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.
•MRD measured by flow cytometry is prognostic in childhood B-ALL even with more effective high-dose methotrexate therapy.•Intensive therapy in MRD-positive patients altered the timing of relapse but did not overcome the poor prognostic significance of MRD.
Philadelphia chromosome-like (Ph-like) acute lymphoblastic leukemia (ALL) is a high-risk subtype characterized by genomic alterations that activate cytokine receptor and kinase signaling. We examined ...the frequency and spectrum of targetable genetic lesions in a retrospective cohort of 1389 consecutively diagnosed patients with childhood B-lineage ALL with high-risk clinical features and/or elevated minimal residual disease at the end of remission induction therapy. The Ph-like gene expression profile was identified in 341 of 1389 patients, 57 of whom were excluded from additional analyses because of the presence of BCR-ABL1 (n = 46) or ETV6-RUNX1 (n = 11). Among the remaining 284 patients (20.4%), overexpression and rearrangement of CRLF2 (IGH-CRLF2 or P2RY8-CRLF2) were identified in 124 (43.7%), with concomitant genomic alterations activating the JAK-STAT pathway (JAK1, JAK2, IL7R) identified in 63 patients (50.8% of those with CRLF2 rearrangement). Among the remaining patients, using reverse transcriptase polymerase chain reaction or transcriptome sequencing, we identified targetable ABL-class fusions (ABL1, ABL2, CSF1R, and PDGFRB) in 14.1%, EPOR rearrangements or JAK2 fusions in 8.8%, alterations activating other JAK-STAT signaling genes (IL7R, SH2B3, JAK1) in 6.3% or other kinases (FLT3, NTRK3, LYN) in 4.6%, and mutations involving the Ras pathway (KRAS, NRAS, NF1, PTPN11) in 6% of those with Ph-like ALL. We identified 8 new rearrangement partners for 4 kinase genes previously reported to be rearranged in Ph-like ALL. The current findings provide support for the precision-medicine testing and treatment approach for Ph-like ALL implemented in Children's Oncology Group ALL trials.
•Ph-like ALL is characterized by a diverse array of genetic alterations activating cytokine receptor and tyrosine kinase signaling.•Pediatric patients with Ph-like ALL can be identified in real time for effective treatment stratification.
Asparaginase (ASNase) is an important component of acute lymphoblastic leukemia (ALL) treatment, but is often discontinued because of toxicity.
ASNase (
) substitution was approved in 2011 for ...allergic reactions.
has, however, been intermittently unavailable because of drug supply issues. The impact of
substitution or complete ASNase discontinuation is unknown.
Patients aged 1-30.99 years in frontline Children's Oncology Group trials for B-cell acute lymphoblastic leukemia between 2004 and 2011 (National Cancer Institute NCI standard risk SR: AALL0331; NCI high risk: AALL0232) were included. The number of prescribed pegaspargase (PEG-ASNase) doses varied by trial and strata. Maintenance therapy did not contain ASNase. Landmark analyses at maintenance compared disease-free survival (DFS) among those receiving all prescribed PEG-ASNase doses versus switching to
but receiving all doses versus not receiving all ASNase doses.
We included 5,195 AALL0331 and 3,001 AALL0232 patients. The cumulative incidence of PEG-ASNase discontinuation was 12.2% ± 4.6% in AALL0331 and 25.4% ± 0.8% in AALL0232. In multivariable analyses, NCI high-risk patients not receiving all prescribed ASNase doses had inferior DFS (hazard ratio HR, 1.5; 95% CI, 1.2 to 1.9;
= .002) compared with those receiving all prescribed PEG-ASNase doses. Patients with
substitution who completed subsequent courses were not at increased risk (HR, 1.1; 95% CI, 0.7 to 1.6;
= .69). NCI SR patients who discontinued ASNase were not at elevated risk (HR, 1.2; 95% CI, 0.9 to 1.6;
= .23), except when restricted to those with slow early response, who were prescribed more ASNase because of therapy intensification (HR, 1.7; 95% CI, 1.1 to 2.7;
= .03).
Discontinuation of ASNase doses is associated with inferior DFS in higher-risk patients. Our results illustrate the severe consequences of
shortages.
Genetic alterations that activate NOTCH1 signaling and T cell transcription factors, coupled with inactivation of the INK4/ARF tumor suppressors, are hallmarks of T-lineage acute lymphoblastic ...leukemia (T-ALL), but detailed genome-wide sequencing of large T-ALL cohorts has not been carried out. Using integrated genomic analysis of 264 T-ALL cases, we identified 106 putative driver genes, half of which had not previously been described in childhood T-ALL (for example, CCND3, CTCF, MYB, SMARCA4, ZFP36L2 and MYCN). We describe new mechanisms of coding and noncoding alteration and identify ten recurrently altered pathways, with associations between mutated genes and pathways, and stage or subtype of T-ALL. For example, NRAS/FLT3 mutations were associated with immature T-ALL, JAK3/STAT5B mutations in HOXA1 deregulated ALL, PTPN2 mutations in TLX1 deregulated T-ALL, and PIK3R1/PTEN mutations in TAL1 deregulated ALL, which suggests that different signaling pathways have distinct roles according to maturational stage. This genomic landscape provides a logical framework for the development of faithful genetic models and new therapeutic approaches.
Infants with KMT2A-rearranged acute lymphoblastic leukemia (KMT2A-r ALL) have a poor prognosis. KMT2A-r ALL overexpresses FLT3, and the FLT3 inhibitor (FLT3i) lestaurtinib potentiates ...chemotherapy-induced cytotoxicity in preclinical models. Children's Oncology Group (COG) AALL0631 tested whether adding lestaurtinib to post-induction chemotherapy improved event-free survival (EFS). After chemotherapy induction, KMT2A-r infants received either chemotherapy only or chemotherapy plus lestaurtinib. Correlative assays included FLT3i plasma pharmacodynamics (PD), which categorized patients as inhibited or uninhibited, and FLT3i ex vivo sensitivity (EVS), which categorized leukemic blasts as sensitive or resistant. There was no difference in 3-year EFS between patients treated with chemotherapy plus lestaurtinib (n = 67, 36 ± 6%) vs. chemotherapy only (n = 54, 39 ± 7%, p = 0.67). However, for the lestaurtinib-treated patients, FLT3i PD and FLT3i EVS significantly correlated with EFS. For FLT3i PD, EFS for inhibited/uninhibited was 59 ± 10%/28 ± 7% (p = 0.009) and for FLTi EVS, EFS for sensitive/resistant was 52 ± 8%/5 ± 5% (p < 0.001). Seventeen patients were both inhibited and sensitive, with an EFS of 88 ± 8%. Adding lestaurtinib did not improve EFS overall, but patients achieving potent FLT3 inhibition and those whose leukemia blasts were sensitive FLT3-inhibition ex vivo did benefit from the addition of lestaurtinib. Patient selection and PD-guided dose escalation may enhance the efficacy of FLT3 inhibition for KMT2A-r infant ALL.
We review recent advances in the biologic understanding and treatment of childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), identify therapeutically challenging subgroups, ...and suggest future directions of research.
A review of English literature on childhood acute leukemias from the past 5 years was performed.
Contemporary treatments have resulted in 5-year event-free survival rates of approximately 80% for childhood ALL and almost 60% for pediatric AML. The advent of high-resolution genome-wide analyses has provided new insights into leukemogenesis and identified many novel subtypes of leukemia. Virtually all ALL and the vast majority of AML cases can be classified according to specific genetic abnormalities. Cooperative mutations involved in cell differentiation, cell cycle regulation, tumor suppression, drug responsiveness, and apoptosis have also been identified in many cases. The development of new formulations of existing drugs, molecularly targeted therapy, and immunotherapies promises to further advance the cure rates and improve quality of life of patients.
The application of new high-throughput sequencing techniques to define the complete DNA sequence of leukemia and host normal cells and the development of new agents targeted to leukemogenic pathways promise to further improve outcome in the coming decade.
Minimal residual disease (MRD) is an important predictor of relapse in acute lymphoblastic leukemia (ALL), but its relationship to other prognostic variables has not been fully assessed. The ...Children’s Oncology Group studied the prognostic impact of MRD measured by flow cytometry in the peripheral blood at day 8, and in end-induction (day 29) and end-consolidation marrows in 2143 children with precursor B-cell ALL (B-ALL). The presence of MRD in day-8 blood and day-29 marrow MRD was associated with shorter event-free survival (EFS) in all risk groups; even patients with 0.01% to 0.1% day-29 MRD had poor outcome compared with patients negative for MRD patients (59% ± 5% vs 88% ± 1% 5-year EFS). Presence of good prognostic markers TEL-AML1 or trisomies of chromosomes 4 and 10 still provided additional prognostic information, but not in National Cancer Insitute high-risk (NCI HR) patients who were MRD+. The few patients with detectable MRD at end of consolidation fared especially poorly, with only a 43% plus or minus 7% 5-year EFS. Day-29 marrow MRD was the most important prognostic variable in multi-variate analysis. The 12% of patients with all favorable risk factors, including NCI risk group, genetics, and absence of days 8 and 29 MRD, had a 97% plus or minus 1% 5-year EFS with nonintensive therapy. These studies are registered at www.clinicaltrials.gov as NCT00005585, NCT00005596, and NCT00005603.
Survival for children and young adults with high-risk B-acute lymphoblastic leukemia has improved significantly, but 20% to 25% of patients are not cured. Children's Oncology Group study AALL0232 ...tested two interventions to improve survival.
Between January 2004 and January 2011, AALL0232 enrolled 3,154 participants 1 to 30 years old with newly diagnosed high-risk B-acute lymphoblastic leukemia. By using a 2 × 2 factorial design, 2,914 participants were randomly assigned to receive dexamethasone (14 days) versus prednisone (28 days) during induction and high-dose methotrexate versus Capizzi escalating-dose methotrexate plus pegaspargase during interim maintenance 1.
Planned interim monitoring showed the superiority of the high-dose methotrexate regimens, which exceeded the predefined boundary and led to cessation of enrollment in January 2011. At that time, participants randomly assigned to high-dose methotrexate during interim maintenance 1 versus those randomly assigned to Capizzi methotrexate had a 5-year event-free survival (EFS) of 82% versus 75.4% (P = .006). Mature final data showed 5-year EFS rates of 79.6% for high-dose methotrexate and 75.2% for Capizzi methotrexate (P = .008). High-dose methotrexate decreased both marrow and CNS recurrences. Patients 1 to 9 years old who received dexamethasone and high-dose methotrexate had a superior outcome compared with those who received the other three regimens (5-year EFS, 91.2% v 83.2%, 80.8%, and 82.1%; P = .015). Older participants derived no benefit from dexamethasone during induction and experienced excess rates of osteonecrosis.
High-dose methotrexate is superior to Capizzi methotrexate for the treatment of high-risk B-acute lymphoblastic leukemia, with no increase in acute toxicity. Dexamethasone given during induction benefited younger children but provided no benefit and was associated with a higher risk of osteonecrosis among participants 10 years and older.
To examine population-based improvements in survival and the impact of clinical covariates on outcome among children and adolescents with acute lymphoblastic leukemia (ALL) enrolled onto Children's ...Oncology Group (COG) clinical trials between 1990 and 2005.
In total, 21,626 persons age 0 to 22 years were enrolled onto COG ALL clinical trials from 1990 to 2005, representing 55.8% of ALL cases estimated to occur among US persons younger than age 20 years during this period. This period was divided into three eras (1990-1994, 1995-1999, and 2000-2005) that included similar patient numbers to examine changes in 5- and 10-year survival over time and the relationship of those changes in survival to clinical covariates, with additional analyses of cause of death.
Five-year survival rates increased from 83.7% in 1990-1994 to 90.4% in 2000-2005 (P < .001). Survival improved significantly in all subgroups (except for infants age ≤ 1 year), including males and females; those age 1 to 9 years, 10+ years, or 15+ years; in whites, blacks, and other races; in Hispanics, non-Hispanics, and patients of unknown ethnicity; in those with B-cell or T-cell immunophenotype; and in those with National Cancer Institute (NCI) standard- or high-risk clinical features. Survival rates for infants changed little, but death following relapse/disease progression decreased and death related to toxicity increased.
This study documents ongoing survival improvements for children and adolescents with ALL. Thirty-six percent of deaths occurred among children with NCI standard-risk features emphasizing that efforts to further improve survival must be directed at both high-risk subsets and at those children predicted to have an excellent chance for cure.
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