Outcome after first relapse in childhood acute lymphoblastic leukaemia - lessons from the United Kingdom R2 trial

Phase 2 study of combination chemotherapy with bortezomib in children with relapsed and refractory acute lymphoblastic leukemia

Treatment outcomes for children with relapsed and refractory acute lymphoblastic leukemia (R/R-ALL) remain poor, and the optimal induction therapy has not been determined. Bortezomib is a proteasome inhibitor that acts synergistically and additively with standard chemotherapy for ALL. We evaluated the efficacy and safety of combination chemotherapy with bortezomib in children with R/R-ALL. This single-arm, multicenter, phase 2 study was conducted in Japan between 2016 and 2020. Eligible patients were divided into two cohorts: a high-risk first-relapse cohort of untreated patients with high-risk first-relapsed ALL and an expansion cohort of patients with refractory ALL, including multiple relapses, relapse after allogeneic hematopoietic cell transplantation, and induction failure. All patients received a single course of chemotherapy as induction therapy. Sixteen patients (10 in the high-risk first-relapse cohort, six in the expansion cohort) were evaluable. The overall remission rate after induction therapy was 60% in the high-risk first-relapse cohort and 16.7% in the expansion cohort. All patients had minimal residual disease. Adverse events were acceptable except for interstitial lung disease and hypoxia in a patient in the expansion cohort, but addition of bortezomib to conventional chemotherapy did not produce obvious improvement in children with R/R-ALL.

Haploidentical vs. HLA-matched donor hematopoietic stem-cell transplantation for pediatric patients with acute lymphoblastic leukemia in second remission: A collaborative retrospective study of the Spanish Group for Bone Marrow Transplantation in Children (GETMON/GETH) and the Spanish Childhood Relapsed ALL Board (ReALLNet)

Introduction

Studies addressing the role of haploidentical as alternative to HLA-matched donors for stem cell transplantation (SCT) often include patients with diverse hematological malignancies in different remission statuses.

Methods

We compared outcomes of children with acute lymphoblastic leukemia (ALL) undergoing SCT in second complete remission (CR2) from haploidentical (n = 25) versus HLA-matched donor (n = 51).

Results

Patients were equally distributed across both groups according to age, immunophenotype, time to and site of relapse, relapse risk-group allocation, and minimal residual disease (MRD) before SCT. Incidence of graft failure, acute graft versus host disease (GVHD), and other early complications did not differ between both groups. We found no differences in overall survival (58.7% versus 59.5%; p = .8), leukemia free survival (LFS) (48% versus 36.4%; p = .5), event free survival (40% versus 34.4%; p = .69), cumulative incidence (CI) of subsequent relapse (28% versus 40.9%; p = .69), treatment related mortality (24% versus 23.6%; p = .83), CI of cGVHD (4.5% versus 18.7%; p = .2), and chronic GVHD-free and leukemia-free survival (44% versus 26.3%; p = .3) after haploidentical donor SCT. Chronic GVHD (HR = 0.09; p=.02) had protective impact, and MRD ≥ 0.01% before SCT (HR = 2.59; p=.01) had unfavorable impact on LFS.

Discussion

These results support the role of haploidentical donor SCT in children with ALL in CR2.

Prognostic impact of total body irradiation dose in pediatric acute lymphoblastic leukemia patients treated with allogeneic hematopoietic stem cell transplantation in second complete remission

Background

Allogeneic HSCT may improve survival in pediatric ALL patients who relapse. In this study, we analyzed the outcome and prognostic factors of 62 ALL patients (35 male, 56.5%) who received allogeneic HSCT in second complete remission (CR) at our institution between April 1st 2009 and December 31st 2019.

Methods

The median time from diagnosis to relapse was 35.1 months (range, 6.0‒113.6 mo). Fifty-three patients (85.5%) experienced bone marrow relapse only. The number of patients who received transplant according to each donor type was as follows: HLA matched family donor 17 (27.4%), matched unrelated donor (UD) 22 (35.5%), mismatched donor 23 (37.1%). All patients received HSCT with a myeloablative conditioning, 58 patients (93.5%) with the incorporation of TBI [31 patients 12 Gray (Gy), 24 patients 13.2 Gy, 3 patients 8 Gy].

Results

The 5-year event-free survival (EFS), and overall survival of the study group was 41.3±6.3% (26/62), and 42.3±6.6% (27/62), respectively. The cumulative incidence of relapse and transplant-related mortality was 57.1±6.4% and 1.6±1.6%, respectively. Infant ALL, shorter time from diagnosis to relapse, and TBI dose of 12 Gy, rather than 13.2 Gy, resulted in significantly worse EFS. In multivariate analysis, infant ALL and TBI dose of 12 Gy during conditioning predicted significantly lower EFS.

Conclusion

In our study group, treatment with a higher dose of TBI during conditioning resulted in better EFS for ALL patients who underwent HSCT in second CR. Further study is needed to determine potential long-term complications associated with a higher TBI dose.

Peripheral Bone Relapse of Paediatric TCF3-HLF Positive Acute Lymphoblastic Leukaemia during Haematopoietic Stem Cell Transplantation: A Case Report

The present case report features a highly uncommon form of a paediatric TCF3-HLF positive acute lymphoblastic leukaemia (ALL) relapse, an extramedullary, peripheral bone manifestation. Following complete remission, during the conditioning for haematopoietic stem cell transplantation (HSCT), our sixteen-year-old male patient complained of fever, pain and swelling of the right forearm. Radiography suggested acute osteomyelitis in the right ulna with subsequent surgical confirmation. Intraoperatively obtained debris culture grew Staphylococcus aureus and Acinetobacter pittii. Measures taken to control the infection were deemed to be successful. However, after the completion of the otherwise uneventful HSCT, a very early medullary relapse was diagnosed. Revising the original surgical samples from the ulna, bone relapse of ALL was immunohistochemically confirmed. Reviewing the previous cases found in the literature, it is advised to consider uncommon forms of ALL relapse when encountering ambiguous cases of osteomyelitis or arthritis during haematological remission.

Thiopurine Enhanced ALL Maintenance (TEAM): study protocol for a randomized study to evaluate the improvement in disease-free survival by adding very low dose 6-thioguanine to 6-mercaptopurine/methotrexate-based maintenance therapy in pediatric and adult patients (0-45 years) with newly diagnosed B-cell precursor or T-cell acute lymphoblastic leukemia treated according to the intermediate risk-high group of the ALLTogether1 protocol

Background

A critical challenge in current acute lymphoblastic leukemia (ALL) therapy is treatment intensification in order to reduce the relapse rate in the subset of patients at the highest risk of relapse. The year-long maintenance phase is essential in relapse prevention. The Thiopurine Enhanced ALL Maintenance (TEAM) trial investigates a novel strategy for ALL maintenance.

Methods

TEAM is a randomized phase 3 sub-protocol to the ALLTogether1 trial, which includes patients 0–45 years of age with newly diagnosed B-cell precursor or T-cell ALL, and stratified to the intermediate risk-high (IR-high) group, in 13 European countries. In the TEAM trial, the traditional methotrexate (MTX)/6-mercaptopurine (6MP) maintenance backbone (control arm) is supplemented with low dose (2.5–12.5 mg/m²/day) oral 6-thioguanine (6TG) (experimental arm), while the starting dose of 6MP is reduced from 75 to 50 mg/m²/day. A total of 778 patients will be included in TEAM during ~ 5 years. The study will close when the last included patient has been followed for 5 years from the end of induction therapy. The primary objective of the study is to significantly improve the disease-free survival (DFS) of IR-high ALL patients by adding 6TG to 6MP/MTX-based maintenance therapy. TEAM has 80% power to detect a 7% increase in 5-year DFS through a 50% reduction in relapse rate. DFS will be evaluated by intention-to-treat analysis. In addition to reducing relapse, TEAM may also reduce hepatotoxicity and hypoglycemia caused by high levels of methylated 6MP metabolites. Methotrexate/6MP metabolites will be monitored and low levels will be reported back to clinicians to identify potentially non-adherent patients.

Discussion

TEAM provides a novel strategy for maintenance therapy in ALL with the potential of improving DFS through reducing relapse rate. Potential risk factors that have been considered include hepatic sinusoidal obstruction syndrome/nodular regenerative hyperplasia, second cancer, infection, and osteonecrosis. Metabolite monitoring can potentially increase treatment adherence in both treatment arms.

Trial registration

EudraCT, 2018–001795-38. Registered 2020-05-15,

Clinicaltrials.gov, NCT04307576. Registered 2020-03-13, https://clinicaltrials.gov/ct2/show/NCT04307576

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09522-3.

Temporal changes in incidence of relapse and outcome after relapse of childhood acute lymphoblastic leukemia over three decades; a Nordic population-based cohort study

Relapse remains the main obstacle to curing childhood acute lymphoblastic leukemia (ALL). The aims of this study were to compare incidence of relapse, prognostic factors, and survival after relapse between three consecutive Nordic Society of Pediatric Hematology and Oncology trials. Relapse occurred as a primary event in 638 of 4 458 children (1.0-14.9 years) diagnosed with Ph-negative ALL between 1992 and 2018. The 5-year cumulative incidence of relapse was 17.3% (95% CI 15.4-19.2%) and 16.5% (95% CI 14.3-18.8%) for patients in the ALL1992 and ALL2000 trials, respectively, but decreased to 8.4% (95% CI 7.0-10.1%) for patients in the ALL2008 trial. No changes in duration of first complete remission and site of relapse were observed over time; however, high hyperdiploidy, and t(12;21) decreased in the ALL2008 trial. The 4-year overall survival after relapse was 56.6% (95% CI 52.5-60.5%) and no statistically significant temporal improvements were observed. Age ≥10 years, T-cell immunophenotype, bone-marrow involvement, early and very early relapse, hypodiploidy, and Down syndrome all independently predicted worse outcome after relapse. Improvements in the primary treatment of childhood ALL has resulted in fewer relapses. However, failure to improve outcome of remaining relapses suggests a selection of harder-to-cure relapses and calls for new therapeutic strategies.

Novel Treatments for Pediatric Relapsed or Refractory Acute B-Cell Lineage Lymphoblastic Leukemia: Precision Medicine Era

With the markedly increased cure rate for children with newly diagnosed pediatric B-cell acute lymphoblastic leukemia (B-ALL), relapse and refractory B-ALL (R/R B-ALL) remain the primary cause of death worldwide due to the limitations of multidrug chemotherapy. As we now have a more profound understanding of R/R ALL, including the mechanism of recurrence and drug resistance, prognostic indicators, genotypic changes and so on, we can use newly emerging technologies to identify operational molecular targets and find sensitive drugs for individualized treatment. In addition, more promising and innovative immunotherapies and molecular targeted drugs that are expected to kill leukemic cells more effectively while maintaining low toxicity to achieve minimal residual disease (MRD) negativity and better bridge hematopoietic stem cell transplantation (HSCT) have also been widely developed. To date, the prognosis of pediatric patients with R/R B-ALL has been enhanced markedly thanks to the development of novel drugs. This article reviews the new advancements of several promising strategies for pediatric R/R B-ALL.

Successful hematopoietic stem cell transplantation for two patients with relapse of intrachromosomal amplification of chromosome 21-positive B-cell precursor acute lymphoblastic leukemia

In children with relapsed acute lymphoblastic leukemia (ALL), it is essential to identify patients in need of treatment intensification. Minimal residual disease (MRD)-based treatment stratification resulted in excellent survival in children with late relapsed B-cell precursor (BCP)-ALL. Chemotherapy alone produced a favorable outcome in patients with negative MRD after induction. The genetic abnormality also plays an important role in determining the prognosis and stratification for treatment. Intrachromosomal amplification of chromosome 21 (iAMP21) is associated with a poor outcome and a high risk for relapse, and there is no standard treatment after relapse. Herein, we present two patients with relapsed iAMP21-positive ALL who were successfully treated by cord blood transplantation (CBT). Although both patients had late bone marrow relapse and favorable MRD response, CBT was performed due to iAMP21 positive. Patients 1 and 2 have been in remission post-CBT for 15 and 45 months, respectively. Patients with relapsed iAMP21-positive ALL may be considered for stem cell transplantation even in late relapses and favorable MRD response.

Allogeneic Hematopoietic Stem Cell Transplantation for Children With Acute Lymphoblastic Leukemia: Shifting Indications in the Era of Immunotherapy

Pediatric acute lymphoblastic leukemia generally carries a good prognosis, and most children will be cured and become long-term survivors. However, a portion of children will harbor high-risk features at the time of diagnosis, have a poor response to upfront therapy, or suffer relapse necessitating more intensive therapy, which may include allogeneic hematopoietic stem cell transplant (HSCT). Recent advances in risk stratification, improved detection and incorporation of minimal residual disease (MRD), and intensification of upfront treatment have changed the indications for HSCT over time. For children in first complete remission, HSCT is generally reserved for those with the highest risk of relapse. These include patients with unfavorable features/cytogenetics who also have a poor response to induction and consolidation chemotherapy, usually reflected by residual blasts after prednisone or by detectable MRD at pre-defined time points. In the relapsed setting, children with first relapse of B-cell ALL are further stratified for HSCT depending on the time and site of relapse, while all patients with T-cell ALL are generally consolidated with HSCT. Alternatives to HSCT have also emerged over the last decade including immunotherapy and chimeric antigen receptor (CAR) T-cell therapy. These novel agents may spare toxicity while attempting to achieve MRD-negative remission in the most refractory cases and serve as a bridge to HSCT. In some situations, these emerging therapies can indeed be curative for some children with relapsed or resistant disease, thus, obviating the need for HSCT. In this review, we seek to summarize the role of HSCT in the current era of immunotherapy.

Multicolor flow cytometry immunophenotyping and characterization of aneuploidy in pediatric B-cell precursor acute lymphoblastic leukemia

The aim of this study was to assess the incidence of DNA aneuploidy in Polish children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) and the relationship between aneuploidy and immunological phenotype, age, leukocyte count, S-phase fraction (SPF) and early response to induction chemotherapy assessed by the percentage of residual blast cells in bone marrow aspirates. The study group consisted of 267 patients. DNA content and immunophenotype were assessed in the bone marrow before treatment using multicolor flow cytometry (FC). DNA aneuploidy was detected in 50/267 (19%) patients. High hyperdiploidy was found to be associated with lower leukocyte count (p = 0.006) and common ALL immunophenotype. Flow cytometry analysis revealed that high hyperdiploid BCP-ALL patients showed significantly higher expression of CD9, CD20, CD22, CD58, CD66c, CD86 and CD123 antigens as compared to other groups of ploidy. In contrast, CD45 showed decreased expression. The percentage of leukemic blasts at diagnosis was lower in high hyperdiploid BCP-ALL cases than in diploid (79% vs. 85.7%, p = 0.001). The difference in minimal residual disease (MRD) levels on day 15 and 33 of induction therapy between analyzed groups was not significant.

This study showed that high hyperdiploidy is associated with lower WBC count and specific immunological phenotype. Flow cytometric evaluation of expression of selected antigens can be used for fast identification of markers of aneuploidy in pediatric BCP-ALL, before genetic tests results are available. Understanding the biological significance of aneuploidy in leukemia can potentially be exploited therapeutically using targeted therapies against specific blast cell subclones.

Pediatric onco-nephrology: time to spread the word : Part I: early kidney involvement in children with malignancy

Onco-nephrology has been a growing field within the adult nephrology scope of practice. Even though pediatric nephrologists have been increasingly involved in the care of children with different forms of malignancy, there has not been an emphasis on developing special expertise in this area. The fast pace of discovery in this field, including the development of new therapy protocols with their own kidney side effects and the introduction of the CD19-targeted chimeric antigen receptor T cell (CAR-T) therapy, has introduced new challenges for general pediatric nephrologists because of the unique effects of these treatments on the kidney. Moreover, with the improved outcomes in children receiving cancer therapy come an increased number of survivors at risk for chronic kidney disease related to both their cancer diagnosis and therapy. Therefore, it is time for pediatric onco-nephrology to take its spot on the expanding subspecialties map in pediatric nephrology.

Risk factors and outcomes in children with high-risk B-cell precursor and T-cell relapsed acute lymphoblastic leukaemia: combined analysis of ALLR3 and ALL-REZ BFM 2002 clinical trials

AIM

Outcomes of children with high-risk (HR) relapsed acute lymphoblastic leukaemia (ALL) (N = 393), recruited to ALLR3 and ALL-REZ BFM 2002 trials, were analysed. Minimal residual disease (MRD) was assessed after induction and at predetermined time points until haematopoietic stem cell transplantation (SCT).

METHODS

Genetic analyses included karyotype, copy-number alterations and mutation analyses. Ten-year survivals were analysed using Kaplan-Meier and Cox models for multivariable analyses.

RESULTS

Outcomes of patients were comparable in ALLR3 and ALL-REZ BFM 2002. The event-free survival of B-cell precursor (BCP) and T-cell ALL (T-ALL) was 22.6% and 26.2% (P = 0.94), respectively, and the overall survival (OS) was 32.6% and 28.2% (P = 0.11), respectively. Induction failures (38%) were associated with deletions of NR3C1 (P = 0.002) and BTG1 (P = 0.03) in BCP-ALL. The disease-free survival (DFS) and OS in patients with good vs poor MRD responses were 57.4% vs 22.6% (P < 0.0001) and 57.8% vs 32.0% (P = 0.0004), respectively. For BCP- and T-ALL, the post-SCT DFS and OS were 42.1% and 56.8% (P = 0.26) and 51.6% and 55.4% (P = 0.67), respectively. The cumulative incidences of post-SCT relapse for BCP- and T-ALL were 36.9% and 17.8% (P = 0.012) and of death were 10.7% and 25.5% (P = 0.013), respectively. Determinants of outcomes after SCT were acute graft versus host disease, pre-SCT MRD (≥10-3), HR cytogenetics and TP53 alterations in BCP-ALL.

CONCLUSION

Improvements in outcomes for HR ALL relapses require novel compounds in induction therapy to improve remission rates and immune targeted therapy after induction to maintain remission after SCT.

TRIAL REGISTRATION

ALLR3: NCT00967057; ALL REZ-BFM 2002: NCT00114348.

Outcomes after late bone marrow and very early central nervous system relapse of childhood B-acute lymphoblastic leukemia: a report from the Children's Oncology Group phase III study AALL0433

Outcomes after relapse of childhood B-acute lymphoblastic leukemia (B-ALL) are poor, and optimal therapy is unclear. The children’s Oncology Group study AALL0433 evaluated a new platform for relapsed ALL. Between March 2007 and October 2013 AALL0433 enrolled 275 participants with late bone marrow or very early isolated central nervous system (iCNS) relapse of childhood B-ALL. Patients were randomized to receive standard versus intensive vincristine dosing; this randomization was closed due to excess peripheral neuropathy in 2010. Patients with matched sibling donors received allogeneic hematopoietic cell transplantation (HCT) after the first three blocks of therapy. The prognostic value of minimal residual disease (MRD) was also evaluated in this study. The 3-year event free and overall survival (EFS/OS) for the 271 eligible patients were 63.6±3.0% and 72.3±2.8% respectively. MRD at the end of Induction-1 was highly predictive of outcome, with 3-year EFS/OS of 84.9±4.0% and 93.8±2.7% for patients with MRD <0.1%, versus 53.7±7.8% and 60.6± 7.8% for patients with MRD ≥0.1% (P<0.0001). Patients who received HCT versus chemotherapy alone had an improved 3-year disease-free survival (77.5±6.2% vs. 66.9 + 4.5%, P=0.03) but not OS (81.5±5.8% for HCT vs. 85.8±3.4% for chemotherapy, P=0.46). Patients with early iCNS relapse fared poorly, with a 3-year EFS/OS of 41.4±9.2% and 51.7±9.3%, respectively. Infectious toxicities of the chemotherapy platform were significant. The AALL0433 chemotherapy platform is efficacious for late bone marrow relapse of B-ALL, but with significant toxicities. The MRD threshold of 0.1% at the end of Induction-1 was highly predictive of the outcome. The optimal role for HCT for this patient population remains uncertain. This trial is registered at clinicaltrials.gov (NCT# 00381680).

Identification of Early Recurrence Factors in Childhood and Adolescent B-Cell Acute Lymphoblastic Leukemia Based on Integrated Bioinformatics Analysis

Over the past 50 years, great progress has been made in the diagnosis and treatment of acute lymphoblastic leukemia (ALL), especially in pediatric patients. However, early recurrence is still an important threat to the survival of patients. In this study, we used integrated bioinformatics analysis to look for biomarkers of early recurrence of B-cell ALL (B-ALL) in childhood and adolescent patients. Firstly, we obtained gene expression profiles from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database and the Gene Expression Omnibus (GEO) database. Then, we identified differentially expressed genes (DEGs) based on whether the disease relapsed early. LASSO and Cox regression analysis were applied to identify a subset of four genes: HOXA7, S100A11, S100A10, and IFI44L. A genetic risk score model was constructed based on these four optimal prognostic genes. Time-dependent receiver operating characteristic (ROC) curves were used to evaluate the predictive value of this prognostic model (3-, 5-, and 10-year AUC values >0.7). The risk model was significantly associated with overall survival (OS) and event-free survival in B-ALL (all p < 0.0001). In addition, a high risk score was an independent poor prognostic risk factor for OS (p < 0.001; HR = 3.396; 95% CI: 2.387-4.832). Finally, the genetic risk model was successfully tested in B-ALL using an external validation set. The results suggested that this model could be a novel predictive tool for early recurrence and prognosis of B-ALL.

Leydig cell failure with testicular radiation doses <20Gy: The clinical effects of total body irradiation conditioned haematopoietic stem cell transplantation for childhood leukaemia during long-term follow-up

OBJECTIVE

Testosterone replacement is generally considered likely to be required only at testicular radiation doses in excess of 20Gy. Long-term data are not available for patients receiving 9-14.4Gy as part of Total Body Irradiation in childhood.

DESIGN

Retrospective cohort study.

DATA COLLECTION

notes review, laboratory results, prescription of testosterone.

PATIENTS

Forty-two of 96 boys who received Total Body Irradiation (9-14.4Gy) and Haematopoietic Stem Cell Transplantation for childhood leukaemia at Great Ormond Street Hospital between 1981-2011 and survived >5 years.

MEASUREMENTS

The serum concentrations of testosterone and gonadotrophins and the prescription of testosterone were recorded.

RESULTS

Of the 42 boys included, 37 (88%) entered puberty spontaneously and 5 required induction. Median length of follow-up was 19.4 years (range 5-33.1). At last follow-up, 23 of the 37 (62%) with spontaneous puberty were receiving testosterone replacement and 4 of the 5 (80%) with induced puberty.

CONCLUSION

This study with the benefit of long follow-up indicates that Leydig cell failure occurs with radiation doses <20Gy. It may occur many years after irradiation and mandates long-term screening for hypogonadism.

Structural Basis of Colchicine-Site targeting Acylhydrazones active against Multidrug-Resistant Acute Lymphoblastic Leukemia

Tubulin is one of the best validated anti-cancer targets, but most anti-tubulin agents have unfavorable therapeutic indexes. Here, we characterized the tubulin-binding activity, the mechanism of action, and the in vivo anti-leukemia efficacy of three 3,4,5-trimethoxy-N-acylhydrazones. We show that all compounds target the colchicine-binding site of tubulin and that none is a substrate of ABC transporters. The crystal structure of the tubulin-bound N-(1′-naphthyl)-3,4,5-trimethoxybenzohydrazide (12) revealed steric hindrance on the T7 loop movement of β-tubulin, thereby rendering tubulin assembly incompetent. Using dose escalation and short-term repeated dose studies, we further report that this compound class is well tolerated to >100 mg/kg in mice. We finally observed that intraperitoneally administered compound 12 significantly prolonged the overall survival of mice transplanted with both sensitive and multidrug-resistant acute lymphoblastic leukemia (ALL) cells. Taken together, this work describes promising colchicine-site-targeting tubulin inhibitors featuring favorable therapeutic effects against ALL and multidrug-resistant cells.

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3,4,5-trimethoxy-N-acylhydrazones bind to the colchicine site of tubulin

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12 forms a single H-bond with αThr179 and causes steric hindrance of tubulin βT7 loop

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3,4,5-trimethoxy-N-acylhydrazones feature low toxicity

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12 shows therapeutic effect against multidrug-resistant acute lymphoblastic leukemia

What is the Role of Hematopoietic Cell Transplantation (HCT) for Pediatric Acute Lymphoblastic Leukemia (ALL) in the Age of Chimeric Antigen Receptor T-Cell (CART) Therapy?

CD19 chimeric antigen receptor T-cell (CART) therapy has revolutionized the treatment of patients with relapsed/refractory hematologic malignancies, especially B-cell acute lymphoblastic leukemia. As CART immunotherapy expands from clinical trials to FDA-approved treatments, a consensus among oncologists and hematopoietic cell transplant (HCT) physicians is needed to identify which patients may benefit from consolidative HCT post-CART therapy. Here, we review CD19 CART therapy and the outcomes of published clinical trials, highlighting the use of post-CART HCT and the pattern of relapse after CD19 CART. At this time, the limited available long-term data from clinical trials precludes us from making definitive HCT recommendations. However, based on currently available data, we propose that consolidative HCT post-CART therapy be considered for all HCT-eligible patients and especially for pediatric patients with KMT2A-rearranged B-cell acute lymphoblastic leukemia.

Mechanisms of extramedullary relapse in acute lymphoblastic leukemia: Reconciling biological concepts and clinical issues

Long-term survival rates in childhood acute lymphoblastic leukemia (ALL) are currently above 85% due to huge improvements in treatment. However, 15-20% of children still experience relapses. Relapses can either occur in the bone marrow or at extramedullary sites, such as gonads or the central nervous system (CNS), formerly referred to as ALL-blast sanctuaries. The reason why ALL cells migrate to and stay in these sites is still unclear. In this review, we have attempted to assemble the evidence concerning the microenvironmental factors that could explain why ALL cells reside in such sites. We present criteria that make extramedullary leukemia niches and solid tumor metastatic niches comparable. Indeed, considering extramedullary leukemias as metastases could be a useful approach for proposing more effective treatments. In this context, we conclude with several examples of potential niche-based therapies which could be successfully added to current treatments of ALL.

Outcomes of patients with childhood B-cell precursor acute lymphoblastic leukaemia with late bone marrow relapses: long-term follow-up of the ALLR3 open-label randomised trial

BACKGROUND

The ALLR3 trial investigated outcomes of children with B-cell precursor acute lymphoblastic leukaemia who had late bone marrow relapses. We analysed long-term follow-up outcomes of these patients.

METHODS

ALLR3 was an open-label randomised clinical trial that recruited children aged 1-18 years with B-cell precursor acute lymphoblastic leukaemia who had late bone marrow relapses. Eligible patients were recruited from centres in Australia, Ireland, the Netherlands, New Zealand, and the UK. Patients were randomly assigned from Jan 31, 2003, to Dec 31, 2007, and the trial closed to recruitment on Oct 31, 2013. Randomly assigned patients were allocated to receive either idarubicin or mitoxantrone in induction by stratified concealed randomisation; after randomisation stopped in Dec 31, 2007, all patients were allocated to receive mitoxantrone. After three blocks of therapy, patients with high minimal residual disease (≥10-4 cells) at the end of induction were allocated to undergo allogeneic stem-cell transplantation and those with low minimal residual disease (<10-4 cells) at the end of induction were allocated to receive chemotherapy. Minimal residual disease level was measured by real-time quantitative PCR analysis of immunoglobulin and T-cell receptor gene rearrangements. The primary endpoint of the original ALLR3 clinical trial was progression-free survival of randomly assigned patients. The primary endpoint of this long-term follow-up analysis was progression-free survival of patients with late bone marrow relapses stratified by minimal residual disease level. Outcomes were correlated with age, site, time to recurrence, and genetic subtypes, and analysed by both intention to treat and actual treatment received. This trial is registered on the ISRCTN registry, number ISRCTN45724312, and on ClinicalTrials.gov, number NCT00967057.

FINDINGS

Between Feb 2, 2003, and Oct 28, 2013, 228 patients with B-cell precursor acute lymphoblastic leukaemia and late bone marrow relapses were treated. After a median follow-up of 84 months (IQR 48-109), progression-free survival of all randomly assigned patients was 60% (95% CI 54-70). 220 patients achieved second complete remission, and minimal residual disease was evaluable in 192 (87%). 110 patients with late bone marrow relapses and high minimal residual disease at the end of induction were allocated to undergo stem-cell transplantation, and 82 patients with low minimal residual disease at the end of induction were allocated to receive chemotherapy. In the patients allocated to undergo stem-cell transplantation, four relapses and three deaths were reported before the procedure, and 11 patients were not transplanted. Of the 92 patients transplanted, 58 (63%) remained in second complete remission, 13 (14%) died of complications, and 21 (23%) relapsed after stem-cell transplantation. In patients allocated to receive chemotherapy, one early treatment-related death was reported and 11 patients were transplanted. Of the 70 patients who continued on chemotherapy, 49 (70%) remained in second complete remission, two (3%) died of complications, and 19 (27%) relapsed. Progression-free survival at 5 years was 56% (95% CI 46-65) in those with high minimal residual disease and 72% (60-81) in patients with low minimal residual disease (p=0·0078). Treatment-related serious adverse events were not analysed in the long-term follow-up.

INTERPRETATION

Patients with B-cell precursor acute lymphoblastic leukaemia with late bone marrow relapses and low minimal residual disease at end of induction had favourable outcomes with chemotherapy without undergoing stem-cell transplantation. Patients with high minimal residual disease benefited from stem-cell transplantation, and targeted therapies might offer further improvements in outcomes for these patients.

FUNDING

Bloodwise (Formerly Leukaemia and Lymphoma Research) UK, Cancer Research UK, Sporting Chance Cancer Foundation, National Health and Medical Research Council Australia, KindreneKankervrij Netherlands, European Union Seventh Framework Programme, India Alliance Wellcome DBT Margdarshi Fellowship.

Bone Mineral Density Corrected for Size in Childhood Leukaemia Survivors Treated with Haematopoietic Stem Cell Transplantation and Total Body Irradiation

BACKGROUND

Childhood leukaemia survivors treated with haematopoietic stem cell transplantation and total body irradiation (HSCT-TBI) have multiple risk factors for reduced bone mineral density (BMD) and growth failure; hence, BMD assessment must take body size into consideration. This study aimed to evaluate size-corrected BMD in leukaemia survivors treated with and without HSCT-TBI.

METHODS

Childhood leukaemia survivors treated with HSCT-TBI (n = 35), aged 17.3 (10.5-20.9) years, were compared with those treated with chemotherapy only, (n = 16) aged 18.5 (16.1-20.9) years, and population references. Outcome measures included anthropometric measurements and BMD by dual-energy X-ray absorptiometry. BMD was corrected for size as bone mineral apparent density (BMAD). Statistical analysis was performed by 1- and 2-sample t tests as well as regression analysis (5% significance).

RESULTS

HSCT-TBI survivors were lighter and shorter with reduced spinal heights compared with chemotherapy-only subjects and population references. Compared with population references, HSCT-TBI survivors showed lower BMD standard deviation scores (SDS) (p = 0.008), but no difference in BMAD-SDS, and chemotherapy-only survivors showed no differences in neither BMD-SDS nor BMAD-SDS. All HSCT-TBI participants with BMD-SDS <-2 had BMAD-SDS >-2. BMAD-SDS was negatively associated with age (r = -0.38, p = 0.029) in HSCT-TBI survivors.

CONCLUSIONS

Size-corrected BMD are normal in HSCT-TBI survivors in young adulthood, but may reduce overtime. BMD measurements should be corrected for size in these patients to be clinically meaningful.

Clinical characteristics and prognosis of pediatric patients with B cell acute lymphoblastic leukemia relapse

The aim of the present study was to investigate the clinical characteristics and prognosis of pediatric patients with B cell acute lymphoblastic leukemia (B-ALL) relapse. A total of 390 pediatric patients diagnosed as B-ALL and receiving regular chemotherapy in Jining First People's Hospital from August 2010 to May 2016 were selected. The clinical characteristics, therapeutic response and prognosis were compared between the two groups. There were significant differences in the comparisons of age, leukocyte count in the initial diagnosis and glucocorticoid sensitive test between B-cell ALL (B-ALL) relapse group and non-relapse group; the minimal residual disease (MRD) levels of pediatric patients in the two groups at 33 days and 12 weeks were significantly different. The 3-year event-free survival (EFS) rates of pediatric patients with early, medium and late B-ALL relapse were 12.5±7.8%, 33.1±9.8% and 63.6±6.1%, respectively, and the prognosis of late relapse was significantly better than that of early relapse (P<0.001). The 3-year EFS rates of pediatric patients with bone marrow relapse in standard risk group, intermediate risk group and high risk group were 29.1±6.9, 31.3±6.5 and 28.3±6.3%, respectively; there were no statistically significant differences (P=0.387, P>0.05). Pediatric patients with B-ALL relapse are characterized by higher onset age (≥10 years old), high leukocyte count and hormone insensitivity. Dynamic monitoring of MRD level in B-ALL pediatric patients can predict the relapse.

Hematopoietic stem cell transplantation for isolated extramedullary relapse of acute lymphoblastic leukemia in children

Relapse of acute lymphoblastic leukemia (ALL) may occur in extramedullary sites, mainly central nervous system (CNS) and testis. Optimal post-remissional treatment for isolated extramedullary relapse (IEMR) is still controversial. We collected data of children treated with hematopoietic stem cell transplantation (HSCT) for ALL IEMR from 1990 to 2015 in Italy. Among 281 patients, 167 had a relapse confined to CNS, 73 to testis, 14 to mediastinum, and 27 to other organs. Ninety-seven patients underwent autologous HSCT, 79 received allogeneic HSCT from a matched family donor, 75 from a matched unrelated donor, and 30 from an HLA-haploidentical donor. The 10-year overall survival was 56% and was not influenced by gender, ALL blast immune-phenotype, age, site of relapse, duration of first remission, and type of HSCT. In multivariable analysis, the only prognostic factors were disease status at HSCT and year of transplantation. Patients transplanted in third or subsequent complete remission (CR) had a risk of death 2.3 times greater than those in CR2. Children treated after 2000 had half the risk of death than those treated before that year. Our results suggest that both autologous and allogeneic HSCT may be considered for the treatment of pediatric ALL IEMR after the achievement of CR2.

Surface expression of Cytokine Receptor-Like Factor 2 increases risk of relapse in pediatric acute lymphoblastic leukemia patients harboring IKZF1 deletions

We prospectively examined whether surface expression of Cytokine Receptor-Like Factor 2 (CRLF2) on leukemic blasts is associated with survival and induction treatment response in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) patients. Flow cytometric analysis of bone marrow-derived leukemia cells revealed that 7.51% (29/286) of 386 pediatric BCP-ALL patients were CRLF2-positive (CRLF2pos) at diagnosis. The median minimal residual disease (MRD) was lower in CRLF2pos than CRLF2-negative (CRLF2neg) patients on day 15 (MRD15) after induction therapy [0.01% (0.001-0.42%) vs. 0.45% (0.05-3.50%); p=0.001]. By contrast, the MRD15 was higher in Ikaros family Zinc Finger Protein 1 (IKZF1)-deleted BCP-ALL patients than in BCP-ALL patients without IKZF1 deletions [1.18% (0.06-12.0%) vs 0.33% (0.03-2.6%); p=0.003]. Subgroup analysis showed that MRD15 levels were lower in IKZF1Δ/CRLF2pos patients than in IKZF1Δ/CRLF2neg patients [0.1% (0.02-5.06%) vs. 2.9% (0.25-12%); p=0.005]. Furthermore, MRD15 levels were higher in IKZF1WT/CRLF2neg patients than in IKZF1WT/CRLF2pos patients [0.40% (0.04-2.7%) vs. 0.001% (0.001-0.01%)]. Despite the low MRD15 levels, IKZF1Δ/CRLF2pos patients showed poorer relapse-free survival (RFS) than other patient groups (p=0.003). These findings demonstrate that surface CRLF2 expression is associated with increased risk of relapse in pediatric BCP-ALL patients harboring IKZF1 deletions.

Treatment outcome of pediatric acute lymphoblastic leukemia in Yeungnam region: Multicenter retrospective study of Study Alliance of Yeungnam Pediatric Hematology-Oncology (SAYPH)

OBJECTIVES

We aimed to evaluate treatment outcomes of pediatric acute lymphoblastic leukemia (ALL) subgroups by risk-stratification, in the Yeungnam region of Korea.

METHODS

We reviewed the courses of 409 newly diagnosed ALL patients from January 2004 to December 2013 in the Yeungnam region.

RESULTS

All patients were classified into three risk groups: standard risk (SR, n=212), high risk (HR, n=153) and very high risk (VHR, n=44). The mean follow-up time was 73.6 ± 39.4 months. The 7-year event-free survival (EFS) and overall survival (OS) rates were 78.7 ± 2.1% and 86.8 ± 1.8%, respectively. Significant 7-year EFS and OS rates for SR (84.0 ± 2.7%, 93.7 ± 1.8%), HR (76.5 ± 3.5%, 82.1 ± 3.3%), and VHR (60.6 ± 7.5%, 69.9 ± 7.5%) were observed (P<0.001), respectively. Relapse occurred in 52 patients, and the cumulative 7-year incidence of relapse differed according to risk groups (SR vs. HR vs. VHR=12.6% vs. 14.0% vs. 29.6%, P=0.003).For the 46 relapsed patients who were treated, the 3-year EFS and OS were 42.3 ± 8.3%and 46.4± 8.4%. Among the 44 VHR patients, EFS was not significantly different between the chemotherapy-treated patients and those received hematopoietic stem cell transplantation (P=0.533). The 7-year EFS of the hyperleukocytosis subgroup (24 cases, 14 under 10 years of age)showed a tendency for better prognosis than that of the other VHR subgroups (P=0.178).

CONCLUSION

Our results revealed improved outcomes in pediatric ALL patients with risk-stratified therapy. The hyperleukocytosis subgroup without any combined chromosomal abnormalities may respond favorably to chemotherapy alone after first complete remission.

Synergistic action of dual IGF1/R and MEK inhibition sensitizes childhood acute lymphoblastic leukemia (ALL) cells to cytotoxic agents and involves downregulation of STAT6 and PDAP1

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Dual insulin-like growth factor 1 receptor (IGF1/R) + mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibition synergistically sensitize apoptosis-resistant acute lymphoblastic leukemia (ALL) cells.

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Dual IGF1/R + MEK inhibition potentiates chemotherapy-induced killing of ALL cells.

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Signal transducer and activator of transcription 6 (STAT6) and platelet-derived growth factor-associated protein 1 (PDAP1) are downregulated differentially by this synergistic action.

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STAT6 and PDAP1 are predicted to act in a putative STAT6–ERK–nuclear factor kappa beta (NF-κB) survival network.

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Targeting this network may be useful for sensitizing ALL to chemotherapy agents.

Heterogeneous upregulation of multiple prosurvival pathways underlies resistance to damage-induced apoptosis in acute lymphoblastic leukemia (ALL) cells despite normal p53 responses. Here, we show that the dual combination of insulin-like growth factor 1 (IGF1)/IGF1 receptor (IGF1/R) and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibition using AG1024 + U0126 can sensitize apoptosis-resistant ALL cells to ionizing radiation-induced DNA damage irrespective of effect of single pathway inhibition in vitro. This AG1024 + U0126 combination also significantly potentiates the ability of the core chemotherapy compounds vincristine, dexamethasone, and daunorubicin to kill ALL cells in vitro. Evidence of the synergistic action of AG1024 + U0126 in samples with variable basal levels of phosphorylated IGF1/Rβ and ERK1/2 suggested additional targets of this drug combination. Consistent with this, gene expression profiling identified 32 “synergy genes” differentially targeted by IGF1/R + MEK inhibition and, among these, Signal transducer and activator of transcription 6 (STAT6) and platelet-derived growth factor-associated protein 1 (PDAP1) were the most differentially downregulated cluster. Pearson correlation analysesrevealed that STAT6 and PDAP1 display significant expression codependency and a common expression pattern linked with other key “synergy” genes, supporting their predicted role in an STAT6–ERK–nuclear factor kappa beta (NF-κB) network. Knockdown studies revealed that loss of STAT6, but not PDAP1, impinges on the cell cycle, causing reduced numbers of viable cells. In combination with daunorubicin, STAT6 loss has an additive effect on cell killing, whereas PDAP1 loss is synergistic, indicating an important role of PDAP1 in the cellular response to this anthracycline. Inhibition of STAT6 or PDAP1 may therefore represent a potential novel therapeutic strategy for resistant ALL by enhancing sensitivity to chemotherapy.

DNA methylation holds prognostic information in relapsed precursor B-cell acute lymphoblastic leukemia

Background

Few biological markers are associated with survival after relapse of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). In pediatric T-cell ALL, we have identified promoter-associated methylation alterations that correlate with prognosis. Here, the prognostic relevance of CpG island methylation phenotype (CIMP) classification was investigated in pediatric BCP-ALL patients.

Methods

Six hundred and one BCP-ALL samples from Nordic pediatric patients (age 1–18) were CIMP classified at initial diagnosis and analyzed in relation to clinical data.

Results

Among the 137 patients that later relapsed, patients with a CIMP− profile (n = 42) at initial diagnosis had an inferior overall survival (pOS_5years 33%) compared to CIMP+ patients (n = 95, pOS_5years 65%) (p = 0.001), which remained significant in a Cox proportional hazards model including previously defined risk factors.

Conclusion

CIMP classification is a strong candidate for improved risk stratification of relapsed BCP-ALL.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0466-3) contains supplementary material, which is available to authorized users.

Gene Expression Profiling of Acute Lymphoblastic Leukemia in Children with Very Early Relapse

BACKGROUND AND AIMS

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer worldwide. Mexican patients have high mortality rates, low frequency of good prognosis biomarkers (i.e., ETV6-RUNX1) and a high proportion is classified at the time of diagnosis with a high risk to relapse according to clinical features. In addition, very early relapses are more frequently observed than in other populations. The aim of the study was to identify new potential biomarkers associated with very early relapse in Mexican ALL children through transcriptome analysis.

METHODS

Microarray gene expression profiling on bone marrow samples of 54 pediatric ALL patients, collected at time of diagnosis and/or at relapse, was performed. Eleven patients presented relapse within the first 18 months after diagnosis. Affymetrix Human Transcriptome Array 2.0 (HTA 2.0) was used to perform gene expression analysis. Annotation and functional enrichment analyses were carried out using Gene Ontology, KEGG pathway analysis and Ingenuity Pathway Analysis tools.

RESULTS

BLVRB, ZCCHC7, PAX5, EBF1, TMOD1 and BLNK were differentially expressed (fold-change >2.0 and p value <0.01) between relapsed and non-relapsed patients. Functional analysis of abnormally expressed genes revealed their important role in cellular processes related to the development of hematological diseases, cancer, cell death and survival and in cell-to-cell signaling interaction.

CONCLUSIONS

Our data support previous findings showing the relevance of PAX5, EBF1 and ZCCHC7 as potential biomarkers to identify a subgroup of ALL children in high risk to relapse.

Outcome of Reinduction Chemotherapy with a Modified Dose of Idarubicin for Children with Marrow-Relapsed Acute Lymphoblastic Leukemia: Results of the Childhood Acute Lymphoblastic Leukemia (CALL)-0603 Study

This multicenter, prospective trial was conducted to develop an effective and safe reinduction regimen for marrow-relapsed pediatric acute lymphoblastic leukemia (ALL) by modifying the dose of idarubicin. Between 2006 and 2009, the trial accrued 44 patients, 1 to 21 years old with first marrow-relapsed ALL. The reinduction regimen comprised prednisolone, vincristine, L-asparaginase, and idarubicin (10 mg/m²/week). The idarubicin dose was adjusted according to the degree of myelosuppression. The second complete remission (CR2) rate was 72.7%, obtained by 54.2% of patients with early relapse < 24 months after initial diagnosis and 95.0% of those with late relapse (P = 0.002). Five patients entered remission with extended treatment, resulting in a final CR2 rate of 84.1%. The CR2 rate was not significantly different according to the idarubicin dose. The induction death rate was 2.3% (1/44). The 5-year event-free and overall survival rates were 22.2% ± 6.4% and 27.3% ± 6.7% for all patients, 4.2% ± 4.1% and 8.3% ± 5.6% for early relapsers, and 43.8% ± 11.4% and 50.0% ± 11.2% for late relapsers, respectively. Early relapse and slow response to reinduction chemotherapy were predictors of poor outcomes. In conclusion, a modified dose of idarubicin was effectively incorporated into the reinduction regimen for late marrow-relapsed ALL with a low toxic death rate. However, the CR2 rate for early relapsers was suboptimal, and the second remission was not durable in most patients.

Meta-analysis of gene expression in relapsed childhood B-acute lymphoblastic leukemia

Background

Relapsed pediatric B-acute lymphoblastic leukemia (B-ALL) remains as the leading cause of cancer death among children. Other than stem cell transplantation and intensified chemotherapy, no other improved treatment strategies have been approved clinically. Gene expression profiling represents a powerful approach to identify potential biomarkers and new therapeutic targets for various diseases including leukemias. However, inadequate sample size in many individual experiments has failed to provide adequate study power to yield translatable findings. With the hope of getting new insights into the biological mechanisms underpinning relapsed ALL and identifying more promising biomarkers or therapeutic targets, we conducted a meta-analysis of gene expression studies involving ALL from 3 separate studies.

Method

By using the keywords “acute lymphoblastic leukemia”, and “microarray”, a total of 280 and 275 microarray datasets were found listed in Gene Expression Omnibus database GEO and ArrayExpress database respectively. Further manual inspection found that only three studies (GSE18497, GSE28460, GSE3910) were focused on gene expression profiling of paired diagnosis-relapsed pediatric B-ALL. These three datasets which comprised of a total of 108 matched diagnosis-relapsed pediatric B-ALL samples were then included for this meta-analysis using RankProd approach.

Results

Our analysis identified a total of 1795 upregulated probes which corresponded to 1527 genes (pfp < 0.01; FC > 1), and 1493 downregulated probes which corresponded to 1214 genes (pfp < 0.01; FC < 1) respectively. S100A8 appeared as the top most overexpressed gene (pfp < 0.01, FC = 1.8) and is a potential target for further validation. Based on gene ontology biological process annotation, the upregulated genes were most enriched in cell cycle processes (enrichment score = 15.3), whilst the downregulated genes were clustered in transcription regulation (enrichment score = 12.6). Elevated expression of cell cycle regulators (e.g kinesins, AURKA, CDKs) was the key genetic defect implicated in relapsed ALL, and serve as attractive targets for therapeutic intervention.

Conclusion

We identified S100A8 as the most overexpressed gene, and the cell cycle pathway as the most promising biomarker and therapeutic target for relapsed childhood B-ALL. The validity of the results warrants further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3103-1) contains supplementary material, which is available to authorized users.

Extramedullary Relapse of Acute Myeloid and Lymphoid Leukemia in Children: A Retrospective Analysis

Background

Extramedullary relapse (EMR) is a recurrence of leukemia in sites other than the bone marrow, and it exhibits a relatively rare presentation of relapse of acute leukemia. However, EMR is an important cause of treatment failure among patients with acute leukemia. Therefore, early detection of these relapses may improve the prognosis.

Objectives

To describe the disease-related demographic and clinical features and radiologic findings for children diagnosed with EMR in acute leukemia.

Patients and Methods

The study was based on 22 children (M: F = 14: 8; mean age 7.30 (2.1 - 15.7) years) with 8 acute myeloid leukemia (AML) and 14 acute lymphoid leukemia (ALL) who had experienced an EMR. Age, gender, clinical symptoms, initial extramedullary disease (EMD), French-American-British (FAB) morphology, cytogenetics, time to and site of EMR, concurrent bone marrow relapse (BMR), radiologic findings, and outcomes were evaluated.

Results

No definite relationship was found between initial EMD and EMR. A predilection for AML to relapse in the central nervous system (CNS), except for the CSF and bone, and for ALL to relapse in the CSF and kidney seemed to occur. Patients with EMR had a significantly higher incidence of t(8: 21) cytogenetics and FAB M2 and L1 morphologies. EMR accompanied with concurrent BMR occurred in 31.8% of the patients, who exhibited a relatively grave clinical course. Radiologic findings were nonspecific and had a great variety of structure involved, including bulging enhancing mass in the CT scan, hypoechoic mass in the US, and enhanced mass-like lesion in the MRI.

Conclusions

Knowledge of the potential sites of EMR, their risk factors, and their clinical and radiologic features may be helpful in the early diagnosis of relapse and planning for therapy.

Feasibility Study of a Novel Experimental Induction Protocol Combining B43-PAP (Anti-CD19) Immunotoxin With Standard Induction Chemotherapy in Children and Adolescents With Relapsed B-Lineage ALL: A Report From the Children's Oncology Group

BACKGROUND

B43-pokeweed antiviral protein (B43-PAP) is a high-affinity anti-CD19 immunotoxin that is capable of causing apoptotic death in B-lineage leukemic cells with a drug-resistant phenotype. B43-PAP exhibited in vivo antileukemic activity in preclinical studies as well as on a single-agent phase I clinical trial. This pediatric phase I/II study evaluated the toxicity profile and efficacy of B43-PAP immunotoxin in combination with standard induction chemotherapy in children and adolescents with relapsed CD19-positive B-lineage acute lymphoblastic leukemia (B-ALL). Pharmacokinetic profile and immunogenicity of B43-PAP were assessed.

EXPERIMENTAL DESIGN

B43-PAP in combination with standard 3 and 4-drug induction chemotherapy was administered on days 9-13 and 21-25 of a 28-day treatment course with vincristine, prednisone, L-asparaginase, daunomycin, and intrathecal methotrexate. Thirty patients with relapsed B-ALL were enrolled on study CCG-0957.

RESULTS

Grade III/IV nonhematologic dose-limiting toxicities were encountered in 4 patients evaluable for toxicity and included myalgias, motor dysfunction, pulmonary toxicity, and elevated liver transaminase. Dose-limiting toxicities occurred only with the 4-drug regimen. Fourteen patients achieved a complete remission at the end of induction among the 20 patients evaluable for response.

CONCLUSIONS

B43-PAP in combination with standard induction chemotherapy can be safely administered and exhibits clinical antileukemic activity against relapsed B-ALL.

Central nervous system disease in childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the commonest childhood malignancy. Despite therapeutic advancements, relapse of the pathological state in the form of central nervous system (CNS) disease remains a challenge. CNS disease appears to be present at diagnosis in at least 40% of patients. This relapse in the form of CNS disease is one of the major hurdles in achieving complete cure. The present review article aims to discuss the important mechanisms of leukemic entry and infiltration patterns of leukemic cells into the CNS. Also, latest updates in the management strategies of ALL will also be focused in the present article.

Relapsed childhood acute lymphoblastic leukemia in the Nordic countries: prognostic factors, treatment and outcome

Relapse is the main reason for treatment failure in childhood acute lymphoblastic leukemia. Despite improvements in the up-front therapy, survival after relapse is still relatively poor, especially for high-risk relapses. The aims of this study were to assess outcomes following acute lymphoblastic leukemia relapse after common initial Nordic Society of Paediatric Haematology and Oncology protocol treatment; to validate currently used risk stratifications, and identify additional prognostic factors for overall survival. Altogether, 516 of 2735 patients (18.9%) relapsed between 1992 and 2011 and were included in the study. There were no statistically significant differences in outcome between the up-front protocols or between the relapse protocols used, but an improvement over time was observed. The 5-year overall survival for patients relapsing in the period 2002-2011 was 57.5±3.4%, but 44.7±3.2% (P<0.001) if relapse occurred in the period 1992-2001. Factors independently predicting mortality after relapse included short duration of first remission, bone marrow involvement, age ten years or over, unfavorable cytogenetics, and Down syndrome. T-cell immunophenotype was not an independent prognostic factor unless in combination with hyperleukocytosis at diagnosis. The outcome for early combined pre-B relapses was unexpectedly poor (5-year overall survival 38.0±10.6%), which supports the notion that these patients need further risk adjustment. Although survival outcomes have improved over time, the development of novel approaches is urgently needed to increase survival in relapsed childhood acute lymphoblastic leukemia.

Outcome of central nervous system relapses in childhood acute lymphoblastic leukaemia--prospective open cohort analyses of the ALLR3 trial

The outcomes of Central Nervous System (CNS) relapses in children with acute lymphoblastic leukaemia (ALL) treated in the ALL R3 trial, between January 2003 and March 2011 were analysed. Patients were risk stratified, to receive a matched donor allogeneic transplant or fractionated cranial irradiation with continued treatment for two years. A randomisation of Idarubicin with Mitoxantrone closed in December 2007 in favour of Mitoxantrone. The estimated 3-year progression free survival for combined and isolated CNS disease were 40.6% (25·1, 55·6) and 38.0% (26.2, 49.7) respectively. Univariate analysis showed a significantly better survival for age <10 years, progenitor-B cell disease, good-risk cytogenetics and those receiving Mitoxantrone. Adjusting for these variables (age, time to relapse, cytogenetics, treatment drug and gender) a multivariate analysis, showed a poorer outcome for those with combined CNS relapse (HR 2·64, 95% CI 1·32, 5·31, p = 0·006 for OS). ALL R3 showed an improvement in outcome for CNS relapses treated with Mitoxantrone compared to Idarubicin; a potential benefit for matched donor transplant for those with very early and early isolated-CNS relapses.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN45724312.

A therapeutic trial of decitabine and vorinostat in combination with chemotherapy for relapsed/refractory acute lymphoblastic leukemia

DNA hypermethylation and histone deacetylation are pathways of leukemia resistance. We investigated the tolerability and efficacy of decitabine and vorinostat plus chemotherapy in relapse/refractory acute lymphoblastic leukemia (ALL). Decitabine (15 mg/m(2) iv) and vorinostat (230 mg/m(2) PO div BID) were given days 1-4 followed by vincristine, prednisone, PEG-asparaginase, and doxorubicin. Genome wide methylation profiles were performed in 8 matched patient bone marrow (BM) samples taken at day 0 and day 5 (postdecitabine). The median age was 16 (range, 3-54) years. All patients had a prior BM relapse, with five relapsing after allogeneic transplant. The most common nonhematological toxicities possibly related to decitabine or vorinostat were infection with neutropenia (grade 3; n = 4) and fever/neutropenia (grade 3, n = 4; grade 4, n = 1). Of the 13 eligible patients, four achieved complete remission without platelet recovery (CRp), two partial response (PR), one stable disease (SD), one progressive disease (PD), two deaths on study and three patients who did not have end of therapy disease evaluations for an overall response rate of 46.2% (CRp + PR). Following decitabine, significant genome-wide hypo-methylation was observed. Comparison of clinical responders with nonresponders identified methylation profiles of clinical and biological relevance. Decitabine and vorinostat followed by re-Induction chemotherapy was tolerable and demonstrated clinical benefit in relapsed patients with ALL. Methylation differences were identified between responders and nonresponders indicating interpatient variation, which could impact clinical outcome. This study was registered at www.clinicaltrials.gov as NCT00882206.

High-throughput screening of human leukemia xenografts to identify dexamethasone sensitizers

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Glucocorticoids (e.g., dexamethasone) form a critical component of chemotherapy regimens for pediatric ALL, and the initial response to glucocorticoid therapy is a major prognostic factor, where resistance is predictive of poor outcome. We have previously established a clinically relevant ALL xenograft model, consisting of primary pediatric ALL biopsies engrafted into immune-deficient mice, in which in vitro and in vivo dexamethasone sensitivity significantly correlated with patient outcome. In this study, we used high-throughput screening (HTS) to identify novel compounds that reverse dexamethasone resistance in a xenograft (ALL-19) derived from a chemoresistant pediatric ALL patient that is representative of the most common pediatric ALL subtype (B-cell precursor [BCP-ALL]). The compound 2-(4-chlorophenoxy)-2-methyl-N-(2-(piperidin-1-yl)phenyl)propanamide showed little cytotoxic activity alone (IC50 = 31 µM), but when combined with dexamethasone, it caused a marked decrease in cell viability. Fixed-ratio combination assays were performed against a broad panel of dexamethasone-resistant and -sensitive xenografts representative of BCP-ALL, T-cell ALL, and Mixed Lineage Leukemia-rearranged ALL, and synergy was observed in six of seven xenografts. We describe here the development of a novel 384-well cell-based high-throughput screening assay for identifying potential dexamethasone sensitizers using a clinically relevant ALL xenograft model.

A phase I study of EZN-3042, a novel survivin messenger ribonucleic acid (mRNA) antagonist, administered in combination with chemotherapy in children with relapsed acute lymphoblastic leukemia (ALL): a report from the therapeutic advances in childhood leukemia and lymphoma (TACL) consortium

To address the therapeutic challenges in childhood relapsed ALL, a phase 1 study combining a survivin mRNA antagonist, EZN-3042, with reinduction chemotherapy was developed for pediatric patients with second or greater bone marrow relapses of B-lymphoblastic leukemia. EZN-3042 was administered as a single agent on days -5 and -2 and then in combination with a 4-drug reinduction platform on days 8, 15, 22, and 29. Toxicity and the biological activity of EZN-3042 were assessed. Six patients were enrolled at dose level 1 (EZN-3042 2.5 mg/kg/dose). Two dose-limiting toxicities were observed: 1 patient developed a grade 3 γ-glutamyl transferase elevation and another patient developed a grade 3 gastrointestinal bleeding. Downmodulation of survivin mRNA and protein were assessed after single-agent dosing and decreased expression was observed in 2 of 5 patients with sufficient material for analysis. Although some biological activity was observed, the combination of EZN-3042 with intensive reinduction chemotherapy was not tolerated at a dose that led to consistent downregulation of survivin expression. The trial was terminated following the completion of dose level 1, after further clinical development of this agent was halted.

Pediatric relapsed or refractory leukemia: new pharmacotherapeutic developments and future directions

Over the past 50 years, numerous advances in treatment have produced dramatic increases in the cure rates of pediatric leukemias. Despite this progress, the majority of children with relapsed leukemia are not expected to survive. With current chemotherapy regimens, approximately 15 % of children with acute lymphoblastic leukemia and 45 % of children with acute myeloid leukemia will have refractory disease or experience a relapse. Advances in the treatment of pediatric relapsed leukemia have not mirrored the successes of upfront therapy, and newer treatments are desperately needed in order to improve survival in these challenging patients. Recent improvements in our knowledge of cancer biology have revealed an extensive number of targets that have the potential to be exploited for anticancer therapy. These advances have led to the development of a number of new treatments that are now being explored in children with relapsed or refractory leukemia. Novel agents seek to exploit the same molecular aberrations that contribute to leukemia development and resistance to therapy. Newer classes of drugs, including monoclonal antibodies, tyrosine kinase inhibitors and epigenetic modifiers are transforming the treatment of patients who are not cured with conventional therapies. As the side effects of many new agents are distinct from those seen with conventional chemotherapy, these treatments are often explored in combination with each other or combined with conventional treatment regimens. This review discusses the biological rationale for the most promising new agents and the results of recent studies conducted in pediatric patients with relapsed leukemia.

Novel cellular therapies for leukemia: CAR-modified T cells targeted to the CD19 antigen

The ability of immune-competent donor T cells to mediate a beneficial graft-versus-leukemia (GVL) effect was first identified in the setting of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for hematologic malignancies. Unfortunately, with the exception of chronic myelogenous leukemia and EBV-induced lymphoproliferative disease, allo-HSCT GVL lacks the potency to significantly affect disease progression or recurrence in most other hematologic malignancies. The inadequacy of a GVL effect using past approaches is particularly evident in patients with lymphoid malignancies. However, with the advent of improved gene transfer technology, genetically modified tumor-specific immune effectors have extended cellular immunotherapy to lymphoid malignancies. One promising strategy entails the introduction of genes encoding artificial receptors called chimeric antigen receptors (CARs), which redirect the specificity and function of immune effectors. CAR-modified T cells targeted to the B cell-specific CD19 antigen have demonstrated promising results in multiple early clinical trials, supporting further investigation in patients with B-cell cancers. However, disparities in clinical trial design and CAR structure have complicated the discovery of the optimal application of this technology. Recent preclinical studies support additional genetic modifications of CAR-modified T cells to achieve optimal clinical efficacy using this novel adoptive cellular therapy.

Children's Oncology Group's 2013 blueprint for research: acute lymphoblastic leukemia

Approximately 90% of the 2,000 children, adolescents, and young adults enrolled each year in Children's Oncology Group acute lymphoblastic leukemia (ALL) trials will be cured. However, high-risk subsets with significantly inferior survival remain, including infants, newly diagnosed patients with age ≥10 years, white blood count ≥50,000/µl, poor early response or T-cell ALL, and relapsed ALL patients. Effective strategies to improve survival include better risk stratification, optimizing standard chemotherapy and combining targeted therapies with cytotoxic chemotherapy, the latter of which is dependent upon identification of key driver mutations present in ALL.

Novel Bruton's tyrosine kinase inhibitors currently in development

Bruton’s tyrosine kinase (Btk) is intimately involved in multiple signal-transduction pathways regulating survival, activation, proliferation, and differentiation of B-lineage lymphoid cells. Btk is overexpressed and constitutively active in several B-lineage lymphoid malignancies. Btk has emerged as a new antiapoptotic molecular target for treatment of B-lineage leukemias and lymphomas. Preclinical and early clinical results indicate that Btk inhibitors may be useful in the treatment of leukemias and lymphomas.

Novel cellular therapies for leukemia: CAR-modified T cells targeted to the CD19 antigen

The ability of immune-competent donor T cells to mediate a beneficial graft-versus-leukemia (GVL) effect was first identified in the setting of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for hematologic malignancies. Unfortunately, with the exception of chronic myelogenous leukemia and EBV-induced lymphoproliferative disease, allo-HSCT GVL lacks the potency to significantly affect disease progression or recurrence in most other hematologic malignancies. The inadequacy of a GVL effect using past approaches is particularly evident in patients with lymphoid malignancies. However, with the advent of improved gene transfer technology, genetically modified tumor-specific immune effectors have extended cellular immunotherapy to lymphoid malignancies. One promising strategy entails the introduction of genes encoding artificial receptors called chimeric antigen receptors (CARs), which redirect the specificity and function of immune effectors. CAR-modified T cells targeted to the B cell–specific CD19 antigen have demonstrated promising results in multiple early clinical trials, supporting further investigation in patients with B-cell cancers. However, disparities in clinical trial design and CAR structure have complicated the discovery of the optimal application of this technology. Recent preclinical studies support additional genetic modifications of CAR-modified T cells to achieve optimal clinical efficacy using this novel adoptive cellular therapy.

Where do we stand in the treatment of relapsed acute lymphoblastic leukemia?

Acute lymphoblastic leukemia (ALL) is the most common and one of the most treatable cancers in children. Although the majority of children with ALL are now cured, 10%-20% of patients are predicted to relapse and outcomes with salvage therapy have been disappointing, with approximately only one-third of children surviving long-term after disease recurrence. Several prognostic factors have been identified, with timing of recurrence relative to diagnosis and site of relapse emerging as the most important variables. Despite heterogeneity in the elements of salvage therapy that are delivered in trials conducted internationally, outcomes have been remarkably similar and have remained static. Because most intensive salvage regimens have reached the limit of tolerability, current strategies are focusing on identifying new agents tailored to the unique biology of relapsed disease and identifying methods to develop these agents efficiently for clinical use. Recently, high-resolution genomic analyses of matched pairs of diagnostic and relapse bone marrow samples are emerging as a promising tool for identifying pathways that impart chemoresistance.