Enhanced Risk Stratification for Children and Young Adults with B-Cell Acute Lymphoblastic Leukemia: A Children's Oncology Group Report

Current strategies to treat pediatric acute lymphoblastic leukemia rely on risk stratification algorithms using categorical data. We investigated whether using continuous variables assigned different weights would improve risk stratification. We developed and validated a multivariable Cox model for relapse-free survival (RFS) using information from 21199 patients. We constructed risk groups by identifying cutoffs of the COG Prognostic Index (PICOG) that maximized discrimination of the predictive model. Patients with higher PICOG have higher predicted relapse risk. The PICOG reliably discriminates patients with low vs. high relapse risk. For those with moderate relapse risk using current COG risk classification, the PICOG identifies subgroups with varying 5-year RFS. Among current COG standard-risk average patients, PICOG identifies low and intermediate risk groups with 96% and 90% RFS, respectively. Similarly, amongst current COG high-risk patients, PICOG identifies four groups ranging from 96% to 66% RFS, providing additional discrimination for future treatment stratification. When coupled with traditional algorithms, the novel PICOG can more accurately risk stratify patients, identifying groups with better outcomes who may benefit from less intensive therapy, and those who have high relapse risk needing innovative approaches for cure.

Outcomes in Children, Adolescents, and Young Adults With Down Syndrome and ALL: A Report From the Children's Oncology Group

PURPOSE

Patients with Down syndrome (DS) and B-ALL experience increased rates of relapse, toxicity, and death. We report results for patients with DS B-ALL enrolled on Children's Oncology Group trials between 2003 and 2019.

METHODS

We analyzed data for DS (n = 743) and non-DS (n = 20,067) patients age 1-30 years on four B-ALL standard-risk (SR) and high-risk trials.

RESULTS

Patients with DS exhibited more frequent minimal residual disease (MRD) ≥0.01% at end induction (30.8% v 21.5%; P < .001). This difference persisted at end consolidation only in National Cancer Institute (NCI) high-risk patients (34.0% v 11.7%; P < .0001). Five-year event-free survival (EFS) and overall survival (OS) were significantly poorer for DS versus non-DS patients overall (EFS, 79.2% ± 1.6% v 87.5% ± 0.3%; P < .0001; OS, 86.8% ± 1.4% v 93.6% ± 0.2%; P < .0001), and within NCI SR and high-risk subgroups. Multivariable Cox regression analysis of the DS cohort for risk factors associated with inferior EFS identified age >10 years, white blood count >50 × 103/μL, and end-induction MRD ≥0.01%, but not cytogenetics or CRLF2 overexpression. Patients with DS demonstrated higher 5-year cumulative incidence of relapse (11.5% ± 1.2% v 9.1% ± 0.2%; P = .0008), death in remission (4.9% ± 0.8% v 1.7% ± 0.1%; P < .0001), and induction death (3.4% v 0.8%; P < .0001). Mucositis, infections, and hyperglycemia were significantly more frequent in all patients with DS, while seizures were more frequent in patients with DS on high-risk trials (4.1% v 1.8%; P = .005).

CONCLUSION

Patients with DS-ALL exhibit an increased rate of relapse and particularly of treatment-related mortality. Novel, less-toxic therapeutic strategies are needed to improve outcomes.

Assessment of proxy-reported responses as predictors of motor and sensory peripheral neuropathy in children with B-lymphoblastic leukemia

Chemotherapy-induced peripheral neuropathy (CIPN), a common condition in children with acute lymphoblastic leukemia, can be challenging to diagnose. Using data from Children's Oncology Group AALL0932 physical function study, we sought to determine if parent/guardian proxy-reported responses from the Pediatric Outcomes Data Collection Instrument could identify children with motor or sensory CIPN diagnosed by physical/occupational therapists (PT/OT). Four variables moderately discriminated between children with and without motor CIPN (c-index 0.76, 95% confidence interval [CI]: 0.64-0.84), but sensory and optimism-corrected models had weak discrimination (c-index sensory models 0.65, 95% CI: 0.54-0.74). New proxy-report measures are needed to identify children with PT/OT diagnosed CIPN.

Surveillance imaging and early surgical intervention for improved CNS tumor outcomes in children with Li-Fraumeni syndrome: Children's National Hospital experience and literature review

OBJECTIVE

Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome caused by germline mutations in the TP53 gene. CNS tumors are the fourth most common tumor type in LFS, and recent screening guidelines demonstrate that early tumor detection is associated with improved long-term survival. However, there is a paucity of data regarding surgical intervention when lesions are identified in asymptomatic patients on surveillance imaging. The authors investigated this through their cohort and literature review.

METHODS

The cohort consisted of children seen in the Pediatric Cancer Genetics Program at Children's National Hospital between August 2012 and August 2021. The authors also include a PubMed (MEDLINE) literature search of articles from 2006 to 2021 related to surveillance and CNS tumors in patients with LFS. Studies in which CNS tumors were not identified or detailed patient information was not provided were excluded. Patients from the selected articles and the authors' cohort were added for further analysis.

RESULTS

Between August 2012 and August 2021, 10 children with LFS and CNS tumors were assessed at Children's National Hospital: 4 who were known carriers of the TP53 mutation had CNS lesions found on surveillance imaging, whereas 6 presented with symptomatic CNS lesions and were either known or subsequently found to have germline TP53 mutations. The literature search identified 148 articles, 7 of which were included in this review. Patients from the literature and the present cohort were added for a total of 56 CNS lesions. A majority of the low-grade CNS lesions (22/24, 92%) were found on surveillance protocols in asymptomatic patients, whereas the majority of the high-grade lesions (22/26, 85%) presented in symptomatic patients who were not undergoing routine surveillance or as the initial diagnosis of LFS. The authors noted a significant survival advantage in pediatric patients with low-grade lesions, with an overall survival of 100% at 30 months. Minor limitations of the study include patient sample size and limitations in the patient cohort due to this being a retrospective rather than a prospective study.

CONCLUSIONS

Data presented in this study support surveillance protocols in LFS and demonstrate the importance of dedicated CNS imaging and early surgical intervention when lesions are identified. Systematic review registration no.: CRD42022372610 (www.crd.york.ac.uk/prospero).

Persistence of Chemotherapy-Induced Peripheral Neuropathy Despite Vincristine Reduction in Childhood B-Acute Lymphoblastic Leukemia

BACKGROUND

Children with B-acute lymphoblastic leukemia (B-ALL) are at risk for chemotherapy-induced peripheral neuropathy (CIPN). Children's Oncology Group AALL0932 randomized reduction in vincristine and dexamethasone (every 4 weeks vs 12 weeks during maintenance in the average-risk subset of National Cancer Institute standard-B-ALL (SR AR B-ALL). We longitudinally measured CIPN, overall and by treatment group.

METHODS

AALL0932 standard-B-ALL patients aged 3 years and older were evaluated at T1-T4 (end consolidation, maintenance month 1, maintenance month 18, 12 months posttherapy). Physical and occupational therapists (PT/OT) measured motor CIPN (hand and ankle strength, dorsiflexion and plantarflexion range of motion), sensory CIPN (finger and toe vibration and touch), function (dexterity [Purdue Pegboard], and walking efficiency [Six-Minute Walk]). Proxy-reported function (Pediatric Outcome Data Collection Instrument) and quality of life (Pediatric Quality of Life Inventory) were assessed. Age- and sex-matched z scores and proportion impaired were measured longitudinally and compared between groups.

RESULTS

Consent and data were obtained from 150 participants (mean age = 5.1 years [SD = 1.7], 48.7% female). Among participants with completed evaluations, 81.8% had CIPN at T1 (74.5% motor, 34.1% sensory). When examining severity of PT/OT outcomes, only handgrip strength (P < .001) and walking efficiency (P = .02) improved from T1-T4, and only dorsiflexion range of motion (46.7% vs 14.7%; P = .008) and handgrip strength (22.2% vs 37.1%; P = .03) differed in vincristine and dexamethasone every 4 weeks vs vincristine and dexamethasone 12 weeks at T4. Proxy-reported outcomes improved from T1 to T4 (P < .001), and most did not differ between groups.

CONCLUSIONS

CIPN is prevalent early in B-ALL therapy and persists at least 12 months posttherapy. Most outcomes did not differ between treatment groups despite reduction in vincristine frequency. Children with B-ALL should be monitored for CIPN, even with reduced vincristine frequency.

Abstract 2002: A genome-wide association study identifies novel sepsis risk loci in children with Down syndrome-associated acute lymphoblastic leukemia: A report from the Children’s Oncology Group

Background: Children with Down syndrome (DS) have an increased risk of acute lymphoblastic leukemia (ALL) and are more likely to experience morbidity and mortality from infectious toxicities during treatment compared to those without DS. We sought to characterize genetic risk factors for sepsis among individuals with DS-ALL.

Methods: We performed a germline genome-wide association (GWAS) study for sepsis among 264 subjects with DS-ALL treated on Children’s Oncology Group (COG) protocols AALL0932 (N=181) and AALL1131 (N=83), for newly-diagnosed standard risk and high risk B-ALL, respectively. Sepsis was defined using Common Terminology Criteria for Adverse Events (v4.0), with a microbiologically confirmed grade 4 or 5 sepsis event reported during any phase of treatment to define the case and comparison groups. Germline genotyping on the Affymetrix SNP 6.0 or Illumina Omni 2.5Exome arrays was imputed to the Haplotype Reference Consortium panel and filtered for quality control. Logistic regression models were used to compare individuals with DS-ALL who experienced sepsis to those who never developed sepsis during treatment. Models were adjusted for principal components of population structure and COG protocol. Analyses included autosomal variants with a minor allele frequency &gt;1% and excluded chromosome 21.

Results: We identified 29 individuals (10.9%) with DS-ALL who developed one or more sepsis events during treatment. In genome-wide analyses, we observed 52 variants in eight genomic loci associated with sepsis at P&lt;10-5 among individuals with DS-ALL. Our top signal was rs77917748 (P=6.02x10-7), an intronic variant in a regulatory region of TMEM163, a protein that is essential for zinc homeostasis. Additionally, we identified a strong linkage signal at rs56288508 on chr6p21.2 (P=5.29x10-6). According to data from the Genotype-Tissue Expression (GTEx) project, this locus is associated with whole blood expression of ZFAND3, a zinc finger protein and transcriptional regulator. Additionally, this variant is associated with intestinal infections (P=0.012) in the UK Biobank. Finally, a third variant we identified in our GWAS is on chr6q24.2 (P=4.33x10-6) and shows strong linkage in GTEx with peripheral blood mononuclear cell expression of APOBEC3A, a viral deaminase that lacks zinc binding activity. Notably, this variant is associated with respiratory failure (P=0.0099) in the UK Biobank.

Conclusion: We identified evidence of genetic associations for sepsis risk in DS-ALL. These findings suggest zinc homeostasis may be an important factor mediating risk of sepsis during treatment of individuals with DS-ALL. Confirmatory studies and validation in additional cohorts are ongoing.

Citation Format: Melissa A. Richard, Meenakshi Devidas, Wenjian Yang, John P. Woodhouse, Vilmarie Rodriguez, Johann K. Hitzler, Reuven J. Schore, Anne L. Angiolillo, Michael J. Burke, Wanda L. Salzer, Elizabeth A. Raetz, Mignon L. Loh, Stephen P. Hunger, Jun J. Yang, Philip J. Lupo, Karen R. Rabin. A genome-wide association study identifies novel sepsis risk loci in children with Down syndrome-associated acute lymphoblastic leukemia: A report from the Children’s Oncology Group [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2002.

Effects of age, obesity, and body surface area on asparaginase-associated toxicities during acute lymphoblastic leukemia induction therapy: A report from the Children’s Oncology Group

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Background: Asparaginase is integral to pediatric-inspired regimens (PIR) to treat acute lymphoblastic leukemia (ALL) in adolescents and young adults (AYA). However, asparaginase-associated toxicities (AAT) often preclude delivery of planned therapy. Older age, obesity and/or large body surface area (BSA) have been associated with higher risk of AAT in PIR, but data are conflicting, and the impact of dose modification based on these factors is unknown. Methods: We examined induction toxicity data from patients ages 1-30 years enrolled in the frontline Children’s Oncology Group (COG) trials for high-risk B-ALL (AALL0232, 2004-2011) and T-ALL (AALL0434, 2007-2014). During Induction, patients received pegaspargase (2,500 IU/m2 without prescribed dose-capping) plus daunorubicin, vincristine, and prednisone or dexamethasone. AAT were defined as CTCAE v4 hyperbilirubinemia (Grade ≥3), elevated alanine aminotransferase (ALT) (Grade ≥4), thrombosis (any), or pancreatitis (any, included consolidation phase). Obesity was classified using population norms as body mass index (BMI) ≥30 (or ≥95th percentile for age/sex). BSA was analyzed continuously and dichotomized at 1.5 m2 (equivalent to pegaspargase 3,750 IU, the threshold for permissible dose-capping in PIR). The association of AAT with end-Induction minimal residual disease (MRD) ≥0.01% was assessed. Results: Among 4,925 patients, 25% were ≥15 years, 39% had BSA >1.5m2, and 18% had obesity. Multivariable logistic analyses inclusive of BMI and BSA together found increased risk for any AAT in age groups ≥10 years (10-15y, odds ratio (OR) 2.0, 15-20y OR 2.2, ≥21 OR 3.3, p=0.002). Only patients with both obesity and high BSA (>1.5m2) were at additional risk (OR 3.3, p<0.0001). Similarly, risks for hyperbilirubinemia, ALT elevations, and thrombosis were increased in patients with both high BSA and obesity (OR 3.5, 95% confidence interval [CI] 2.2-5.7), OR 3.3, 95%CI 1.7-6.6, and OR 3.1 95%CI 1.5-6.5, respectively), but not in those with high BSA without obesity. The risk of hyperbilirubinemia was greater with increasing obesity (p<0.0001) and was also higher in all age groups ≥10 years (OR 6.3-7.9, p<0.0001). Age was not associated with thrombosis or ALT elevation; risk for pancreatitis was associated with Hispanic ethnicity, but not with age, BMI, or BSA. AAT were not associated with pooled trial MRD ≥0.01%. Conclusions: We report here the largest dataset of AAT in children and AYAs receiving ALL Induction therapy without routinely prescribed dose-capping of pegaspargase. Risk for AAT was increased in patients >10 years and in those with obesity, but not high BSA alone. Dose capping may not be necessary for children and AYAs with high BSA without obesity. Prospective studies of AAT pharmacogenomics and modifiable risk factors will support safer dosing in PIR. Clinical trial information: NCT00075725, NCT00408005.

Prognostic impact of minimal residual disease at the end of consolidation in NCI standard-risk B-lymphoblastic leukemia: A report from the Children's Oncology Group

The 5-year disease-free survival (DFS) of National Cancer Institute (NCI) high-risk (HR) B-lymphoblastic leukemia (B-ALL) patients with end of induction (EOI) minimal residual disease (MRD) ≥0.1% and end of consolidation (EOC) MRD ≥0.01% is 39 ± 7%, warranting consideration of hematopoietic stem cell transplant (HSCT). However, the impact of EOC MRD in NCI standard-risk (SR) B-ALL patients using COG regimens is unknown. We found that SR patients with MRD ≥0.01% at both EOI and EOC have a 4-year DFS/overall survival (OS) of 72.9 ± 19.0%/91.7 ± 10.8% versus 90.7 ± 2.9%/95.5 ± 2.0% (p = .0019/.25) for those with EOI MRD ≥0.01% and EOC MRD <0.01%. These data suggest that routine use of HSCT may not be warranted in EOC MRD ≥0.01% SR patients.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A Pediatric Case of Transformed Mycosis Fungoides in a BRCA2 Positive Patient

Cutaneous T-cell lymphomas are very rare in children. Although mycosis fungoides is the most common of these rare cutaneous T-cell lymphomas in children, transformation to an aggressive malignancy remains extremely uncommon, and there are no clear guidelines for clinical management in the pediatric population. In addition, the increased usage of next-generation sequencing for pediatric patients with unusual malignancies may result in the discovery of pathogenic germline mutations, though the association between these mutations and the patient's cancer is not always clear. We present here a unique pediatric case of transformed mycosis fungoides in a patient with BRCA2 mutation.

Outcomes in children with Down syndrome (DS) and B-lymphoblastic leukemia (B-ALL): A Children’s Oncology Group (COG) report

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Background: Patients with DS and B-ALL experience increased rates of relapse and toxicities. Here, we report results from 4 COG trials (2003-2018). Methods: We analyzed clinical, and outcome data for DS (n = 743) and non-DS (n = 21,703) patients age 1-30 enrolled on standard-risk (SR) trials AALL0331 and AALL0932 and high-risk (HR) trials AALL0232 and AALL1131. Initially, DS-ALL patients on AALL0232/AALL0331 experienced excess mortality, prompting enhanced supportive care and omission of induction anthracycline except for slow responders on AALL1131. Other modifications included: non-random assignment to treatment strata without investigational agents; leucovorin rescue after intrathecal methotrexate (MTX); equal maintenance length for boys and girls; every 12-week maintenance vincristine/steroid pulses; and reduced anthracycline and intravenous MTX for HR patients. Results: Across all 4 trials, DS and non-DS patients did not differ significantly in age, sex, initial WBC, or CNS status. DS-ALL patients had significantly higher end of induction (EOI) minimal residual disease (MRD) vs non-DS patients on both AALL0932 and AALL1131, but the difference persisted at end of consolidation (EOC) only on AALL1131, with fewer EOI MRD+ DS patients achieving EOC MRD < 0.01% (76.1 vs 88.0%, p = 0.001). 5-year EFS and OS were significantly poorer for DS vs non-DS across all trials (EFS 79.6+2.1% vs 86.3+0.3%, p < 0.0001; OS 86.5+1.8% vs 93.1+0.2%, p < 0.0001), as well as on each individual trial. In Cox regression analysis for all DS patients, inferior EFS was associated with several known risk factors (age > 10, EOI MRD >0.01%) but not with cytogenetics or CRLF2 status Induction death was more frequent in DS patients (3.4% vs 0.8%, p < 0.0001) as was death in remission (4.8+0.8% vs 1.8+0.1%, p < 0.0001). For death in remission, the increased frequency occurred pre-maintenance and in patients taken off protocol therapy, but not during maintenance, in contrast to prior reports. Grade >3 mucositis, infections, and hyperglycemia were significantly more frequent in DS patients on all trials. Grade >3 seizures were significantly more frequent in DS patients on HR but not SR trials (4.1% vs 1.7%. p = 0.001) and occurred in all phases pre-maintenance. Conclusions: Patients with DS and B-ALL continue to have inferior outcomes compared to non-DS, with increased relapse and toxicities. Less toxic approaches such as immunotherapies and targeted therapies hold promise to improve outcomes in both these areas.

Outcomes with reduced intensity therapy in a low-risk subset of children with National Cancer Institute (NCI) standard-risk (SR) B-lymphoblastic leukemia (B-ALL): A report from Children’s Oncology Group (COG) AALL0932

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Background: Post-hoc analysis of COG P9904 identified a low risk (LR) group of SR B-ALL patients aged 1-9.99 years with WBC < 50,000/µL, no CNS3, and either ETV6/RUNX1 or double trisomies (DT) of chromosomes 4 and 10 with day 8 peripheral blood (PB) and day 29 marrow (BM) minimal residual disease (MRD) < 0.01% who had a 5-year event-free survival (EFS) of 97±2% and overall survival (OS) 98.8±0.8%. Outstanding results were also obtained for LR patients on COG AALL0331 using CCG-based ALL therapy. AALL0932 tested prospectively whether LR B-ALL patients could attain a 5-year EFS ≥95% with these regimens. Methods: Following a 3-drug induction, eligible AALL0932 LR patients had NCI SR B-ALL (no testicular leukemia, unfavorable genetics or Down syndrome) with DT or ETV6/RUNX1 fusion, CNS1, no steroid pre-treatment, with Day 8 PB and Day 29 BM MRD < 0.01%. Between 2010-16, 603 LR patients were randomized to P9904-based regimen LR-M (n = 301) or CCG 1991/COG AALL0331-based regimen LR-C (n = 302). LR-M included 6 24-hour infusions of 1 gm/m2 of methotrexate (MTX) with leucovorin rescue, but no anthracyclines or alkylating agents. Maintenance followed with daily 6-mercaptopurine (6-MP) and weekly oral MTX, and every 16 week 7-day pulses of dexamethasone (DEX) with vincristine (VCR) on days 1 and 8. Boys and girls were treated for 2.5 years from diagnosis. LR-C had no 24-hour MTX infusions, but included 2 Interim Maintenance (IM) phases with VCR and escalating IV MTX without leucovorin rescue given every 10 days for 5 doses, flanking an 8-week Delayed Intensification (DI) phase that included DEX, VCR, pegasparagase, doxorubicin (75 mg/m2), cyclophosphamide (1 gm/m2) and 8 doses of low-dose cytarabine (75 mg/m2/dose). LR-C Maintenance included daily 6-MP and weekly oral MTX with 5-day pulses of DEX and 1 dose of VCR given every 12 weeks. Girls received 2 years and boys 3 years of therapy from the start of IM I. Results: Both regimens achieved outstanding outcomes: 5-yr disease-free survival (±SE) 98.8%±0.8% for LR-M and 98.5%±0.9% for LR-C (p = 0.67). Both had 5-yr OS 100%. Therapies were well tolerated with higher rates of mucositis (12.9 vs 6.3%; p = 0.008) and allergic reactions (2.3% vs 0%; p = 0.02) on LR-C. Conclusions: AALL0932 demonstrated that application of stringent risk criteria can identify a favorable B-ALL subgroup almost certain to be cured with either LR-M or LR-C, allowing physicians and families to select the optimal treatment approach in the future. Clinical trial information: NCT01190930.

Impact of asparaginase discontinuation on outcome in childhood ALL: A report from the Children’s Oncology Group (COG)

10005

Background: Asparaginase (ASP) is an important component of acute lymphoblastic leukemia (ALL) treatment, but is often discontinued due to toxicity. For allergic reactions, but not other toxicities, Erwinia Asparaginase (EA) is often substituted. The majority of treatment protocols use discrete, discontinuous periods of asparagine depletion. In the context of such protocols, the impact of EA substitution or complete ASP discontinuation is unknown. Methods: Patients age 1-30.99 years enrolled on frontline COG trials for B-ALL [standard risk (NCI SR): AALL0331; high risk (NCI HR) AALL0232] were included. The number of prescribed pegaspargase (PEG) doses varied by trial, risk strata, and randomization (Table). Maintenance therapy did not contain ASP. Landmark analyses starting at Maintenance compared event free survival (EFS) between those receiving all prescribed doses of PEG vs. those switched to EA but receiving all doses vs. those not receiving all ASP doses. Results: This study included 5,195 AALL0331 and 3,001 AALL0232 patients. The cumulative incidence of PEG discontinuation was 12.2±4.6% on AALL0331 and 25.4%±0.8% on AALL0232. In multivariable analyses adjusted for patient and disease variables, NCI HR patients who did not receive all prescribed ASP doses had inferior EFS [hazard ratio (HR) 1.5, 95% confidence interval (95CI) 1.2-1.9; p=0.002] compared to those receiving all prescribed PEG doses. Patients with EA substitution who completed their courses were not at increased risk (HR 1.1, 95CI 0.7-1.6; p=0.69). Sensitivity analyses excluding patients discontinuing ASP due to pancreatitis or thrombosis yielded similar results. NCI SR patients who discontinued ASP were not at elevated risk (HR 1.2, 95CI 0.9-1.6; p=0.23), except when analyses were restricted to NCI SR patients with slow early response (HR 1.7, 95CI 1.1-2.7; p=0.03). Conclusions: Discontinuation of ASP doses is associated with significantly inferior EFS and must be balanced against the risks of ASP re-challenge. Our results also illustrate the potentially severe consequences of EA shortages. Prescribed pegasparagase doses. [Table: see text]

Plasma asparaginase activity and asparagine depletion in acute lymphoblastic leukemia patients treated with pegaspargase on Children's Oncology Group AALL07P4

The efficacy of asparaginase in acute lymphoblastic leukemia (ALL) is dependent on depletion of asparagine, an essential amino acid for ALL cells. The target level of plasma asparaginase activity to achieve asparagine depletion has been between 0.05 and 0.4 IU/mL. COG AALL07P4 examined the asparaginase activity and plasma and CSF asparagine concentration of pegaspargase when given intravenously in the treatment of NCI high risk ALL. Matched plasma asparaginase/asparagine levels of the clearance of 54 doses of pegaspargase given in induction or consolidation demonstrated that all patients who had a plasma asparaginase level >0.02 IU/mL had undetectable plasma asparagine. No difference was observed in CSF asparagine levels associated with matched plasma asparaginase levels of 0.02-0.049 versus 0.05-0.22 IU/mL (p = .25). Our data suggest that a plasma asparaginase activity level of 0.02 IU/mL can effectively deplete plasma asparagine. The data also indicate that the 95% CI for plasma asparagine depletion after a pegaspargase dose is 22-29 days. Clinical trial registration: clinicaltrials.gov identifier NCT00671034.

Longitudinal analysis of quality-of-life outcomes in children during treatment for acute lymphoblastic leukemia: A report from the Children's Oncology Group AALL0932 trial

BACKGROUND

Children with average-risk acute lymphoblastic leukemia (AR-ALL) face many challenges that can adversely affect their quality of life (QOL). However, to the authors' knowledge, patterns and predictors of QOL impairment during therapy have not been well characterized to date.

METHODS

Patients with AR-ALL who were enrolled on the Children's Oncology Group AALL0932 trial were offered participation in this prospective cohort study if they were aged ≥4 years at the time of diagnosis and had an English-speaking parent. At approximately 2 months, 8 months, 17 months, 26 months, and 38 months (boys only) after diagnosis, parents completed the Pediatric Quality of Life Inventory Generic Core Scales Version 4.0 (PedsQL4.0) and McMaster Family Assessment Device instruments for QOL (physical, emotional, and social functioning) and family functioning, respectively. The proportions of individuals scoring in the impaired range (2 standard deviations below the population mean) were calculated at each time point. Longitudinal impairment patterns and predictors were examined.

RESULTS

A total of 594 participants with AR-ALL were diagnosed at a mean age of 6.0 years (standard deviation, 1.6 years). At 2 months, a substantial proportion of participants had impaired scores for physical (36.5%; 95% confidence interval [95% CI], 32.3%-40.8%) and emotional (26.2%; 95% CI, 22.5%-30.2%) functioning compared with population norms of 2.3%. These elevations persisted at 26 months. Emotional impairment at 2 months (odds ratio, 3.4; 95% CI, 1.5-7.7) was found to significantly predict emotional impairment at 26 months. In repeated measures analysis with multivariate modeling, unhealthy family functioning (odds ratio, 1.5; 95% CI, 1.1-2.1) significantly predicted emotional impairment controlling for age and sex. QOL outcomes were similar between sexes at the end of therapy (26 months for girls and 38 months for boys).

CONCLUSIONS

Many children with AR-ALL experience physical and emotional functioning impairment that begins early in treatment and persists. Early screening may identify high-risk patients who might benefit from family-based interventions. Cancer 2018;124:571-9. © 2017 American Cancer Society.

Redefining treatment failure for pediatric acute leukemia in the era of minimal residual disease testing

Technologies for the detection of minimal residual disease (MRD) in leukemia and our understanding of the prognostic implications of MRD at different phases of treatment have significantly improved over the past decade. As a result, definitions of treatment failure based on bone marrow morphology by light microscopy are becoming increasingly inadequate for clinical care and trial design. In addition, novel therapies that may have increased efficacy and decreased toxicity in the setting of MRD compared to overt disease are changing clinical practice and challenging investigators to redefine treatment failure, the role of disease surveillance in remission, and clinical trial eligibility in the era of MRD.

The genomic landscape of juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a myeloproliferative neoplasm (MPN) of childhood with a poor prognosis. Mutations in NF1, NRAS, KRAS, PTPN11 and CBL occur in 85% of patients, yet there are currently no risk stratification algorithms capable of predicting which patients will be refractory to conventional treatment and therefore be candidates for experimental therapies. In addition, there have been few other molecular pathways identified aside from the Ras/MAPK pathway to serve as the basis for such novel therapeutic strategies. We therefore sought to genomically characterize serial samples from patients at diagnosis through relapse and transformation to acute myeloid leukemia in order to expand our knowledge of the mutational spectrum in JMML. We identified recurrent mutations in genes involved in signal transduction, gene splicing, the polycomb repressive complex 2 (PRC2) and transcription. Importantly, the number of somatic alterations present at diagnosis appears to be the major determinant of outcome.

Pharmacokinetic and pharmacodynamic properties of calaspargase pegol Escherichia coli L-asparaginase in the treatment of patients with acute lymphoblastic leukemia: results from Children's Oncology Group Study AALL07P4

PURPOSE

Asparaginase is a critical agent used to treat acute lymphoblastic leukemia (ALL). Pegaspargase (SS-PEG), a pegylated form of Escherichia coli L-asparaginase with a succinimidyl succinate (SS) linker, is the first-line asparaginase product used in Children's Oncology Group (COG) ALL trials. Calaspargase pegol (SC-PEG) replaces the SS linker in SS-PEG with a succinimidyl carbamate linker, creating a more stable molecule. COG AALL07P4 was designed to determine the pharmacokinetic and pharmacodynamic comparability of SC-PEG to SS-PEG in patients with newly diagnosed high-risk (HR) B-cell ALL.

PATIENTS AND METHODS

A total of 165 evaluable patients were randomly assigned at a 2:1 ratio to receive SC-PEG at 2,100 (SC-PEG2100; n = 69) or 2,500 IU/m(2) (SC-PEG2500; n = 42) versus SS-PEG 2,500 IU/m(2) (SS-PEG2500; n = 54) as part of an otherwise identical chemotherapy regimen. The groups were similar demographically, except more female patients received SC-PEG2500.

RESULTS

The mean half-life of plasma asparaginase activity for both SC-PEG doses was approximately 2.5× longer than that of SS-PEG2500. The total systemic exposure, as defined by induction area under the curve from time 0 to 25 days, was greater with SC-PEG2500 than with SS-PEG2500 or SC-PEG2100. The proportion of patients with plasma asparaginase activity ≥ 100 mIU/mL and ≥ 400 mIU/mL was higher in patients who received SC-PEG as compared with SS-PEG2500. After one dose of pegylated asparaginase on induction day 4, plasma asparagine was undetectable for 11 days for SS-PEG2500 and 18 days for both SC-PEG groups.

CONCLUSION

SC-PEG2500 achieves a significantly longer period of asparaginase activity above defined thresholds and asparagine depletion compared with SS-PEG2500 and has a comparable toxicity profile in children with HR B-cell ALL.

Pharmacokinetic (PK) and pharmacodynamics (PD) properties of SC-PEG e. coli L-asparaginase (EZN-2285) in the treatment of patients with acute lymphoblastic leukemia (ALL): Results from Children's Oncology Group (COG) study AALL07P4

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Background: Asparaginase is a critical therapeutic agent in the treatment of childhood ALL, and pegaspargase (Oncospar, ONC) is now the preferred product in COG frontline ALL trials. EZN-2285 replaces the succinimidyl succinate linker in ONC with a succinimidyl carbamate linker creating a more stable molecule. AALL07P4 was designed to determine the PK comparability of EZN-2285 to ONC when given intravenously in newly diagnosed patients with NCI high-risk (HR) B-precursor ALL. Methods: 162 eligible patients were randomized to receive EZN-2285 at 2100 (LD, n=66) or 2500 (HD, n=42) IU/m2 vs. 2500 IU/m2 of ONC (n=51) in a 2:1 manner based on the prednisone/Capizzi methotrexate arm of COG AALL0232. All groups were similar demographically with the exception of number of patients over the age of 16 years were 6, 5, and 19 in the ONC, HD and LD, respectively. Results: PK, PD and targeted AEs (Gr 3-5) after the first doses of study drug are presented in the table below. Adverse events in induction were not significantly different between arms with the exception of a higher incidence of hyperglycemia (p=0.042). Conclusions: Based on Cmax , AUC0-25d , and asparaginase activity 25 days post drug, EZN-2285 2500 IU/m2 appears to have an improved PK/PD profile compared to pegaspargase 2500 IU/m2 and a comparable toxicity profile in children with HR ALL. [Table: see text]