BACKGROUND B-cell acute lymphoblastic leukemia (B-cell ALL) is the most common childhood cancer. Despite a high overall cure rate, relapsed B-cell ALL remains a leading cause of cancer-related death among children. The addition of the bispecific T-cell engager molecule blinatumomab (an anti-CD19 and anti-CD3 single-chain molecule) to therapy for newly diagnosed standard-risk (as defined by the National Cancer Institute) B-cell ALL in children may improve outcomes. METHODS We conducted a phase 3 trial involving children with newly diagnosed standard-risk B-cell ALL who had an average or high risk of relapse. Patients were randomly assigned to receive chemotherapy alone or chemotherapy plus two nonsequential 28-day cycles of blinatumomab. The primary end point was disease-free survival. RESULTS The data and safety monitoring committee reviewed the results from the first interim efficacy analysis, which included 1440 patients who had undergone randomization (722 to chemotherapy alone and 718 to blinatumomab and chemotherapy) and recommended early termination of randomization. At a median follow-up of 2.5 years, the estimated 3-year disease-free survival (SE) was 96.01.2% with blinatumomab and chemotherapy and 87.9 +/- 2.1% with chemotherapy alone (difference in restricted mean survival time, 72 days; 95% confidence interval, 36 to 108; P<0.001 by stratified log-rank test). The estimated 3-year disease-free survival among patients with an average relapse risk was 97.5 +/- 1.3% with blinatumomab and chemotherapy and 90.2 +/- 2.3% with chemotherapy alone; among those with a high relapse risk, the corresponding values were 94.1 +/- 2.5% and 84.8 +/- 3.8%. Cytokine release syndrome, seizures, and sepsis of grade 3 or higher were rare during blinatumomab cycles, but the overall incidence of nonfatal sepsis and catheter-related infections was significantly higher among patients with an average relapse risk who had been assigned to receive blinatumomab and chemotherapy than among those assigned to receive chemotherapy alone. CONCLUSIONS Adding blinatumomab to combination chemotherapy in patients with newly diagnosed childhood standard-risk B-cell ALL of average or high risk of relapse significantly improved disease-free survival.

PURPOSE:Clinical and histopathologic diagnosis of pediatric mature B-cell lymphomas (eg, Burkitt lymphoma [BL]) must be accurate to select appropriate risk-based treatment. The Central American Pediatric Hematology-Oncology Association (AHOPCA) in 2000 implemented standardized, resource-adapted treatments for these lymphomas. We evaluated the concordance of local histopathologic diagnoses through central review, determined the impact on therapy selection, and described the clinical characteristics and outcomes of pediatric patients with these lymphomas. We suggest recommendations to improve the accuracy of diagnoses. METHODS:Pathology samples and reports were submitted by six AHOPCA sites to St Jude Children's Research Hospital for central review. The concordance of sample assessments was evaluated using three criteria: histologic diagnosis, morphology, and immunohistochemistry. Clinical characteristics, treatment, and outcomes were also analyzed. RESULTS:Of the 68 eligible patients, 53 (78%) received an accurate pathologic diagnosis of BL. For nine (13%) patients, diagnoses changes with therapy implications were made upon central review, while in six patients, there was a minor disagreement with no therapy implications. Most (87%) patients presented with advanced disease. Detailed cellular features were absent in many reports, and immunohistochemistry was routinely performed at only one site. Of the 50 patients whose treatment data were reported, 44 (88%) completed therapy, five died during treatment, and one abandoned treatment. Treatment outcome was satisfactory: 3-year event-free survival was 74% (SE ± 11%), and overall survival was 73% (SE ± 11%). CONCLUSION:Pathology laboratories in limited-resource hospitals and regions need further optimization to increase accurate diagnoses of mature B-cell lymphomas. Creating regional pathology networks will enhance diagnostic support. Despite resource limitations and advanced disease at presentation, the AHOPCA sites' adapted treatment strategies have improved patient outcomes.

Refractoriness to initial chemotherapy and relapse after remission are the main obstacles to curing T cell acute lymphoblastic leukemia (T-ALL). While tumor heterogeneity has been implicated in treatment failure, the cellular and genetic factors contributing to resistance and relapse remain unknown. Here we linked tumor subpopulations with clinical outcome, created an atlas of healthy pediatric hematopoiesis and applied single-cell multiomic analysis to a diverse cohort of 40 T-ALL cases. We identified a bone marrow progenitor (BMP)-like leukemia subpopulation associated with treatment failure and poor overall survival. The single-cell-derived molecular signature of BMP-like blasts predicted poor outcome across multiple subtypes of T-ALL and revealed that NOTCH1 mutations additively drive T-ALL blasts away from the BMP-like state. Through in silico and in vitro drug screenings, we identified a therapeutic vulnerability of BMP-like blasts to apoptosis-inducing agents including venetoclax. Collectively, our study establishes multiomic signatures for rapid risk stratification and targeted treatment of high-risk T-ALL. Tan and colleagues conducted a single-cell multiomic analysis of T cell acute lymphoblastic leukemia and identified a treatment-resistant subpopulation of bone marrow progenitor-like blasts associated with poor outcomes.

T-lineage acute lymphoblastic leukaemia (T-ALL) is a high-risk tumour1 that has eluded comprehensive genomic characterization, which is partly due to the high frequency of noncoding genomic alterations that result in oncogene deregulation2,3. Here we report an integrated analysis of genome and transcriptome sequencing of tumour and remission samples from more than 1,300 uniformly treated children with T-ALL, coupled with epigenomic and single-cell analyses of malignant and normal T cell precursors. This approach identified 15 subtypes with distinct genomic drivers, gene expression patterns, developmental states and outcomes. Analyses of chromatin topology revealed multiple mechanisms of enhancer deregulation that involve enhancers and genes in a subtype-specific manner, thereby demonstrating widespread involvement of the noncoding genome. We show that the immunophenotypically described, high-risk entity of early T cell precursor ALL is superseded by a broader category of 'early T cell precursor-like' leukaemia. This category has a variable immunophenotype and diverse genomic alterations of a core set of genes that encode regulators of hematopoietic stem cell development. Using multivariable outcome models, we show that genetic subtypes, driver and concomitant genetic alterations independently predict treatment failure and survival. These findings provide a roadmap for the classification, risk stratification and mechanistic understanding of this disease. Comprehensive genomic and transcriptomics analyses of more than 1,300 cases of childhood T-lineage acute lymphoblastic leukaemia identify 15 distinct subtypes that are associated with specific outcomes.

Background: Children's Oncology Group (COG) trials AALL0932 and AALL1131 enrolled children with newly diagnosed National Cancer Institute (NCI) standard-risk (SR) and high-risk (HR) B-ALL from 2010-2019 and 2012-2019, respectively. In 2016, COG amended these trials to incorporate additional induction intrathecal (IT) therapy for patients with B-ALL and CNS2 status [CSF <5/μL WBCs and cytospin positive for blasts; or traumatic lumbar puncture (LP) with ≥5/μL WBCs and cytospin positive for blasts that was negative by Steinherz/Bleyer algorithm]. Based on data demonstrating worse outcomes for CNS2 patients enrolled on prior COG B-ALL trials compared to those without CNS disease at diagnosis (CNS1), COG added IT cytarabine on day 4, maintained day 8 IT methotrexate, then continued twice weekly IT cytarabine until 3 consecutive LPs returned negative cerebrospinal fluid (CSF) results. Methods: Event free survival (EFS), overall survival (OS), and cumulative incidence of relapse (CIR) were compared among CNS2 pre- vs post-amendment patients, stratified by NCI risk group. Multivariable models were also constructed to adjust for demographic and disease variables. Results: When stratified by trial, pre- and post-amendment patients did not differ significantly by demographic or disease factors, including age at diagnosis, end of induction bone marrow MRD status, and blast cytogenetics. For patients with NCI SR B-ALL and CNS2 enrolled on AALL0932 (8% of study population, n=535 pre-amendment, n=207 post-amendment), the 5-year EFS pre- vs post-amendment was 86.7% (SE, 1.5%) vs 88.9% (SE, 2.3%), p=0.44, and 5-year OS pre- vs post-amendment was 95.5% (SE, 0.9%) vs 96.0% (SE, 1.5%), p=0.50. The 5-year CIR for isolated CNS relapse was 3.6% (SE, 0.8%) vs 4.0% (SE, 1.4%) pre- vs post-amendment, p=0.71, and for combined marrow and CNS relapses was 1.0% (SE, 0.4%) vs 1.0% (SE, 0.7%), p=0.71. Among post-amendment NCI SR patients (CNS1 n=2033, CNS2 n=207), the adverse impact of CNS2 status remained statistically significant, with 5-year EFS of 93.2% (SE, 0.6%) vs 88.9% (SE, 2.3%) for CNS1 vs CNS2, p=0.025. For patients with NCI HR B-ALL and CNS2 status (16.6% of study population, n=488 pre-amendment, n=313 post-amendment), the 5-year EFS pre- vs post-amendment was 66.5% (SE, 2.4%) vs 73.5% (SE, 3.4%), p=0.095 and OS pre- vs post-amendment was 80.2% (SE, 2.0%) vs 84.0% (SE, 2.8%), p=0.20. The 5-year CIR for isolated CNS relapse was 5.9% (SE, 1.1%) vs 5.6% (SE, 1.4%) pre- vs post-amendment, p=0.92, and for combined marrow and CNS relapses was 2.7% (SE, 0.8%) vs 0.7% (SE, 0.5%) pre- vs post-amendment, p=0.068. The post-amendment impact of CNS status on outcomes remained significant for NCI HR patients (CNS1 n=1326, CNS2 n=313), with 5-year EFS of 78.4% (SE 1.5%) vs 73.5% for CNS1 vs CNS2, p=0.049. In multivariable analyses conducted separately for AALL0932 and AALL1131 and adjusting for disease prognosticators and race/ethnicity, treatment post-amendment was not significantly associated with any difference in EFS (AALL0932: hazard ratio 0.99, 95CI 0.6-1.6, p=0.95; AALL1131: hazard ratio 0.80, 95CI 0.6-1.1, p=0.14). Additional analyses evaluating subgroups defined by cytogenetics (favorable, neutral, unfavorable) or disease response did not find any subpopulation that significantly benefited from extra IT chemotherapy. The additional therapy was not associated with an increase in toxicity. Conclusions: Additional IT cytarabine during induction for patients with CNS2 disease on AALL0932 and AALL1131 did not improve outcomes or mitigate the adverse prognostic impact of CNS2 status. Rates of CNS2 status and impact on outcome vary greatly between cooperative groups, and factors such as variability in CSF analysis and post-induction therapy need to be considered in order to identify this population accurately and treat accordingly. Given these results showing lack of improvements in outcome and concerns surrounding repeated anesthesia exposure, future frontline B-ALL COG studies will not include additional IT cytarabine for the CNS2 population. Alternative methods of improving outcomes for CNS2 patients are needed.

Background: Molecular characterization of B-lymphoblastic lymphoma (B-LLy) has yet to identify prognostic biomarkers for use in treatment stratification or driver mutations to explain its extramedullary clinical phenotype distinct from B-lymphoblastic leukemia (B-ALL). Patients with B-LLy (with morphologically identical lymphoblasts but <25% bone marrow (BM) involvement) are empirically treated on B-ALL protocols based on clinical stage (Murphy I/II: localized/standard risk (SR); III/IV: disseminated/high risk (HR)), although debate remains as to whether B-LLy represents a separate entity. The unique clinical characteristics of B cell cancers are often presumed to reflect their stage of development at malignant transformation. In normal B cells, ordered rearrangement of immunoglobulin (Ig) heavy (IgH) and light chain genes is linked to stage of development. Upon malignant transformation, distinctive clonal Ig genomic rearrangements expand, and thus afford disease tracking. We applied Ig high-throughput sequencing (HTS) to compare the clonal composition of B-LLy with B-ALL to test whether Ig rearrangement state indicates distinct biology between these entities, and to test whether minimal disseminated disease (MDD) measured by HTS at diagnosis can refine currently limited B-LLy clinical staging. Methods: We performed Ig HTS (Adaptive ClonoSEQ) to define and compare the Ig rearrangement state of B-LLy with that of B-ALL using extracted gDNA from paraffin-embedded tumor slide preparations from 34 patients with B-LLy (N=15 SR; N=17 HR; N=2 stage unknown) from Children's Oncology Group (COG) protocols APEC14B1 and AALL0932, and diagnostic BM from 283 patients with B-ALL from COG protocols AALL0331 (N=141; SR) and AALL0232 (N=142; HR). We also measured B-LLy MDD in 31 patients by tracking tumor-associated Ig rearrangements in pre-treatment BM and peripheral blood (PB). Results: All 34 B-LLy and 281/283 B-ALL samples had dominant IgH and/or Ig light chain clone(s). We detected IgH clones in 91.1% of B-LLy, 86.7% of which reflected complete V(D)J rather than partial diversity (D)-joining (J) rearrangements (vs. 74.8% complete V(D)J in B-ALL). In contrast, patients with B-ALL had more incomplete DJ rearrangements (P=0.04) indicative of a transformation state prior to variable (V) gene recombination. B-ALL V(D)J clones were enriched for usage of the most D-proximal V genes, IGHV06-01 and IGHV01-02, consistent with data indicating preferential D-proximal V gene usage in immature lymphoid progenitors and leukemia. B-LLy did not share this preferential V gene usage and lacked representation of IGHV06-01, distinguishing it from B-ALL. Further, 82.4% of B-LLy (vs. 59.7% of B-ALL; P=0.017) had dominant Ig light chain clone(s), indicative of a more mature rearrangement state. Ig HTS data from the BM and/or PB were available for 31 patients: 80.6% were MDD+, including 69.2% (N=9 of 13) with localized/SR B-LLy. BM/PB MDD level did not significantly vary between patients with localized/SR (median 0.012%; range 0-88.13%) vs. disseminated/HR (median 0.052%; range 0-24.31%) clinical staging. There was also no significant difference in MDD level between the BM and PB among 16 patients with evaluable samples from both sites. While a low event rate limited association with outcome, 0 of 6 patients without measurable MDD experienced relapse/progression/death (vs. 3 of 25 MDD+ patients). Conclusions: B-LLy Ig clonal composition reflects a more mature developmental state than B-ALL and a spectrum of BM/PB MDD across clinical stages. Developmentally ordered Ig rearrangement first involves IgH D-J recombination, followed by V gene rearrangement, and finally Ig light chain V-J rearrangement at kappa and then lambda loci. Thus, Ig clonal composition provides biologically informative data relevant to B cell maturation stage, which here supports classification of B-LLy as a distinct entity from B-ALL. Further, the spectrum of MDD observed in this cohort agnostic of clinical stage suggests that Ig HTS may have novel utility in refining currently limited B-LLy risk stratification by distinguishing select patients who lack measurable disease dissemination or for tracking treatment response via PB HTS. In sum, Ig HTS may have a role in informing therapeutic strategies based on the unique features of B-LLy and in characterizing it as a biologically distinct entity from B-ALL.

Introduction: T-cell lymphoblastic lymphoma (T-LL) is the second most common subtype of non-Hodgkin lymphoma in children. T-LL mirrors T-cell acute lymphoblastic leukemia (T-ALL) in morphology and immunophenotype. Historically, T-ALL and T-LL were considered a spectrum of one disease; as such, treatment regimens have harmonized over time. However, recent Children's Oncology Group (COG) phase 3 trials demonstrated different outcomes for T-LL and T-ALL when treated with identical investigational agents. For example, outcomes for T-LL were significantly improved with the addition of bortezomib, with no benefit for T-ALL. Identification of informative genomic biomarkers may give insight into biologic differences between these two entities. Sequencing from formalin fixed T-LL samples is now possible, providing robust DNA/RNA that can be compared with T-ALL samples. Herein we present comprehensive transcriptional analysis of T-LL in one of the largest cohorts of patients sequenced to date. Methods: RNA was derived from formalin fixed, paraffin-embedded tissue sections of 203 T-LL patients (ages 1-29 years) treated on COG AALL0434 (NCT00408005) and AALL1231(NCT02112916). Healthy bone marrow and thymi samples were used as controls (n=6). Material was scraped from 1-2 slides per sample. A nuclease protection assay (HTG EdgeSeq Transcriptome panel kit) with 19398 gene-specific probes was conducted followed by barcoded cDNA and sequencing library generation. FASTQ files were demultiplexed and parsed using HTG Reveal software. HTG sequencing has been validated to highly correlate with RNA-sequencing data (PMID 35712667). Differential expression analysis between patients who experienced an event (induction failure/relapse/death) versus patients without event was conducted using DESeq2 (PMID 25516281). A log2 fold change cut-off of 2 and adjusted P-value threshold of 0.05 (corrected using the Benjamini and Hochberg method) was implemented. Results: Comprehensive transcriptome profiling was successfully obtained from 166/203 (81.8%) samples. We observed that Epigenetic, Ribosome, and Transcriptional regulation pathway-associated genes were overexpressed. LEF1, RPL3, B2M, and HISTH1H2AE were amongst the highest expressed genes. JAK2 and STAT5B were overall underexpressed, and NOTCH1 was relatively overexpressed among patients in comparison to control samples (P<0.001). Downregulation of CDKN2A was also common (n=85, 51%). We compared gene expression profiles between individuals who had events (n=17: 12% induction failure, 65% progression/relapse, 24% death) to individuals without events (n=149). We identified 8 genes with a log2 fold change > 2 and adjusted P<0.05 between event/no-event cohorts. Specifically, NRARP was overexpressed among patients with events, whereas SPINK2, C1QTNF4, SERHL2, BAALC, and homeobox genes (HOXA9, HOXA7, and HOXA3) were significantly under-expressed. We also compared gene expression between patients with (>=1%) and without (<1%) bone marrow flow-based minimal disseminated disease (MDD) at diagnosis and identified enhanced expression of 20 genes, including MYCN, FLT3, TCTEX1D1, and HOXA13 in MDD+ patients as compared with MDD- patients. Discussion: Herein we report significant differences in gene expression between T-LL patients who experienced refractory disease/relapse/death as compared to patients without these events. Notably, NRARP was upregulated in T-LL patients with events. In T-ALL, NRARP has been shown to block NOTCH1 signaling, promote proliferation of T-ALL blasts and potentiate Wnt pathway signaling (PMID 31586130). We observed lower HOXA gene expression among T-LL patients experiencing refractory disease/relapse/death - potentially suggesting homeobox alterations may be more common in the lower-risk T-LL cohort. We identified differential gene expression between MDD+ and MDD- patients; there may be alternative pathways of lymphomagenesis between these cohorts. Whole genome sequencing (WGS) is completed on 174 cases and analysis is underway. Integrated analysis of WGS with gene expression may further elucidate mechanisms driving differential deregulation and prognostic associations in T-LL, as well as provide opportunity for comparison with T-ALL. HN/LU/RS and DTT/RM/MH contributed equally.

Background Translocation t(1;19)(q23;p13.3) resulting in the TCF3::PBX1 fusion is a recurrent cytogenetic alteration in 5-7% of B-cell acute lymphoblastic leukemia (B-ALL) that occurs more frequently in Black children. Historically, t(1;19) was associated with inferior outcomes with higher rates of central nervous system (CNS) relapse; contemporary prognostic impact is unclear. We assessed t(1;19) outcomes with modern Children's Oncology Group (COG) therapy. Methods From 2010 to 2019, children and young adults with newly diagnosed B-ALL enrolled on standard risk (SR)(AALL0932; NCT01190930) or high risk (HR) (AALL1131; NCT02883049) protocols based on initial white blood cell count (WBC), age, extramedullary disease status, cytogenetic subtype, day 8 peripheral blood and end of induction (EOI) bone marrow flow cytometric minimal residual disease (MRD). Cytogenetic alterations were classified as favorable (ETV6::RUNX1 or double trisomies of chromosomes 4 and 10), unfavorable (iAMP21, KMT2A rearrangement, hypodiploidy) or neutral (all others). The t(1;19), detected by metaphase karyotyping and confirmed by central review, was considered a neutral cytogenetic lesion not impacting risk stratification. Patients 1-10 years of age with WBC <50,000/uL without unfavorable cytogenetics, CNS3 or testicular disease and EOI marrow MRD <0.01% were treated on AALL0932 while NCI HR (age ≥10 years and/or WBC ≥50,000/uL) and any patients with unfavorable cytogenetics, EOI MRD ≥0.01% and/or CNS3 or testicular leukemia or steroid pretreatment were treated on AALL1131. Patients with Down syndrome or Philadelphia chromosome-positive B-ALL were excluded from this analysis. Results Among 6417 patients 1-31 years, 270 (4.2%) had t(1;19) by karyotype, including 90 (33%) and 180 (67%) with a balanced and unbalanced translocation, respectively. The t(1;19) was associated with age ≥ 10 years, female sex, WBC ≥ 50,000/µL, CNS2/3 disease, Black race or Hispanic ethnicity, and Day 29 MRD < 0.01%. The 5-year (yr) disease-free (DFS) and overall survival (OS) for all patients with and without t(1;19) were not significantly different (DFS 92.1% ± 1.8% vs 91.2% ± 0.4%, P =0.39; OS 95.1% ± 1.4% vs 96.4% ± 0.3%, P=0.46) and there were no significant differences between balanced or unbalanced translocations (DFS 91.0% ± 3.2% vs 92.6% ± 2.1%, P = 0.61; OS 94.4% ± 2.6% vs 95.5% ± 1.7%, P=0.69). When separately analyzing 5-yr DFS and OS among NCI SR and NCI HR patients with and without t(1;19), there were similarly no significant differences [NCI SR: DFS 96.8% ± 1.6% vs. 94.0% ± 0.4%, P=0.11 and OS 97.6% ± 1.4%, vs. 98.3% ± 0.2%, P=0.78; NCI HR: DFS 87.7% ± 3.0% vs. 83.4% ± 1.0%, P=0.14 and OS 92.8%±2.3% vs. 90.9% ± 0.8%, P=0.35]. When compared to other patients with neutral cytogenetics, patients with t(1;19) had improved 5-yr DFS and similar OS (DFS 92.1% ± 1.8% vs 87.2% ± 0.7%, P = 0.01; OS 95.1% ± 1.4% vs 94.6% ± 0.5%, P = 0.853). Notably, NCI SR patients with t(1;19) fared as well as those with favorable cytogenetics (DFS 96.8% ± 1.6% vs 95.9% ± 0.4%, P = 0.34, OS 97.6% ± 1.4% vs 98.9% ± 0.2%, P = 0.37). Relapses occurred in 16 (5.9%) patients with t(1;19) compared to 480 (7.8%) without t(1;19) with a similar percentage of isolated CNS relapses (1.9% vs 1.7%), respectively. In a multivariable Cox regression model adjusted for other disease related variables, t(1;19) was significantly associated with decreased risk vs. unfavorable cytogenetics (hazard ratio 0.25, 95% CI: 0.15-0.41, P <.001) and other neutral cytogenetics (hazard ratio 0.62, 95% CI: 0.40-0.97, P = 0.04); and was not statistically significantly different than favorable cytogenetics outcomes (hazard ratio 1.27, 95% CI: 0.79-1.98, P = 0.33). Conclusions With contemporary therapy, t(1;19) did not confer an inferior prognosis overall. Notably, patients with t(1;19) had improved DFS and OS compared to those with other neutral cytogenetics and, among the NCI SR group, fared as well as those with favorable cytogenetics. T(1;19) did not confer an increase in CNS relapse. Our data support that patients with t(1;19) do not need therapy intensification when treated on contemporary risk-directed COG regimens.

Abstract Background Infectious diseases in childhood cancer patients are frequent and increase the morbimortality of these patients. Hospital del Niño doctor José Renán Esquivel initiated data collection in a registry of fever and neutropenia (FEVEREG) to evaluate outcomes and management of these diseases and identify opportunities for quality improvement. The objective of this study is to describe data collected to date. Methods Data was collected through a data collection instrument (CRF) using Trial Master platform. It was analyzed with R Data Analytics (version 4.3.2) and descriptive statistics summarized. Only patients who were admitted due to the febrile episode or were hospitalized when fever started were included. Results From Sept 2021 to October 2023, we captured 138 episodes in 70 patients, with a mean age of 8 years (range 0-15) and a similar percentage of female and male patients. The most common diagnosis was acute lymphoblastic leukemia (57.14%) and the episodes occurred more during the induction phase (24%) and in patients with a relapse protocol (31.5%). The time of administration of the antibiotic varied depending on the patient location at fever onset. 44% of outpatients (46/105) received the first dose of antibiotic more than 4 hours after the onset of fever, while hospitalized patients received this dose in the first hour in 64% of cases (21/33). Time from registration of outpatients until the first dose of antibiotic was an average of 71 minutes, with 60% of the patients receiving the antibiotic during the first 60 minutes. In 45.8% of the episodes, a blood culture was taken before starting the antibiotic. The febrile neutropenia algorithm was followed on 64.5% of the days evaluated, with the main cause of deviation being treatment to the focus of infection (55%) followed by clinical decision (41%). Bacteremia occurred in 26% of episodes (20/78) and 14% of episodes had documented viral infection (11/78). The most frequently isolated bacteria in blood was Pseudomonas aeruginosa (13/33, 39.3%). Approximately 4% of the episodes (6/138) were admitted to the intensive care unit and died, half from septic shock and half from progressive disease. The average length of hospital stay was 12 days. Conclusion Data from FEVEREG has suggested opportunities for quality improvement in time to antibiotics and use of guideline compliant antibiotics (antimicrobial stewardship).

The influence of genetic ancestry on biology, survival outcomes, and risk stratification in T-cell Acute Lymphoblastic Leukemia (T-ALL) has not been explored. Genetic ancestry was genomically-derived from DNA-based single nucleotide polymorphisms in children and young adults with T-ALL treated on Children's Oncology Group trial AALL0434. We determined associations of genetic ancestry, leukemia genomics and survival outcomes; co-primary outcomes were genomic subtype, pathway alteration, overall survival (OS), and event-free survival (EFS). Among 1309 patients, T-ALL molecular subtypes varied significantly by genetic ancestry, including increased frequency of genomically defined ETP-like, MLLT10, and BCL11B-activated subtypes in patients of African ancestry. In multivariable Cox models adjusting for high-risk subtype and pathways, patients of Admixed American ancestry had superior 5-year EFS/OS compared with European; EFS/OS for patients of African and European ancestry were similar. The prognostic value of five commonly altered T-ALL genes varied by ancestry - including NOTCH1 , which was associated with superior OS for patients of European and Admixed American ancestry but non-prognostic among patients of African ancestry. Furthermore, a published five-gene risk classifier accurately risk stratified patients of European ancestry, but misclassified patients of African ancestry. We developed a penalized Cox model which successfully risk stratified patients across ancestries. Overall, 80% of patients had a genomic alteration in at least one gene with differential prognostic impact by genetic ancestry. T-ALL genomics and prognostic associations of genomic alterations vary by genetic ancestry. These data demonstrate the importance of incorporating genetic ancestry into analyses of tumor biology for risk classification algorithms.

Biallelic mutation in the DNA-damage repair gene NBN is the genetic cause of Nijmegen Breakage Syndrome, which is associated with predisposition to lymphoid malignancies. Heterozygous carriers of germline NBN variants may also be at risk for leukemia development, although this is much less characterized. We systematically examined the frequency of germline NBN variants in pediatric B-ALL and identified 25 putatively damaging NBN coding variants in 50 of 4,183 B-ALL patients. Compared with the frequency of NBN variants in 118,479 gnomAD non-cancer controls we found significant overrepresentation in pediatric B-ALL (p=0.004, OR=1.77). Most B-ALL-risk variants were missense and cluster within the NBN N-terminal domains. Using two functional assays, we verified 14 of 25 variants with severe loss-of-function phenotypes and thus classified these as pathogenic or likely pathogenic. Finally, we found that heterozygous germline NBN variant carriers showed similar survival outcomes relative to those with WT status. Taken together, our findings provide novel insights into the genetic predisposition to B-ALL, the impact of NBN variants on protein function and suggest that heterozygous NBN variant carriers may safely receive B-ALL therapy.

Agulnik, Asya1; Robles Murguia, Maricela1; Muniz-Talavera, Hilmarie1; Pham, Linh T.D.1; Cardenas Aguirre, Adolfo1; Aragón Joya, Yefry Andrés2; Arce, Daniela3; Blasco Arriaba, Erika Esther4; Costa, Juliana5; De Leon, Claudia6; Díaz-Coronado, Rosdali7; Montalvo, Erika8; Miralda Mendez, Scheybi Teresa9; Ocampo, Diego10; Pineda Urquilla, Estuardo11; Aguiar de Paula, Andreia Ribeiro Pereira12; Sánchez-Martín, María13; Chen, Yichen1; Devidas, Meenakshi1; Rodriguez-Galindo, Carlos1 Author Information

Defining fi ning prognostic variables in T-lymphoblastic lymphoma (T-LL) remains a challenge. AALL1231 was a Children's Oncology Group phase 3 clinical trial for newly diagnosed patients with T acute lymphoblastic leukemia or T-LL, randomizing children and young adults to a modified fi ed augmented Berlin-Frankfurt-M & uuml;nster backbone to receive standard therapy (arm A) or with addition of bortezomib (arm B). Optional bone marrow samples to assess minimal residual disease (MRD) at the end of induction (EOI) were collected in T-LL analyzed to assess the correlation of MRD at the EOI to event-free survival (EFS). Eightysix (41%) of the 209 patients with T-LL accrued to this trial submitted samples for MRD assessment. Patients with MRD <0.1% (n = 75) at EOI had a superior 4-year EFS vs those with MRD >= 0.1% (n = 11) (89.0% +/- 4.4% vs 63.6% +/- 17.2%; P = .025). Overall survival did not significantly fi cantly differ between the 2 groups. Cox regression for EFS using arm A as reference demonstrated that MRD EOI >= 0.1% was associated with a greater risk of inferior outcome (hazard ratio, 3.73; 95% confidence fi dence interval, 1.12-12.40; P = .032), which was independent of treatment arm assignment. Consideration to incorporate MRD at EOI into future trials will help establish its value in defining fi ning risk groups. CT# NCT02112916.

Intensification of chemotherapy for pediatric B-cell acute lymphoblastic leukemia (B-ALL) has improved survival. In recently completed Children's Oncology Group (COG) frontline trials for B-ALL, a second interim maintenance (IM2) phase including escalating dose methotrexate, vincristine, ±pegaspargase was utilized to intensify therapy. On AALL1131 for high risk B-ALL (HR-ALL), very high risk (VHR) patients received IM2. On AALL0932 for standard risk B-ALL (SR-ALL), patients were randomized to steroid/vincristine pulses every 4 (q4weeks) or 12 weeks (q12weeks); all patients received IM2 to maintain treatment intensity in the context of dose-reduced Maintenance therapy. However, the efficacy of IM2 has never been established in either HR-ALL or SR-ALL. Thus, we performed secondary analyses comparing outcomes for matched cohorts treated ±IM2 in sequential COG trials in HR-ALL treated on AALL0232 (no IM2) and AALL1131 (+IM2) and in SR-ALL treated on AALL0331 (no IM2) and AALL0932 (+IM2). The primary objective was to compare disease-free (DFS) and overall survival (OS) in patients receiving identical systemic COG ALL therapy ±IM2. Secondary objectives were to examine the efficacy of IM2 in SR-ALL with the current standard q12week steroid/vincristine pulses and within cytogenetic subsets. Eligibility criteria for these analyses were designed to match treatment arms between trials. For HR-ALL, inclusion criteria were age ≥13 years old and end of induction (EOI) minimal residual disease (MRD) <0.01%, based on eligibility for the AALL1131 VHR arm. For SR-ALL, patients with neutral or favorable cytogenetics (ETV6::RUNX1 or double trisomies 4 and 10) and EOI MRD <0.01% were included. Patients with BCR::ABL1, KMT2A rearrangement, hypodiploidy, or EOI MRD ≥0.01% were excluded due to treatment variation among trials. Statistical analyses compared DFS and OS via log-rank test and were reported at five years with standard errors. Cox multivariable models analyzed hazard ratios (HR) adjusted for presenting features (demographics, white blood cell count, cytogenetics, central nervous system status). In HR-ALL, 249 patients from AALL0232 and 65 patients from AALL1131 VHR were eligible. For AALL1131 VHR versus AALL0232, the addition of IM2 was not associated with a difference in DFS (85%±4.7 vs 85%±2.5, p=0.91) or OS (90%±4.0 vs 90%±2.1, p=0.63). In SR-ALL patients receiving q4week pulses in Maintenance, 1,317 patients were eligible from AALL0331 and 1,186 patients from AALL0932. As compared to AALL0331, addition of IM2 in AALL0932 was associated with significantly higher DFS (94%±0.7 vs 91%±0.8, p= 0.0024) and OS (99%±0.4 vs 97%±0.5, p<0.0001). In the Cox multivariable model comparing SR-ALL patients receiving q4week pulses, IM2 significantly decreased risk for an event (HR 0.67, p=0.0048). In SR-ALL patients enrolled in AALL0932 who were randomized to receive q12week pulses (n=1,178), addition of IM2 was associated with higher DFS and OS versus AALL0331 (95%±0.7 vs 91%±0.8, p<0.0001 and 99%±0.3 vs 97%±0.5, p<0.0001, respectively). However, adjusted Cox models demonstrated the decreased event risk was largely in those with neutral cytogenetics (HR=0.62, p=0.0179), with OS (HR=0.58, p=0.0783). No difference in DFS/OS was noted in SR-ALL with favorable cytogenetics. Within the limitations of unplanned subset analyses, we determined that IM2 may be able to be safely omitted in MRD-negative patients with HR-ALL or with SR-ALL with favorable cytogenetics and that IM2 may provide a survival advantage for patients with SR-ALL, neutral cytogenetics, and MRD <0.01%. Whether IM2 is necessary in patients with higher risk B-ALL due to adverse cytogenetics or persistent MRD was not addressed in these analyses.

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.

Infants less than 1 year old diagnosed with KMT2A-rearranged (KMT2A-r) acute lymphoblastic leukemia (ALL) are at high risk of failure to achieve remission, relapse, and death due to leukemia, despite intensive therapies. Infant KMT2A-r ALL blasts are characterized by DNA hypermethylation. Epigenetic priming with DNA methyltransferase inhibitors increases the cytotoxicity of chemotherapy in preclinical studies. The Children's Oncology Group trial AALL15P1 tested the safety and tolerability of 5 days of azacitidine treatment immediately prior to the start of chemotherapy on day 6, in four post-induction chemotherapy courses for infants with newly diagnosed KMT2A-r ALL. The treatment was well-tolerated, with only two of 31 evaluable patients (6.5%) experiencing dose-limiting toxicity. Whole genome bisulfite sequencing of peripheral blood mononuclear cells demonstrated decreased DNA methylation in 87% of samples tested following 5 days of azacitidine treatment. Event-free survival was similar to that in prior studies of newly diagnosed infant ALL. Azacitidine is safe and results in decreased DNA methylation of peripheral blood mononuclear cells in infants with KMT2A-r ALL, but the incorporation of azacitidine to enhance cytotoxicity did not impact survival. Clinicaltrials.gov identifier: NCT02828358.

Introduction: Pediatric Hispanic and non-Hispanic (NH) Black patients with newly diagnosed acute lymphoblastic leukemia (ALL) experience worse overall survival (OS) compared to NH White patients (Gupta, Lancet Haematol 2023). We hypothesized that differential outcomes by race and ethnicity (R/E) following relapse may contribute to these disparities. Methods: We examined children and young adults with ALL enrolled on 12 frontline Children's Oncology Group (COG) trials from 1996-2014 who subsequently relapsed. We assessed association of R/E with relapse survival predictors including time-to-relapse, relapse site, ALL risk group, and cytogenetics. We examined association of R/E with post-relapse 5-year OS and assessed the effect of disease characteristics and socioeconomic status. Socioeconomic status was evaluated using US ZIP code-based median household yearly income from the 2020 Census and US insurance status. Analyses of OS used univariate (crude) and multivariable (adjusted) Cox regression models. Results: Among 16,115 patients with ALL treated on frontline COG trials, 2,053 (1,147 NH White, 492 Hispanic, 145 NH Black, 65 NH Asian, 184 other/unknown) relapsed and formed our primary cohort. For B-ALL, post-relapse OS differed by R/E (p=0.002), and specifically, Hispanic patients had worse survival (46.2±2.4%, crude hazard ratio [cHR] 1.39, 95% confidence interval [CI] 1.19-1.63) compared to NH White patients (55.7±1.7%). Disease-related prognosticators, including time-to relapse (p=0.0002), white blood cell count at initial diagnosis (p=0.03), and presence of central nervous system disease at initial diagnosis (p=0.03), varied by R/E. The overall association of OS with R/E was substantially attenuated when adjusted for disease-related prognosticators and ZIP-based income (p=0.53). However, Hispanic ethnicity still associated with worse OS but by a lower magnitude (adjusted HR [aHR] 1.19, 95% CI 1.01-1.41). Post-relapse OS in B-ALL also differed based on ZIP-based income on univariate (p=0.008) but not multivariable analysis. Focusing on the highest and lowest ZIP-based income, patients with ZIP-based income >$85,000 had better OS (56.4±2.9%) compared to those with <$50,000 (48.4±2.7%, aHR 0.77, 95% CI 0.61-0.96). NH Black patients most commonly had based income <$50,000 (46.8%), followed by Hispanic (30.6%), NH White (15.8%), and NH Asian (6.3%) patients. US insurance status also differed based on R/E (univariate p<0.0001), with NH Black patients most commonly being Medicaid insured (42.0%), followed by Hispanic (41.1%), NH White (18.3%), and NH Asian (18.0%) patients. OS was not associated with US insurance status. For T-ALL, neither R/E nor socioeconomic status were associated with OS. For infant ALL, R/E was associated with OS on multivariable analysis (p=0.03). Conclusions: In this large retrospective cohort of patients with relapsed ALL, we found that although R/E were associated with post relapse-OS, multivariable analyses suggest that inferior post-relapse outcomes among Hispanic and NH Black patients are in large part driven by a higher prevalence of adverse disease-related risk factors present at the time of relapse. The persistent disparity observed in Hispanic patients may be related to unmeasured underlying disease biology (such as the higher prevalence CRLF2-rearranged/Philadelphia chromosome-like B-ALL in Hispanic patients). Differing toxicities, supportive care, and adherence to treatment in the frontline setting for R/E minorities may also contribute to the differences in time-to-relapse. Our findings suggest that while post-relapse interventions are needed, the greatest impact in decreasing R/E-based ALL outcome disparities will come through identifying and targeting mechanisms in the frontline treatment setting that contribute to increased high-risk relapse among Hispanic and NH Black patients.