Improved outcome for children with acute lymphoblastic leukemia: results of Total Therapy Study XIIIB at St Jude Children's Research Hospital

Insufficient secretion of pancreatic FGF21 is the toxicological mechanism and therapeutic target of asparaginase-associated pancreatitis

Asparaginase-associated pancreatitis (AAP) is a severe and potentially life-threatening drug-induced pancreas targeted toxicity in the combined chemotherapy of acute lymphoblastic leukemia among children and adolescents. The toxicological mechanism of AAP is not yet clear, and there are no effective preventive and treatment measures available clinically. Fibroblast growth factor 21 (FGF21) is a secretory hormone that regulates lipid, glucose, and energy metabolism balance. Acinar tissue is the main source of pancreatic FGF21 protein and plays an important role in maintaining pancreatic metabolic balance. In this study, we found that the decrease of FGF21 in pancreas is closely related to AAP. Pegaspargase (1 IU/g) induces widespread edema and inflammatory infiltration in the pancreas of rats/mice. The specific expression of FGF21 in the acinar tissue of AAP rats was significantly downregulated. Asparaginase caused dysregulation of the ATF4/ATF3/FGF21 axis in acinar tissue or cells, and thus mediated the decrease of FGF21. It greatly activated ATF3 in the acinar, which competed with ATF4 for the Fgf21 promoter, thereby inhibiting the expression of FGF21. Pharmacological replacement of FGF21 (1 mg/kg) or PERK inhibitors (GSK2656157, 25 mg/kg) can significantly mitigate the pancreatic tissue damage and reduce markers of inflammation associated with AAP, representing potential strategies for the prevention and treatment of AAP.

Treatment of Pediatric Acute Lymphoblastic Leukemia: A Historical Perspective

Acute lymphoblastic leukemia (ALL) is the most common disease in pediatric oncology. The history of developmental therapeutics for ALL began in the 1960s with the repetition of "unreliable" medical interventions against this lethal disease. By the 1990s, the development of multi-agent chemotherapy and various types of supportive care rendered ALL treatable. Highly sophisticated, molecular, diagnostic techniques have enabled highly accurate prediction of the relapse risk, and the application of risk-adapted treatments has increased the survival rate in the standard-risk group to nearly 100% in most European nations and North America. Incorporation of state-of-the-art, molecularly targeted agents and novel treatments, including cell and immunotherapy, is further improving outcomes even in the high-risk group. On the other hand, the financial burden of treating children with ALL has increased, imperiling the availability of these diagnostic and treatment strategies to patients in low- and middle-income countries (LMICs). The fundamental treatment strategy, consisting of corticosteroid and classical cytotoxic therapy, has achieved fairly good outcomes and should be feasible in LMICs as well. The present review will discuss the history of developmental therapeutics for childhood ALL in various countries through an extensive literature review with the aim of proposing a model for a treatment backbone for pediatric ALL. The discussion will hopefully benefit LMICs and be useful as a base for future clinical trials of novel treatments.

Survival benefit of pediatric-based regimen for adults with acute lymphoblastic leukemia: A single-center retrospective cohort

INTRODUCTION

Improving survival of Acute Lymphoblastic Leukemia (ALL) in adult patients has been a challenge. Despite intensive chemotherapy treatment, overall survival is poor. However, several studies demonstrate that young adult patients have better survival when treated with pediatric-based intensive regimens. Considering these results, We decided to treat newly diagnosed ALL patients according to age and risk factors. The goal of this study was to describe the results of this intensive chemotherapy treatment approach for ALL adult patients diagnosed at our institution.

METHODS

Fifty-eight ALL patients, diagnosed from 2004 to 2013, were included in the analysis. Patients were assigned to either the St. Jude Total Therapy XIIIB high-risk arm (St Jude) or the CALGB 8811 (CALGB). The Kaplan-Meier survival curve was used for the survival analyses and the Cox proportional hazard regression, for multivariable analysis.

RESULTS

The overall survival was 22.9% at 10 years. The St. Jude improved survival, compared to the CALGB (p = 0.007), with 32.6% vs. 7.4% survival rate at 10 years. However, no survival benefit was found for patients younger than 20 years old (p = 0.32). The multivariable analysis demonstrated that undetectable minimal residual disease (MRD) and hematopoietic stem cell transplantation (HSCT) had beneficial impact on survival (p = 0.0007 and p = 0.004, respectively).

CONCLUSION

ALL is a disease of poor prognosis for adults. The joint effort to standardize treatment and seek solutions is the way to start improving this scenario.

Impact of pre-hydration duration on high-dose methotrexate induced nephrotoxicity in childhood acute lymphoblastic leukaemia in resource constraint centers: a randomized crossover study

PURPOSE

Hydration before starting high-dose methotrexate (HD-MTX) ensures good renal perfusion and alkaline urinary pH. The duration of pre-hydration is not uniform across protocols. We compared 6-h versus 12-h of pre-hydration for HD-MTX therapy in childhood acute lymphoblastic leukaemia (ALL) at our centre where serial MTX level monitoring is not feasible.

METHODS

This randomised cross-over study consecutively enrolled children  < 12 years with ALL receiving HD-MTX. Children with pre-existing renal disease or those exposed to nephrotoxic drugs were excluded. Two groups receiving 6-h versus 12-h pre-hydration on alternate basis in same patient (each exposed to four cycles of 2-5 g/m² of HD-MTX) were compared for HD-MTX induced nephrotoxicity (primary outcome) and other HD-MTX toxicities (HMT) as per common terminology criteria for adverse events (CTCAE-4.0). HD-MTX was administered over 24 h as per BFM-protocol-2009. Solitary MTX levels at 36-h (MTX36) were outsourced and leucovorin (LV) was started at 36 h at 15 mg/m²/dose for 6-8 doses 6-hourly depending on MTX36. Hydration fluid was dextrose normal saline with sodium-bicarbonate and administered till last LV dose.

RESULTS

Total 136 HD-MTX cycles in 34 patients (age range 5-144 months) were evaluated. Nephrotoxicity [2/68 (2.9%) in 6-h versus 1/68 (1.5%) in 12-h] and HMT incidence was comparable in two pre-hydration groups. Median MTX36 levels were not affected by duration of hydration irrespective of administered dose of HD-MTX. Median serum creatinine at baseline, post-pre-hydration and at 36-h post start of HD-MTX were comparable.

CONCLUSION

Reduction of pre-hydration duration does not affect HD-MTX induced nephrotoxicity and MTX36 levels in children < 12 years.

Clinical and Cytogenetic Characteristics of Children With Leukemia 20-Year Retrospective Study

Acute leukemias are the most common malignant diseases in childhood. The aims of this retrospective cohort study were to investigate the frequency of cytogenetic abnormalities in acute pediatric leukemia; the correlation between cytogenetic abnormalities and 5-year survival; and the correlation between cytogenetic abnormalities and clinical and laboratory features. We included 105 patients; acute lymphoblastic leukemia (ALL) had 80.9% patients, B-cell lineage ALL (B-ALL) 84.7% of them, and T-cell lineage (T-ALL) 15.3%. The overall 5-year survival for B-ALL was 85.9% and for T-ALL was 84.6%. The most common cytogenetic abnormalities in patients with B-ALL were t(12;21)(p13.2;q22.1); ETV6-RUNX1 with 22.2% and hyperdiploidy with 19.4%. Our survival analysis showed that t(12;21)(p13.2;q22.1); ETV6-RUNX1 and t(1;19)(q23;p13.3); TCF3-PBX1 had the best 5-year survival with 100% of patients surviving, whereas t(v;11q23.3); KMT2A rearranged had the worst 5-year survival of just 33.3% of patients surviving after 5 years. We found no difference in 5-year survival in B-ALL when comparing clinical features. Acute myelogenous leukemia had 20 patients with 70.6% 5-year survival. The most common cytogenetic abnormality in acute myelogenous leukemia was t(8;21)(q21;q22.1); RUNX1-RUNX1T1 (20%). In conclusion, this study showed the correlation of different cytogenetic abnormalities with 5-year survival in B-ALL patients. Such correlation was not found when comparing clinical features and 5-year survival of patients with B-ALL. This emphasized the significance of cytogenetic analysis in pediatric leukemia.

The Landscape of Secondary Genetic Rearrangements in Pediatric Patients with B-Cell Acute Lymphoblastic Leukemia with t(12;21)

The most frequent chromosomal rearrangement in childhood B-cell acute lymphoblastic leukemia (B-ALL) is translocation t(12;21)(p13;q22). It results in the fusion of the ETV6::RUNX1 gene, which is active in the regulation of multiple crucial cellular pathways. Recent studies hypothesize that many translocations are influenced by RAG-initiated deletions, as well as defects in the RAS and NRAS pathways. According to a "two-hit" model for the molecular pathogenesis of pediatric ETV6::RUNX1-positive B-ALL, the t(12;21) translocation requires leukemia-causing secondary mutations. Patients with ETV6::RUNX1 express up to 60 different aberrations, which highlights the heterogeneity of this B-ALL subtype and is reflected in differences in patient response to treatment and chances of relapse. Most studies of secondary genetic changes have concentrated on deletions of the normal, non-rearranged ETV6 allele. Other predominant structural changes included deletions of chromosomes 6q and 9p, loss of entire chromosomes X, 8, and 13, duplications of chromosome 4q, or trisomy of chromosomes 21 and 16, but the impact of these changes on overall survival remains unclarified. An equally genetically diverse group is the recently identified new B-ALL subtype ETV6::RUNX1-like ALL. In our review, we provide a comprehensive description of recurrent secondary mutations in pediatric B-ALL with t(12;21) to emphasize the value of investigating detailed molecular mechanisms in ETV6::RUNX1-positive B-ALL, both for our understanding of the etiology of the disease and for future clinical advances in patient treatment and management.

Feasibility of Delivering High-Dose Methotrexate in Adolescent and Adult All Patients: A Retrospective Study

Introduction HD-MTX is a key drug in the treatment protocols for ALL. The regimen needs to be administered with appropriate supportive measures and serum methotrexate level monitoring. A limited testing strategy is relevant in resource constraint settings since it allows a shorter duration of hospitalization. We report our experience with this strategy and its impact on the patient safety outcomes. Methods This is a retrospective study of all patients ≥ 15 years of age with newly diagnosed ALL or Lymphoblastic lymphoma (LBL) who were administered HDMTX (part of BFM-90 ALL protocol) at our institute between March 2013 to November 2013.The medical records were reviewed for clinical characteristics, disease-related details, HDMTX dose and cycles administered, leucovorin rescue and toxicities. Results A total of 423 cycles of HD-MTX were administered to 106 patients during the study period. The median duration for completion of all 4 cycles of HDMTX was 53 (IQR 49-60) days. The grade 3 or higher toxicities were anemia in 9.6%, neutropenia 19.4%, febrile neutropenia 5.7%, thrombocytopenia 4.4% and mucositis in 0.7%. There was statistically significant correlation between the levels at 42 h (≤ 1 mmol/L vs > 1 mmol/L) and toxicity- anemia, FN and mucositis observed more in the late clearance group. With limited sampling strategy whereby if the 42- hour level MTX level are < 1 mmol/L, 57% of patients could be discharged early. Conclusion HD-MTX can be safely administered to adolescent and adult ALL patients. A limited methotrexate level monitoring is a safe strategy that can optimize the resources better.

Outcomes of blinatumomab based therapy in children with relapsed, persistent, or refractory acute lymphoblastic leukemia: a multicenter study focusing on predictors of response and post-treatment immunoglobulin production

The management of Refractory/Relapsed B-cell Acute Lymphoblastic Leukemia (R/R ALL) remains challenging. Incorporating blinatumomab in R/R ALL treatment has shown encouraging results. We describe the outcome and predictors of response in children receiving blinatumomab as a bridge to definitive therapy. Immunoglobulin (Ig) G and viral serology before and after therapy were evaluated. Thirty-three patients that failed standard first-line treatments due to relapsed ALL (n = 22), persistent minimal residual disease (MRD) (n = 8), or refractory disease (n = 3) received blinatumomab. Grade 2 toxicity occurred in 27.2% of patients. MRD remission (<0.01%) was achieved in 72.7% of patients. Pre-blinatumomab absolute lymphocyte count (ALC) and MRD/ALC ratio significantly associated with MRD-response. Patients with t(1;19) translocation had lower response rate, compared to all other cytogenetic categories (p = 0.013). One-year event-free survival (EFS) and overall survival (OS) were 69.2% and 79.7%, respectively. Analysis of OS and EFS showed pre-blinatumomab MRD level, ALC, MRD/ALC ratio, t(1;19), and post-blinatumomab MRD remission associated with survival. Following blinatumomab, 83% (15/18) of tested patients had low IgG levels. IgG seronegative status was observed in 83% (12/15) for varicella zoster, 35% (6/17) for herpes zoster, 18% (3/17) for cytomegalovirus, and 26% (5/17) for Epstein Barr virus. Blinatumomab produced encouraging results in children with R/R ALL and low disease burden bridging to definitive therapy. Incorporating baseline genetics and biomarkers may help identify subgroups likely to be responsive/resistant to therapy. Viral serological testing pre- and post-blinatumomab is recommended to optimize supportive and preemptive therapy.Supplemental data for this article is available online at https://doi.org/10.1080/08880018.2022.2049936 .

Molecular Mechanisms of ARID5B-Mediated Genetic Susceptibility to Acute Lymphoblastic Leukemia

BACKGROUND

There is growing evidence for the inherited basis of susceptibility to childhood acute lymphoblastic leukemia (ALL). Genome-wide association studies have identified non-coding ALL risk variants at the ARID5B gene locus, but their exact functional effects and the molecular mechanism linking ARID5B to B-cell ALL leukemogenesis remain largely unknown.

METHODS

We performed targeted sequencing of ARID5B in germline DNA of 5008 children with ALL. Variants were evaluated for association with ALL susceptibility using 3644 patients from the UK10K cohort as non-ALL controls, under an additive model. Cis-regulatory elements in ARID5B were systematically identified using dCas9-KRAB-mediated enhancer interference system enhancer screen in ALL cells. Disruption of transcription factor binding by ARID5B variant was predicted informatically and then confirmed using chromatin immunoprecipitation and coimmunoprecipitation. ARID5B variant association with hematological traits was examined using UK Biobank dataset. All statistical tests were 2-sided.

RESULTS

We identified 54 common variants in ARID5B statistically significantly associated with leukemia risk, all of which were noncoding. Six cis-regulatory elements at the ARID5B locus were discovered using CRISPR-based high-throughput enhancer screening. Strikingly, the top ALL risk variant (rs7090445, P = 5.57 × 10-45) is located precisely within the strongest enhancer element, which is also distally tethered to the ARID5B promoter. The variant allele disrupts the MEF2C binding motif sequence, resulting in reduced MEF2C affinity and decreased local chromosome accessibility. MEF2C influences ARID5B expression in ALL, likely via a transcription factor complex with RUNX1. Using the UK Biobank dataset (n = 349 861), we showed that rs7090445 was also associated with lymphocyte percentage and count in the general population (P = 8.6 × 10-22 and 2.1 × 10-18, respectively).

CONCLUSIONS

Our results indicate that ALL risk variants in ARID5B function by modulating cis-regulatory elements at this locus.

Hypoalbuminemia and not undernutrition predicts high-dose methotrexate-induced nephrotoxicity in children with acute lymphoblastic leukemia in resource-constrained centers

BACKGROUND

The standard practice to mitigate high-dose methotrexate (HD-MTX)-induced nephrotoxicity (HMN) in acute lymphoblastic leukemia (ALL) is to monitor levels until serum MTX falls below a predefined threshold. It is not feasible in most resource-constrained centers. Literature on the various factors affecting HMN in these centers is limited, retrospective, and heterogeneous. Though hypoalbuminemia has been postulated as a risk factor for HMN, the relationship of undernutrition with HMN has not been studied.

PROCEDURE

This prospective observational study consecutively enrolled children < 12 years old with ALL receiving HD-MTX. Children with preexisting renal disease and exposed to nephrotoxic drugs two weeks preceding HD-MTX infusion were excluded. HD-MTX was administered over 24 hours (BFM-2009 protocol) with 12 hours of prehydration. Solitary MTX levels at 36 hours (MTX36) were outsourced, and 6-8 doses of leucovorin were given six-hourly. Hydration was continued till last dose of leucovorin. Various factors affecting HMN (rise in creatinine to 1.5 times baseline) were recorded: age, sex, type of ALL, risk group of ALL, first dose of MTX, dose of MTX, undernourishment, serum protein, and albumin along with C-reactive protein and MTX36 levels.

RESULTS

Forty-four children who received 150 HD-MTX cycles were analyzed. HMN was seen in 14% of cycles. On univariate analysis, undernourishment, MTX36 levels, hypoproteinemia, and hypoalbuminemia were significantly associated with HMN. On multivariate analysis, hypoalbuminemia and MTX36 levels significantly predicted the development of HMN with odds ratios of 4.71 and 1.45.

CONCLUSION

Hypoalbuminemia and solitary serum MTX levels predict HMN in centers where serial MTX level monitoring is not feasible.

The first Japanese biobank of patient-derived pediatric acute lymphoblastic leukemia xenograft models

A lack of practical resources in Japan has limited preclinical discovery and testing of therapies for pediatric relapsed and refractory acute lymphoblastic leukemia (ALL), which has poor outcomes. Here, we established 57 patient-derived xenografts (PDXs) in NOD.Cg-Prkdc^scid ll2rg^tm1Sug /ShiJic (NOG) mice and created a biobank by preserving PDX cells including 3 extramedullary relapsed ALL PDXs. We demonstrated that our PDX mice and PDX cells mimicked the biological features of relapsed ALL and that PDX models reproduced treatment-mediated clonal selection. Our PDX biobank is a useful scientific resource for capturing drug sensitivity features of pediatric patients with ALL, providing an essential tool for the development of targeted therapies.

St. Jude Total Therapy studies from I to XVII for childhood acute lymphoblastic leukemia: a brief review

The therapy design of childhood acute lymphoblastic leukemia (ALL) has evolved over the past 60 years. The St. Jude Children's Research Hospital has developed 17 treatment protocols from 1962 to 2017, aiming to have the most effective and least toxic treatment form. This review summarizes each protocol's objectives, inclusion criteria, treatment phases, pharmacological agents, irradiation therapy, response criteria, risk stratification, type of relapse, and overall survival. The enhancement and successful application of preventive therapy for ALL and following a risk-stratified approach have progressively improved the cure rate of childhood ALL, with relatively few adverse sequelae. Moreover, St. Jude's scientific theme serves as a reminder of the principal factor of research directed to a catastrophic disease such as ALL.

Utility of repeated drug level measurements after high dose methotrexate infusion for treatment planning in pediatric leukemia

Introduction: Although high-dose Methotrexate (MTX) is a successful chemotherapeutic agent used in the treatment of acute lymphoblastic leukemia in childhood, life-threatening toxic effects are rarely seen. Therefore, frequent follow-up of drug levels is recommended. The study researched the necessity of drug level measurement and a minimum safe number of measurements. Materials and Methods: The files of pediatric patients with Acute Lymphoblastic Leukemia receiving high-dose MTX treatment in a single center between 2018 and 2021 were retrospectively reviewed. The treatment protocol was: 3000 mL/m2 alkaline hydration fluid was continued until the 72nd hour together with 2 gr/m2 continuous MTX infusion in the low-risk group and 5 gr/m2 in moderate and high-risk groups, and 15 mg/m2 /dose folinic acid was given at the 42nd, 48thand 54th hours. Findings: 456 MTX treatments were evaluated in 114 patients. Similar results (p>0.05) were obtained in the MTX level measurements performed at the 24th, 42nd, 48th, and 54th hours after MTX administration. In the repeated measurements, the data at the 42nd hour were similar (p=0.021). The number of cases that were >150 µmol/L at the 24th hour of methotrexate infusion and above 1 µmol/L at the 42nd, 48th, and 52nd hours were found to be similar in the repeated measurements. Conclusion: Although recommended, frequent follow-up of MTX levels might not always indicate toxicity. In centers with limited laboratory facilities, the MTX level measured at the 42nd hour in the first treatment might be a practical approach to guide the management of other MTX treatments.

T-Cell Acute Lymphoblastic Leukemia-Current Concepts in Molecular Biology and Management

T-cell acute lymphoblastic leukemia (T-ALL) is an uncommon, yet aggressive leukemia that accounts for approximately one-fourth of acute lymphoblastic leukemia (ALL) cases. CDKN2A/CDKN2B and NOTCH1 are the most common mutated genes in T-ALL. Children and young adults are treated with pediatric intensive regimens and have superior outcomes compared to older adults. In children and young adults, Nelarabine added to frontline chemotherapy improves outcomes and end of consolidation measurable residual disease has emerged as the most valuable prognostic marker. While outcomes for de-novo disease are steadily improving, patients with relapsed and refractory T-ALL fare poorly. Newer targeted therapies are being studied in large clinical trials and have the potential to further improve outcomes. The role of allogeneic stem cell transplant (HSCT) is evolving due to the increased use of pediatric-inspired regimens and MRD monitoring. In this review we will discuss the biology, treatment, and outcomes in pediatric and adult T-ALL.

A causal inference approach to compare leukaemia treatment outcome in the absence of randomization and with dependent censoring

BACKGROUND

One cause of poor outcomes in children of low-income countries affected by acute lymphoblastic leukaemia (ALL) is loss to follow-up due to abandonment of treatment. Assuming this type of loss to follow-up as independent censoring, as in standard Kaplan-Meier estimates, ignores the likely association of abandonment with biologic and socio-economic factors related to outcome. Moreover, when comparing treatment protocols adopted in different time periods, possible imbalances in patients' characteristics must be considered. We aim to compare the outcome of children enrolled in two subsequent protocols for ALL treatment (2000-2007 and 2008-2015) in Honduras, taking both dependent censoring due to abandonment of treatment and imbalances between patient characteristics into account.

METHODS

Marginal structural models based on inverse probability of treatment and censoring (IPTC) weighting allow the estimation of potential event-free survival (EFS) as if no abandonment of treatment occurred and the whole cohort was exposed, or not, to both protocols. An Aalen additive model and a logistic-regression model were used to build abandonment and treatment weights, respectively.

RESULTS

The two protocols recruited 514 and 717 patients. Measured baseline covariates in both protocols were gender, age, white blood cell count, central nervous system involvement, tumour histology and socio-economic status. The potential EFS is slightly higher under the more recent protocol in the first 3 years but no difference is estimated in the long period [survival difference at 5 years (95% confidence interval) = 0.1% (-0.97%; 1.13%)]. Both protocols would allow reducing the event rate by 12-13% if there was no abandonment of treatment.

CONCLUSIONS

Using IPTC weighting, we found a similar potential effect of the two treatment protocols if the imbalance due to the different distribution of potential confounders and to abandonment of therapy was removed.

Outcome of young adult patients with very-high-risk acute lymphoblastic leukemia treated with pediatric-type chemotherapy - a single institute experience

BACKGROUND/PURPOSE

Adult patients of acute lymphoblastic leukemia (ALL) with very high-risk (VHR) characteristics have an inferior outcome, and allogeneic hematopoietic stem cell transplantation (HSCT) is usually performed. In contrast, VHR pediatric patients can be treated effectively with minimal residual disease (MRD)-guided pediatric protocols and HSCT are not always needed.

METHODS

We retrospectively reviewed young adult ALL VHR patients treated with the pediatric-type (TPOG-ALL-2002 VHR) regimen in our institute from 2008 to 2019 and compared the event-free survival (EFS) with patients treated with an adult-type regimen (Hyper-CVAD alternating with high dose methotrexate and cytarabine).

RESULTS

We identified 16 patients treated with the TPOG and 11 treated with the Hyper-CVAD regimen. Philadelphia chromosome-positive (n = 10) and T-cell immunophenotype (n = 11) are the most common VHR features. Compared with the Hyper-CVAD group, patients treated with the TPOG regimen showed a trend toward better EFS with a hazard ratio (HR) of 0.42 (p = 0.16). Compared with untransplanted patients, HSCT showed a positive trend in the Hyper-CVAD (HR 0.22, p = 0.12) but not in the TPOG group (p = 0.37). Untransplanted patients treated initially with the hyper-CVAD regimen had a significantly worse outcome than the TPOG regimen (HR 4.19, p < 0.05). In the TPOG group, patients with negative MRD at the end of consolidation had a significantly better outcome (HR 0.12, p = 0.03).

CONCLUSION

Young adult VHR patients can be effectively treated with the TPOG-ALL-2002 protocol, and those who achieved MRD negativity before the end of consolidation have a good outcome without allogeneic HSCT.

Increase in polymorphonuclear myeloid-derived suppressor cells and regulatory T-cells in children with B-cell acute lymphoblastic leukemia

Our study aimed to evaluate the levels of MDSCs and Tregs in pediatric B-cell acute lymphoblastic leukemia (B-ALL), their relation to patients' clinical and laboratory features, and the impact of these cells on the induction response. This study included 31 pediatric B-ALL patients and 27 healthy controls. All patients were treated according to the protocols of the modified St. Jude Children's Research Hospital total therapy study XIIIB for ALL. Levels of MDSCs and Tregs were analyzed using flow cytometry. We observed a reduction in the levels of CD4 + T-cells and an increase in both the polymorphonuclear MDSCs (PMN-MDSCs) and Tregs. The frequencies of PMN-MDSCs and Tregs were directly related to the levels of peripheral and bone marrow blast cells and CD34 + cells. Complete postinduction remission was associated with reduced percentages of PMN-MDSCs and Tregs, with the level of PMN-MDCs in this subpopulation approaching that of healthy controls. PMN-MDSCs and Tregs jointly play a critical role in maintaining an immune-suppressive state suitable for B-ALL tumor progression. Thereby, they could be independent predictors of B-ALL progress, and finely targeting both PMN-MDSCs and Tregs may be a promising approach for the treatment of B-ALL.

Genome-Wide Association Study of Susceptibility Loci for TCF3-PBX1 Acute Lymphoblastic Leukemia in Children

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. TCF3-PBX1 fusion defines a common molecular subtype of ALL with unique clinical features, but the molecular basis of its inherited susceptibility is unknown. In a genome-wide association study of 1494 ALL cases and 2057 non-ALL controls, we identified a germline risk locus located in an intergenic region between BCL11A and PAPOLG: rs2665658, P = 1.88 × 10-8 for TCF3-PBX1 ALL vs non-ALL, and P = 1.70 × 10-8 for TCF3-PBX1 ALL vs other-ALL. The lead variant was validated in a replication cohort, and conditional analyses pointed to a single causal variant with subtype-specific effect. The risk variant is located in a regulatory DNA element uniquely activated in ALL cells with the TCF3-PBX1 fusion and may distally modulate the transcription of the adjacent gene REL. Our results expand the understanding of subtype-specific ALL susceptibility and highlight plausible interplay between germline variants and somatic genomic abnormalities in ALL pathogenesis.

Germline RUNX1 variation and predisposition to childhood acute lymphoblastic leukemia

Genetic alterations in the RUNX1 gene are associated with benign and malignant blood disorders, particularly of megakaryocyte and myeloid lineages. The role of RUNX1 in acute lymphoblastic leukemia (ALL) is less clear, particularly how germline genetic variation influences the predisposition to this type of leukemia. Sequencing 4,836 children with B-ALL and 1,354 cases of T-ALL, we identified 31 and 18 germline RUNX1 variants, respectively. RUNX1 variants in B-ALL consistently showed minimal damaging effects. By contrast, 6 T-ALL-related variants result in drastic loss of RUNX1 activity as a transcription activator in vitro. Ectopic expression of dominant-negative RUNX1 variants in human CD34+ cells repressed differentiation into erythroid, megakaryocytes, and T cells, while promoting myeloid cell development. Chromatin immunoprecipitation sequencing of T-ALL models showed distinctive patterns of RUNX1 binding by variant proteins. Further whole genome sequencing identified JAK3 mutation as the most frequent somatic genomic abnormality in T-ALL with germline RUNX1 variants. Co-introduction of RUNX1 variant and JAK3 mutation in hematopoietic stem and progenitor cells in mice gave rise to T-ALL with early T-cell precursor phenotype. Taken together, these results indicated that RUNX1 is an important predisposition gene for T-ALL and pointed to novel biology of RUNX1-mediated leukemogenesis in the lymphoid lineages.

Hospital acquired pneumonia risk factors in children with Acute Lymphoblastic Leukemia on chemotherapy

Background

Over the past 10 years, infection has remained as the main cause of illness and mortality among children with Acute Lymphoblastic Leukemia on chemotherapy. The high incidence of Hospital-Acquired Pneumonia in children with Acute Lymphoblastic Leukemia on chemotherapy with risk factors should be intervened earlier

Methods

An observational case control study of children with Acute Lymphoblastic Leukemia on chemotherapy. Patient with Hospital-Acquired Pneumonia considered as case and patient without Hospital-Acquired Pneumonia as control to analyze risk factors that affect the incidence of Hospital-Acquired Pneumonia in children with Acute Lymphoblastic Leukemia on chemotherapy from 2016 to 2018 was performed in the pediatric ward Dr. Soetomo General Academic Hospital with a total sampling technique. Nine risk factors were analyzed: age, gender, nutritional status, length of stay, risk stratification, chemotherapy phase, anemia, neutropenia, and thrombocytopenia. Bivariate and multivariate analysis using chi-square, continuity correction, and logistic regression was used for statistical analysis.

Results

120 children enrolled the study. Analyzed of risk factors showed risk stratification (p = 0.009), chemotherapy phase (p < 0.001), and neutropenia (p < 0.001) was proven to significantly affect the incidence of Hospital-Acquired Pneumonia in children with Acute Lymphoblastic Leukemia on chemotherapy. Age, gender, nutritional status, length of stay, anemia, and thrombocytopenia were not proven to be a risk factor that affects the incidence of Hospital-Acquired Pneumonia in children with Acute Lymphoblastic Leukemia on chemotherapy.

Conclusion

The incidence of Hospital-Acquired Pneumonia in children with Acute Lymphoblastic Leukemia on chemotherapy is significantly affected by the risk stratification, chemotherapy phase, and neutropenia.

Acute lymphoblastic leukemia: A population-based study of outcome in the United States based on the surveillance, epidemiology, and end results (SEER) database, 1980-2017

The treatment in acute lymphoblastic Leukemia (ALL) has evolved and improved dramatically over the past four decades. We assessed the outcome of ALL overall, and the two major subsets of Philadelphia chromosome (Ph)-positive and Ph-negative ALL by age, time periods, ethnicity, median household income, and geographic county area. A total of 12 788 patients diagnosed with ALL from 1980 to 2017 were included. We performed an analysis to better evaluate the outcome evolution in ALL according to time period and patient's demographic factors. The overall 5-year survival rates have improved significantly over time, from 51% before 1990 to 72% since 2010. The survival rates for children (age 0 to 14 years) and adolescents (age 15 to 19 years) have improved from 73% and 55% before 1990 to 93% and 74% since 2010, respectively. Similarly, the rates had improved from 33% to 59% for adults 20 to 29 years old, 24% to 59% for 30 to 39 years old, and 14% to 43% for 40 to 59 years old between the two time periods. The rates remained under 30% in older patients (60+ years). Since 2010, patients with Ph-negative ALL had 5-year survival rate of 73% and those with Ph-positive ALL 50%. African Americans, Hispanic ethnicity, and lower household income were associated with inferior survival. The outcome of patients with ALL showed continued improvement across all age groups in the US. The recent introduction of targeted therapies, together with optimized supportive care, will continue to improve outcomes, particularly in older patients.

CNS-3 status remains an independent adverse prognosis factor in children with acute lymphoblastic leukemia (ALL) treated without cranial irradiation: Results of EORTC Children Leukemia Group study 58951

AIM

To evaluate the prognostic significance of initial central nervous system (CNS) involvement of children with acute lymphoblastic leukemia (ALL) enrolled in the EORTC 58951 trial.

PATIENTS AND METHODS

From 1998 to 2008, 1930 ALL patients were included in the randomized EORTC 58951 trial. Overall treatment intensity was adjusted according to known prognostic factors including the level of minimal residual disease after induction treatment. CNS-directed therapy comprised four to 11 courses of i.v. methotrexate (5g/m²), and 10 to 19 intrathecal chemotherapy injections, depending on risk group and CNS status. Cranial irradiation was omitted for all patients.

RESULTS

The overall 8-year event-free survival (EFS) and overall survival (OS) rates were 81.3% and 88.1%, respectively. In the CNS-1, TPL+, CNS-2, and CNS-3 groups, the 8-year EFS rates were 82.1%, 77.1%, 78.3%, and 57.4%, respectively. Multivariable analysis indicated that initial CNS-3 status, but not CNS-2 or TLP+, was an independent adverse predictor of outcome. The 8-year incidence of isolated CNS relapse was 1.7% and of isolated or combined CNS relapse it was 3.7%. NCI high-risk group, male sex, CNS-2 and CNS-3 status were independent predictors for a higher incidence of any CNS relapse.

CONCLUSIONS

CNS-3 status remains associated with poor prognosis and requires intensification of both systemic and CNS-directed therapy. This trial was registered at https://clinicaltrials.gov/under/NCT00003728.

Clinical Utility of Pegaspargase in Children, Adolescents and Young Adult Patients with Acute Lymphoblastic Leukemia: A Review

Acute lymphoblastic leukemia (ALL) is a heterogenous hematological malignancy representing 25% of all cancers in children less than 15 years of age. Significant improvements in survival and cure rates have been made over the past four decades in pediatric ALL treatment. Asparaginases, derived from Escherichia coli and Erwinia chrysanthemi, have become a critical component of ALL therapy since the 1960s. Asparaginases cause depletion of serum asparagine, leading to deprivation of this critical amino acid for protein synthesis, and hence limit survival of lymphoblasts. Pegaspargase, a conjugate of monomethoxypolyethylene glycol (mPEG) and L-asparaginase, has become an integral component of pediatric upfront and relapsed ALL protocols due to its longer half-life and improved immunogenicity profile compared to native asparaginase preparations. Over the past two decades great strides have been made in outcomes for pediatric ALL due to risk stratification, incorporation of multiagent chemotherapy protocols, and central nervous system prophylaxis with pegaspargase having played an important role in this success. However, adolescents and young adults (AYA) with ALL when treated on contemporaneous trials using adult ALL regimens, continue to have poor outcomes. There is increasing realization of adapting pediatric trial regimens for treating AYAs, especially those incorporating higher intensity of chemotherapeutic agents with pegaspargase being one such agent. Dose or treatment-limiting toxicity is observed in 25-30% of patients, most notable being hypersensitivity reactions. Other toxicities include asparaginase-associated pancreatitis, thrombosis, liver dysfunction, osteonecrosis, and dyslipidemia. Discontinuation or subtherapeutic levels of asparaginase are associated with inferior disease-free survival leading to higher risk of relapse, and in cases of relapse, a higher risk for remission failure. This article provides an overview of available evidence for use of pegaspargase in pediatric acute lymphoblastic leukemia.

In-Hospital Management Might Reduce Induction Deaths in Pediatric Patients With Acute Lymphoblastic Leukemia: Results From a Japanese Cohort

Induction deaths (ID) remain a critical issue in the treatment of pediatric patients with acute lymphoblastic leukemia (ALL). The reported rate of ID in this population is 1% or higher. We speculate that this proportion might be lower in Japan because of mandatory hospitalization during induction therapy to manage complications. We retrospectively analyzed the incidence of ID among children with ALL enrolled in 4 Japanese study groups between 1994 and 2013. Among 5620 children, 41 (0.73%) cases of ID were noted. The median age was 6.5 years; 24 children were female, and 7 had T-cell ALL. Infection was the most common cause of ID (n=22), but the incidence (0.39%) was lower than that reported in western countries. Mortality within 48 hours from the onset of infection was low, comprising 25% of infection-related deaths. The incidence of infections caused by Bacillus species was low. Only 1 patient died because of Aspergillus infection. Fatal infections mostly occurred during the third week of induction therapy. Our findings suggest that close monitoring, stringent infection control, and immediate administration of appropriate antibiotics through hospitalization might be important strategies in reducing the rate of infection-related ID in pediatric patients with ALL.

Pharmacogenomics of intracellular methotrexate polyglutamates in patients' leukemia cells in vivo

BACKGROUNDInterpatient differences in the accumulation of methotrexate's active polyglutamylated metabolites (MTXPGs) in leukemia cells influence its antileukemic effects.METHODSTo identify genomic and epigenomic and patient variables determining the intracellular accumulation of MTXPGs, we measured intracellular MTXPG levels in acute lymphoblastic leukemia (ALL) cells from 388 newly diagnosed patients after in vivo high-dose methotrexate (HDMTX) (1 g/m2) treatment, defined ALL subtypes, and assessed genomic and epigenomic variants influencing folate pathway genes (mRNA, miRNA, copy number alterations [CNAs], SNPs, single nucleotide variants [SNVs], CpG methylation).RESULTSWe documented greater than 100-fold differences in MTXPG levels, which influenced its antileukemic effects (P = 4 × 10-5). Three ALL subtypes had lower MTXPG levels (T cell ALL [T-ALL] and B cell ALL [B-ALL] with the TCF3-PBX1 or ETV6-RUNX1 fusions), and 2 subtypes had higher MTXPG levels (hyperdiploid and BCR-ABL like). The folate pathway genes SLC19A1, ABCC1, ABCC4, FPGS, and MTHFD1 significantly influenced intracellular MTXPG levels (P = 2.9 × 10-3 to 3.7 × 10-8). A multivariable model including the ALL subtype (P = 1.1 × 10-14), the SLC19A1/(ABCC1 + ABCC4) transporter ratio (P = 3.6 × 10-4), the MTX infusion time (P = 1.5 × 10-3), FPGS mRNA expression (P = 2.1 × 10-3), and MTX systemic clearance (P = 4.4 × 10-2) explained 42% of the variation in MTXPG accumulation (P = 1.1 × 10-38). Model simulations indicated that a longer infusion time (24 h vs. 4 h) was superior in achieving higher intracellular MTXPG levels across all subtypes if ALL.CONCLUSIONSThese findings provide insights into mechanisms underlying interpatient differences in intracellular accumulation of MTXPG in leukemia cells and its antileukemic effectsFUNDINGTHE National Cancer Institute (NCI) and the Institute of General Medical Sciences of the NIH, the Basque Government Programa Posdoctoral de Perfeccionamiento de Personal Investigador doctor, and the American Lebanese Syrian Associated Charities (ALSAC).

Excellent Outcomes With Reduced Frequency of Vincristine and Dexamethasone Pulses in Standard-Risk B-Lymphoblastic Leukemia: Results From Children's Oncology Group AALL0932

PURPOSE

AALL0932 evaluated two randomized maintenance interventions to optimize disease-free survival (DFS) while reducing the burden of therapy in children with newly diagnosed NCI standard-risk (SR) B-acute lymphoblastic leukemia (B-ALL).

METHODS

AALL0932 enrolled 9,229 patients with B-ALL; 2,364 average-risk (AR) patients were randomly assigned (2 × 2 factorial design) at the start of maintenance therapy to vincristine/dexamethasone pulses every 4 (VCR/DEX4) or every 12 (VCR/DEX12) weeks, and a starting dose of weekly oral methotrexate of 20 mg/m² (MTX20) or 40 mg/m² (MTX40).

RESULTS

Five-year event-free survival and overall survival (OS) from enrollment (with 95% CIs), for all eligible and evaluable SR B-ALL patients (n = 9,226), were 92.0% (91.1% and 92.8%) and 96.8% (96.2% and 97.3%), respectively. The 5-year DFS and OS from the start of maintenance for randomly assigned AR patients were 94.6% (93.3% and 95.9%) and 98.5% (97.7% and 99.2%), respectively. The 5-year DFS and OS for patients randomly assigned to receive VCR/DEX4 (n = 1,186) versus VCR/DEX12 (n = 1,178) were 94.1% (92.2% and 96.0%) and 98.3% (97.2% and 99.4%) v 95.1% (93.3% and 96.9%) and 98.6% (97.7% and 99.6%), respectively (P = .86 and .69). The 5-year DFS and OS for AR patients randomly assigned to receive MTX20 versus MTX40 were 95.1% (93.3% and 96.8%) and 98.8% (97.9% and 99.7%) v 94.2% (92.2% and 96.1%) and 98.1% (97.0% and 99.2%), respectively (P = .92 and .89).

CONCLUSIONS

The 0NCI-SR AR B-ALL who received VCR/DEX12 had outstanding outcomes despite receiving one third of the vincristine/dexamethasone pulses previously used as standard of care on Children's Oncology Group (COG) trials. The higher starting dose of MTX of 40 mg/m²/week did not improve outcomes when compared with 20 mg/m²/week. The decreased frequency of vincristine/dexamethasone pulses has been incorporated into frontline COG B-ALL trials to decrease the burden of therapy for patients and their families.

High-dose methotrexate-induced reversible grade 4 hyperbilirubinaemia and transaminitis in an adolescent with Burkitt Leukaemia

Symptomatic drug-induced liver injury (DILI) is an uncommon problem. Direct DILI is dose-related, predictable with short latency (hour to days) and is generally associated with transient and reversible transaminitis without jaundice. Antimetabolites including methotrexate are a common cause for direct DILI. Hepatotoxicity associated with high-dose methotrexate (HD-MTX) is generally transient and includes reversible elevation of transaminase in up to 60% and associated hyperbilirubinaemia (≤grade 2) in 25% of courses and therefore is of no clinical significance. Severe grades of DILI with HD-MTX (grade ≥4) are extremely rare. We describe an adolescent with Burkitt leukaemia who had reversible grade 4 DILI including hyperbilirubinaemia postfirst course of HD-MTX. Rechallenge with two-third dose of HD-MTX in subsequent chemotherapeutic cycle did not cause recurrence of DILI.

Outcomes in Pediatric Acute Lymphoblastic Leukemia-A Single-Center Romanian Experience

BACKGROUND

This study evaluates the main (para)clinical aspects and outcomes in a group of Romanian children diagnosed with acute lymphoblastic leukemia (ALL), under the conditions of antileukemic treatment according to an adapted ALL IC Berlin-Frankfurt-Munster (BFM) 2002 protocol.

METHODS

We performed a retrospective single-center study of 125 children diagnosed with ALL between 2010 and 2016. Standard forms were used for data collection of variate clinical and paraclinical parameters.

RESULTS

The children were predominantly male (64.8%) and their median age at diagnosis was 5 years. A total of 107 patients were diagnosed with precursor B-cell acute lymphoblastic leukemia (BCP)-ALL and 18 with T-cell acute lymphoblastic leukemia T-ALL. Multiplex reverse transcription polymerase chain reaction RT-PCR assay for ETV6-RUNX1, BCR-ABL, E2A-PBX1, KMT2A-AFF1, and STIL-TAL1 fusion genes was performed in 111 patients. ETV6-RUNX1 translocation was detected in 18.9% of patients, while BCR-ABL1 and E2A-PBX1 rearrangements were seen in 2.7% and 3.6%, respectively. Complete remission at the end of induction phase was obtained in 89.6% of patients. The overall relapse rate was 11.2%, with 11 early and 3 late relapses. The 5-year overall survival rate in BCP-ALL was 81.6% and in T-ALL 71.4%.

CONCLUSIONS

The 5-year overall and event-free survival rates in our study were slightly lower than those reported in developed countries, so the patients' outcomes are encouraging.

CAR T cells vs allogeneic HSCT for poor-risk ALL

For subgroups of children with B-cell acute lymphoblastic leukemia (B-ALL) at very high risk of relapse, intensive multiagent chemotherapy has failed. Traditionally, the field has turned to allogeneic hematopoietic stem cell transplantation (HSCT) for patients with poor outcomes. While HSCT confers a survival benefit for several B-ALL populations, often HSCT becomes standard-of-care in subsets of de novo ALL with poor risk features despite limited or no data showing a survival benefit in these populations, yet the additive morbidity and mortality can be substantial. With the advent of targeted immunotherapies and the transformative impact of CD19-directed chimeric antigen receptor (CAR)-modified T cells on relapsed or refractory B-ALL, this approach is currently under investigation in frontline therapy for a subset of patients with poor-risk B-ALL: high-risk B-ALL with persistent minimal residual disease at the end of consolidation, which has been designated very high risk. Comparisons of these 2 approaches are fraught with issues, including single-arm trials, differing eligibility criteria, comparisons to historical control populations, and vastly different toxicity profiles. Nevertheless, much can be learned from available data and ongoing trials. We will review data for HSCT for pediatric B-ALL in first remission and the efficacy of CD19 CAR T-cell therapy in relapsed or refractory B-ALL, and we will discuss an ongoing international phase 2 clinical trial of CD19 CAR T cells for very-high-risk B-ALL in first remission.

Safe administration of high-dose methotrexate with minimal drug level monitoring: Experience from a center in north India

BACKGROUND

High-dose methotrexate (HDMTX) is recommended to be administered with serial monitoring of methotrexate (MTX) levels, which may not be universally feasible in resource-limited settings. In this study, we evaluated the overall experience of administration of HDMTX at our center by monitoring a single drug level at 54 h from the start of MTX infusion.

METHODS

This retrospective study was performed at a tertiary level hospital in north India, over a 5-year period (2011-2015). All patients <18 years of age with newly diagnosed acute lymphoblastic leukemia (ALL) and T-non-Hodgkin lymphoma (T-NHL) were enrolled in the study. Details of HDMTX and all significant toxicities requiring prolonged or repeat hospitalization were retrieved from the medical records. All eligible patients received HDMTX as per the recommendations followed by at least three doses of leucovorin rescue, before drug levels were sent at 54 h. Subsequent leucovorin doses were adjusted accordingly.

RESULTS

The records of 598 cycles of HDMTX in 184 patients were reviewed. A total of 531 of 598 cycles (88.7%) were managed with monitoring only a single plasma drug level at 54 h from the beginning of infusion. Delayed MTX clearance was seen in 260 of 598 cycles (43.5%). Only three episodes (0.5%) were associated with significant toxicity. There were no deaths.

CONCLUSIONS

The strategy of monitoring MTX concentration at 54 h was safe in our cohort. Although recommended, dynamic monitoring of plasma drug levels may not always predict toxicity.

CD9 knockdown suppresses cell proliferation, adhesion, migration and invasion, while promoting apoptosis and the efficacy of chemotherapeutic drugs and imatinib in Ph+ ALL SUP‑B15 cells

Philadelphia chromosome‑positive acute lymphoblastic leukemia (Ph+ ALL) is regarded as a prognostically unfavorable subgroup, as this ALL subgroup has an increased risk of relapse/refractory disease. CD9, which belongs to the tetraspanin membrane proteins, is implicated in several pathological processes, including tumor progression. However, the role of CD9 in the pathogenesis of Ph+ ALL and the potential benefit of applying CD9‑targeted RNA interference strategies for treatment of Ph+ ALL require further investigation. The aim of the present study was to determine the effects of CD9 on leukemic cell progression and the efficacy of therapeutic agents in Ph+ ALL cells, in addition to assessing the in vitro anti‑leukemia activity of CD9‑targeted RNA interference in Ph+ ALL cells. In the present study, a lentiviral short hairpin RNA (shRNA) expression vector targeting CD9 gene in Ph+ ALL SUP‑B15 cells was constructed. The present results demonstrated that treatment of SUP‑B15 cells with lentiviral‑mediated shRNA against CD9 decreased CD9 mRNA and protein expression compared with the shControl cells transduced with a blank vector. In addition, CD9 knockdown could suppress cell proliferation, adhesion, migration and invasion, and promote apoptosis and the efficacy of chemotherapeutic drugs (such as vincristine, daunorubicin, cyclophosphamide and dexamethasone) and the tyrosine kinase inhibitor imatinib in SUP‑B15 cells. Furthermore, CD9 knockdown suppressed cell proliferation and promoted apoptosis in SUP‑B15 cells via a p53‑dependent pathway. These findings suggested that gene silencing of CD9 using a shRNA‑expressing lentivirus vector may provide a promising treatment for Ph+ ALL.

Clinical Characteristics and Treatment Results of Childhood Acute Lymphoblastic Leukemia in North Macedonia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. This study was designed to determine the clinical, biological features and outcomes among children with ALL treated at the only pediatric hematology-oncology center in North Macedonia.

PATIENTS AND METHODS

Seventy four consecutive children age 1 to 14 years, diagnosed with ALL between January 1, 2010 and October 31, 2017 and treated according to ALL IC BFM 2002 protocol were retrospectively evaluated.

RESULTS

The median age at diagnosis was 5 years and males were predominant (60.8%). Precursor B-cell ALL was diagnosed in 81.1% of patients, while 18.9% had T cell ALL. CNS involvement at the time of diagnoses was present in 6.8% of patients. Complete remission was achieved in 93.2% of patients. The induction death rate was 5.4%. The rate of death during first complete remission was 4.1%. Relapse occurred in 13.5% of patients. After a median observation time of 44 months, the 5-year overall survival (OS) and event-free survival (EFS) rates (± standard error) were 79.4% ± 5.2% and 74% ± 5.7%, respectively. The 5-year EFS rate for patients categorized as standard risk by NCI criteria was significantly higher than for high risk patients (83.3% versus 46.7%; P<0.001). Patients with precursor B-cell ALL and negative minimal residual disease (MRD) status at the end of induction had the best prognoses.

CONCLUSION

Our study demonstrated that the treatment results of childhood ALL in North Macedonia are comparable to those obtained in the ALL IC BFM 2002 trial.

MiR-7 Functions as a Tumor Suppressor by Targeting the Oncogenes TAL1 in T-Cell Acute Lymphoblastic Leukemia

BACKGROUND

T-cell acute lymphoblastic leukemia is a hematologic malignancy characterized by T-cell proliferation, and in many cases, the ectopic expression of the oncogenic transcription factor T-cell acute lymphocytic leukemia protein 1 (TAL1). MicroRNA-7 has been shown to play a critical role in proliferation, migration, and treatment sensitivity in a diverse array of cancers. In this study, we sought to establish a novel link between microRNA-7 and T-cell acute lymphoblastic leukemia oncogenesis.

MATERIAL AND METHOD

To do so, we characterized gene expression of microRNA-7 as well as TAL1 in both T-cell acute lymphoblastic leukemia patient-derived tissue and cell lines, as well as performing functional luciferase assays to assess microRNA-7 binding to the TAL1 3'-untranslated region. We also performed growth, apoptosis, and migration experiments using 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide, Annexin V, and transwell assays in the context of microRNA-7 overexpression.

RESULTS

We found that microRNA-7 expression is attenuated and inversely correlated with TAL1 expression in TAL1 + T-cell acute lymphoblastic leukemia cells. Additionally, microRNA-7 directly targets and suppresses TAL1 levels. Finally, microRNA-7 overexpression reduces growth, motility, and migration while inducing apoptosis in T-cell acute lymphoblastic leukemia cells, phenotypes that can be rescued by concomitant overexpression of TAL1.

CONCLUSIONS

These results indicate that microRNA-7 functions as a potent tumor suppressor by inhibiting the oncogene TAL1 and suggest microRNA-7 could function as a prognostic biomarker and possible therapeutic in the clinical management of T-cell acute lymphoblastic leukemia.

Using Pharmacology to Squeeze the Life Out of Childhood Leukemia, and Potential Strategies to Achieve Breakthroughs in Medulloblastoma Treatment

Eliminating cancer was once thought of as a war. This analogy is still apt today; however, we now realize that cancer is a much more formidable enemy than scientists originally perceived, and in some cases, it harbors a profound ability to thwart our best efforts to defeat it. However, before we were aware of the complexity of cancer, chemotherapy against childhood acute lymphoblastic leukemia (ALL) was successful because it applied the principles of pharmacology. Herein, we provide a historic perspective of the experience at St. Jude Children's Research Hospital. In 1962, when the hospital opened, fewer than 3% of patients experienced durable cure. Through judicious application of pharmacologic principles (e.g., combination therapy with agents using different mechanisms of action) plus appropriate drug scheduling, dosing, and pharmacodynamics, the survival of patients with ALL now exceeds 90%. We contrast this approach to treating ALL with the contemporary approach to treating medulloblastoma, in which genetics and molecular signatures are being used to guide the development of more-efficacious treatment strategies with minimal toxicity. Finally, we highlight the emerging technologies that can sustain and propel the collaborative efforts to squeeze the life out of these cancers. SIGNIFICANCE STATEMENT: Up until the early 1960s, chemotherapy for childhood acute lymphoblastic leukemia was mostly ineffective. This changed with the knowledge and implementation of rational approaches to combination therapy. Although the therapeutics of brain cancers such as medulloblastoma are not as refined (in part because of the blood-brain barrier obstacle), recent extraordinary advances in knowledge of medulloblastoma pathobiology has led to innovations in disease classification accompanied with strategies to improve therapeutic outcomes. Undoubtedly, additional novel approaches, such as immunological therapeutics, will open new avenues to further the goal of taming cancer.

Solitary serum methotrexate level 36 hours post high-dose methotrexate: A safe, efficacious, and cost-effective strategy to monitor methotrexate toxicities in childhood leukemia in resource-limited centers

BACKGROUND

The standard practice during high-dose methotrexate (HD-MTX) in acute lymphoblastic leukemia (ALL) to mitigate toxicity is to serially monitor levels till serum MTX < 0.01 μmol/L. Most resource-limited centers lack in-house access to MTX levels, and therefore repeated monitoring is costly and cumbersome. We studied the efficacy and safety of "solitary 36 hours post HD-MTX levels (MTX₃₆ )."

PROCEDURE

This prospective observational study consecutively enrolled children with ALL receiving HD-MTX. Cycles with unavailable MTX₃₆ and MTX₃₆  > 10 μmol/L were excluded. HD-MTX was administered over 24 hours (BFM-2009 protocol) with 12 hours of prehydration. MTX₃₆ were performed at other centers. Leucovorin was given in six hourly doses 36 hours post HD-MTX. Hydration was continued until the last dose of leucovorin. MTX toxicities, including change of creatinine from baseline at 36 hours (∆Cr₃₆ ), were noted. Two groups depending on MTX₃₆ (≤1 μmol/L vs > 1 μmol/L) received six versus eight doses of leucovorin, and toxicities were compared.

RESULTS

Twenty-nine children with median age five years (1-11) who received 100 HD-MTX cycles with a median MTX dose of 3 g/m² (2-5) were analyzed. The median MTX₃₆ level was 1.165 μmol/L (0.1-7.32). Toxicities of HD-MTX (CTCAE-4.0): transaminitis-22%; creatinine elevation ≥ 1.25 times baseline-24%; cytopenias-16%; mucositis-17%; acute kidney injury (AKI)-6%. All toxicities were ≤CTCAE grade 3. Creatinine elevation, AKI, and mucositis were significantly higher in the group with higher MTX₃₆ . There was no correlation (r = 0.3) between ∆Cr₃₆ and MTX₃₆ . MTX₃₆ was thrice more economical than the standard protocol.

CONCLUSION

MTX₃₆ is a potential cost-effective, efficacious, and safe limited sample strategy to monitor HD-MTX, particularly in centers where in-house MTX levels are unavailable.

Characterization of pharmacogenetic markers related to Acute Lymphoblastic Leukemia toxicity in Amazonian native Americans population

Acute Lymphoblastic Leukemia (ALL) is the most common cancer in children. Differences are found among ethnic groups in the results of the treatment of pediatric ALL. In general, children with a high level of native American ancestry tend to respond less positively to ALL treatments, which may be related to specific genomic variants found in native American groups. Despite the evidence, few data are available on the distribution of the pharmacogenomic variants relevant to the treatment of ALL in traditional Amerindian populations, such the those of the Amazon region. Given this, the present study investigated 27 molecular markers related to the treatment of ALL in Amerindians from Brazilian Amazonia and compared the frequencies with those recorded previously on five continents, that are available in the 1,000 Genomes database. The variation in the genotype frequencies among populations was evaluated using Fisher's exact test. The False Discovery Rate method was used to correct the results of the multiple analyses. Significant differences were found in the frequencies of the majority of markers between the Amerindian populations and those of other regions around the world. These findings highlight the unique genetic profile of the indigenous population of Brazilian Amazonia, which may reflect a distinct therapeutic profile for the treatment of ALL in these populations.

Cost-Effectiveness Analysis of Tisagenlecleucel in the Treatment of Relapsed or Refractory B-Cell Acute Lymphoblastic Leukaemia in Children and Young Adults in Spain

Purpose

Tisagenlecleucel, a chimeric antigen receptor T-cell (CAR-T) therapy, is a promising alternative for the management of children and young adults with relapsed and refractory B-cell acute lymphoblastic leukemia (r/r ALL). The aim of this study was to determine whether treatment with tisagenlecleucel is a cost-effective intervention compared with salvage chemotherapy in paediatric and young adult patients with r/r ALL in Spain.

Materials and Methods

A partitioned survival model of monthly cycles with three health states was used (event-free survival, progressive/relapsed disease and death). A lifetime time horizon and the Spanish National Health System perspective were adopted. During the first 5 years, permanence in the different health states was determined according to the results in the clinical studies. In successive years, mortality tables of the Spanish general population adjusted by standardized mortality rate for survivors of childhood cancer were used. Clinical, economic, and quality of life parameters were drawn from clinical trials and the literature. Only direct health costs (pharmacological costs and the costs derived from health resource use) were included. The robustness of the results was evaluated in a sensitivity analysis.

Results

This cost-effectiveness analysis showed a greater benefit (10.10 and 8.97 life-years gained [LYGs] and quality-adjusted life-years [QALYs] gained, respectively) and a higher cost (€ 258,378.40) for tisagenlecleucel compared to salvage chemotherapy. The resulting incremental cost-effectiveness and cost-utility ratios were € 25,576.80 per LYG and € 28,818.52 per QALY gained, respectively. In the sensitivity analysis, all the results were below € 50,000/QALY.

Conclusion

Tisagenlecleucel would represent a cost-effective intervention for the treatment of children and young adults with r/r ALL in Spain.

Reduced-dose intensity therapy for pediatric lymphoblastic leukemia: long-term results of the Recife RELLA05 pilot study

Treatment-related mortality is common among children with acute lymphoblastic leukemia (ALL) treated in poor-resource settings. We applied a simplified flow cytometric assay to identify patients with precursor B-cell ALL (B-ALL) at very low risk (VLR) of relapse and treated them with a reduced-intensity treatment plan (RELLA05). VLR criteria include favorable presenting features (age ≥ 1 and < 10 years), white blood cell count of <50 ×109/L, lack of extramedullary leukemia, and minimal residual disease level of <0.01% on remission induction day 19. Except for 2 doses of daunorubicin, treatment of patients with VLR B-ALL consisted of a combination of agents with relatively low myelotoxicity profiles, including corticosteroids, vincristine, L-asparaginase, methotrexate, and 6-mercaptopurine. Cyclophosphamide, systemic cytarabine, and central nervous system radiotherapy were not used. Of 454 patients with ALL treated at the Instituto de Medicina Integral Professor Fernando Figueira in Recife, Brazil, between December 2005 and June 2015, 101 were classified as having VLR B-ALL. There were no cases of death resulting from toxicity or treatment abandonment during remission induction. At a median follow-up of 6.6 years, there were 8 major adverse events: 6 relapses, 1 treatment-related death (from septicemia) during remission, and 1 secondary myeloid leukemia. The estimated 5-year event-free and overall survival rates were 92.0% ± 3.9% and 96.0% ± 2.8%, respectively. The 5-year cumulative risk of relapse was 4.24% ± 2.0%. The treatment was well tolerated. Episodes of neutropenia were of short duration. Patients with B-ALL selected by a combination of presenting features and degree of early response can be successfully treated with a mildly myelosuppressive chemotherapy regimen.

Leptomeningeal malignancy of childhood: sharing learning between childhood leukaemia and brain tumour trials

Leptomeningeal malignancy complicates childhood cancers, including leukaemias, brain tumours, and solid tumours. In leukaemia, such malignancy is thought to invade leptomeninges via the vascular route. In brain tumours, dissemination from the primary tumour, before or after surgery, via CSF pathways is assumed; however, evidence exists to support the vascular route of dissemination. Success in treating leptomeningeal malignancy represents a rate-limiting step to cure, which has been successfully overcome in leukaemia with intensified systemic therapy combined with intra-CSF therapy, which replaced cranial radiotherapy for many patients. This de-escalated CNS-directed therapy is still associated with some neurotoxicity. The balanced benefit justifies exploration of ways to further de-escalate CNS-directed therapy. For primary brain tumours, standard therapy is craniospinal radiotherapy, but attendant risk of acute and delayed brain injury and endocrine deficiencies compounds post-radiation impairment of spinal growth. Alternative ways of treating leptomeninges by intensifying drug therapy delivered to CSF are being investigated-preliminary evidence suggests improved outcomes. This Review seeks to describe methods of intra-CSF drug delivery and drugs in use, and consider how the technique could be modified and additional drugs might be selected for this route of administration.

Mutational landscape and patterns of clonal evolution in relapsed pediatric acute lymphoblastic leukemia

Relapse of acute lymphoblastic leukemia (ALL) remains a leading cause of childhood death. Prior studies have shown clonal mutations at relapse often arise from relapse-fated subclones that exist at diagnosis. However, the genomic landscape, evolutionary trajectories and mutational mechanisms driving relapse are incompletely understood. In an analysis of 92 cases of relapsed childhood ALL, incorporating multimodal DNA and RNA sequencing, deep digital mutational tracking and xenografting to formally define clonal structure, we identify 50 significant targets of mutation with distinct patterns of mutational acquisition or enrichment. CREBBP, NOTCH1, and Ras signaling mutations rose from diagnosis subclones, whereas variants in NCOR2, USH2A and NT5C2 were exclusively observed at relapse. Evolutionary modeling and xenografting demonstrated that relapse-fated clones were minor (50%), major (27%) or multiclonal (18%) at diagnosis. Putative second leukemias, including those with lineage shift, were shown to most commonly represent relapse from an ancestral clone rather than a truly independent second primary leukemia. A subset of leukemias prone to repeated relapse exhibited hypermutation driven by at least three distinct mutational processes, resulting in heightened neoepitope burden and potential vulnerability to immunotherapy. Finally, relapse-driving sequence mutations were detected prior to relapse using deep digital PCR at levels comparable to orthogonal approaches to monitor levels of measurable residual disease. These results provide a genomic framework to anticipate and circumvent relapse by earlier detection and targeting of relapse-fated clones.

Identification of four novel associations for B-cell acute lymphoblastic leukaemia risk

There is increasing evidence for a strong inherited genetic basis of susceptibility to acute lymphoblastic leukaemia (ALL) in children. To identify new risk variants for B-cell ALL (B-ALL) we conducted a meta-analysis with four GWAS (genome-wide association studies), totalling 5321 cases and 16,666 controls of European descent. We herein describe novel risk loci for B-ALL at 9q21.31 (rs76925697, P = 2.11 × 10-8), for high-hyperdiploid ALL at 5q31.1 (rs886285, P = 1.56 × 10-8) and 6p21.31 (rs210143 in BAK1, P = 2.21 × 10-8), and ETV6-RUNX1 ALL at 17q21.32 (rs10853104 in IGF2BP1, P = 1.82 × 10-8). Particularly notable are the pleiotropic effects of the BAK1 variant on multiple haematological malignancies and specific effects of IGF2BP1 on ETV6-RUNX1 ALL evidenced by both germline and somatic genomic analyses. Integration of GWAS signals with transcriptomic/epigenomic profiling and 3D chromatin interaction data for these leukaemia risk loci suggests deregulation of B-cell development and the cell cycle as central mechanisms governing genetic susceptibility to ALL.

Randomized assessment of delayed intensification and two methods for parenteral methotrexate delivery in childhood B-ALL: Children's Oncology Group Studies P9904 and P9905

The delayed intensification (DI) enhanced outcome for patients with acute lymphoblastic leukemia (ALL) treated on BFM 76/79 and CCG 105 after a prednisone-based induction. Childrens Oncology Group protocols P9904/9905 evaluated DI via a post-induction randomization for eligible National Cancer Institute (NCI) standard (SR) and high-risk (HR) patients. A second randomization compared intravenous methotrexate (IV MTX) as a 24- (1 g/m²) vs. 4-h (2 g/m²) infusion. NCI SR patients received a dexamethasone-based three-drug and NCI HR/CNS 3 SR patients a prednisone-based four-drug induction. End induction MRD (minimal residual disease) was obtained but did not impact treatment. DI improved the 10-year continuous complete remission (CCR) rate; 75.5 ± 2.5% vs. 81.8 ± 2.2% p = 0.002, whereas MTX administration did not; 4-h 80.8 ± 1.9%; 24-h 81.4 ± 1.9% (p = 0.7780). Overall survival (OS) at 10 years did not differ with DI: 91.4 ± 1.6% vs. 90.9 ± 1.7% (p = 0.25) without but was higher with the 24-h MTX infusion; 4-h 91.1 ± 1.4%; 24-h 93.9 ± 1.2% (p = 0.0209). MRD predicted outcome; 10-year CCR 87.7 ± 2.2 and 82.1 ± 2.5% when MRD was <0.01% with/without DI (p = 0.007) and 54.3 ± 8% and 44 ± 8% for patients with MRD ≥ 0.01% with/without DI (p = 0.11). DI improved CCR for patients with B-ALL with and without end induction MRD.

Gene expression profiling by mRNA sequencing reveals dysregulation of core genes in Rictor deficient T-ALL mouse model

T-cell acute lymphoblastic leukemia (T-ALL) is a neoplastic disorder with peak incidence in children and young adults. The mTOR complex is an important component of the PI3K/Akt/mTOR signaling cascade and holds great promise for the treatment of hematopoietic malignancies. Previous studies have shown that the depression of Rictor, one of the components of the mTOR complex, prevents myeloproliferative disorders and leukemia However, knowledge of the progression of mTOR has not greatly improved the prognosis of T-ALL. To identify potential prognostic biomarkers for T-ALL, a whole-genome expression profile of Rictior deficient T-ALL mice was performed. As a result, 1475 differentially expressed genes (DEGs) were identified. Network analysis revealed 46 genes with a high network degree and fold-change value. Kaplan-Meier analysis identified ten crucial genes which significantly associated with survival in Rictor deficient T-ALL mice. These findings provide potential therapeutic targets in leukemia and bear immediate relevance to patients with leukemia.

Adrenal function following acute discontinuation of glucocorticoids in children with acute lymphocytic leukemia: A prospective study

Background: Children with acute lymphocytic leukemia (ALL) are enrolled in advanced treatment protocols involving high doses of glucocorticoids (GCs). Current protocols do not advocate tapering of GCs doses postinduction phase. Prolonged administration of supra-physiologic doses of GCs can induce transient suppression of the hypothalamic pituitary adrenal axis (HPA). Timely recognition of adrenal insufficiency is important in order to ensure that children at risk receive the necessary treatment and follow-up including stress coverage during illness and surgical procedures. Methods: 21 newly diagnosed patients with ALL aged 3-10 years old were prospectively enrolled in the study over a 2-year period. All enrolled patients received high doses of GCs as part of a chemotherapy treatment protocol. The HPA axis was assessed prior to the induction phase of chemotherapy and 1-2 weeks after un-tapered discontinuation of GCs. Results: All children had normal HPA axis at baseline. Postinduction 1 mcg ACTH stimulation test result was normal (cortisol > 500 nmol/L) in 75% of children and partially responsive in 25% (cortisol 300-500 nmol/L). None of the participants demonstrated clinically significant adrenal insufficiency following abrupt cessation of GCs. Conclusion: All children in our cohort had either normal or subnormal cortisol response during a low dose ACTH stimulation test 1 to 2 weeks following abrupt discontinuation of GCs, suggesting that any inhibition of the HPA axis is of short duration. We suggest that future studies investigate the timing of adrenal function recovery following GC discontinuation as well as whether tapering of the GC should be recommended.

PEGylated E. coli asparaginase desensitization: an effective and feasible option for pediatric patients with acute lymphoblastic leukemia who have developed hypersensitivity to pegaspargase in the absence of asparaginase Erwinia chrysanthemi availability

Asparaginase is an important component of multi-agent chemotherapy for the treatment of pediatric acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LLy). Hypersensitivity to the PEGylated form, pegaspargase, is the most common toxicity observed and is ideally addressed by substituting multiple doses of erwinia asparaginase for each subsequent dose of pegaspargase. An international shortage of erwinia asparaginase has limited the therapeutic options for those experiencing pegaspargase hypersensitivity. Here, we report pegaspargase can be safely administered, while maintaining sustained levels of asparaginase activity, to patients who have had a prior hypersensitivity reaction to pegaspargase by using a standard rapid desensitization protocol. Ten patients with prior hypersensitivity reactions to pegaspargase were treated by using a standardized rapid desensitization protocol. Eight patients had therapeutic asparaginase levels between days 4 and 7 of ≥0.05 IU/mL, and seven patients continued to have sustained levels above ≥0.1 IU/mL between days 10 and 14. Based on chemotherapy regimens, five of these patients successfully received more than one dose of pegaspargase utilizing this protocol.

Mechanisms of NT5C2-Mediated Thiopurine Resistance in Acute Lymphoblastic Leukemia

Relapse remains a formidable challenge for acute lymphoblastic leukemia (ALL). Recently, recurrent mutations in NT5C2 were identified as a common genomic lesion unique in relapsed ALL and were linked to acquired thiopurine resistance. However, molecular mechanisms by which NT5C2 regulates thiopurine cytotoxicity were incompletely understood. To this end, we sought to comprehensively characterize the biochemical and cellular effects of NT5C2 mutations. Compared with wild-type NT5C2, mutant proteins showed elevated 5'-nucleotidase activity with a stark preference of thiopurine metabolites over endogenous purine nucleotides, suggesting neomorphic effects specific to thiopurine metabolism. Expression of mutant NT5C2 mutations also significantly reduced thiopurine uptake in vitro with concomitant increase in efflux of 6-mercaptopurine (MP) metabolites, plausibly via indirect effects on drug transporter pathways. Finally, intracellular metabolomic profiling revealed significant shifts in nucleotide homeostasis induced by mutant NT5C2 at baseline; MP treatment also resulted in global changes in metabolomic profiles with completely divergent effects in cells with mutant versus wild-type NT5C2. Collectively, our data indicated that NT5C2 mutations alter thiopurine metabolism and cellular disposition, but also influence endogenous nucleotide homeostasis and thiopurine-induced metabolomic response. These complex mechanisms contributed to NT5C2-mediated drug resistance in ALL and pointed to potential opportunities for therapeutic targeting in relapsed ALL.

Long-Term Outcomes of Modified St Jude Children's Research Hospital Total Therapy XIIIB and XV Protocols for Thai Children With Acute Lymphoblastic Leukemia

BACKGROUND

We studied long-term outcomes and prognostic features of Thai children with acute lymphoblastic leukemia treated with modified St Jude Children's Research Hospital (SJCRH) protocols.

PATIENTS AND METHODS

Pediatric patients newly diagnosed with acute lymphoblastic leukemia were included. From 1997 to 2003, the first group received modified Total Therapy XIIIB (previous protocol). From 2004 to 2014, the latter had modified Total Therapy XV (current protocol).

RESULTS

In 250 patients, the event-free survival rates (± standard error) of the previous protocol (n = 95) were 82.8 ± 3.9%, 81.7 ± 4.0%, and 81.7 ± 4.0% at 5, 10, and 15 years, respectively; current protocol event-free survival rates (n = 155) were 84 ± 3.0%, 80.8 ± 3.4%, and 80.8 ± 3.4%, respectively. Previous protocol overall survival rates for the same years were 89.2 ± 3.2%, 84.8 ± 3.8%, and 84.8 ± 3.8%, and for the current protocol were 90 ± 2.5%, 86.9 ± 3.2%, and 83.7 ± 4.4%. Previous protocol relapses were 10.5% (10 patients), with 7 having isolated hematologic and 3 isolated/combined central nervous system relapses. Current protocol relapses were 9.7% (15 patients), with 7 having isolated hematologic, 6 isolated/combined central nervous system, and 2 extramedullary relapses. Patients with leukocyte counts over 100 × 10⁹/L and who had disease classified as high risk had worse event-free survival using the previous protocol. However, only initial leukocyte counts of ≥ 100 × 10⁹/L predicted adverse outcomes under the current protocol. Minimal residual disease positivity was a prognostic factor of worse overall survival only for previous protocol patients.

CONCLUSION

Favorable outcomes of childhood acute lymphoblastic leukemia occurred using adapted SJCRH protocols, perhaps because of multidisciplinary care teams and improved parent advocacy. Inferior outcomes might be prevented by addressing predictive factors to ameliorate monitoring and care.