-year overall survival (OS) rate and event-free survival (EFS) rate were 82.8%±4.7% and 75.0%±5.4%, respectively. On d90, the concordance rate of the MRD results from the two methods was 98.4%, and the related kappa value was 0.792 (P < 0.001), which were significantly higher than those on d33. After induction chemotherapy (d33), the 5-year EFS rate of MRD-FCM- group (79.3%±5.3%) was significantly better than that of MRD-FCM+ group (40.0%±21.9%) (P =0.028), there were no significant differences in the 5-year OS rate and EFS rate between MRD-PCR+ group and MRD-PCR- group, and the 5-year EFS rate of MRD-FCM-/PCR- group (85.4%±5.5%) was significantly better than that of MRD-FCM+/PCR+ group (40.0 %±21.9%) (P =0.026). CONCLUSION: In children with TCF3/PBX1+ B-ALL, the MRD results detected by FCM and PCR methods show good consistency, especially in consolidation therapy period (d90). The MRD level at the end of induction therapy (d33) is an important factor affecting the long-term prognosis, especially the MRD results detected by FCM method, which is significantly associated with prognosis.

Prognostic Significance of CD20 Expression in Children with Philadelphia Chromosome-Negative B-Cell Precursor Acute Lymphoblastic Leukemia.

INTRODUCTION: The prognostic significance of CD20 in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) remains unclear. Therefore, in this study, we evaluated the prognostic value of CD20 expression in leukemia blasts in pediatric BCP-ALL at our institute. METHODS: Between 2005 and 2017, 796 children with newly diagnosed Philadelphia-negative BCP-ALL were enrolled consecutively; clinical characteristics and treatment outcomes were analyzed and compared between CD20-positive and CD20-negative groups. RESULTS: CD20 positivity was observed in 22.7% of enrolled patients. The analysis of overall and event-free survival showed that white blood cell count ≥50 × 109/L, no ETV6-RUNX1, day 33 minimal residual disease (MRD) ≥0.1%, and week 12 MRD ≥0.01% were independent risk factors. Meanwhile, in the CD20-positive group, week 12 MRD ≥0.01% was the only factor associated with long-term survival. Moreover, subgroup analysis revealed that in patients with extramedullary involvement (p = 0.047), MRD ≥0.1% on day 33 (p = 0.032), or MRD ≥0.01% at week 12 (p = 0.004), CD20 expression led to a poorer outcome compared to those without CD20 expression. CONCLUSIONS: Pediatric BCP-ALL with CD20 expression had unique clinicopathological characteristics, and MRD remained the major prognostic factor. CD20 expression had no prognostic value in pediatric BCP-ALL.

Clinical Analysis of Pediatric T-Cell Acute Lymphoblastic Leukemia Using the MRD-Oriented Strategy System.

Pediatric T-cell acute lymphoblastic leukemia (T-ALL) has historically been associated with a poor prognosis. However, prognostic indicators and methods of treatment used for T-ALL remain controversial. A total of 136 children newly diagnosed with T-ALL between 2005 and 2018 were consecutively enrolled in this study. We assessed the effect of different prognostic factors, such as clinical characteristics, minimal residual disease (MRD), and the role of transplantation in postremission treatment, as the outcomes. Compared with B-ALL patients, patients with T-ALL are generally older, more likely to be male and have a higher white blood cell count. The complete remission (CR) rate was 95.6%, while the 5-year overall survival (OS), event-free survival (EFS), and cumulative incidence of relapse (CIR) were 74.3 ± 3.7%, 71.3 ± 3.9%, and 24.4 ± 3.8%, respectively. In the multivariate analysis, day 33 MRD ≥0.1% and hyperleukocytosis were associated with a significantly worse prognosis in the whole group. Transplantation resulted in a significant survival advantage, compared with chemotherapy, for high-risk (HR) patients (5-year CIR: 15.6 ± 10.2% vs. 55.6 ± 11.7%, P = .029). The prognosis of children with T-ALL was poor, and the MRD on day 33 was found to be an important predictive factor of clinical outcome at our center.

Prognostic significance of Wilms' tumor gene 1 expression in children with B-cell precursor acute lymphoblastic leukemia.

Introduction: The prognostic role of Wilms' tumor 1 (WT1) gene expression at diagnosis in children with B cell precursor acute lymphoblastic leukemia (BCP-ALL) is still controversial. Methods: We detected the WT1 transcript levels of 533 de novo pediatric BCP-ALL patients using TaqMan-based real-time quantitative PCR and analyzed their clinical features. Results: The WT1 transcript levels differed among the distinct molecularly defined groups, with the highest levels in the KMT2A rearrangements (KMT2A-r) group. According to the results of the X-tile software, all patients were divided into two groups: WT1/ABL ≥ 0.24% (group A) and <0.24% (group B). The proportions of patients whose age was ≥10 years old, with immunophenotype of Pro-B, belonging in high-risk group, or with minimal residual disease (MRD) ≥ 0.01% at week 12 were significantly higher in group A than in group B. In the B-other group, WT1 overexpression was an independent risk factor of overall survival (OS) rate (P = 0.042), and higher MRD ≥ 0.01% at week 12 was associated with lower OS rate (P<0.001) and event-free survival rate (P<0.001). Moreover, the subgroup analysis revealed that, in patients with initial WBC<50 × 109/L or MRD<0.1% at day 33 or MRD<0.01% at week 12 or in the standard-risk group, WT1 overexpression led to a poorer outcome in comparison with those with WT1 downexpression (P<0.05). Discussion: Therefore, pediatric BCP-ALL with WT1 overexpression had unique clinico-pathological characteristics and poor treatment response. In B-other patients, WT1 overexpression at diagnosis predicted an inferior prognosis. The WT1 gene may serve as a biomarker for monitoring residual disease in the B-other population, especially in children in the standard-risk group.

[Clinical features and prognosis of childhood B-lineage acute lymphoblastic leukemia expressing the PRAME gene]. / 表达PRAMEåŸºå› çš„å„¿ç«¥æ€¥æ€§Bæ·‹å·´ç»†èƒžç™½è¡€ç— çš„ä¸´åºŠç‰¹ç‚¹åŠé¢„åŽåˆ†æž.

OBJECTIVES: To study the clinical and prognostic significance of the preferentially expressed antigen of melanoma (PRAME) gene in the absence of specific fusion gene expression in children with B-lineage acute lymphoblastic leukemia (B-ALL). METHODS: A total of 167 children newly diagnosed with B-ALL were enrolled, among whom 70 were positive for the PRAME gene and 97 were negative. None of the children were positive for MLL-r, BCR/ABL, E2A/PBX1, or ETV6/RUNX1. The PRAME positive and negative groups were analyzed in terms of clinical features, prognosis, and related prognostic factors. RESULTS: Compared with the PRAME negative group, the PRAME positive group had a significantly higher proportion of children with the liver extending >6 cm below the costal margin (P<0.05). There was a significant reduction in the PRAME copy number after induction chemotherapy (P<0.05). In the minimal residual disease (MRD) positive group after induction chemotherapy, the PRAME copy number was not correlated with the MRD level (P>0.05). In the MRD negative group, there was also no correlation between them (P>0.05). The PRAME positive group had a significantly higher 4-year event-free survival rate than the PRAME negative group (87.5%±4.6% vs 73.5%±4.6%, P<0.05), while there was no significant difference between the two groups in the 4-year overall survival rate (88.0%±4.4% vs 85.3%±3.8%, P>0.05). The Cox proportional-hazards regression model analysis showed that positive PRAME expression was a protective factor for event-free survival rate in children with B-ALL (P<0.05). CONCLUSIONS: Although the PRAME gene cannot be monitored as MRD, overexpression of PRAME suggests a good prognosis in B-ALL.

Low EVI1 expression at diagnosis predicted poor outcomes in pediatric Ph-negative B cell precursor acute lymphoblastic leukemia patients.

Abnormally high ecotropic viral integration site 1 (EVI1) expression has been recognized as a poor prognostic factor in acute myeloid leukemia patients. However, its prognostic impact in B cell precursor acute lymphoblastic leukemia (BCP-ALL) remains unknown. A total of 176 pediatric Ph-negative BCP-ALL patients who received at least 1 course of chemotherapy and received chemotherapy only during follow-up were retrospectively tested for EVI1 transcript levels by real-time quantitative PCR at diagnosis, and survival analysis was performed. Clinical and EVI1 expression data of 129 pediatric BCP-ALL patients were downloaded from therapeutically applicable research to generate effective treatments (TARGET) database for validation. In our cohort, the median EVI1 transcript level was 0.33% (range, 0.0068-136.2%), and 0.10% was determined to be the optimal cutoff value for patient grouping by receiver operating characteristic curve analysis. Low EVI1 expression (<0.10%) was significantly related to lower 5-year relapse-free survival (RFS) and overall survival (OS) rates (P = 0.017 and 0.018, respectively). Multivariate analysis showed that EVI1 expression <0.10% was an independent adverse prognostic factor for RFS and OS. TARGET data showed that low EVI1 expression tended to be related to a lower 5-year OS rate (P = 0.066). In conclusion, low EVI1 expression at diagnosis could predict poor outcomes in pediatric Ph-negative BCP-ALL patients receiving chemotherapy.Supplemental data for this article is available online at https://doi.org/10.1080/08880018.2021.1939818 .

Outcomes of Adolescent Patients with Acute Lymphoblastic Leukemia: Long-term Follow-up of 335 Patients.

BACKGROUND: Adolescents (aged 10-17 years) with acute lymphoblastic leukemia (ALL) represent a unique patient population, with a disproportionate survival disadvantage compared with younger patients. We aimed to determine the outcomes and prognostic factors of adolescent patients treated at our institution. PATIENTS AND METHODS: Between 2005 and 2017, 335 adolescents with ALL were enrolled; clinical characteristics and treatment outcomes were analyzed and compared between adolescents and younger children (1-9 years old, n = 704). RESULTS: Adolescents were more likely to have high-risk factors such as hyperleukocytosis, a T-cell immunophenotype, BCR-ABL1, and/or poor early treatment responses. Compared with younger children, adolescents had significantly worse 5-year event-free survival (EFS) (73.0% ± 2.5% vs. 82.6% ± 1.5%; P < .001) and overall survival (OS) (77.1% ± 2.3% vs. 87.7% ± 1.3%; P < .001). Furthermore, younger adolescents (10-14 years) tended to have better outcomes compared with those older than 15 years (5-year OS: 79.3% ± 2.5% vs. 68.4% ± 5.7%; P = .042), mainly because of the lower frequencies of toxicities. On multivariate analysis, white blood count ≥ 50 × 109/L and extramedullary involvement at diagnosis were the most powerful prognostic factors for both OS and EFS. CONCLUSION: The outcomes among adolescent patients were not as good as that of younger children. Further studies are required to define optimal treatment strategies for adolescents, particularly those aged 15 to 17 years.

Predictive impact of residual disease detected using multiparametric flow cytometry on risk stratification of paediatric acute myeloid leukaemia with normal karyotype.

INTRODUCTION: Residual disease (RD) detected using multiparametric flow cytometry (MFC) is an independent predictive variable of relapse in acute myeloid leukaemia (AML). However, RD thresholds and optimal assessment time points remain to be validated. MATERIAL AND METHODS: We investigated the significance of RD after induction therapy in paediatric AML with normal karyotype between June 2008 and June 2018. Bone marrow samples from 73 patients were collected at the end of the first (BMA-1) and second (BMA-2) induction courses to monitor RD using MFC. RESULTS: Presence of RD after BMA-1 and/or BMA-2 correlated with poor relapse-free (RFS) and overall survival at 0.1% RD cutoff level. Receiver operating characteristic curve showed that RD cutoff levels of 1.3% and 0.5% after BMA-1 and BMA-2, respectively, predicted events with the highest sensitivity and specificity. In multivariable analysis, RD after BMA-2 was the strongest independent risk predictor for poor RFS (hazard ratio 2.934; 95% confidence interval: 1.106-7.782; P = .031). CONCLUSIONS: Our study therefore suggests that an RD level ≥0.5% after BMA-2 has a significant predictive impact on the prognosis of AML patients having normal karyotype and thus guide the stratification of treatment strategies.

Unmanipulated haploidentical hematopoietic stem cell transplantation is an excellent option for children and young adult relapsed/refractory Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia after CAR-T-cell therapy.

Although chimeric antigen receptor T-cell (CAR-T) therapy produces a high complete remission rate among patients with relapsed/refractory B-cell acute lymphoblastic leukemia, relapse remains an urgent issue. It is uncertain whether consolidative haploidentical-allogeneic hematopoietic stem cell transplantation (haplo-HSCT) is suitable for achieving sustainable remission. Therefore, we aimed to assess the efficacy and safety of bridging CAR-T therapy to haplo-HSCT. Fifty-two patients with relapsed/refractory Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia who underwent haplo-HSCT after CAR-T therapy were analyzed. The median time from CAR-T therapy to haplo-HSCT was 61 days. After a median follow-up of 24.6 months, the 1-year probabilities of event-free survival, overall survival, and cumulative incidence of relapse were 80.1% (95% confidence interval (CI), 69.0-90.9), 92.3% (95% CI, 85.0-99.5), and 14.1% (95% CI, 10.7-17.4), respectively, while the corresponding 2-year probabilities were 76.0% (95% CI, 64.2-87.7), 84.3% (95% CI, 74.3-94.3), and 19.7% (95% CI, 15.3-24.0), respectively. No increased risk of 2-year cumulative incidence of graft-versus-host disease, treatment-related mortality, or infection was observed. A pre-HSCT measurable residual disease-positive status was an independent factor associated with poor overall survival (hazard radio: 4.201, 95% CI: 1.034-17.063; P = 0.045). Haplo-HSCT may be a safe and effective treatment strategy to improve event-free survival and overall survival after CAR-T therapy.

[The Impact of Induction Treatment Response on the Prognosis of Pediatric Core Binding Factor-Acute Myeloid Leukemia Patients].

OBJECTIVE: To explore the impact of induction treatment response on the prognosis of pediatric core binding factor-acute myeloid leukemia (CBF-AML). METHODS: The result of induce reaction and survival data of 157 pediatric CBF-AML patients in our hospital from September 2008 to December 2018 were retrospectively analyzed．The survival rate of the patients with different degrees of morphological remission after induction chemotherapy was comparative analyzed. RESULTS: Among the 157 children with CBF-AML, 113 (72.4%) patients achieved morphologic leukemia-free state (MLFS) after the first course of induction chemotherapy, 153 (98.1%) patients achieved MLFS after the second course of induction chemotherapy. The 5-year event-free survival (EFS) rate and 5-year overall survival (OS) rate of patients with non-remission (NR) status after the first course of induction of chemotherapy was significantly lower than the patients achieved MLFS and the patients achieved partial remission (PR). The 5-year EFS rate and 5-year OS rate of the patients with PR status after the second course of induction chemotherapy were lower than the patients achieved MLFS, but the difference was not statistically significant. Multivariable analyze showed that NR after the first course of induction chemotherapy and myeloid sarcoma were the independent risk factors affecting EFS of the patients. There were six patients with NR status after the first course of induction chemotherapy, in which all of them harbored t(8;21), three of them with sex chromosome deletion, two of them with myeloid sarcoma. CONCLUSION: NR status after the first course of induction chemotherapy was the independent risk factor affecting EFS and OS of CBF-AML patients, it can be taken as an indicator for higher risk stratification. PR status after the first course of induction chemotherapy may not be used as a diagnostic criterion for primary drug resistance.

The role of minimal residual disease in specific subtypes of pediatric acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is a heterogeneous disease whose prognostic factors include minimal residual disease (MRD) and cytogenetic abnormalities. To explore the significance of MRD in ALL subtypes, we analyzed the outcomes of 1126 children treated with risk-stratified therapy based on sequential MRD monitoring. MRD distributions and treatment outcomes differed between distinct leukemia subtypes. Patients with ETV6-RUNX1 or hyperdiploidy had the best prognosis (5-year OS: 97 ± 1.5% and 89.2 ± 2.7%). However, hyperdiploidy patients with MRD ≥ 10% on day 15 had a higher risk of relapse (36.4%) than those with ETV6-RUNX1. TCF3-PBX1 patients had the fastest disease clearance (negative MRD rate on day 33: 92.1%), but the overall prognosis was intermediate (5-year OS: 82.5%). Patients with high-risk characteristics and ALL-T had inferior outcomes: even with undetectable MRD on day 33, cumulative incidence of relapse was 19.9% and 23.4%, respectively. Moreover, those with poor early-treatment response and detectable week-12 MRD had a worse prognosis. After adjusting for other risk factors, re-emergent MRD was the most significant adverse prognostic indicator overall. Sequential MRD measurement is important for MRD-guided therapy, and integration of MRD values at different timepoints based on leukemia subtype could allow for more refined risk stratification.

Chimeric Antigens Receptor T Cell Therapy Improve the Prognosis of Pediatric Acute Lymphoblastic Leukemia With Persistent/Recurrent Minimal Residual Disease in First Complete Remission.

Background: The presence of minimal residual disease (MRD) is an independent risk factor for poor prognosis in patients with acute lymphoblastic leukemia (ALL). Moreover, the role of chimeric antigen receptor T-cell (CAR-T) therapy in patients with MRD is currently unclear. Methods: We conducted a prospective study to investigate the role of CAR-T therapy in patients with persistent/recurrent MRD-positive ALL in first remission. Results: A total of 77 patients who had persistent/recurrent MRD were included. Of these patients, 43 were enrolled in the CAR-T group, 20 received chemotherapy as a bridge to allogeneic hematopoietic cell transplantation (allo-HSCT), and 14 patients received intensified chemotherapy. MRD negativity was achieved in 90.7% of the patients after CAR-T infusion. Patients who received CAR-T therapy had a higher 3-year leukemia-free survival (LFS) than patients who did not (77.8% vs. 51.1%, P = 0.033). Furthermore, patients in the CAR-T group had a higher 3-year LFS than those in the chemotherapy bridge-to-allo-HSCT group [77.8% (95% CI, 64.8-90.7%) vs. 68.7% (95% CI, 47.7-89.6%), P = 0.575] and had a significantly higher 3-year LFS than those in the intensified chemotherapy group [77.8% (95% CI, 64.8-90.7%) vs. 28.6% (95% CI, 4.9-52.3%), P = 0.001]. Among the patients who received CAR-T therapy, eight were not bridged to allo-HSCT, and six (75%) remained in remission with a median follow-up of 23.0 months after CAR-T infusion. Conclusions: Our findings show that CAR-T therapy can effectively eliminate MRD and improve survival in patients with a suboptimal MRD response.

Efficacy of Haploidentical Hematopoietic Stem Cell Transplantation Compared With Chemotherapy as Postremission Treatment of Children With Intermediate-risk Acute Myeloid Leukemia in First Complete Remission.

BACKGROUND: The role of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) for children with intermediate-risk acute myeloid leukemia (IR-AML) in first complete remission has been controversial. The present study compared the effect of chemotherapy with unmanipulated haplo-HSCT as treatment of patients with IR-AML in first complete remission (CR1). PATIENTS AND METHODS: We retrospectively analyzed the outcomes of 80 children with IR-AML and compared the effects of chemotherapy (n = 47) with those of haplo-HSCT (n = 33) as treatment in CR1. RESULTS: The 3-year overall survival, event-free survival (EFS), and cumulative incidence of relapse (CIR) was 85.4% ± 4.1%, 73.2% ± 5.0%, and 25.4% ± 4.5%, respectively. Compared with the chemotherapy group, the patients in the haplo-HSCT group had a lower CIR (P = .059) and better EFS (P = .108), but roughly equivalent overall survival (P = .841). Multivariate analysis revealed chemotherapy and minimal residual disease (MRD) of ≥ 10-3 after induction therapy as independent risk factors affecting CIR and EFS. EFS (P = .045) and CIR (P = .045) differed significantly between the 2 treatment groups in patients with MRD of ≥ 10-3 after induction therapy. CONCLUSION: Haplo-HSCT might be a feasible option for children with IR-AML in CR1, especially for patients with MRD of ≥ 10-3 after induction therapy.

Retrospective analysis of data from 73 patients with childhood acute promyelocytic leukaemia receiving modified chemotherapy: a single-centre study.

PURPOSE: Early death (ED) and treatment-related toxicity emerge as two major barriers for curing paediatric acute promyelocytic leukaemia (APL) patients. This study aims to investigate the effect of idarubicin on controlling hyperleukocytosis in induction therapy and the efficacy and safety of a risk-adapted attenuated consolidation chemotherapy. METHODS: We summarised the characteristics and long-term outcomes of 73 paediatric APL patients treated at our institution from February 2002 to October 2018, during which treatment protocols evolved over three periods and were defined as protocol A, B and C chronologically. All of the patients received an all-trans retinoic acid (ATRA)-arsenic trioxide (ATO) combination remission induction therapy, with hydroxyurea (group A) or idarubicin (group B and C) to control hyperleukocytosis. Consolidation chemotherapy was modified with risk-adapted attenuated intensity and minimised cumulative doses of anthracyclines for group C (144 mg/m2 and 288 mg/m2 of daunorubicin equivalents for standard- and high-risk patients, respectively). RESULTS: The median initial WBC, platelet count, and fibrinogen were 2.9 × 109/L (range 0.9-158.3 × 109/L), 32 × 109/L (range 4-226 × 109/L), and 160 mg/dL (range 53-549 mg/dL), respectively. High-risk and standard-risk were seen in 20.5% and 79.5% of patients, respectively. Three patients (4.1%) suffered early haemorrhagic death. At the end of induction therapy, 68 (93.2%) patients achieved haematologic complete remission (HCR). At a median follow-up of 91.97 months, the estimated 5-year overall survival (OS) and event-free survival (EFS) rates for the whole cohort were 95.9 ± 2.3% and 88.7 ± 3.8%, respectively. A comparison of HCR rates and documented instances of toxicity between groups A and B + C showed no significant differences. However, idarubicin significantly reduced the peak WBC count (Z = - 3.292, P = 0.001) and duration of hyperleukocytosis (Z = - 2.827, P = 0.005). Estimated 3-year EFS (91.7 ± 8.0%) and OS (100%) rates for group C were not significantly different from those for group B, whereas the risk of treatment-related infections was significantly reduced (χ2 = 5.515, P = 0.019). CONCLUSIONS: Idarubicin (8-10 mg/m2/day for 2 days) for hyperleukocytosis control in induction therapy is safe and effective for paediatric APL. Risk-adapted attenuated consolidation chemotherapy is advocated.

Long-Term Results of the Risk-Stratified Treatment of TCF3-PBX1-Positive Pediatric Acute Lymphoblastic Leukemia in China.

BACKGROUND: Acute lymphoblastic leukemia (ALL) with t(1;19)/TCF3-PBX1 is a common genotype, and its prognosis has significantly improved owing to risk stratification and intensive treatment. This study aimed to determine the outcomes and prognostic factors of patients with TCF3-PBX1 treated with the modified Berlin-Frankfurt-Münster protocol. PATIENTS AND METHODS: Between 2005 and 2017, a total of 1051 pediatric patients with ALL were enrolled. TCF3-PBX1 was detected by reverse-transcriptase PCR and/or cytogenetic analysis. Clinical characteristics and treatment outcomes were analyzed and compared in patients with TCF3-PBX1 and with other B-precursor ALL (B-ALL). RESULTS: TCF3-PBX1 was detected in 64 patients with ALL (6.1%), and all were of B-cell lineage. These patients were more likely to express the pre-B-ALL immunophenotype (P < .001), be in the National Cancer Institute high-risk group (P = .030), and exhibit more rapid disease clearance during induction therapy (P < .001) compared to patients with other B-ALL. However, the outcomes of this genotype were not better than those of other patients with intermediate risk. At a median (range) follow-up of 60.6 (0.8-184.5) months, the estimated 5-year overall survival was 85.2 ± 4.6% versus 88.2 ± 1.8% (P = .500) and 5-year event-free survival was 76.8 ± 5.5% versus 83.0 ± 2.0% (P = .210) for patients with TCF3-PBX1 and those with other B-ALL. After adjusting for other risk factors, reemergent minimal residual disease (MRD) was the most significant poor prognostic indicator for patients with TCF3-PBX1. CONCLUSION: The overall outcome of patients with TCF3-PBX1 was intermediate at our institution. Sequential MRD measurement is important for this genotype. Thus, more efforts should be made to eradicate reemergent MRD to improve prognosis.

[Clinical characteristics and prognostic analysis of pediatric pro-B cell acute lymphoblastic leukemia].

OBJECTIVE: To explore the clinical-biological characteristics and prognosis of pediatric pro-B cell acute lymphoblastic leukemia (pro-B-ALL). METHODS: A total of 64 patients aged less than 18 years old with pro-BALL were enrolled. Clinical characteristics, therapeutic effect and prognostic factors were retrospectively analyzed. RESULTS: Pro-B-ALL occurred in 6.23% (64/1 028) of pediatric ALL. Among the 64 patients, 35 were male and 29 were female. The median age was 7.0 years (range 0.4-16.0 years) at diagnosis, of which 39% and 6% were ≥ 10 years old and < 1 year old respectively. The median WBC count was 25.5×109/L[range (0.4-831.9)×109/L], of which 35.9% were ≥ 50×109/L. MLL-r positivity was the most frequent genetic alteration in pro-B ALL, occurring in 34% of patients, with lower frequency of CD22 and CD13 expression and higher frequency of CD7 expression, while lower frequency of CD33 expression was found in patients with MLL-AF4 positivity. At a median follow-up of 60.0 months (range 4.9-165.3 months), the estimated 5-year overall survival (OS) and event-free survival (EFS) in the 64 patients were (85±5)% and (78±5)% respectively. Cox proportional hazards regression analysis identified MRD ≥ 0.1% at 3 months after chemotherapy as an independent adverse prognostic factor for both 5-year OS and EFS. CONCLUSIONS: Pediatric pro-B ALL is a heterogeneous disease with clinical and biological diversity. Biological characteristics, such as immunological markers, genetic alterations, and MRD at 3 months after chemotherapy may be important factors for the long-term prognosis.

Expanded activated autologous lymphocyte infusions improve outcomes of low- and intermediate-risk childhood acute myeloid leukemia with low level of minimal residual disease.

The presence of minimal residual disease (MRD) is a risk factor for relapse among children with acute myeloid leukemia (AML), and eliminating MRD can usually improve survival rates. To investigate the effect of expanded activated autologous lymphocytes (EAALs) combined with chemotherapy on eliminating MRD and improving survival rates of children with AML, we retrospectively analyzed the results of 115 children with low- or intermediate-risk AML with MRD treated at the Pediatric Hematological Center, Peking University People's Hospital, between January 2010 and January 2016. The patients were assigned to the chemotherapy plus EAAL (combined therapy) group (n = 61) and chemotherapy group (n = 54). The MRD-negativity rates were 95.1% (58/61) in the combined therapy group and 63.0% (34/54) in the chemotherapy group (P < 0.0001) during consolidation treatment. The 5-year event-free survival rate was higher in the combined therapy group than in the chemotherapy group (86.3 ± 4.6% vs. 72.1 ± 6.1%, P = 0.025). No severe adverse event was observed after EAAL infusion. The present study showed that EAAL combined with chemotherapy could improve the MRD-negativity rate and event-free survival rate among children with AML with low level MRD-positive status.