Faculty Bibliography

Trisomy 21, the genetic cause of Down syndrome (DS), is the most common congenital chromosomal anomaly. It is associated with a 20-fold increased risk of acute lymphoblastic leukemia (ALL) during childhood and results in distinctive leukemia biology. To comprehensively define the genomic landscape of DS-ALL, we performed whole genome sequencing and whole-transcriptome sequencing (RNA-Seq) on 295 cases. Our integrated genomic analyses identified 15 molecular subtypes of DS-ALL, with marked enrichment of CRLF2-r, IGH::IGF2BP1, and C/EBP altered (C/EBPalt) subtypes compared to 2257 non-DS-ALL cases. We observed abnormal activation of the CEBPD, CEBPA, and CEBPE genes in 10.5% of DS-ALL cases, via a variety of genomic mechanisms, including chromosomal rearrangements and noncoding mutations leading to enhancer hijacking. 42.3% of C/EBP-activated DS-ALL also have concomitant FLT3 point mutation or indel, relative to 4.1% in other subtypes (P=7.2×10-6). CEBPD overexpression enhanced the differentiation of mouse hematopoietic progenitor cells into pro-B cells in vitro, particularly in a DS genetic background. Notably, RAG-mediated somatic genomic abnormalities were common in DS-ALL, accounting for a median of 27.5% of structural alterations, compared to 7.7% in non-DS-ALL (P=2.1×10-12). Unsupervised hierarchical clustering analyses of CRLF2-rearranged DS-ALL identified substantial heterogeneity within this group, with the BCR::ABL1-like subset linked to an inferior event-free survival (hazard ratio=5.27, P=9.3×10-8), even after adjusting for known clinical risk factors (hazard ratio=4.32; P=0.0020). These results provide important insights into the biology of DS-ALL and point to opportunities for targeted therapy and treatment individualization.

BACKGROUND:The outcome of children with Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukaemia significantly improved with the combination of imatinib and intensive chemotherapy. We aimed to investigate the efficacy of dasatinib, a second-generation ABL-class inhibitor, with intensive chemotherapy in children with newly diagnosed Ph-positive acute lymphoblastic leukaemia. METHODS:orally once daily from day 15 of induction. Patients with minimal residual disease of at least 0·05% after induction 1B or who were positive for minimal residual disease after the three consolidation blocks were classified as high risk and allocated to receive haematopoietic stem-cell transplantation (HSCT) in first complete remission. The remaining patients were considered standard risk and received chemotherapy plus dasatinib for 2 years. The primary endpoint was the 3-year event-free survival of dasatinib plus chemotherapy compared with external historical controls. The trial was considered positive if one of the following conditions was met: superiority over chemotherapy alone in the AIEOP-BFM 2000 high-risk group; or non-inferiority (with a margin of -5%) or superiority to imatinib plus chemotherapy in the EsPhALL 2010 cohort. All participants who received at least one dose of dasatinib were included in the safety and efficacy analyses. This trial was registered with ClinicalTrials.gov, NCT01460160, and recruitment is closed. FINDINGS/RESULTS:Between March 13, 2012, and May 27, 2014, 109 patients were enrolled at 69 sites (including 51 COG sites in the USA, Canada, and Australia, and 18 EsPhALL sites in Italy and the UK). Three patients were ineligible and did not receive dasatinib. 106 patients were treated and included in analyses (49 [46%] female and 57 [54%] male; 85 [80%] White, 13 [12%] Black or African American, five [5%] Asian, and three [3%] other races; 24 [23%] Hispanic or Latino ethnicity). All 106 treated patients reached complete remission; 87 (82%) were classified as standard risk and 19 (18%) met HSCT criteria and were classified as high risk, but only 15 (14%) received HSCT in first complete remission. The 3-year event-free survival of dasatinib plus chemotherapy was superior to chemotherapy alone (65·5% [90% Clopper-Pearson CI 57·7 to 73·7] vs 49·2% [38·0 to 60·4]; p=0·032), and was non-inferior to imatinib plus chemotherapy (59·1% [51·8 to 66·2], 90% CI of the treatment difference: -3·3 to 17·2), but not superior to imatinib plus chemotherapy (65·5% vs 59·1%; p=0·27). The most frequent grade 3-5 adverse events were febrile neutropenia (n=93) and bacteraemia (n=21). Nine remission deaths occurred, which were due to infections (n=5), transplantation-related (n=2), due to cardiac arrest (n=1), or had an unknown cause (n=1). No dasatinib-related deaths occurred. INTERPRETATION/CONCLUSIONS:Dasatinib plus EsPhALL chemotherapy is safe and active in paediatric Ph-positive acute lymphoblastic leukaemia. 3-year event-free survival was similar to that of previous Ph-positive acute lymphoblastic leukaemia trials despite the limited use of HSCT in first complete remission. FUNDING/BACKGROUND:Bristol Myers Squibb.

The benefit associated with the incorporation of vincristine-corticosteroid pulses into maintenance therapy for pediatric acute lymphoblastic leukemia (ALL) is unclear, particularly in the context of modern intensive therapy. This systematic review and meta-analysis examined the impact of reducing frequency of vincristine-steroid pulses during maintenance for newly diagnosed pediatric patients with B-cell ALL. Two authors reviewed all eligible studies identified through a comprehensive search, extracted data from the 25 included publications (12 513 patients), and assessed risk of bias. We created historical and contemporary subgroups; the latter included trials providing a version of Protocol III from early Berlin-Frankfurt-Munster trials and eliminating routine prophylactic cranial radiation. Meta-analysis of event-free survival data suggested no benefit between more frequent or less frequent pulses in contemporary trials (HR 0.96, 95%CI 0.85-1.09) which differs significantly from historical trials (HR 0.79, 95%CI 0.68-0.91, p=0.04). We found no significant impact of reduced pulse frequency on overall survival or relapse risk. There was however an increased odds of Grade 3+ non-hepatic toxicity in the high pulse frequency group (OR 1.31, 95%CI 1.12-1.52). This systematic review suggests that the previous benefit conferred by frequent pulses of vincristine-steroids in maintenance therapy for pediatric B-cell ALL in historical trials no longer applies in contemporary trials but is associated with toxicity. These results will help guide development of the next phase of clinical trials in the field of pediatric ALL and question the continued use of pulses in maintenance for patients not on clinical trials, particularly those experiencing toxicity.

PURPOSE/OBJECTIVE:Blinatumomab, a bispecific T-cell engager immunotherapy, is efficacious in relapsed/refractory B-cell ALL (B-ALL) and has a favorable toxicity profile. One aim of the Children's Oncology Group AALL1331 study was to compare survival of patients with low-risk (LR) first relapse of B-ALL treated with chemotherapy alone or chemotherapy plus blinatumomab. PATIENTS AND METHODS/METHODS:After block 1 reinduction, patients age 1-30 years with LR first relapse of B-ALL were randomly assigned to block 2/block 3/two continuation chemotherapy cycles/maintenance (arm C) or block 2/two cycles of continuation chemotherapy intercalated with three blinatumomab blocks/maintenance (arm D). Patients with CNS leukemia received 18 Gy cranial radiation during maintenance and intensified intrathecal chemotherapy. The primary and secondary end points were disease-free survival (DFS) and overall survival (OS). RESULTS:= .53). Blinatumomab was well tolerated and patients had low adverse event rates. CONCLUSION/CONCLUSIONS:For children, adolescents, and young adults with B-ALL in LR first relapse, there was no statistically significant difference in DFS or OS between the blinatumomab and standard chemotherapy arms overall. However, blinatumomab significantly improved DFS and OS for the two thirds of patients with BM ± EM relapse, establishing a new standard of care for this population. By contrast, similar outcomes and poor DFS for both arms were observed in the one third of patients with IEM; new treatment approaches are needed for these patients (ClinicalTrials.gov identifier: NCT02101853).

We measured minimal residual disease (MRD) by multiparameter flow cytometry at three time points (TP) in 117 infants with KMT2A (lysine [K]-specific methyltransferase 2A)-rearranged and 58 with KMT2A-germline acute lymphoblastic leukemia (ALL) on Children's Oncology Group AALL0631 study. For KMT2A-rearranged patients, 3-year event-free survival (EFS) by MRD-positive (≥0.01%) versus MRD-negative (<0.01%) was: TP1: 25% (±6%) versus 49% (±7%; p = .0009); TP2: 21% (±8%) versus 47% (±7%; p < .0001); and TP3: 22% (±14%) versus 51% (±6%; p = .0178). For KMT2A-germline patients, 3-year EFS was: TP1: 88% (±12%) versus 87% (±5%; p = .73); TP2: 100% versus 88% (±5%; p = .24); and TP3: 100% versus 87% (±5%; p = .53). MRD was a strong independent outcome predictor in KMT2A-rearranged, but not KMT2A-germline infant ALL.

To determine the prognostic significance of central nervous system (CNS) leukemic involvement in newly diagnosed T-cell acute lymphoblastic leukemia (T-ALL), outcomes on consecutive, phase 3 Children's Oncology Group (COG) clinical trials were examined. AALL0434 and AALL1231 tested efficacy of novel agents incorporated into augmented Berlin-Frankfurt-Münster (aBFM) therapy. In addition to testing study-specific chemotherapy through randomization, the AALL0434 regimen delivered cranial radiation (CRT) to the majority of subjects (90.8%), while AALL1231 intensified chemotherapy to eliminate CRT in 88.2% of subjects. In combined analysis of 2,164 T-ALL subjects (AALL0434: 1,550; AALL1231: 614), 1,564 were CNS-1 (72.3%), 441 CNS-2 (20.4%), and 159 CNS-3 (7.3%). The 4-year event-free survival (EFS) was similar for CNS-1 (85.1±1.0%) and CNS-2 (83.2±2.0%), but lower for CNS-3 (71.8±4.0%); p=0.0004. Subjects with CNS-1 and CNS-2 had similar 4-year overall-survival (OS) (90.1±0.8% and 90.5±1.5%), with OS for CNS-3 (82.7±3.4%); p=0.005. Despite therapeutic differences, outcomes for CNS-1 and CNS-2 were similar regardless of CRT, intensified corticosteroids or novel agents. Except for significantly superior outcomes with nelarabine on AALL0434 (4-year disease-free survival 93.1%±5.2%), EFS/OS was inferior with CNS-3 status, all of whom received CRT. Combined analyses of over 2,000 subjects with T-ALL, found that those with CNS-1 and CNS-2 status at diagnosis had similar outcomes. Unlike with B-ALL, CNS-2 status in T-ALL does not impact outcome in the context of aBFM therapy, without additional intrathecal therapy, with or without CRT. Although nelarabine improved outcomes for those with CNS-3 status, novel approaches are needed for further improvements.

AALL1931 (NCT04145531), a phase 2/3 study conducted in collaboration with the Children's Oncology Group, investigated the efficacy and safety of JZP458 (asparaginase erwinia chrysanthemi (recombinant)-rywn), a recombinant Erwinia asparaginase derived from a novel expression platform, in patients with acute lymphoblastic leukemia/lymphoblastic lymphoma who developed hypersensitivity/silent inactivation to E. coli-derived asparaginases. Each dose of a pegylated E. coli-derived asparaginase remaining in patients' treatment plan was substituted by six doses of intramuscular (IM) JZP458 on Monday/Wednesday/Friday (MWF). Three dosing regimens were evaluated: Cohort 1a, 25 mg/m2 MWF; Cohort 1b, 37.5 mg/m2 MWF; Cohort 1c, 25/25/50 mg/m2 MWF. The primary and key secondary efficacy outcomes were the proportion of patients maintaining adequate nadir serum asparaginase activity (NSAA ≥0.1 IU/mL) at 72 hours as well as at 48 hours during the first treatment course, respectively. 167 patients were enrolled: Cohort 1a (n=33), 1b (n=83), and 1c (n=51). Mean SAA levels (IU/mL) at 72-hr were 0.16 for Cohort 1a, 0.33 for Cohort 1b, and 0.47 for Cohort 1c; and 0.45, 0.88, and 0.66 at 48-hr, respectively. The proportion of patients achieving NSAA ≥0.1 IU/mL at 72-hr and 48-hr in Cohort 1c was 90% (44/49) and 96% (47/49), respectively. Simulated data from a population pharmacokinetic model matched the observed data well. Grade 3/4 treatment-related adverse events (TRAEs) occurred in 86/167 (51%) patients; TRAEs leading to discontinuation included pancreatitis (6%), allergic reactions (5%), increased alanine aminotransferase (1%), and hyperammonemia (1%). Study results demonstrate that IM JZP458 at 25/25/50 mg/m2 MWF is efficacious and has a safety profile consistent with those of other asparaginases.