Long-term results of the Italian Association of Pediatric Hematology and Oncology (AIEOP) Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia

Long-term outcomes for children with acute lymphoblastic leukemia (ALL) treated on The Cancer Institute of New Jersey ALL trial (CINJALL)

The Cancer Institute of New Jersey Acute Lymphoblastic Leukemia trial (CINJALL) employed a post-induction regimen centered on intensive oral antimetabolite therapy, with no intravenous methotrexate (MTX). Fifty-eight patients enrolled between 2001 and 2005. A high rate of induction death (n = 3) or induction failure (n = 1) was observed. Among those who entered remission, five-year DFS is 80 ± 8.9% for those at standard risk of relapse and 76 ± 7.8% for high-risk patients, with median follow up over six years. The estimated cumulative incidence of testicular relapse among boys was elevated (13 ± 7.2%) compared to the rate observed on contemporary protocols. We conclude that post-induction therapy using intensive oral antimetabolites for children with acute lymphoblastic leukemia (ALL) can result in overall long-term DFS comparable to that observed among children treated with regimens including intravenous MTX. However, an increased risk of late extramedullary relapse among boys was observed, supporting the prevailing opinion that high-dose MTX improves outcome for children with ALL.

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.

Stanniocalcin1 gene expression in patients with acute leukemia: impact on response to therapy and disease outcome

INTRODUCTION

Stanniocalcin1 (STC1) is a hormone that regulates cell growth and survival; this study aimed to evaluate the STC1 gene expression in patients with acute leukemia and assess its prognostic significance.

METHODS

Seventy-six patients with acute leukemia were enrolled for determination of mRNA STC1 by real-time quantitative polymerase chain reaction at diagnosis and at day 28.

RESULTS

Median STC1 gene expression was 16.2 and 4.43 in patients with acute myeloid leukemia and 9.67 and 2.37 in patients with acute lymphoblastic leukemia on days 0 and 28, respectively. A cutoff level for STC1 gene expression was established subdividing patients into high- and low-STC1 gene expression groups. Median STC1 gene expression at days 0 and 28 was significantly higher among patients who were nonresponders to therapy than among those who were therapy responders in both groups. Patients achieving complete remission had significantly lower baseline STC1 gene expression than those in relapse. High STC1 gene expression was associated with shorter overall and disease-free survival times.

CONCLUSION

STC1 gene expression at diagnosis might be a useful prognostic marker for clinical outcome and monitoring therapeutic response in patients with acute leukemia.

In vitro and in vivo single-agent efficacy of checkpoint kinase inhibition in acute lymphoblastic leukemia

BACKGROUND

Although progress in children, in adults, ALL still carries a dismal outcome. Here, we explored the in vitro and in vivo activity of PF-00477736 (Pfizer), a potent, selective ATP-competitive small-molecule inhibitor of checkpoint kinase 1 (Chk1) and with lower efficacy of checkpoint kinase 2 (Chk2).

METHODS

The effectiveness of PF-00477736 as single agent in B-/T-ALL was evaluated in vitro and in vivo studies as a single agent. The efficacy of the compound in terms of cytotoxicity, induction of apoptosis, and changes in gene and protein expression was assessed using different B-/T-ALL cell lines. Finally, the action of PF-00477736 was assessed in vivo using leukemic mouse generated by a single administration of the tumorigenic agent N-ethyl-N-nitrosourea.

RESULTS

Chk1 and Chk2 are overexpressed concomitant with the presence of genetic damage as suggested by the nuclear labeling for γ-H2A.X (Ser139) in 68 % of ALL patients. In human B- and T-ALL cell lines, inhibition of Chk1/2 as a single treatment strategy efficiently triggered the Chk1-Cdc25-Cdc2 pathway resulting in a dose- and time-dependent cytotoxicity, induction of apoptosis, and increased DNA damage. Moreover, treatment with PF-00477736 showed efficacy ex vivo in primary leukemic blasts separated from 14 adult ALL patients and in vivo in mice transplanted with T-ALL, arguing in favor of its future clinical evaluation in leukemia.

CONCLUSIONS

In vitro, ex vivo, and in vivo results support the inhibition of Chk1 as a new therapeutic strategy in acute lymphoblastic leukemia, and they provide a strong rationale for its future clinical investigation.

Childhood Acute Lymphoblastic Leukemia: Progress Through Collaboration

PURPOSE

To review the impact of collaborative studies on advances in the biology and treatment of acute lymphoblastic leukemia (ALL) in children and adolescents.

METHODS

A review of English literature on childhood ALL focusing on collaborative studies was performed. The resulting article was reviewed and revised by the committee chairs of the major ALL study groups.

RESULTS

With long-term survival rates for ALL approaching 90% and the advent of high-resolution genome-wide analyses, several international study groups or consortia were established to conduct collaborative research to further improve outcome. As a result, treatment strategies have been improved for several subtypes of ALL, such as infant, MLL-rearranged, Philadelphia chromosome-positive, and Philadelphia chromosome-like ALL. Many recurrent genetic abnormalities that respond to tyrosine kinase inhibitors and multiple genetic determinants of drug resistance and toxicities have been identified to help develop targeted therapy. Several genetic polymorphisms have been recognized that show susceptibility to developing ALL and that help explain the racial/ethnic differences in the incidence of ALL.

CONCLUSION

The information gained from collaborative studies has helped decipher the heterogeneity of ALL to help improve personalized treatment, which will further advance the current high cure rate and the quality of life for children and adolescents with ALL.

Prediction of outcomes by early treatment responses in childhood T-cell acute lymphoblastic leukemia: a retrospective study in China

BACKGROUND

Early treatment responses are important prognostic factors in childhood T-cell acute lymphoblastic leukemia (T-ALL) patients. The predictive values of early treatment responses in Chinese childhood T-ALL patients were still unknown.

METHODS

From January 2003 to December 2012, 74 consecutive patients aged ≤ 15 years with newly diagnosed T-ALL were treated with BCH-2003 protocol or CCLG-2008 protocol in the Department of Pediatric, Institute of Hematology and Blood Diseases Hospital in China. Predictive values of early treatment responses, including prednisone response, bone marrow morphology at day 15 and day 33 during induction chemotherapy, and minimal residual disease (MRD) monitored by flow cytometry after induction therapy (time point 1, TP1) and before consolidation therapy (time point 2, TP2), were analyzed.

RESULTS

The 5-year event free survival (EFS) and overall survival (OS) rates for these patients were 62.5% (SE, 6.4) and 62.7% (SE, 6.6), respectively. Prednisone poor responder was strongly associated with increased chance of induction failure (14.8%) and decreased survival rate (5 year EFS rate, 51.1 % (SE, 10.5)). Patients with ≥ 25% blast cells in bone marrow at day 15 were more likely to have an inferior outcome. 93.2% of the T-ALL patients achieved complete remission at day 33 while patients with resistant disease all died of disease progression. MRD ≥ 10(-2) at TP1 or MRD ≥ 10(-3) at TP2 was significantly related to dismal prognosis. Risk groups classified by MRD at two time points could stratify patients into different groups: 29.0% of the patients were MRD standard risk (MRD < 10(-4) at both time points) with 3-year EFS rate of 100%, 29.0% were MRD high risk (MRD ≥ 10(-2) at TP1 or MRD ≥ 10(-2) at TP2) with 3-year EFS rate of 55.6% (SE, 16.6) , and the rest of patients were defined as MRD intermediate risk with 3-year EFS rate of 85.7% (SE, 13.2).

CONCLUSION

Our study demonstrated that MRD was the most powerful predictor of treatment outcome in childhood T-ALL patients and conventional morphological assessments of treatment response still played important roles in predicting treatment outcome and tailoring treatment intensity especially in countries with inadequate skills or financial resources for MRD monitoring.

Prognostic significance of minimal residual disease in high risk B-ALL: a report from Children's Oncology Group study AALL0232

Minimal residual disease (MRD) is highly prognostic in pediatric B-precursor acute lymphoblastic leukemia (B-ALL). In Children's Oncology Group high-risk B-ALL study AALL0232, we investigated MRD in subjects randomized in a 2 × 2 factorial design to receive either high-dose methotrexate (HD-MTX) or Capizzi methotrexate (C-MTX) during interim maintenance (IM) or prednisone or dexamethasone during induction. Subjects with end-induction MRD ≥0.1% or those with morphologic slow early response were nonrandomly assigned to receive a second IM and delayed intensification phase. MRD was measured by 6-color flow cytometry in 1 of 2 reference labs, with excellent agreement between the two. Subjects with end-induction MRD <0.01% had a 5-year event-free survival (EFS) of 87% ± 1% vs 74% ± 4% for those with MRD 0.01% to 0.1%; increasing MRD amounts was associated with progressively worse outcome. Subjects converting from MRD positive to negative by end consolidation had a relatively favorable 79% ± 5% 5-year disease-free survival vs 39% ± 7% for those with MRD ≥0.01%. Although HD-MTX was superior to C-MTX, MRD retained prognostic significance in both groups (86% ± 2% vs 58% ± 4% for MRD-negative vs positive C-MTX subjects; 88% ± 2% vs 68% ± 4% for HD-MTX subjects). Intensified therapy given to subjects with MRD >0.1% did not improve either 5-year EFS or overall survival (OS). However, these subjects showed an early relapse rate similar to that seen in MRD-negative ones, with EFS/OS curves for patients with 0.1% to 1% MRD crossing those with 0.01% to 0.1% MRD at 3 and 4 years, thus suggesting that the intensified therapy altered the disease course of MRD-positive subjects. Additional interventions targeted at the MRD-positive group may further improve outcome. This trial was registered at www.clinicaltrials.gov as #NCT00075725.

Transplantation Outcomes for Children with Hypodiploid Acute Lymphoblastic Leukemia

Children with hypodiploid acute lymphoblastic leukemia (ALL) have inferior outcomes despite intensive risk-adapted chemotherapy regimens. We describe 78 children with hypodiploid ALL who underwent hematopoietic stem cell transplantation between 1990 and 2010. Thirty-nine (50%) patients had ≤ 43 chromosomes, 12 (15%) had 44 chromosomes, and 27 (35%) had 45 chromosomes. Forty-three (55%) patients underwent transplantation in first remission (CR1) and 35 (45%) underwent transplantation in ≥ second remission (CR2). Twenty-nine patients (37%) received a graft from a related donor and 49 (63%) from an unrelated donor. All patients received a myeloablative conditioning regimen. The 5-year probabilities of leukemia-free survival, overall survival, relapse, and treatment-related mortality for the entire cohort were 51%, 56%, 27%, and 22%, respectively. Multivariate analysis confirmed that mortality risks were higher for patients who underwent transplantation in CR2 (hazard ratio, 2.16; P = .05), with number of chromosomes ≤ 43 (hazard ratio, 2.15; P = .05), and for those who underwent transplantation in the first decade of the study period (hazard ratio, 2.60; P = .01). Similarly, treatment failure risks were higher with number of chromosomes ≤ 43 (hazard ratio, 2.28; P = .04) and the earlier transplantation period (hazard ratio, 2.51; P = .01). Although survival is better with advances in donor selection and supportive care, disease-related risk factors significantly influence transplantation outcomes.

Survival of Mexican Children with Acute Lymphoblastic Leukaemia under Treatment with the Protocol from the Dana-Farber Cancer Institute 00-01

Our aim in this paper is to describe the results of treatment of acute lymphoblastic leukaemia (ALL) in Mexican children treated from 2006 to 2010 under the protocol from the Dana-Farber Cancer Institute (DFCI) 00-01. The children were younger than 16 years of age and had a diagnosis of ALL de novo. The patients were classified as standard risk if they were 1–9.9 years old and had a leucocyte count <50 × 10⁹/L, precursor B cell immunophenotype, no mediastinal mass, CSF free of blasts, and a good response to prednisone. The rest of the patients were defined as high risk. Of a total of 302 children, 51.7% were at high risk. The global survival rate was 63.9%, and the event-free survival rate was 52.3% after an average follow-up of 3.9 years. The percentages of patients who died were 7% on induction and 14.2% in complete remission; death was associated mainly with infection (21.5%). The relapse rate was 26.2%. The main factor associated with the occurrence of an event was a leucocyte count >100 × 10⁹/L. The poor outcomes were associated with toxic death during induction, complete remission, and relapse. These factors remain the main obstacles to the success of this treatment in our population.

Identification of mutant alleles of JAK3 in pediatric patients with acute lymphoblastic leukemia

Children with acute lymphoblastic leukemia (ALL) have an 80% chance of long-term survival. Despite the high rate of cure, children relapse, and recurrent ALL is difficult to cure with chemotherapeutic regimens. Therefore, improved biological understanding of ALL and the development of rationally designed therapeutics targeting molecules associated with the pathogenesis of ALL are essential. We identified missense and synonymous JAK3 mutations in 16 of 91 pediatric patients with ALL. The expression of JAK3(V722I) mutant caused the cytokine-independent activation of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling and conferred the factor-independent growth of murine interleukin-3 (IL-3)-dependent pro-B Ba/F3 cells. Importantly, inhibition of JAK3 by the known JAK3 inhibitor CP-690 550 converted the Ba/F3-JAK3(V722I) cells back to factor-dependent growth. These observations suggest that JAK3 may contribute to the pathogenesis of pediatric ALL and serve as an important therapeutic target which can be leveraged to improve outcomes for pediatric patients with ALL.

Indoleamine 2,3-dioxygenase 1 (IDO1) activity in leukemia blasts correlates with poor outcome in childhood acute myeloid leukemia

Microenvironmental factors contribute to the immune dysfunction characterizing acute myeloid leukemia (AML). Indoleamine 2,3-dioxygenase 1 (IDO1) is an interferon (IFN)-γ-inducible enzyme that degrades tryptophan into kynurenine, which, in turn, inhibits effector T cells and promotes regulatory T-cell (Treg) differentiation. It is presently unknown whether childhood AML cells express IDO1 and whether IDO1 activity correlates with patient outcome.

We investigated IDO1 expression and function in 37 children with newly diagnosed AML other than acute promyelocytic leukemia. Blast cells were cultured with exogenous IFN-γ for 24 hours, followed by the measurement of kynurenine production and tryptophan consumption. No constitutive expression of IDO1 protein was detected in blast cells from the 37 AML samples herein tested. Conversely, 19 out of 37 (51%) AML samples up-regulated functional IDO1 protein in response to IFN-γ. The inability to express IDO1 by the remaining 18 AML samples was not apparently due to a defective IFN-γ signaling circuitry, as suggested by the measurement of signal transducer and activator of transcription 3 (STAT3) phosphorylation. Co-immunoprecipitation assays indicated the occurrence of physical interactions between STAT3 and IDO1 in AML blasts. In line with this finding, STAT3 inhibitors abrogated IDO1 function in AML blasts. Interestingly, levels of IFN-γ were significantly higher in the bone marrow fluid of IDO-expressing compared with IDO-nonexpressing AMLs. In mixed tumor lymphocyte cultures (MTLC), IDO-expressing AML blasts blunted the ability of allogeneic naïve T cells to produce IFN-γ and promoted Treg differentiation. From a clinical perspective, the 8-year event-free survival was significantly worse in IDO-expressing children (16.4%, SE 9.8) as compared with IDO-nonexpressing ones (48.0%, SE 12.1; p=0.035).

These data indicate that IDO1 expression by leukemia blasts negatively affects the prognosis of childhood AML. Moreover, they speak in favor of the hypothesis that IDO can be targeted, in adjunct to current chemotherapy approaches, to improve the clinical outcome of children with AML.

Detection and management of minimal residual disease in acute lymphoblastic leukemia

The detection of minimal residual disease (MRD) has become part of the state-of-the-art diagnostics to guide treatment both in pediatric and adult acute lymphoblastic leukemia (ALL). This applies to the treatment of de novo and recurrent ALL. In high-risk ALL, MRD detection is considered an important tool to adjust therapy before and after hematopoietic stem cell transplantation. Precise quantification and quality control is instrumental to avoid false treatment assignment. A new methodological approach to analyzing MRD has become available and is based on next-generation sequencing. In principle, this technique will be able to detect a large number of leukemic subclones at a much higher speed than before. Carefully designed prospective studies need to demonstrate concordance or even superiority compared with those techniques in use right now: detection of aberrant expression of leukemia-specific antigens by flow cytometry of blood or bone marrow, or detection of specific rearrangements of the T-cell receptor or immunoglobulin genes by real-time quantitative polymerase chain reaction using DNA of leukemic cells. In some cases with known fusion genes, such as BCR/ABL, reverse transcriptase-polymerase chain reaction has been used as additional method to identify leukemic cells by analyzing RNA in patient samples. MRD detection may be used to modulate treatment intensity once it has been demonstrated at well-defined informative checkpoints that certain levels of MRD can reliably predict the risk of relapse. In addition, MRD is used as end point to determine the activity of a given agent or treatment protocol. If activity translates into antileukemic efficacy, MRD may be considered a surrogate clinical end point.

Low expressions of ARS2 and CASP8AP2 predict relapse and poor prognosis in pediatric acute lymphoblastic leukemia patients treated on China CCLG-ALL 2008 protocol

ARS2 protein is important to early development and cell proliferation, in which ARS2-CASP8AP2 interaction is implicated. However, the predictive significance of ARS2 in childhood acute lymphoblastic leukemia (ALL) is unknown. Here we evaluate the predictive values of ARS2 expression and combined ARS2 and CASP8AP2 expression in relapse. We showed that ARS2 expression in ALL bone marrow samples at initial diagnosis was markedly lower than that in complete remission (CR). Likewise, the levels of ARS2 expression in the patients suffering from relapse were significantly lower than that of patients in continuous CR. Furthermore, low expression of ARS2 was closely correlated to poor treatment response including poor prednisone response and high minimal residual disease (MRD), and the patients with high MRD (≥10(-4)) and low ARS2 were more subject to relapse. The multivariate analyses for relapse free survival and event free survival revealed that ARS2 expression remained an independent prognostic factor after adjusting other risk factors. In addition, combined assessment of ARS2 and CASP8AP2 expression was more accurate to predict relapse, based on which an algorithm composed of ARS2 and CASP8AP2 expression, prednisone response and MRD (day 78) was proposed. Together, ARS2 and CASP8AP2 expressions can precisely predict high-risk of relapse and ALL prognosis.

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.

Cranial radiation for pediatric T-lineage acute lymphoblastic leukemia: a systematic review and meta-analysis

There are heterogeneous approaches to cranial radiation therapy (CRT) for T-lineage acute lymphoblastic leukemia (T-ALL). We performed a systematic review of studies that specified a radiation strategy and reported survival for pediatric T-ALL. Our analysis included 62 publications reporting 78 treatment groups (patient n = 5844). The average event-free survival (EFS) was higher by 6% per 5 years (P < 0.001). Adjusting for year, EFS differed by radiation strategy. Compared to the reference group (CRT for all) which had a year-adjusted EFS of 65% (95% confidence interval, CI: 61-69%) the adjusted EFS was significantly worse (rate difference (RD) = -9%, 95% CI: -15 to -2%) among studies that used a risk-directed approach to CRT (P = 0.004). The adjusted EFS for the other strategies were not significantly different compared to the reference group: CRT for central nervous system positive patients only (RD = -3%, 95% CI: -14 to 7%, P = 0.49); CRT omitted for all patients (RD = 5%, 95% CI: -4 to 15%, P = 0.33). CRT may not be necessary with current chemotherapy for T-ALL. These findings, however, are susceptible to bias and caution should be applied in drawing conclusions on the comparative effectiveness of alternative CRT strategies.

Mercaptopurine/Methotrexate maintenance therapy of childhood acute lymphoblastic leukemia: clinical facts and fiction

The antileukemic mechanisms of 6-mercaptopurine (6MP) and methotrexate (MTX) maintenance therapy are poorly understood, but the benefits of several years of myelosuppressive maintenance therapy for acute lymphoblastic leukemia are well proven. Currently, there is no international consensus on drug dosing. Because of significant interindividual and intraindividual variations in drug disposition and pharmacodynamics, vigorous dose adjustments are needed to obtain a target degree of myelosuppression. As the normal white blood cell counts vary by patients' ages and ethnicity, and also within age groups, identical white blood cell levels for 2 patients may not reflect the same treatment intensity. Measurements of intracellular levels of cytotoxic metabolites of 6MP and MTX can identify nonadherent patients, but therapeutic target levels remains to be established. A rise in serum aminotransferase levels during maintenance therapy is common and often related to high levels of methylated 6MP metabolites. However, except for episodes of hypoglycemia, serious liver dysfunction is rare, the risk of permanent liver damage is low, and aminotransferase levels usually normalize within a few weeks after discontinuation of therapy. 6MP and MTX dose increments should lead to either leukopenia or a rise in aminotransferases, and if neither is experienced, poor treatment adherence should be considered. The many genetic polymorphisms that determine 6MP and MTX disposition, efficacy, and toxicity have precluded implementation of pharmacogenomics into treatment, the sole exception being dramatic 6MP dose reductions in patients who are homozygous deficient for thiopurine methyltransferase, the enzyme that methylates 6MP and several of its metabolites. In conclusion, maintenance therapy is as important as the more intensive and toxic earlier treatment phases, and often more challenging. Ongoing research address the applicability of drug metabolite measurements for dose adjustments, extensive host genome profiling to understand diversity in treatment efficacy and toxicity, and alternative thiopurine dosing regimens to improve therapy for the individual patient.

Final height and body mass index in adult survivors of childhood acute lymphoblastic leukemia treated without cranial radiotherapy: a retrospective longitudinal multicenter Italian study

Background

Young adult survivors of childhood acute lymphoblastic leukemia (ALL) treated with protocols including cranial radiotherapy demonstrate a persistent weight gain and reduced final height. Published reports on the effects on growth of different oncologic therapies are conflicting and difficult to interpret because they combined children treated with both cranial irradiation and multi-agent chemotherapy. Our study investigated the effect of chemotherapy alone on body mass index (BMI) and on growth at the achievement of final height in a homogeneous cohort of Italian childhood ALL survivors.

Methods

We retrospectively studied 162 Caucasian patients treated on the Italian Association of Pediatric Hematology and Oncology protocols without radiotherapy between 1989 and 2000 at five Italian centers with 107 inclusions (58 males). Height- and BMI-standard deviation score (SDS) were collected at diagnosis of ALL, at the end of treatment and at the achievement of final height. Changes in height SDS and BMI SDS with time were analyzed using dependent sample Student's t-test.

Results

A significant reduction of height-SDS was documented during treatment in both genders. This reduction of height-SDS was not followed by an appropriate catch-up growth, despite the achievement of a mean final height within the normal range. At diagnosis females showed a lower mean BMI-SDS than males. During treatment, in the whole population, BMI-SDS increased significantly. After it, while males lost BMI-SDS, females showed its persistent increase.

Conclusions

Survivors of childhood ALL generally seemed to achieve a normal final height with a BMI within the normal range. These parameters appeared to be only minimally affected by chemotherapy. Nevertheless, height catch-up growth was not completed after chemotherapy in both genders and all patients experienced an increase of BMI-SDS during chemotherapy that only females seemed to conserve until the achievement of final height.

Current approach to relapsed acute lymphoblastic leukemia in children

Recurrent acute lymphoblastic leukaemia (ALL) is a common disease for pediatric oncologists and accounts for more deaths from cancer in children than any other malignancy. Although most patients achieve a second remission, about 50% of relapsed ALL patients do not respond to salvage therapy or suffer a second relapse and most children with relapse die. Treatment must be tailored after relapse of ALL, since outcome will be influenced by well-established prognostic features, including the timing and site of disease recurrence, the disease immunophenotype, and early response to retrieval therapy in terms of minimal residual disease (MRD). After reinduction chemotherapy, high risk (HR) patients are clear candidates for allogeneic stem cell transplantation (SCT) while standard risk patients do better with conventional chemotherapy and local therapy. Early MRD response assessment is currently applied to identify those patients within the more heterogeneous intermediate risk group who should undergo SCT as consolidation therapy. Recent evidence suggests distinct biological mechanisms for early vs late relapse and the recognition of the involvement of certain treatment resistance related genes as well cell cycle regulation and B-cell development genes at relapse, provides the opportunity to search for novel target therapies.

Dose intensification of methotrexate and cytarabine during intensified continuation chemotherapy for high-risk B-precursor acute lymphoblastic leukemia: POG 9406: a report from the Children's Oncology Group

PURPOSE

To determine the efficacy and toxicity of higher dose versus standard dose intravenous methotrexate (MTX) and pulses of high-dose cytosine arabinoside with asparaginase versus standard dose cytosine arabinoside and teniposide during intensified continuation therapy for higher risk pediatric B-precursor acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

From 1994 to 1999, the Pediatric Oncology Group conducted a randomized phase III clinical trial in higher risk pediatric B-precursor ALL. A total of 784 patients were randomized in a 2×2 factorial design to receive MTX 1 g/m versus 2.5 g/m and to cytosine arabinoside/teniposide versus high-dose cytosine arabinoside/asparaginase during intensified continuation therapy.

RESULTS

Patients receiving standard dose MTX had a 5-year disease-free survival (DFS) of 71.8±2.4%; patients receiving higher dose MTX had a 5-year DFS of 71.7±2.4% (P=0.55). Outcomes on cytosine arabinoside/teniposide (DFS of 70.4±2.4) were similar to higher dose cytosine arabinoside/asparaginase (DFS of 73.1±2.3%) (P=0.41). Overall survival rates were not different between MTX doses or cytosine arabinoside/teniposide versus cytosine arabinoside/asparaginase.

CONCLUSIONS

Increasing MTX dosing to 2.5 g/m did not improve outcomes in higher risk pediatric B-precursor ALL. Giving high-dose cytarabine and asparaginase pulses instead of standard dose cytarabine and teniposide produced nonsignificant differences in outcomes, allowing for teniposide to be removed from ALL therapy.

Management of relapsed acute lymphoblastic leukemia in childhood with conventional and innovative approaches

PURPOSE OF REVIEW

To review and summarize the available evidence on factors predicting prognosis of children with relapsed acute lymphoblastic leukemia (ALL) and on the currently used treatment strategies, as well as on the most promising and innovative molecular or cellular therapies.

RECENT FINDINGS

Relapse still represents the most common cause of treatment failure, occurring in approximately 15-20% of childhood ALL. Risk-oriented standard salvage regimens are mostly based on combinations of the same agents incorporated in frontline therapies. Allogeneic hematopoietic stem cell transplantation (HSCT) is largely employed as postremission therapy, being superior to chemotherapy in high-risk patients. With conventional therapies including HSCT, 40-50% of children with relapsed ALL can be rescued. Thus, innovative approaches are needed to further improve the outcome of patients, especially when carrying poor prognostic factors. The last decade has witnessed the development of novel agents, including nucleoside analogues, anti-CD22 monoclonal antibodies and bi-specific, anti-CD3/CD19 antibodies, together with new formulations of existing chemotherapeutic agents and targeted molecules, such as tyrosine kinase inhibitors and FLT3 inhibitors.

SUMMARY

A significant proportion of children with relapsed ALL are salvaged by risk-oriented therapies. Novel agents should be integrated into combination regimens with the aim of further improving outcome of patients.

Cure rates of childhood acute lymphoblastic leukemia in Lithuania and the benefit of joining international treatment protocol

BACKGROUND

Childhood acute lymphoblastic leukemia (ALL) represents the largest group of pediatric malignancies with long-term survival rates of more than 80% achieved in developed countries. Epidemiological data and survival rates of childhood ALL in Lithuania were lacking. Therefore, the aim of this study was to analyze the population-based long-term treatment results of childhood ALL in Lithuania during 1992-2012.

MATERIALS AND METHODS

Data of all 459 children with T-lineage and B-cell precursor ALL treated in Lithuania from 1992 to 2012 were collected and analyzed. Results were compared among four time-periods: 1992-1996 (N=132), 1997-2002 (N=136), 2003-2008 (N=109) and 2009-2012 (N=82).

RESULTS

The incidence of childhood ALL in Lithuania was 3.2-3.6 cases per 100000 children per year during the study period. Five-year probability of event-free survival increased from 50%± 4% in 1992-1996 to 71%± 4% in 2003-2008 (P<0.001). Five-year cumulative incidence of relapses reduced from 27%± 4.5% in 1992-1996 to 14%± 3.6% in 2003-2008 (P=0.042). After introduction of high-dose methotrexate of 5 g/m(2), cumulative incidence of CNS-involving relapses reduced from 17%± 3.9% in 1992-1996 to 1%± 1.0% in 2003-2008 (P<0.001). Trend for further improvement in survival was seen in 2009-2012 when Lithuania joined international the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL-2008 treatment protocol.

CONCLUSIONS

Cure rates of childhood ALL in Lithuania are improving steadily and are now approaching those reported by the largest international study groups. The reasons for such a positive effect are both better financial support for treatment of children with cancer in Lithuania and international collaboration with joining international treatment protocol for childhood ALL.

The evolution of clinical trials for infant acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) in infants has a significantly inferior outcome in comparison with older children. Despite initial improvements in survival of infants with ALL since establishment of the first pediatric cooperative group ALL trials, the poor outcome has plateaued in recent years. Historically, infants were treated on risk-adapted childhood ALL protocols. These studies were pivotal in identifying the need for infant-specific protocols, delineating prognostic categories and the requirement for a more unified approach between study groups to overcome limitations in accrual because of low incidence. This subsequently led to the development of collaborative infant-specific studies. Landmark outcomes have included the elimination of cranial radiotherapy following the discovery of intrathecal and high-dose systemic therapy as a superior and effective treatment strategy for central nervous system disease prophylaxis, with improved neurodevelopmental outcome. Universal prospective identification of independent adverse prognostic factors, including presence of a mixed lineage leukemia rearrangement and young age, has established the basis for risk stratification within current trials. The infant-specific trials have defined limits to which conventional chemotherapeutic agents can be intensified to optimize the balance between treatment efficacy and toxicity. Despite variations in therapeutic intensity, there has been no recent improvement in survival due to the equilibrium between relapse and toxicity. Ultimately, to improve the outcome for infants with ALL, key areas still to be addressed include identification and adaptation of novel prognostic markers and innovative therapies, establishing the role of hematopoietic stem cell transplantation in first complete remission, treatment strategies for relapsed/refractory disease and monitoring and timely intervention of late effects in survivors. This would be best achieved through a single unified international trial.

Childhood high-risk acute lymphoblastic leukemia in first remission: results after chemotherapy or transplant from the AIEOP ALL 2000 study

Intensive BFM therapy is effective for HR childhood ALL if low MRD levels are achieved at the end of the induction/consolidation phase. Childhood ALL with high MRD levels at the end of induction/consolidation phase has a poor prognosis despite intensive BFM therapy or HSCT.

Survival improvement by decade of patients aged 0-14 years with acute lymphoblastic leukemia: a SEER analysis

To evaluate treatment outcomes in children with acute lymphoblastic leukemia (ALL) over the past 3 decades, we assessed the survival of children with ALL in the Surveillance, Epidemiology, and End Results (SEER) database. Among 12,096 patients from 18 SEER sites diagnosed from 1981 to 2010, survival rates improved each decade from 74.8% to 84.5% to 88.6% at 5 years and from 69.3% to 80.9% to 85.5% at 10 years (P < 0.0001). For ages 10–14 years, 10-year survival increased by more than 20 percentage points to 75.3%, but for infants, it remained low at 54.7%. Improvements in survival rates were observed in both sexes, but survival rates were higher in girls than in boys. For ages 0–14 years during the 2001–2010 period, the 10-year relative survival rates were 87.8% in girls and 83.6% in boys (P < 0.01). Survival rates in child with ALL are expected to further improve with continuous advance in therapies such as targeted therapy and personalized therapy.

MYCN is a novel oncogenic target in pediatric T-cell acute lymphoblastic leukemia

MYCN is an oncogene frequently overexpressed in pediatric solid tumors whereas few evidences suggest his involvement in the pathogenesis of haematologic malignancies. Here we show that MYCN is overexpressed in a relevant proportion (40 to 50%) of adult and pediatric T-cell acute lymphoblastic leukemias (T-ALL). Focusing on pediatric T-ALL, MYCN-expressing samples were found almost exclusively in the TAL1-positive subgroup. Moreover, TAL1 knockdown in T-ALL cell lines resulted in a reduction of MYCN expression, and TAL1 directly binds to MYCN promoter region, suggesting that TAL1 pathway activation could sustain the up-regulation of MYCN. The role of MYCN in T-ALL was investigated by peptide nucleic acid (PNA-MYCN)-mediated transcriptional silencing of MYCN and by siRNAs. MYCN knockdown in T-ALL cell lines resulted in a reduction of cell viability, up to 50%, while no effect was elicited with a mismatch PNA. The inhibitory effect of PNA-MYCN on cell viability was due to a significant increase in apoptosis. PNA-MYCN treatment in pediatric T-ALL samples reduced cell viability of leukemic cells from patients with high MYCN expression, while no effect was obtained in MYCN-negative blast cells. These results showed that MYCN is frequently overexpressed in pediatric T-ALL and suggested his role as a candidate for molecularly-directed therapies.

Intensive chemotherapy for childhood acute lymphoblastic leukemia: results of the randomized intercontinental trial ALL IC-BFM 2002

PURPOSE

From 2002 to 2007, the International Berlin-Frankfurt-Münster Study Group conducted a prospective randomized clinical trial (ALL IC-BFM 2002) for the management of childhood acute lymphoblastic leukemia (ALL) in 15 countries on three continents. The aim of this trial was to explore the impact of differential delayed intensification (DI) on outcome in all risk groups.

PATIENTS AND METHODS

For this trial, 5,060 eligible patients were divided into three risk groups according to age, WBC, early treatment response, and unfavorable genetic aberrations. DI was randomized as follows: standard risk (SR), two 4-week intensive elements (protocol III) versus one 7-week protocol II; intermediate risk (IR), protocol III × 3 versus protocol II × 1; high risk (HR), protocol III × 3 versus either protocol II × 2 (Associazione Italiana Ematologia Oncologia Pediatrica [AIEOP] option), or 3 HR blocks plus single protocol II (Berlin-Frankfurt-Münster [BFM] option).

RESULTS

At 5 years, the probabilities of event-free survival and survival were 74% (± 1%) and 82% (± 1%) for all 5,060 eligible patients, 81% and 90% for the SR (n = 1,564), 75% and 83% for the IR (n = 2,650), and 55% and 62% for the HR (n = 846) groups, respectively. No improvement was accomplished by more intense and/or prolonged DI.

CONCLUSION

The ALL IC-BFM 2002 trial is a good example of international collaboration in pediatric oncology. A wide platform of countries able to run randomized studies in ALL has been established. Although the alternative DI did not improve outcome compared with standard treatment and the overall results are worse than those achieved by longer established leukemia groups, the national results have generally improved.

Predicting relapse risk in childhood acute lymphoblastic leukaemia

Intensive multi-agent chemotherapy regimens and the introduction of risk-stratified therapy have substantially improved cure rates for children with acute lymphoblastic leukaemia (ALL). Current risk allocation schemas are imperfect, as some children are classified as lower-risk and treated with less intensive therapy relapse, while others deemed higher-risk are probably over-treated. Most cooperative groups previously used morphological clearance of blasts in blood and marrow during the initial phases of chemotherapy as a primary factor for risk group allocation; however, this has largely been replaced by the detection of minimal residual disease (MRD). Other than age and white blood cell count (WBC) at presentation, many clinical variables previously used for risk group allocation are no longer prognostic, as MRD and the presence of sentinel genetic lesions are more reliable at predicting outcome. Currently, a number of sentinel genetic lesions are used by most cooperative groups for risk stratification; however, in the near future patients will probably be risk-stratified using genomic signatures and clustering algorithms, rather than individual genetic alterations. This review will describe the clinical, biological, and response-based features known to predict relapse risk in childhood ALL, including those currently used and those likely to be used in the near future to risk-stratify therapy.

Between-course targeting of methotrexate exposure using pharmacokinetically guided dosage adjustments

PURPOSE

It is advantageous to individualize high-dose methotrexate (HDMTX) to maintain adequate exposure while minimizing toxicities. Previously, we accomplished this through within-course dose adjustments.

METHODS

In this study, we evaluated a strategy to individualize HDMTX based on clearance of each individual's previous course of HDMTX in 485 patients with newly diagnosed acute lymphoblastic leukemia. Doses were individualized to achieve a steady-state plasma concentration (Cpss) of 33 or 65 μM (approximately 2.5 or 5 g/m(2)/day) for low- and standard-/high-risk patients, respectively.

RESULTS

Individualized doses resulted in 70 and 63 % of courses being within 20 % of the targeted Cpss in the low- and standard-/high-risk arms, respectively, compared to 60 % (p < 0.001) and 61 % (p = 0.43) with conventionally dosed therapy. Only 1.3 % of the individualized courses in the standard-/high-risk arm had a Cpss greater than 50 % above the target compared to 7.3 % (p < 0.001) in conventionally dosed therapy. We observed a low rate (8.5 % of courses) of grade 3-4 toxicities. The odds of gastrointestinal toxicity were related to methotrexate plasma concentrations in both the low (p = 0.021)- and standard-/high-risk groups (p = 0.003).

CONCLUSIONS

Individualizing HDMTX based on the clearance from the prior course resulted in fewer extreme Cpss values and less delayed excretion compared to conventional dosing.

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.

Second malignant neoplasms after treatment of childhood acute lymphoblastic leukemia

PURPOSE

Second malignant neoplasms (SMNs) after diagnosis of childhood acute lymphoblastic leukemia (ALL) are rare events.

PATIENTS AND METHODS

We analyzed data on risk factors and outcomes of 642 children with SMNs occurring after treatment for ALL from 18 collaborative study groups between 1980 and 2007.

RESULTS

Acute myeloid leukemia (AML; n = 186), myelodysplastic syndrome (MDS; n = 69), and nonmeningioma brain tumor (n = 116) were the most common types of SMNs and had the poorest outcome (5-year survival rate, 18.1% ± 2.9%, 31.1% ± 6.2%, and 18.3% ± 3.8%, respectively). Five-year survival estimates for AML were 11.2% ± 2.9% for 125 patients diagnosed before 2000 and 34.1% ± 6.3% for 61 patients diagnosed after 2000 (P < .001); 5-year survival estimates for MDS were 17.1% ± 6.4% (n = 36) and 48.2% ± 10.6% (n = 33; P = .005). Allogeneic stem-cell transplantation failed to improve outcome of secondary myeloid malignancies after adjusting for waiting time to transplantation. Five-year survival rates were above 90% for patients with meningioma, Hodgkin lymphoma, thyroid carcinoma, basal cell carcinoma, and parotid gland tumor, and 68.5% ± 6.4% for those with non-Hodgkin lymphoma. Eighty-nine percent of patients with brain tumors had received cranial irradiation. Solid tumors were associated with cyclophosphamide exposure, and myeloid malignancy was associated with topoisomerase II inhibitors and starting doses of methotrexate of at least 25 mg/m(2) per week and mercaptopurine of at least 75 mg/m(2) per day. Myeloid malignancies with monosomy 7/5q- were associated with high hyperdiploid ALL karyotypes, whereas 11q23/MLL-rearranged AML or MDS was associated with ALL harboring translocations of t(9;22), t(4;11), t(1;19), and t(12;21) (P = .03).

CONCLUSION

SMNs, except for brain tumors, AML, and MDS, have outcomes similar to their primary counterparts.

Biology of childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common malignancy in childhood, accounting for almost 30% of pediatric cancers. Despite the high rate of cure, ALL is one of the leading causes of death in children with tumor. For this reason, there is a keen interest in identifying genetic and biological features that influence the pathogenesis of ALL and the risk of treatment failure. The application of standard diagnostic technologies such as a conventional karyotype and polymerase chain reaction methodologies, together with gene expression profiling and genome-wide analyses, allows us to genetically characterize almost 100% of children with ALL. This review provides basic information about well-established genetic alterations associated with specific clinical subtypes and new molecular lesions with potential prognostic impact. New insights are reported on the natural history of ALL. Genetic aberrations in childhood ALL are considered both markers of disease and potential targets of treatment. Here, each biological subtype under the genetic point of view has been dissected, including genes involved in the development of lymphocytes and considerations on ALL in infancy. It is also crucial to discuss the issue of relapse. Finally, as future treatment will be individualized on the basis of biological features, the pediatric hemato-oncologists need to be ready and prepared to tailor the "right treatment" to the "right children" with ALL.

Hematopoietic stem cell transplantation for children with high-risk acute lymphoblastic leukemia in first complete remission: a report from the AIEOP registry

Children with high-risk acute lymphoblastic leukemia in first complete remission can benefit from allogeneic hematopoietic stem cell transplantation. We analyzed the outcome of 211 children with high-risk acute lymphoblastic leukemia in first complete remission who were given an allogeneic transplant between 1990 and 2008; the outcome of patients who, despite having an indication for transplantation and a suitable donor, did not receive the allograft for different reasons in the same time period was not analyzed. Sixty-nine patients (33%) were transplanted between 1990 and 1999, 58 (27%) between 2000 and 2005, and 84 (40%) between 2005 and 2008. A matched family donor was employed in 138 patients (65%) and an unrelated donor in 73 (35%). The 10-year probabilities of overall and disease-free survival were 63.4% and 61%, respectively. The 10-year cumulative incidences of transplantation-related mortality and relapse were 15% and 24%, respectively. After 1999, no differences in either disease-free survival or transplant-related mortality were observed in patients transplanted from unrelated or matched family donors. In multivariate analysis, grade IV acute graft-versus-host disease was an independent factor associated with worse disease-free survival. By contrast, grade I acute graft-versus-host disease and age at diagnosis between 1 and 9 years were favorable prognostic variables. Our study, not intended to evaluate whether transplantation is superior to chemotherapy for children with acute lymphoblastic leukemia in first complete remission and high-risk features, shows that the allograft cured more than 60% of these patients; in the most recent period, the outcome of recipients of grafts from matched family and unrelated donors was comparable.

A health-care system perspective on implementing genomic medicine: pediatric acute lymphoblastic leukemia as a paradigm

The promise of genomic medicine has received great attention over the past decade, projecting how genomics will soon guide the prevention, diagnosis, and treatment of human diseases. However, this evolution has been slower than forecast, even where evidence is often strong (e.g., pharmacogenomics). Reasons include the requirement for institutional resources and the need for the will to push beyond barriers impeding health-care changes. Here, we illustrate how genomics has been deployed to advance the treatment of childhood leukemia.

Minimal residual disease: optimal methods, timing, and clinical relevance for an individual patient

After approximately 20 years of development and after several prospective clinical trials, the detection of minimal residual disease (MRD) has emerged as part of state-of-the-art diagnostics to guide the majority of contemporary treatment programs both in pediatric and adult acute lymphoblastic leukemia (ALL). For ALL, several methods of MRD analysis are available, but 2 are widely applicable. One is based on the detection of aberrant expression of leukemia specific antigens by flow cytometry and the other one uses the specific rearrangements of the TCR or Ig genes, which can be detected by quantitative PCR in the DNA of leukemic cells. In some cases with known fusion genes such as BCR/ABL, RT-PCR can be used as a third method of identifying leukemic cells by analyzing RNA in patient samples. Clinical application of such sophisticated tools in the stratification and treatment of ALL requires reliable, reproducible, and quality-assured methods to ensure patient safety.

Clinical features, early treatment responses, and outcomes of pediatric acute lymphoblastic leukemia in China with or without specific fusion transcripts: a single institutional study of 1,004 patients

Acute lymphoblastic leukemia (ALL) with distinct fusion transcripts has unique clinical features. In this study, the incidence, clinical characteristics, early treatment response, and outcomes of 1,004 Chinese pediatric ALLs were analyzed. Patients with TEL-AML1 and E2A-PBX1 fusion genes or other B cell precursor ALLs (BCP-ALL) had favorable clinical features, were sensitive to prednisone, had low minimal residual disease (MRD), and an excellent prognosis, with a 5-year event-free survival (EFS) of 84-92%. T-ALL was associated with a high WBC, increased age, more central nervous system involvement, a poor prednisone response, and high MRD, with a 5-year EFS of 68.4 ± 5.2%. Patients with BCR-ABL and MLL rearrangements usually had adverse clinical presentations and treatment responses, and a dismal prognosis, with 5-year EFS of 27.3 and 57.4%, respectively. We also showed that BCR-ABL and MLL rearrangements, the prednisone response, and MRD were independent prognostic factors. Interestingly, the BCH-2003 protocol resulted in a better outcome for E2A-PBX1(+) patients than the CCLG-2008 protocol. Intermediate and late relapses were more common in TEL-AML1(+) patients and other BCP-ALLs compared with other subgroups (P = 0.018). Therefore, this study suggests that a fusion gene-specific chemotherapy regimen and/or targeted therapy should be developed to improve further the cure rate of pediatric ALL.

Acute lymphoblastic leukemia in children: treatment planning via minimal residual disease assessment

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common type of cancer in children and adolescents, accounting for 30% of all cases of malignancy in this age group. The cure rate of ALL is now above 80%. The clinical and biological characteristics of ALL that have been studied to date are of limited use in predicting the individual response. Newly developed methods for the assessment of minimal residual disease (MRD) are more helpful in this regard.

METHODS

Review of pertinent literature retrieved by a selective search in Medline.

RESULTS

MRD assessment has gradually been incorporated into ALL treatment planning over the past two decades. In the largest study to date of the use of MRD for this purpose, which included 3648 children with ALL, the MRD status on days 33 and 78 after the start of treatment was found to be the most important prognostic factor. The study group included 3184 patients with B-precursor ALL (leukemia consisting of immature B-lymphocytes), of whom a large subgroup (standard risk profile, 42%) had a seven-year event-free survival rate (7Y-EFS) of 91.1%; for the 6% of B-ALL patients with a high-risk profile, the cumulative rate of recurrence was 38.5 %.The remaining 464 patients had T-ALL (leukemia consisting of T-lymphocytes). The leukemia cells were eliminated more slowly overall in these patients than in those with B-ALL. Nonetheless, the T-ALL patients with a standard risk profile (16% of all T-ALL patients) had an excellent 7Y-EFS rate (91.1%), while the high-risk group (21% of all T-ALL patients) had an MRD recurrence rate of 37.7%. These findings are representative of current data from around the world on children and adults with ALL.

CONCLUSION

MRD analysis enables more accurate prediction of ALL patients' response to treatment. Risk-group stratification by MRD assessment has already brought about considerable improvement in individualized treatment planning.

Prognosis and outcome of relapsed acute lymphoblastic leukemia: a Hong Kong Pediatric Hematology and Oncology Study Group report

BACKGROUND

In 2000, the Hong Kong Pediatric Hematology Oncology Study Group started a new relapsed acute lymphoblastic leukemia (ALL) treatment protocol based on modified ALL-REZ BFM 96 protocol aiming at improving the treatment outcome in Chinese children.

PROCEDURE

All patients in Hong Kong with first relapse of childhood ALL were included. Patients were stratified into four risk groups (S1, S2, S3, and S4) and the treatment consisted of intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation, if indicated.

RESULTS

Fifty-six patients were recruited and median age at diagnosis of ALL was 4.6 (range, 0.3-17) years. The median time from initial diagnosis to relapse was 2.5 (range, 0.3-9.1) years and follow-up time was 2.7 (range, 0-9.9) years. Forty-nine patients (87.5%) achieved second complete remission (CR2). CR2 rates for S1, S2, S3, and S4 groups were 100%, 93%, 90%, and 67%, respectively. Five-year overall survival (OS) was 50.5 ± 6.9% and event-free survival (EFS) was 41.5 ± 7.1%. There was no significant difference in survival among S1, S2, and S3 groups but S4 patients performed significantly worse with 5-year OS and EFS of 8% and 0%, respectively.

CONCLUSION

Children with relapsed ALL of S1-S3 risk groups could be successfully treated with intensified treatment protocol. The S4 high risk group needs more innovative approach to improve treatment outcome.

How I treat relapsed childhood acute lymphoblastic leukemia

The most common cause of treatment failure in childhood acute lymphoblastic leukemia (ALL) remains relapse, occurring in ~ 15%-20% of patients. Survival of relapsed patients can be predicted by site of relapse, length of first complete remission, and immunophenotype of relapsed ALL. BM and early relapse (< 30 months from diagnosis), as well as T-ALL, are associated with worse prognosis than isolated extramedullary or late relapse (> 30 months from diagnosis). In addition, persistence of minimal residual disease (MRD) at the end of induction or consolidation therapy predicts poor outcome because children with detectable MRD are more likely to relapse than those in molecular remission, even after allogeneic hematopoietic stem cell transplantation. We offer hematopoietic stem cell transplantation to any child with high-risk features because these patients are virtually incurable with chemotherapy alone. By contrast, we treat children with first late BM relapse of B-cell precursor ALL and good clearance of MRD with a chemotherapy approach. We use both systemic and local treatment for extramedullary relapse, mainly represented by radiotherapy and, in case of testicular involvement, by orchiectomy. Innovative approaches, including new agents or strategies of immunotherapy, are under investigation in trials enrolling patients with resistant or more advanced disease.

Pediatric acute lymphoblastic leukemia: where are we going and how do we get there?

Improved supportive care, more precise risk stratification, and personalized chemotherapy based on the characteristics of leukemic cells and hosts (eg, pharmacokinetics and pharmacogenetics) have pushed the cure rate of childhood acute lymphoblastic leukemia to near 90%. Further increase in cure rate can be expected from the discovery of additional recurrent molecular lesions, coupled with the development of novel targeted treatment through high-throughput genomics and innovative drug-screening systems. We discuss specific areas of research that promise to further refine current treatment and to improve the cure rate and quality of life of the patients.

Absence of biallelic TCRγ deletion predicts induction failure and poorer outcomes in childhood T-cell acute lymphoblastic leukemia

BACKGROUND

The absence of biallelic TCRγ deletion (ABD) is a characteristic of early thymocyte precursors before V(D)J recombination. The ABD was reported to predict early treatment failure in T-cell acute lymphoblastic leukemia (ALL). This study aimed to investigate its prognostic value in Taiwanese patients with T-cell ALL.

PROCEDURE

Forty-five children with T-cell ALL were enrolled from six medical centers in Taiwan. Quantitative DNA polymerase chain reaction (Q-PCR) was performed to check the status of TCRγ deletion. The threshold for homozygous deletions by Q-PCR was defined as a fold-change <0.35.

RESULTS

ABD was found in 20 patients [20:45] who had higher incidences of induction failure than those without ABD (P = 0.03; hazard ratio [HR] = 8.13; 95% confidence interval [95% CI] = 1.23-53.77) after multivariate regression analysis. Patents with ABD also had inferior EFS and OS (P = 0.071 and 0.0196, respectively). Multivariate Cox analysis indicated that the association between ABD and overall survival was independent of age and leukocyte count on presentation (P = 0.036; HR = 4.25; 95% CI = 1.10-16.42).

CONCLUSIONS

The absence of TCRγ deletion is a predictor of a poor response to induction chemotherapy for pediatric patients with T-cell ALL in Taiwan. Providing patients with T-cell ALL and ABD with alternative regimens may be worthwhile to test in future clinical trials.