BFM-oriented treatment for children with acute lymphoblastic leukemia without cranial irradiation and treatment reduction for standard risk patients: results of DCLSG protocol ALL-8 (1991-1996)

The Prognostic Effect of IKZF1 Deletions in ETV6::RUNX1 and High Hyperdiploid Childhood Acute Lymphoblastic Leukemia

IKZF1 deletions are an established prognostic factor in childhood acute lymphoblastic leukemia (ALL). However, their relevance in patients with good risk genetics, namely ETV6::RUNX1 and high hyperdiploid (HeH), ALL remains unclear. We assessed the prognostic impact of IKZF1 deletions in 939 ETV6::RUNX1 and 968 HeH ALL patients by evaluating data from 16 trials from 9 study groups. Only 3% of ETV6::RUNX1 cases (n = 26) were IKZF1-deleted; this adversely affected survival combining all trials (5-year event-free survival [EFS], 79% versus 92%; P = 0.02). No relapses occurred among the 14 patients with an IKZF1 deletion treated on a minimal residual disease (MRD)-guided protocols. Nine percent of HeH cases (n = 85) had an IKZF1 deletion; this adversely affected survival in all trials (5-year EFS, 76% versus 89%; P = 0.006) and in MRD-guided protocols (73% versus 88%; P = 0.004). HeH cases with an IKZF1 deletion had significantly higher end of induction MRD values (P = 0.03). Multivariate Cox regression showed that IKZF1 deletions negatively affected survival independent of sex, age, and white blood cell count at diagnosis in HeH ALL (hazard ratio of relapse rate [95% confidence interval]: 2.48 [1.32-4.66]). There was no evidence to suggest that IKZF1 deletions affected outcome in the small number of ETV6::RUNX1 cases in MRD-guided protocols but that they are related to higher MRD values, higher relapse, and lower survival rates in HeH ALL. Future trials are needed to study whether stratifying by MRD is adequate for HeH patients or additional risk stratification is necessary.

Outcomes of Childhood Noninfant Acute Lymphoblastic Leukemia With 11q23/KMT2A Rearrangements in a Modern Therapy Era: A Retrospective International Study

PURPOSE

We aimed to study prognostic factors and efficacy of allogeneic hematopoietic stem-cell transplantation (allo-HSCT) in first remission of patients with noninfant childhood acute lymphoblastic leukemia (ALL) with 11q23/KMT2A rearrangements treated with chemotherapy regimens between 1995 and 2010.

PATIENTS AND METHODS

Data were retrospectively retrieved from 629 patients with 11q23/KMT2A-rearranged ALL from 17 members of the Ponte-di-Legno Childhood ALL Working Group. Clinical and biologic characteristics, early response assessed by minimal residual disease at the end of induction (EOI) therapy, and allo-HSCT were analyzed for their impact on outcomes.

RESULTS

A specific 11q23/KMT2A translocation partner gene was identified in 84.3% of patients, with the most frequent translocations being t(4;11)(q21;q23) (n = 273; 51.5%), t(11;19)(q23;p13.3) (n = 106; 20.0%), t(9;11)(p21_22;q23) (n = 76; 14.3%), t(6;11)(q27;q23) (n = 20; 3.8%), and t(10;11)(p12;q23) (n = 14; 2.6%); 41 patients (7.7%) had less frequently identified translocation partner genes. Patient characteristics and early response varied among subgroups, indicating large biologic heterogeneity and diversity in therapy sensitivity among 11q23/KMT2A-rearranged ALL. The EOI remission rate was 93.2%, and the 5-year event-free survival (EFS) for the entire cohort was 69.1% ± 1.9%, with a range from 41.7% ± 17.3% for patients with t(9;11)-positive T-ALL (n = 9) and 64.8% ± 3.0% for patients with t(4;11)-positive B-ALL (n = 266) to 91.2% ± 4.9% for patients with t(11;19)-positive T-ALL (n = 34). Low EOI minimal residual disease was associated with favorable EFS, and induction failure was particularly predictive of nonresponse to further therapy and relapse and poor EFS. In addition, EFS was not improved by allo-HSCT compared with chemotherapy only in patients with both t(4;11)-positive B-ALL (n = 64 v 51; P = .10) and 11q23/KMT2A-rearranged T-ALL (n = 16 v 10; P = .69).

CONCLUSION

Compared with historical data, prognosis of patients with noninfant 11q23/KMT2A-rearranged ALL has improved, but allo-HSCT failed to affect outcome. Targeted therapies are needed to reduce relapse and treatment-related mortality rates.

The Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 kidney analysis examined long-term glomerular dysfunction in childhood cancer survivors

This investigation aimed to evaluate glomerular dysfunction among childhood cancer survivors in comparison with matched controls from the general population. In the Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 kidney analysis, a nationwide cross-sectional cohort study, 1024 survivors five or more years after diagnosis, aged 18 or more years at study, treated between 1963-2001 with nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide or hematopoietic stem cell transplantation participated. In addition, 500 age- and sex-matched controls from Lifelines, a prospective population-based cohort study in the Netherlands, participated. At a median age of 32.0 years (interquartile range 26.6-37.4), the glomerular filtration rate was under 60 ml/min/1.73m² in 3.7% of survivors and in none of the controls. Ten survivors had kidney failure. Chronic kidney disease according to age-thresholds (glomerular filtration rate respectively under 75 for age under 40, under 60 for ages 40-65, and under 40 for age over 65) was 6.6% in survivors vs. 0.2% in controls. Albuminuria (albumin-to-creatinine ratio over3 mg/mmol) was found in 16.2% of survivors and 1.2% of controls. Risk factors for chronic kidney disease, based on multivariable analyses, were nephrectomy (odds ratio 3.7 (95% Confidence interval 2.1-6.4)), abdominal radiotherapy (1.8 (1.1-2.9)), ifosfamide (2.9 (1.9-4.4)) and cisplatin over 500 mg/m² (7.2 (3.4-15.2)). For albuminuria, risk factors were total body irradiation (2.3 (1.2-4.4)), abdominal radiotherapy over 30 Gy (2.6 (1.4- 5.0)) and ifosfamide (1.6 (1.0-2.4)). Hypertension and follow-up 30 or more years increased the risk for glomerular dysfunction. Thus, lifetime monitoring of glomerular function in survivors exposed to these identified high risk factors is warranted.

Shrunken pore syndrome in childhood cancer survivors treated with potentially nephrotoxic therapy

Childhood cancer survivors (CCS) are at risk of kidney dysfunction. Recently, the shrunken pore syndrome (SPS) has been described, which is characterized by selectively impaired filtration of larger molecules like cystatin C, while filtration of smaller molecules like creatinine is unaltered. It has been associated with increased mortality, even in the presence of a normal estimated glomerular filtration rate (eGFR). The aim of this study was to evaluate the prevalence of SPS in CCS exposed to potentially nephrotoxic therapy. In the Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 Renal study, a nationwide cross-sectional cohort study, 1024 CCS ≥5 years after diagnosis, aged ≥18 years at study, treated between 1963-2001 with nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide or hematopoietic stem cell transplantation participated, and 500 age- and sex-matched controls form Lifelines. SPS was defined as an eGFR_cys/eGFR_cr ratio <0.6 in the absence of non-GFR determinants of cystatin C and creatinine metabolism (i.e. hyperthyroidism, corticosteroids, underweight). Three pairs of eGFR-equations were used; CKD-EPI_cys/CKD-EPI_cr, CAPA/LMR, and FAS_cys/FAS_age. Median age was 32 years. Although an eGFR_cys/eGFR_cr ratio <0.6 was more common in CCS (1.0%) than controls (0%) based on the CKD-EPI equations, most cases were explained by non-GFR determinants. The prevalence of SPS in CCS was 0.3% (CKD-EPI equations), 0.2% (CAPA/LMR) and 0.1% (FAS equations), and not increased compared to controls. CCS treated with nephrotoxic therapy are not at increased risk for SPS compared to controls. Yet, non-GFR determinants are more common and should be taken into account when estimating GFR.

Hypertension in long-term childhood cancer survivors after treatment with potentially nephrotoxic therapy; DCCSS-LATER 2: Renal study

PURPOSE

To evaluate the prevalence of and risk factors for hypertension in childhood cancer survivors (CCSs) who were treated with potentially nephrotoxic therapies.

METHODS

In the Dutch Childhood Cancer Survivor Study LATER cohort part 2 renal study, 1024 CCS ≥5 years after diagnosis, aged ≥18 years at study participation, treated between 1963 and 2001 with nephrectomy, abdominal radiotherapy, total body irradiation (TBI), cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide (≥1 g/m² per single dose or ≥10 g/m² total) or haematopoietic stem cell transplantation participated and 500 controls from Lifelines. Hypertension was defined as blood pressure (BP) (mmHg) systolic ≥140 and/or diastolic ≥90 or receiving medication for diagnosed hypertension. At the study visit, the CKD-EPI 2012 equation including creatinine and cystatin C was used to estimate the glomerular filtration rate (GFR). Multivariable regression analyses were used. For ambulatory BP monitoring (ABPM), hypertension was defined as BP daytime: systolic ≥135 and/or diastolic ≥85, night time: systolic ≥120 and/or diastolic ≥70, 24-h: systolic ≥130 and/or diastolic ≥80. Outcomes were masked hypertension (MH), white coat hypertension and abnormal nocturnal dipping (aND).

RESULTS

Median age at cancer diagnosis was 4.7 years (interquartile range, IQR 2.4-9.2), at study 32.5 years (IQR 27.7-38.0) and follow-up 25.5 years (IQR 21.4-30.3). The prevalence of hypertension was comparable in CCS (16.3%) and controls (18.2%). In 12% of CCS and 17.8% of controls, hypertension was undiagnosed. A decreased GFR (<60 ml/min/1.73 m²) was associated with hypertension in CCS (OR 3.4, 95% CI 1.4-8.5). Risk factors were abdominal radiotherapy ≥20 Gy and TBI. The ABPM-pilot study (n = 77) showed 7.8% MH, 2.6% white coat hypertension and 20.8% aND.

CONCLUSION

The prevalence of hypertension was comparable among CCS who were treated with potentially nephrotoxic therapies compared to controls, some of which were undiagnosed. Risk factors were abdominal radiotherapy ≥20 Gy and TBI. Hypertension and decreased GFR were associated with CCS. ABPM identified MH and a ND.

Long-Term Tubular Dysfunction in Childhood Cancer Survivors; DCCSS-LATER 2 Renal Study

The aim of this nationwide cross-sectional cohort study was to determine the prevalence of and risk factors for tubular dysfunction in childhood cancer survivors (CCS). In the DCCSS-LATER 2 Renal study, 1024 CCS (≥5 years after diagnosis), aged ≥ 18 years at study, treated between 1963 and 2001 with potentially nephrotoxic therapy (i.e., nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide, or hematopoietic stem cell transplantation) participated, and 500 age- and sex-matched participants from Lifelines acted as controls. Tubular electrolyte loss was defined as low serum levels (magnesium < 0.7 mmol/L, phosphate < 0.7 mmol/L and potassium < 3.6 mmol/L) with increased renal excretion or supplementation. A α1-microglobulin:creatinine ratio > 1.7 mg/mmol was considered as low-molecular weight proteinuria (LMWP). Multivariable risk analyses were performed. After median 25.5 years follow-up, overall prevalence of electrolyte losses in CCS (magnesium 5.6%, potassium 4.5%, phosphate 5.5%) was not higher compared to controls. LMWP was more prevalent (CCS 20.1% versus controls 0.4%). LMWP and magnesium loss were associated with glomerular dysfunction. Ifosfamide was associated with potassium loss, phosphate loss (with cumulative dose > 42 g/m2) and LMWP. Cisplatin was associated with magnesium loss and a cumulative dose > 500 mg/m2 with potassium and phosphate loss. Carboplatin cumulative dose > 2800 mg/m2 was associated with potassium loss. In conclusion, long-term tubular dysfunction is infrequent. Yet, ifosfamide, cisplatin and carboplatin are risk factors.

Pediatric Acute Lymphoblastic Leukemia, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Advancements in technology that enhance our understanding of the biology of the disease, risk-adapted therapy, and enhanced supportive care have contributed to improved survival rates. However, additional clinical management is needed to improve outcomes for patients classified as high risk at presentation (eg, T-ALL, infant ALL) and who experience relapse. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for pediatric ALL provide recommendations on the workup, diagnostic evaluation, and treatment of the disease, including guidance on supportive care, hematopoietic stem cell transplantation, and pharmacogenomics. This portion of the NCCN Guidelines focuses on the frontline and relapsed/refractory management of pediatric ALL.

Cerebrospinal Fluid Biomarkers in Childhood Leukemias

Involvement of the central nervous system (CNS) in childhood leukemias remains a major cause of treatment failures. Analysis of the cerebrospinal fluid constitutes the most important diagnostic pillar in the detection of CNS leukemia and relies primarily on cytological and flow-cytometry studies. With increasing survival rates, it has become clear that treatments for pediatric leukemias pose a toll on the developing brain, as they may cause acute toxicities and persistent neurocognitive deficits. Preclinical research has demonstrated that established and newer therapies can injure and even destroy neuronal and glial cells in the brain. Both passive and active cell death forms can result from DNA damage, oxidative stress, cytokine release, and acceleration of cell aging. In addition, chemotherapy agents may impair neurogenesis as well as the function, formation, and plasticity of synapses. Clinical studies show that neurocognitive toxicity of chemotherapy is greatest in younger children. This raises concerns that, in addition to injury, chemotherapy may also disrupt crucial developmental events resulting in impairment of the formation and efficiency of neuronal networks. This review presents an overview of studies demonstrating that cerebrospinal fluid biomarkers can be utilized in tracing both CNS disease and neurotoxicity of administered treatments in childhood leukemias.

Recurrent NR3C1 Aberrations at First Diagnosis Relate to Steroid Resistance in Pediatric T-Cell Acute Lymphoblastic Leukemia Patients

The glucocorticoid receptor NR3C1 is essential for steroid-induced apoptosis, and deletions of this gene have been recurrently identified at disease relapse for acute lymphoblastic leukemia (ALL) patients. Here, we demonstrate that recurrent NR3C1 inactivating aberrations—including deletions, missense, and nonsense mutations—are identified in 7% of pediatric T-cell ALL patients at diagnosis. These aberrations are frequently present in early thymic progenitor-ALL patients and relate to steroid resistance. Functional modeling of NR3C1 aberrations in pre-B ALL and T-cell ALL cell lines demonstrate that aberrations decreasing NR3C1 expression are important contributors to steroid resistance at disease diagnosis. Relative NR3C1 messenger RNA expression in primary diagnostic patient samples, however, does not correlate with steroid response.

Progress against childhood and adolescent acute lymphoblastic leukaemia in the Netherlands, 1990-2015

We assessed the epidemiologic progress against childhood and adolescent acute lymphoblastic leukaemia (ALL) in the Netherlands over a 26 year period. ALL patients <18 years were selected from the Netherlands Cancer Registry and the Dutch Childhood Oncology Group. Trend analyses were performed over time and by age group and ALL subtype. Between 1990 and 2015, 2997 ALL patients were diagnosed, i.e. 115 patients (range 87-147) per year. Overall incidence remained stable at 37 per million children, despite increases for B-cell precursor ALL (BCP-ALL) at age 10-14 years (AAPC + 1.4%, p = 0.04) and T-cell ALL at 15-17 years (AAPC + 3.7%, p = 0.01). Five-year survival increased from 80% in 1990-94 to 91% in 2010-15 (p < 0.01). Mortality decreased by 4% annually (p < 0.01). Patients 15-17 years were increasingly treated in a paediatric oncology centre, from 35% in 1990-94 to 87% in 2010-15 and experienced a 70% reduction of risk of death compared to those treated outside such a centre (p < 0.01). Significant progress against childhood ALL has been made in the Netherlands, visible by improved survival rates coinciding with declining mortality rates. These outcomes were accompanied by stable incidence rates, despite increases for BCP-ALL at age 10-14 years and T-cell ALL at age 15-17 years.

Upfront Treatment Influences the Composition of Genetic Alterations in Relapsed Pediatric B-Cell Precursor Acute Lymphoblastic Leukemia

Supplemental Digital Content is available in the text

Genomic alterations in relapsed B-cell precursor acute lymphoblastic leukemia (BCP-ALL) may provide insight into the role of specific genomic events in relapse development. Along this line, comparisons between the spectrum of alterations in relapses that arise in different upfront treatment protocols may provide valuable information on the association between the tumor genome, protocol components and outcome. Here, we performed a comprehensive characterization of relapsed BCP-ALL cases that developed in the context of 3 completed Dutch upfront studies, ALL8, ALL9, and ALL10. In total, 123 pediatric BCP-ALL relapses and 77 paired samples from primary diagnosis were analyzed for alterations in 22 recurrently affected genes. We found pronounced differences in relapse alterations between the 3 studies. Specifically, CREBBP mutations were observed predominantly in relapses after treatment with ALL8 and ALL10 which, in the latter group, were all detected in medium risk-treated patients. IKZF1 alterations were enriched 2.2-fold (p = 0.01) and 2.9-fold (p < 0.001) in ALL8 and ALL9 relapses compared to diagnosis, respectively, whereas no significant enrichment was found for relapses that were observed after treatment with ALL10. Furthermore, IKZF1 deletions were more frequently preserved from a major clone at diagnosis in relapses after ALL9 compared to relapses after ALL8 and ALL10 (p = 0.03). These data are in line with previous studies showing that the prognostic value of IKZF1 deletions differs between upfront protocols and is particularly strong in the ALL9 regimen. In conclusion, our data reveal a correlation between upfront treatment and the genetic composition of relapsed BCP-ALL.

Reduced vs. standard dose native E. coli-asparaginase therapy in childhood acute lymphoblastic leukemia: long-term results of the randomized trial Moscow-Berlin 2002

Purpose

Favorable outcomes were achieved for children with acute lymphoblastic leukemia (ALL) with the first Russian multicenter trial Moscow–Berlin (ALL-MB) 91. One major component of this regimen included a total of 18 doses of weekly intramuscular (IM) native Escherichia coli-derived asparaginase (E. coli-ASP) at 10000 U/m² during three consolidation courses. ASP was initially available from Latvia, but had to be purchased from abroad at substantial costs after the collapse of Soviet Union. Therefore, the subsequent trial ALL-MB 2002 aimed at limiting costs to a reasonable extent and also at reducing toxicity by lowering the dose for standard risk (SR−) patients to 5000 U/m² without jeopardizing efficacy.

Methods

Between April 2002 and November 2006, 774 SR patients were registered in 34 centers across Russia and Belarus, 688 of whom were randomized. In arm ASP-5000 (n = 334), patients received 5000 U/m² and in arm ASP-10000 (n = 354) 10 000 U/m² IM.

Results

Probabilities of disease-free survival, overall survival and cumulative incidence of relapse at 10 years were comparable: 79 ± 2%, 86 ± 2% and 17.4 ± 2.1% (ASP-5000) vs. 75 ± 2% and 82 ± 2%, and 17.9 ± 2.0% (ASP-10000), while death in complete remission was significantly lower in arm ASP-5000 (2.7% vs. 6.5%; p = 0.029).

Conclusion

Our findings suggest that weekly 5000 U/m²E. coli-ASP IM during consolidation therapy are equally effective, more cost-efficient and less toxic than 10000 U/m² for SR patients with childhood ALL.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-02854-x) contains supplementary material, which is available to authorized users.

High STAP1 expression in DUX4-rearranged cases is not suitable as therapeutic target in pediatric B-cell precursor acute lymphoblastic leukemia

Approximately 25% of the pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cases are genetically unclassified. More thorough elucidation of the pathobiology of these genetically unclassified (‘B-other’) cases may identify novel treatment options. We analyzed gene expression profiles of 572 pediatric BCP-ALL cases, representing all major ALL subtypes. High expression of STAP1, an adaptor protein downstream of the B-cell receptor (BCR), was identified in BCR-ABL1-like and non-BCR-ABL1-like B-other cases. Limma analysis revealed an association between high expression of STAP1 and BCR signaling genes. However, STAP1 expression and pre-BCR signaling were not causally related: cytoplasmic Igμ levels were not abnormal in cases with high levels of STAP1 and stimulation of pre-BCR signaling did not induce STAP1 expression. To elucidate the role of STAP1 in BCP-ALL survival, expression was silenced in two human BCP-ALL cell lines. Knockdown of STAP1 did not reduce the proliferation rate or viability of these cells, suggesting that STAP1 is not a likely candidate for precision medicines. Moreover, high expression of STAP1 was not predictive for an unfavorable prognosis of BCR-ABL1-like and non-BCR-ABL1-like B-other cases. Remarkably, DUX4-rearrangements and intragenic ERG deletions, were enriched in cases harboring high expression of STAP1.

Augmenting Total Body Irradiation with a Cranial Boost before Stem Cell Transplantation Protects Against Post-Transplant Central Nervous System Relapse in Acute Lymphoblastic Leukemia

The purpose of this study was to determine the effect of a pretransplant cranial boost (CB) on post-transplant central nervous system (CNS) relapse and survival in acute lymphoblastic leukemia (ALL) patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) using a total body irradiation (TBI)-containing preparation regimen. Two hundred thirteen ALL patients were treated consecutively at our institution with allogeneic HSCT. Conditioning included TBI (1320 cGy in 8 fractions given twice daily) and cyclophosphamide (120 mg/kg) with or without fludarabine (75 mg/m²). Patients were divided into 4 groups based on history of CNS disease and whether a CB was given. Of the 160 patients with no history of CNS disease, none received a CB (CNS-/CB-). Of the 53 patients with prior CNS disease, 41 had not received prior cranial irradiation. Thirty of these 41 received a CB of 900 to 1000 cGy in 5 daily fractions (CNS+/CB+), whereas the other 11 did not receive a CB because of physician preference (CNS+/CB-). The remaining 12 patients with prior CNS involvement had previously received cranial irradiation and thus were not candidates for a CB (CNS + PriorRT). Two-year CNS relapse risk, overall survival (OS), and disease-free survival (DFS) were calculated using Kaplan-Meier analysis. Seven patients experienced post-transplant CNS relapse: 4 in the CNS-/CB- group, 2 in the CNS+/CB- group, and 1 in the CNS + PriorRT group. None of the 30 patients who received a CB relapsed in the CNS. Two-year CNS relapse risk was 0% in the CNS+/CB+ group compared with 21% (95% CI, 0% to 45%) in the CNS+/CB- group (P = .03). Two-year OS and DFS did not differ between the groups. In conclusion, among ALL patients with prior CNS leukemia, there was a trend toward a reduced risk of post-transplant CNS relapse in patients who received a CB. However, the addition of a CB did not appear to have an impact on OS or DFS.

JAK2 aberrations in childhood B-cell precursor acute lymphoblastic leukemia

JAK2 abnormalities may serve as target for precision medicines in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). In the current study we performed a screening for JAK2 mutations and translocations, analyzed the clinical outcome and studied the efficacy of two JAK inhibitors in primary BCP-ALL cells. Importantly, we identify a number of limitations of JAK inhibitor therapy. JAK2 mutations mainly occurred in the poor prognostic subtypes BCR-ABL1-like and non- BCR-ABL1-like B-other (negative for sentinel cytogenetic lesions). JAK2 translocations were restricted to BCR-ABL1-like cases. Momelotinib and ruxolitinib were cytotoxic in both JAK2 translocated and JAK2 mutated cells, although efficacy in JAK2 mutated cells highly depended on cytokine receptor activation by TSLP. However, our data also suggest that the effect of JAK inhibition may be compromised by mutations in alternative survival pathways and microenvironment-induced resistance. Furthermore, inhibitors induced accumulation of phosphorylated JAK2^Y1007, which resulted in a profound re-activation of JAK2 signaling upon release of the inhibitors. This preclinical evidence implies that further optimization and evaluation of JAK inhibitor treatment is necessary prior to its clinical integration in pediatric BCP-ALL.

Neurotoxicity after high-dose methotrexate (MTX) is adequately explained by insufficient folinic acid rescue

PURPOSE

To challenge the view that the dose of folinic acid rescue after high-dose methotrexate (MTX) has no significance in the prevention of neurotoxicity and to present the minority view that neurotoxicity can be prevented by an adequate dose of folinic acid, without compromising treatment results. Several fallacies that led to the misunderstanding of post MTX neurotoxicity are presented.

METHODS

Data mining using search engines was used to find relevant publications, and an e-mail survey of more than 60 authors of articles in this field was performed. All relevant articles identified were read in their entirety.

RESULTS

Examples of clinical studies with neurotoxicity following inadequate rescue are given. Some studies demonstrated no neurotoxicity when adequate doses of folinic acid rescue were started 24-36 h after the start of HDMTX rescue even after mega doses of MTX. Rescue started after 42 h was associated with neurotoxicity except in patients with low serum MTX levels after 24 and 36 h. ALL protocols with neurotoxicity, especially BFM-like protocols, are presented. Protocol is reported in which single protocol changes prevented neurotoxicity.

CONCLUSIONS

From the published data, when folinic acid rescue is given in a sufficiently high enough dose and is started 24-36 h after the beginning of the methotrexate exposure, and virtually all forms of post MTX neurotoxicity can be prevented without compromising therapeutic results.

Long-term Results of the Risk-adapted Treatment for Childhood B-Cell Acute Lymphoblastic Leukemia: Report From the Japan Association of Childhood Leukemia Study ALL-97 Trial

PURPOSE

This study was conducted as the first clinical trial by Japan Association of Childhood Leukemia Study to improve the outcome of B-cell acute lymphoblastic leukemia and explore a less toxic reinduction block.

PATIENTS AND METHODS

From 1997 to 2002, 563 patients with B-cell acute lymphoblastic leukemia aged 1 to 15 years were enrolled. The patients were assigned into 4 risk groups (standard, intermediate, high, or extremely high risk) and treated with regimens intensified according to the risk. Two randomized trials were conducted to compare 2 regimens with and without a 3-week reinduction therapy in the standard-risk group, and to compare the efficacy of pirarubicin with daunorubicin in the intermediate-risk and high-risk groups. Prophylactic cranial irradiation was restricted in patients with high or extremely high risk.

RESULTS

The event-free survival (EFS) rate at 10 years for all patients was 77.0%. Those in the standard-risk to extremely high-risk groups were 79.3%, 72.5%, 71.7%, and 66.3%, respectively. The 15-week induction/consolidation not followed by reinduction produced 76.4% of the EFS at 10 years comparable with the regimen with reinduction therapy. Pirarubicin at 25 mg/m administered 11 times throughout the treatment produced the EFS comparable with daunorubicin at 30 mg/m.

CONCLUSION

The trial produced high survival rates in NCI-HR patients, although the outcomes in NCI-SR patients were not satisfactory possibly due to less intensive central nervous system-directed therapy.

The effect of central nervous system involvement and irradiation in childhood acute lymphoblastic leukemia: Lessons from the NOPHO ALL-92 and ALL-2000 protocols

BACKGROUND

Central nervous system irradiation (CNS-RT) has played a central role in the cure of acute lymphoblastic leukemia (ALL), but due to the risk of long-term toxicity, it is now considered a less-favorable method of CNS-directed therapy.

PROCEDURES

Retrospectively, we estimated the effect of CNS involvement and CNS-RT on events and overall survival (OS) in 835 children treated for high-risk ALL in the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL-92 and ALL-2000 trials.

RESULTS

We did not observe a statistically significant difference in the OS or event-free survival (EFS) in patients with CNS involvement at diagnosis, but the risk of isolated CNS relapse was higher (hazard ratio [HR] 7.09, P < 0.001). CNS-RT was given to 169 of the 783 patients in first complete remission, of which 16 had CNS involvement at diagnosis. In general, CNS-RT improved EFS (HR 0.58, P < 0.05) but not OS (HR 0.69, P = n.s.). The adjusted HRs for all relapses, isolated bone marrow relapse, CNS-involving relapse, and isolated CNS relapse, were 0.47 (P < 0.01), 0.50 (P < 0.05), 0.34 (P < 0.01), and 0.12 (P < 0.01), respectively, in irradiated patients.

CONCLUSIONS

CNS-RT was associated with an advantage in EFS by decreasing the risk of relapse but without improving OS.

Successful Therapy Reduction and Intensification for Childhood Acute Lymphoblastic Leukemia Based on Minimal Residual Disease Monitoring: Study ALL10 From the Dutch Childhood Oncology Group

PURPOSE

Outcome of childhood acute lymphoblastic leukemia (ALL) improved greatly by intensifying chemotherapy for all patients. Minimal residual disease (MRD) levels during the first months predict outcome and may select patients for therapy reduction or intensification.

METHODS

Patients 1 to 18 years old with ALL were stratified on the basis of MRD levels after the first and second course of chemotherapy. Thereafter, therapy was substantially reduced in patients with undetectable MRD (standard risk) and intensified in patients with intermediate (medium risk) and high (high risk) levels of MRD. Seven hundred seventy-eight consecutive patients were enrolled. The method of analysis was intention-to-treat. Outcome was compared with historical controls.

RESULTS

In MRD-based standard-risk patients, the 5-year event-free survival (EFS) rate was 93% (SE 2%), the 5-year survival rate was 99% (SE 1%), and the 5-year cumulative incidence of relapse rate was 6% (SE 2%). The safety upper limit of number of observation years was reached and therapy reduction was declared safe.MRD-based medium-risk patients had a significantly higher 5-year EFS rate (88%, SE 2%) with therapy intensification (including 30 weeks of asparaginase exposure and dexamethasone/vincristine pulses) compared with historical controls (76%, SE 6%). Intensive chemotherapy and stem cell transplantation in MRD-based high-risk patients resulted in a significantly better 5-year EFS rate (78%, SE 8% v 16%, SE 8% in controls). Overall outcome improved significantly (5-year EFS rate 87%, 5-year survival rate 92%, and 5-year cumulative incidence of relapse rate 8%) compared with preceding Dutch Childhood Oncology Group protocols.

CONCLUSION

Chemotherapy was substantially reduced safely in one-quarter of children with ALL who were selected on the basis of undetectable MRD levels, without jeopardizing the survival rate. Outcomes of patients with intermediate and high levels of MRD improved with therapy intensification.

Shorter Maintenance Therapy in Childhood Acute Lymphoblastic Leukemia: The Experience of the Prospective, Randomized Brazilian GBTLI ALL-93 Protocol

AIM

Maintenance therapy is an important phase of the childhood ALL treatment, requiring 2-year long therapy adherence of the patients and families. Weekly methotrexate with daily 6-mercaptopurine (6MP) constitutes the backbone of maintenance therapy. Reduction in the maintenance therapy could overweight problems related with poverty of children with ALL living in limited-income countries (LIC).

OBJECTIVE

To compare, prospectively, the EFS rates of children with ALL treated according to two maintenance regimens: 18 vs. 24 months duration.

MATERIALS AND METHODS

From October 1993 to September 1999, 867 consecutive untreated ALL patients <18 years of age were treated according to the Brazilian Cooperative Group for Childhood ALL Treatment (GBTLI) ALL-93 protocol. Risk classification was based exclusively on patient's age and leukocyte count (NCI risk group) and clinical extra medullary involvement of the disease. Data were analyzed by the intention-to-treat approach.

RESULTS

Fourteen patients (1.6%) were excluded: wrong diagnosis (n = 7) and previous corticosteroid (n = 7). Of the 853 eligible patients, 421 were randomly allocated, at study enrollment, to receive 18-month (group 1) and 432 to receive 24-month (group 2) maintenance therapy. Complete remission rate was achieved in 96% of the patients (817/853). Twenty-eight patients (3.4%) died during the induction phase. Thirty-four patients (4.0%) were lost to follow-up. The overall EFS was 66.1 ± 1.7% at 15 years. No difference was seen according to maintenance: EFS_15y was 65.8 ± 2.3% (group 1) and 66.3 ± 2.3% (group 2; p = 0.79). No difference between regimens was detected after stratifying the analyses according to factors associated with adverse prognosis in this study (age group <1 year or >10 years and high WBC at diagnosis). Overall death in remission rate was 6.85% (56 patients). Deaths during maintenance were 13 in group 1 and 12 in group 2, all due to infection. Over 15 years of follow-up, two patients both from group 2 presented a second malignancy (Hodgkin's disease and thyroid carcinoma) after 8.3 and 11 years off therapy, respectively.

CONCLUSION

Six-month reduction of maintenance therapy in ALL children treated according to the GBTLI ALL-93 protocol provided the same overall outcome as 2-year duration regimen.

Clinical updates in adult acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a clonal disease characterized by B or T lineage. Here we cover the clinical manifestations, pathophysiology and therapy for ALL. Additionally, we will discuss the evidence for minimal residual disease assessment, novel molecular targets and newly developed targeted therapies. The separation of ALL into Philadelphia chromosome positive and recently into Philadelphia-like disease represents the most exciting developments in this disease. Finally, the advent of new immunotherapeutic approaches led us to predict that in few years, ALL therapy might be based heavily on non-chemotherapeutic approaches.

Assessment of mercaptopurine (6MP) metabolites and 6MP metabolic key-enzymes in childhood acute lymphoblastic leukemia

Pediatric acute lymphoblastic leukemia (ALL) is treated with combination chemotherapy including mercaptopurine (6MP) as an important component. Upon its uptake, 6MP undergoes a complex metabolism involving many enzymes and active products. The prognostic value of all the factors engaged in this pathway still remains unclear. This study attempted to determine which components of 6MP metabolism in leukemic blasts and red blood cells are important for 6MP's sensitivity and toxicity. In addition, changes in the enzymatic activities and metabolite levels during the treatment were analyzed. In a cohort (N=236) of pediatric ALL patients enrolled in the Dutch ALL-9 protocol, we studied the enzymes inosine-5'-monophosphate dehydrogenase (IMPDH), thiopurine S-methyltransferase (TPMT), hypoxanthine guanine phosphoribosyl transferase (HGPRT), and purine nucleoside phosphorylase (PNP) as well as thioguanine nucleotides (TGN) and methylthioinosine nucleotides (meTINs). Activities of selected enzymes and levels of 6MP derivatives were measured at various time points during the course of therapy. The data obtained and the toxicity related parameters available for these patients were correlated with each other. We found several interesting relations, including high concentrations of two active forms of 6MP--TGN and meTIN--showing a trend toward association with better in vitro antileukemic effect of 6MP. High concentrations of TGN and elevated activity of HGPRT were found to be significantly associated with grade III/IV leucopenia. However, a lot of data of enzymatic activities and metabolite concentrations as well as clinical toxicity were missing, thereby limiting the number of assessed relations. Therefore, although a complex study of 6MP metabolism in ALL patients is feasible, it warrants more robust and strict data collection in order to be able to draw more reliable conclusions.

PTEN microdeletions in T-cell acute lymphoblastic leukemia are caused by illegitimate RAG-mediated recombination events

Phosphatase and tensin homolog (PTEN)-inactivating mutations and/or deletions are an independent risk factor for relapse of T-cell acute lymphoblastic leukemia (T-ALL) patients treated on Dutch Childhood Oncology Group or German Cooperative Study Group for Childhood Acute Lymphoblastic Leukemia protocols. Some monoallelic mutated or PTEN wild-type patients lack PTEN protein, implying that additional PTEN inactivation mechanisms exist. We show that PTEN is inactivated by small deletions affecting a few exons in 8% of pediatric T-ALL patients. These microdeletions were clonal in 3% and subclonal in 5% of patients. Conserved deletion breakpoints are flanked by cryptic recombination signal sequences (cRSSs) and frequently have non-template-derived nucleotides inserted in between breakpoints, pointing to an illegitimate RAG recombination-driven activity. Identified cRSSs drive RAG-dependent recombination in a reporter system as efficiently as bona fide RSSs that flank gene segments of the T-cell receptor locus. Remarkably, equivalent microdeletions were detected in thymocytes of healthy individuals. Microdeletions strongly associate with the TALLMO subtype characterized by TAL1 or LMO2 rearrangements. Primary and secondary xenotransplantation of TAL1-rearranged leukemia allowed development of leukemic subclones with newly acquired PTEN microdeletions. Ongoing RAG activity may therefore actively contribute to the acquisition of preleukemic hits, clonal diversification, and disease progression.

Flow cytometric chemosensitivity assay using JC‑1, a sensor of mitochondrial transmembrane potential, in acute leukemia

PURPOSE

The purpose of the study is to establish a simple and relatively inexpensive flow cytometric chemosensitivity assay (FCCA) for leukemia to distinguish leukemic blasts from normal leukocytes in clinical samples.

METHODS

We first examined whether the FCCA with the mitochondrial membrane depolarization sensor, 5, 50, 6, 60-tetrachloro-1, 10, 3, 30 tetraethyl benzimidazolo carbocyanine iodide (JC-1), could detect drug-induced apoptosis as the conventional FCCA by annexin V/7-AAD detection did and whether it was applicable in the clinical samples. Second, we compared the results of the FCCA for prednisolone (PSL) with clinical PSL response in 18 acute lymphoblastic leukemia (ALL) patients to evaluate the reliability of the JC-1 FCCA. Finally, we performed the JC-1 FCCA for bortezomib (Bor) in 25 ALL or 11 acute myeloid leukemia (AML) samples as the example of the clinical application of the FCCA.

RESULTS

In ALL cells, the results of the JC-1 FCCA for nine anticancer drugs were well correlated with those of the conventional FCCA using anti-annexin V antibody (P < 0.001). In the clinical samples from 18 children with ALL, the results of the JC-1 FCCA for PSL were significantly correlated with the clinical PSL response (P = 0.005). In ALL samples, the sensitivity for Bor was found to be significantly correlated with the sensitivity for PSL (P = 0.005). In AML samples, the Bor sensitivity was strongly correlated with the cytarabine sensitivity (P = 0.0003).

CONCLUSIONS

This study showed the reliability of a relatively simple and the FCCA using JC-1, and the possibility for the further clinical application.

The BCL2-938 C > A promoter polymorphism is associated with risk group classification in children with acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer. While current treatment regimens achieve almost 80% overall survival, long-term side effects of chemotherapeutic agents can be severe. The functional BCL2-938C > A promoter polymorphism is known to influence the balance between survival and apoptosis of malignant hematolymphoid cells. We investigated its usefulness as a marker for treatment stratification for children with ALL.

METHODS

We analyzed DNA from 182 children suffering from ALL in this study to determine genotypes of the -938 C > A polymorphism by "slow-down" PCR.

RESULTS

ALL patients with the BCL2-938CC genotype had an approximately 3-fold higher risk of belonging to a high-risk group. Within the high-risk group, 50% of BCL2-938CC patients were classified as high-risk due to poor prednisone response whereas only 33% of patients with AC and AA genotypes were classified as high-risk for the same reason.

CONCLUSIONS

Our results suggest that BCL2-938C > A genotyping may be beneficial for therapy response prediction in ALL patients, and warrant examination in a larger cohort to validate its usefulness for treatment stratification of pediatric ALL patients.

Immature MEF2C-dysregulated T-cell leukemia patients have an early T-cell precursor acute lymphoblastic leukemia gene signature and typically have non-rearranged T-cell receptors

Three distinct immature T-cell acute lymphoblastic leukemia entities have been described including cases that express an early T-cell precursor immunophenotype or expression profile, immature MEF2C-dysregulated T-cell acute lymphoblastic leukemia cluster cases based on gene expression analysis (immature cluster) and cases that retain non-rearranged TRG@ loci. Early T-cell precursor acute lymphoblastic leukemia cases exclusively overlap with immature cluster samples based on the expression of early T-cell precursor acute lymphoblastic leukemia signature genes, indicating that both are featuring a single disease entity. Patients lacking TRG@ rearrangements represent only 40% of immature cluster cases, but no further evidence was found to suggest that cases with absence of bi-allelic TRG@ deletions reflect a distinct and even more immature disease entity. Immature cluster/early T-cell precursor acute lymphoblastic leukemia cases are strongly enriched for genes expressed in hematopoietic stem cells as well as genes expressed in normal early thymocyte progenitor or double negative-2A T-cell subsets. Identification of early T-cell precursor acute lymphoblastic leukemia cases solely by defined immunophenotypic criteria strongly underestimates the number of cases that have a corresponding gene signature. However, early T-cell precursor acute lymphoblastic leukemia samples correlate best with a CD1 negative, CD4 and CD8 double negative immunophenotype with expression of CD34 and/or myeloid markers CD13 or CD33. Unlike various other studies, immature cluster/early T-cell precursor acute lymphoblastic leukemia patients treated on the COALL-97 protocol did not have an overall inferior outcome, and demonstrated equal sensitivity levels to most conventional therapeutic drugs compared to other pediatric T-cell acute lymphoblastic leukemia patients.

Dose intensification of daunorubicin and cytarabine during treatment of adult acute lymphoblastic leukemia: results of Cancer and Leukemia Group B Study 19802

BACKGROUND

Cancer and Leukemia Group B (CALGB) Study 19802, a phase 2 study, evaluated whether dose intensification of daunorubicin and cytarabine could improve disease-free survival (DFS) in adults with acute lymphoblastic leukemia (ALL) and whether high-dose systemic and intrathecal methotrexate could replace cranial radiotherapy for central nervous system (CNS) prophylaxis.

METHODS

One hundred sixty-one eligible, previously untreated patients ages 16 to 82 years (median age, 40 years) were enrolled, and 33 (20%) were aged ≥60 years.

RESULTS

One hundred twenty-eight patients (80%) achieved complete remission (CR). Dose intensification of daunorubicin and cytarabine was feasible. At a median follow-up of 10.4 years for surviving patients, the 5-year DFS rate was 25% (95% confidence interval, 18%-33%), and the overall survival (OS) rate was 30% (95% confidence interval, 23%-37%). Patients aged <60 years who received the 80 mg/m(2) dose of daunorubicin had a DFS of 33% (95% confidence interval, 22%-44%) and an OS of 39% (95% confidence interval, 29%-49%) at 5 years. Eighty-four patients (52%) relapsed, including 9 patients (6%) who had isolated CNS relapses. The omission of cranial irradiation did not result in higher than historic CNS relapse rates.

CONCLUSIONS

Intensive systemic, oral, and intrathecal methotrexate dosing permitted the omission of CNS irradiation in adult patients with ALL. This intensive approach using higher doses of daunorubicin and cytarabine failed to result in an overall improvement in DFS or OS compared with historic CALGB studies. Future therapeutic strategies for adults with ALL should be tailored to specific age and molecular genetic subsets.

Neuropsychological outcomes of standard risk and high risk patients treated for acute lymphoblastic leukemia on Dana-Farber ALL consortium protocol 95-01 at 5 years post-diagnosis

BACKGROUND

Children treated for acute lymphoblastic leukemia (ALL) as High Risk (HR) patients may be more vulnerable to neurocognitive late effects because of the greater intensity of their therapy. We compared neuropsychological outcomes in children treated for Standard Risk (SR) or HR ALL on Dana-Farber Cancer Institute (DFCI) Consortium ALL Protocol 95-01. We also evaluated their performance relative to normative expectations.

PROCEDURE

Between 1996 and 2000, 498 children with newly diagnosed ALL were treated on Protocol 95-01, 298 of whom were eligible for neuropsychological follow-up. A feature of this protocol was modification of risk group criteria to treat more children as SR rather than HR patients, intended to minimize toxicities. Testing was completed at a median of 5.3 years post-diagnosis for 211 patients (70.8%; ages 6-25 years; 45.5% male; 40% HR), all of whom were in continuous complete remission.

RESULTS

Test scores for both groups were generally at or above normative expectation, with the exception of verbal working memory, processing complex visual information, and parent ratings of metacognitive skills. After adjusting for covariates, the SR group performed better on measures of IQ and academic achievement, working memory and visual learning. Effect sizes, however, were only in the small to moderate range.

CONCLUSIONS

HR patients exhibited neuropsychological deficits relative to SR patients, though the differences were modest in degree. Modification of the risk group criteria to treat more children on the SR protocol therefore likely afforded some benefit in terms of neurocognitive late effects.

The significance of PTEN and AKT aberrations in pediatric T-cell acute lymphoblastic leukemia

BACKGROUND

PI3K/AKT pathway mutations are found in T-cell acute lymphoblastic leukemia, but their overall impact and associations with other genetic aberrations is unknown. PTEN mutations have been proposed as secondary mutations that follow NOTCH1-activating mutations and cause cellular resistance to γ-secretase inhibitors.

DESIGN AND METHODS

The impact of PTEN, PI3K and AKT aberrations was studied in a genetically well-characterized pediatric T-cell leukemia patient cohort (n=146) treated on DCOG or COALL protocols.

RESULTS

PTEN and AKT E17K aberrations were detected in 13% and 2% of patients, respectively. Defective PTEN-splicing was identified in incidental cases. Patients without PTEN protein but lacking exon-, splice-, promoter mutations or promoter hypermethylation were present. PTEN/AKT mutations were especially abundant in TAL- or LMO-rearranged leukemia but nearly absent in TLX3-rearranged patients (P=0.03), the opposite to that observed for NOTCH1-activating mutations. Most PTEN/AKT mutant patients either lacked NOTCH1-activating mutations (P=0.006) or had weak NOTCH1-activating mutations (P=0.011), and consequently expressed low intracellular NOTCH1, cMYC and MUSASHI levels. T-cell leukemia patients without PTEN/AKT and NOTCH1-activating mutations fared well, with a cumulative incidence of relapse of only 8% versus 35% for PTEN/AKT and/or NOTCH1-activated patients (P=0.005).

CONCLUSIONS

PI3K/AKT pathway aberrations are present in 18% of pediatric T-cell acute lymphoblastic leukemia patients. Absence of strong NOTCH1-activating mutations in these cases may explain cellular insensitivity to γ-secretase inhibitors.

Outcome in children with Down's syndrome and acute lymphoblastic leukemia: role of IKZF1 deletions and CRLF2 aberrations

Children with Down's syndrome (DS) have an increased risk of developing acute lymphoblastic leukemia (ALL) and have a low frequency of established genetic aberrations. We aimed to determine which genetic abnormalities are involved in DS ALL. We studied the frequency and prognostic value of deletions in B-cell development genes and aberrations of janus kinase 2 (JAK2) and cytokine receptor-like factor 2 (CRLF2) using array-comparative genomic hybridization, and multiplex ligation-dependent probe amplification in a population-based cohort of 34 Dutch Childhood Oncology Group DS ALL samples. A population-based cohort of 88 DS samples from the UK trials was used to validate survival estimates for IKZF1 and CRLF2 abnormalities. In total, 50% of DS ALL patients had ≥1 deletion in the B-cell development genes: PAX5 (12%), VPREB1 (18%) and IKZF1 (35%). JAK2 was mutated in 15% of patients, genomic CRLF2 rearrangements in 62%. Outcome was significantly worse in patients with IKZF1 deletions (6-year event-free survival (EFS) 45 ± 16% vs 95 ± 4%; P=0.002), which was confirmed in the validation cohort (6-year EFS 21 ± 12% vs 58 ± 11%; P=0.002). This IKZF1 deletion was a strong independent predictor for outcome (hazard ratio EFS 3.05; P=0.001). Neither CRLF2 nor JAK2 were predictors for worse prognosis. If confirmed in prospective series, IKZF1 deletions may be used for risk-group stratification in DS ALL.

Different outcome in older children with acute lymphoblastic leukemia with different treatment protocols in the Netherlands

BACKGROUND

From 1991 until 2004 children with acute lymphoblastic leukemia (ALL) in the Netherlands were treated according to protocols ALL-8 and ALL-9 which were based on different principles. An earlier study showed that the outcome of adolescents highly differed on these protocols.

PROCEDURE

In this retrospective study, we analyzed whether the outcome of older children 10-15 years of age at diagnosis differed between the Berlin-Frankfurt-Münster (BFM)-based ALL-8 regimen and the ALL-9 regimen. Two hundred fifty-four older children who were treated according to protocol ALL-8 (n = 82) or ALL-9 (n = 172) were included in the analysis.

RESULTS

A higher 5-year event-free survival (EFS) rate was found for patients treated according to ALL-8 compared to ALL-9 (79 ± 5% vs. 65 ± 4%, P = 0.02). Patient characteristics did not differ except for a slightly higher age in ALL-8. Therefore, additional analyses were done including only patients who were 12-15 years of age. In this age group there was also a difference in the 5-year EFS (82 ± 5% vs. 61 ± 5%, P = 0.00) as well as in the 5-year overall survival rate; 89 ± 4% compared to 68 ± 5%, respectively (P = 0.01). Major difference between protocols was the use of a consolidation and reinduction/intensification course and higher cumulative doses of asparaginase, methotrexate, and anthracyclines in ALL-8.

CONCLUSIONS

Children 10-15 years of age have been undertreated with the ALL-9 regimen and benefit by intensive treatment components as used in ALL-8. We recommend using BFM-based protocols for these older children with ALL.

Outcome after first relapse in children with acute lymphoblastic leukemia: a report based on the Dutch Childhood Oncology Group (DCOG) relapse all 98 protocol

BACKGROUND

We report on the treatment of children and adolescents with acute lymphoblastic leukemia (ALL) in first relapse. The protocol focused on: (1) Intensive chemotherapy preceding allogeneic stem cell transplantation (SCT) in early bone marrow relapse; (2) Rotational chemotherapy in late relapse, without donor; (3) Postponement of cerebro-spinal irradiation in late isolated CNS relapse; and (4) Treatment in very late bone marrow relapse with chemotherapy only.

METHODS

From January 1999 until July 2006 all 158 Dutch pediatric patients with ALL in first relapse were recorded. Ninety-nine patients were eligible; 54 patients with early and 45 with late relapse. Eighteen patients had an isolated extra-medullary relapse; 69 patients had bone marrow involvement only.

RESULTS

Five-years EFS rates for early and late relapses were 12% and 35%, respectively. For early relapses 5 years EFSs were 25% for patients transplanted; 0% for non-transplanted patients. For late relapses 5 years EFS was 64% for patients treated with chemotherapy only, and 16% for transplanted patients. For very late relapses EFS was 58%.

CONCLUSIONS

Our data suggest the superiority of SCT for early relapse patients. For late relapses a better outcome is achieved with chemotherapy only using the rotational chemotherapy scheme. The most important factor for survival was interval between first CR and occurrence of the first relapse.

Escalating intravenous methotrexate improves event-free survival in children with standard-risk acute lymphoblastic leukemia: a report from the Children's Oncology Group

Children's Cancer Group-1991 selected 2 components from the Children's Cancer Group studies shown to be effective in high-risk acute lymphoblastic leukemia and examined them in children with National Cancer Institute standard-risk acute B-precursor lymphoblastic leukemia. These were (1) vincristine and escalating IV methotrexate (MTX) without leucovorin rescue during the interim maintenance (IM) phases and (2) addition of a second delayed intensification (DI) phase. Eligible patients (n = 2078) were randomly assigned to regimens containing either oral (PO) MTX, PO mercaptopurine, dexamethasone, and vincristine or IV MTX during IM phases, and regimens with either single DI or double DI. Five-year event-free survival (EFS) and overall survival for patients on the PO MTX arms were 88.7% ± 1.4% and 96% ± 0.9% versus 92.6% ± 1.2% and 96.5% ± 0.8% for those on the IV MTX arms (P = .009, P = .66). Five-year EFS and overall survival for patients who received single DI were 90.9% ± 1.3% and 97.1% ± 0.8% versus 90.5% ± 1.3% and 95.4% ± 3.8% for those who received double DI (P = .71, P = .12). No advantage was found for a second DI; however, replacement of PO MTX, PO mercaptopurine, vincristine, and dexamethasone during IM with vincristine and escalating IV MTX improved EFS.

Association of polymorphisms in the TLR4 gene with the risk of developing neutropenia in children with leukemia

Infections are a major cause of morbidity and mortality in children with acute lymphoblastic leukemia (ALL). Susceptibility to infections increases as the neutrophil count decreases. Despite identical treatment patients vary considerably in the number of neutropenic episodes. Toll-like receptor 4 (TLR4) has been shown to have a role in inhibiting apoptosis of neutrophils. Therefore, we hypothesized that polymorphisms in the TLR4 gene may influence the number of chemotherapy-induced neutropenic episodes. Eight single-nucleotide polymorphisms (SNPs) of the TLR4 gene were determined in 194 children aged 0-17 years, who were diagnosed with ALL. We compared the genotype distributions of the SNPs with the frequency of neutropenic episodes during treatment with chemotherapeutic regimens. The number of neutropenic episodes varied from 0 to 17, with a median of four neutropenic episodes. Four SNPs in the TLR4 gene (rs10759931, rs11536889, rs1927911 and rs6478317) were associated with an increased risk of developing chemotherapy-induced neutropenia, each sustaining correction for multiple testing. Further studies are required to elucidate whether pediatric patients with ALL with the particular SNPs in the TLR4 gene also experience more infections and would benefit from prophylactic antibiotic treatment, by a reduction of morbidity and mortality due to infections.

NOTCH1 and/or FBXW7 mutations predict for initial good prednisone response but not for improved outcome in pediatric T-cell acute lymphoblastic leukemia patients treated on DCOG or COALL protocols

Aberrant activation of the NOTCH1 pathway by inactivating and activating mutations in NOTCH1 or FBXW7 is a frequent phenomenon in T-cell acute lymphoblastic leukemia (T-ALL). We retrospectively investigated the relevance of NOTCH1/FBXW7 mutations for pediatric T-ALL patients enrolled on Dutch Childhood Oncology Group (DCOG) ALL7/8 or ALL9 or the German Co-Operative Study Group for Childhood Acute Lymphoblastic Leukemia study (COALL-97) protocols. NOTCH1-activating mutations were identified in 63% of patients. NOTCH1 mutations affected the heterodimerization, the juxtamembrane and/or the PEST domains, but not the RBP-J-κ-associated module, the ankyrin repeats or the transactivation domain. Reverse-phase protein microarray data confirmed that NOTCH1 and FBXW7 mutations resulted in increased intracellular NOTCH1 levels in primary T-ALL biopsies. Based on microarray expression analysis, NOTCH1/FBXW7 mutations were associated with activation of NOTCH1 direct target genes including HES1, DTX1, NOTCH3, PTCRA but not cMYC. NOTCH1/FBXW7 mutations were associated with TLX3 rearrangements, but were less frequently identified in TAL1- or LMO2-rearranged cases. NOTCH1-activating mutations were less frequently associated with mature T-cell developmental stage. Mutations were associated with a good initial in vivo prednisone response, but were not associated with a superior outcome in the DCOG and COALL cohorts. Comparing our data with other studies, we conclude that the prognostic significance for NOTCH1/FBXW7 mutations is not consistent and may depend on the treatment protocol given.

Methotrexate-induced side effects are not due to differences in pharmacokinetics in children with Down syndrome and acute lymphoblastic leukemia

BACKGROUND

Children with Down syndrome have an increased risk of developing acute lymphoblastic leukemia and a poor tolerance of methotrexate. This latter problem is assumed to be caused by a higher cellular sensitivity of tissues in children with Down syndrome. However, whether differences in pharmacokinetics play a role is unknown.

DESIGN AND METHODS

We compared methotrexate-induced toxicity and pharmacokinetics in a retrospective case-control study between patients with acute lymphoblastic leukemia who did or did not have Down syndrome. Population pharmacokinetic models were fitted to data from all individuals simultaneously, using non-linear mixed effect modeling.

RESULTS

Overall, 468 courses of methotrexate (1-5 g/m(2)) were given to 44 acute lymphoblastic leukemia patients with Down syndrome and to 87 acute lymphoblastic leukemia patients without Down syndrome. Grade 3-4 gastrointestinal toxicity was significantly more frequent in the children with Down syndrome than in those without (25.5% versus 3.9%; P=0.001). The occurrence of grade 3-4 gastrointestinal toxicity was not related to plasma methotrexate area under the curve. Methotrexate clearance was 5% lower in the acute lymphoblastic leukemia patients with Down syndrome (P=0.001); however, this small difference is probably clinically not relevant, because no significant differences in methotrexate plasma levels were detected at 24 and 48 hours.

CONCLUSIONS

We did not find evidence of differences in the pharmacokinetics of methotrexate between patients with and without Down syndrome which could explain the higher frequency of gastrointestinal toxicity and the greater need for methotrexate dose reductions in patients with Down syndrome. Hence, these problems are most likely explained by differential pharmaco-dynamic effects in the tissues between children with and without Down syndrome. Although the number of patients was limited to draw conclusions, we feel that it may be safe in children with Down syndrome to start with intermediate dosages of methotrexate (1-3 g/m(2)) and monitor the patients carefully.

Outcome of childhood acute lymphoblastic leukemia with induction failure treated by the Japan Association of Childhood Leukemia study (JACLS) ALL F-protocol

BACKGROUND

Children with acute lymphoblastic leukemia (ALL) who fail to achieve complete remission (CR) after induction therapy (induction failure: IF) have a poor prognosis; however, there have been few prospective studies in patients with IF.

PATIENTS AND METHODS

Between April 1997 and March 2005, 27 of 1,237 leukemic patients (2.2%) failed to achieve CR after four- or five-drug induction therapy. Twenty-three of these patients entered the F-protocol study, which mainly consisted of acute-myeloid-leukemia-oriented chemotherapy followed by scheduled hematopoietic cell transplantation (HCT).

RESULTS

Seventeen (73.9%) of the 23 patients responded to re-induction chemotherapy with CR. Of note, 15 (93.8%) of 16 patients with Philadelphia-chromosome-negative (non-Ph(+)) ALL achieved CR; in contrast, only 2 (28.6%) of 7 Ph(+) patients achieved CR. Fourteen (82.4%) of 17 patients remained in CR (CCR) until their scheduled HCT, 12 of the 14 with CCR underwent HCT as scheduled, and 6 patients remain in first CR after a median of 78 months (range, 49-107 months). The 5-year overall survival (OS) rates of 16 patients with non-Ph(+) and 7 patients with Ph(+) were 43.8 +/- 12.4% and 14.3 +/- 13.2%, respectively (P = 0.012). The 5-year OS rate of the 17 patients who obtained CR by re-induction therapy and the 6 who did not were 47.1 +/- 12.1% and 0%, respectively (P < 0.001).

CONCLUSION

Acute-myeloid-leukemia-oriented chemotherapy followed by scheduled HCT is a promising treatment strategy for non-Ph(+) ALL patients with IF.

Long-term results of Dutch Childhood Oncology Group studies for children with acute lymphoblastic leukemia from 1984 to 2004

The Dutch Childhood Oncology Group (DCOG) has used two treatment strategies for children with acute lymphoblastic leukemia (ALL) based on Pinkel's St Jude Total Therapy or the Berlin-Frankfurt-Münster (BFM) backbone. In four successive protocols, 1734 children were treated. Studies ALL-6 and ALL-9 followed the Total Therapy approach; cranial irradiation was replaced by medium-dose methotrexate infusions and prolonged triple intrathecal therapy; dexamethasone was used instead of prednisone. Studies ALL-7 and ALL-8 had a BFM backbone, including more intensive remission induction, early reinduction and maintenance therapy without vincristine and prednisone pulses. The 5-year event-free survival and overall survival increased from 65.4 to 80.6% (P<0.001) and from 78.7 to 86.4% (P=0.07) in ALL-7 and ALL-9, respectively. In ALL-7 and ALL-8 National Cancer Institute (NCI) high-risk criteria, male gender, T-lineage ALL and high white blood cells (WBCs) predict poor outcome. In ALL-9 NCI criteria, gender, WBC >100 x 109/l, and T-lineage ALL have prognostic impact. We conclude that the chemotherapy-only approach in children with ALL in Total Therapy-based strategies and BFM-backbone treatment does not jeopardize survival and preserves cognitive functioning. This experience is implemented in the current DCOG-ALL-10 study using a BFM backbone and minimal residual disease-based stratification.

Dexamethasone-based therapy for childhood acute lymphoblastic leukaemia: results of the prospective Dutch Childhood Oncology Group (DCOG) protocol ALL-9 (1997-2004)

BACKGROUND

A population-based cohort of children aged 1-18 years with acute lymphoblastic leukaemia (ALL) was treated with a dexamethasone-based protocol (Dutch Childhood Oncology Group [DCOG] ALL-9). We aimed to confirm the results of the most effective DCOG ALL protocol for non-high-risk (NHR) patients to date (ALL-6), compare results with ALL-7 and ALL-8, and study prognostic factors in a non-randomised setting.

METHODS

From Jan 1, 1997, until Nov 1, 2004, patients with ALL were treated according to the ALL-9 protocol in eight Dutch academic centres with their affiliated peripheral hospitals. Patients were stratified into NHR and high risk (HR) groups. HR criteria were white-blood-cell count of 50,000 cells per microL or more, T-cell phenotype, mediastinal mass, CNS or testicular involvement, and Philadelphia chromosome or MLL rearrangement; patients who did not fulfil these criteria were deemed to be NHR. The NHR group was treated with a three-drug induction (dexamethasone, vincristine, and asparaginase) for 6 weeks, medium-dose methotrexate for 3 weeks, then maintenance therapy. HR patients received a four-drug induction (as for the NHR patients plus daunorubicin) for 6 weeks, high-dose methotrexate for 8 weeks, and two intensification courses before receiving maintenance therapy. Triple intrathecal medication was given 13 times in NHR patients, 15 times in HR patients (17 times for patients with initial CNS involvement). No patient received cranial irradiation. Maintenance therapy was given until 109 weeks for all patients and consisted of mercaptopurine and methotrexate for 5 weeks, alternated with dexamethasone and vincristine for 2 weeks. Kaplan-Meier analysis was done on an intention-to-treat basis with event-free survival as the primary endpoint. This trial is registered at trialregister.nl, number NTR460/SNWLK-ALL-9.

FINDINGS

859 patients were recruited to the study. Complete remission was achieved in 592 (98.5%) of the 601 patients in the NHR group and 250 (96.9%) of the 258 in the HR group. Five patients in the NHR group and four in the HR group died during induction. Median follow-up for patients alive was 72.2 (range 4.8-132.7) months as of August, 2008. 5-year event-free survival was 81% (SE 1%) in all patients: 84% (2%) in NHR patients, and 72% (3%) in HR patients. Isolated CNS relapses occurred in 22 (2.6%) of 842 patients. In a multivariate analysis, DNA index was the strongest predictor of outcome (<1.16 vs >or=1.16; relative risk 0.42, 95% CI 0.22-0.78), followed by age (1-9 vs >or=10 years; 2.23, 1.60-3.11) and white-blood-cell count (<50,000 vs >or=50,000 cells per microL; 1.60, 1.13-2.26).

INTERPRETATION

The overall results of the dexamethasone-based DCOG ALL-9 protocol are better than those of our previous Berlin-Frankfurt-Münster-based protocols ALL-7 and ALL-8. The results for NHR patients were achieved with high cumulative doses of dexamethasone and vincristine, but without the use of anthracyclines, etoposide, cyclophosphamide, or cranial irradiation, therefore minimising the risk of side-effects.

FUNDING

Dutch Health Insurers.

Treating childhood acute lymphoblastic leukemia without cranial irradiation

BACKGROUND

Prophylactic cranial irradiation has been a standard treatment in children with acute lymphoblastic leukemia (ALL) who are at high risk for central nervous system (CNS) relapse.

METHODS

We conducted a clinical trial to test whether prophylactic cranial irradiation could be omitted from treatment in all children with newly diagnosed ALL. A total of 498 patients who could be evaluated were enrolled. Treatment intensity was based on presenting features and the level of minimal residual disease after remission-induction treatment. The duration of continuous complete remission in the 71 patients who previously would have received prophylactic cranial irradiation was compared with that of 56 historical controls who received it.

RESULTS

The 5-year event-free and overall survival probabilities for all 498 patients were 85.6% (95% confidence interval [CI], 79.9 to 91.3) and 93.5% (95% CI, 89.8 to 97.2), respectively. The 5-year cumulative risk of isolated CNS relapse was 2.7% (95% CI, 1.1 to 4.3), and that of any CNS relapse (including isolated relapse and combined relapse) was 3.9% (95% CI, 1.9 to 5.9). The 71 patients had significantly longer continuous complete remission than the 56 historical controls (P=0.04). All 11 patients with isolated CNS relapse remained in second remission for 0.4 to 5.5 years. CNS leukemia (CNS-3 status) or a traumatic lumbar puncture with blast cells at diagnosis and a high level of minimal residual disease (> or = 1%) after 6 weeks of remission induction were significantly associated with poorer event-free survival. Risk factors for CNS relapse included the genetic abnormality t(1;19)(TCF3-PBX1), any CNS involvement at diagnosis, and T-cell immunophenotype. Common adverse effects included allergic reactions to asparaginase, osteonecrosis, thrombosis, and disseminated fungal infection.

CONCLUSIONS

With effective risk-adjusted chemotherapy, prophylactic cranial irradiation can be safely omitted from the treatment of childhood ALL. (ClinicalTrials.gov number, NCT00137111.)