Maloney, Kelly W.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Pediatric Acute Lymphoblastic Leukemia (ALL) were developed as a result of meetings convened by a multidisciplinary panel of pediatric ALL experts, with the goal of providing recommendations on standard treatment approaches based on current evidence. The NCCN Guidelines for pediatric ALL focus on risk assessment and stratification of risk-adapted therapy; treatment strategies for BCR::ABL1 (Philadelphia chromosome [Ph])-negative and BCR::ABL1-positive B-cell lineage, T-cell lineage, and infant ALL; and supportive care considerations. This selection from the NCCN Guidelines for pediatric ALL focuses on the diagnosis of and management of pediatric T-ALL.

PURPOSE Although cure rates for childhood acute lymphoblastic leukemia (ALL) exceed 90%, ALL remains a leading cause of cancer death in children. Half of relapses arise in children initially classified with standard-risk (SR) disease. MATERIALS AND METHODS To identify genomic determinants of relapse in children with SR ALL, we performed genome and transcriptome sequencing of diagnostic and remission samples of children with SR (n = 1,381) or high-risk B-ALL with favorable cytogenetic features (n = 115) enrolled on Children's Oncology Group trials. We used a case-control study design analyzing 439 patients who relapsed and 1,057 who remained in complete remission for at least 5 years. RESULTS Genomic subtype was associated with relapse, which occurred in approximately 50% of cases of PAX5 -altered ALL (odds ratio [OR], 3.31 [95% CI, 2.17 to 5.03]; P = 3.18 × 10 –8 ). Within high-hyperdiploid ALL, gain of chromosome 10 with disomy of chromosome 7 was associated with favorable outcome (OR, 0.27 [95% CI, 0.17 to 0.42]; P = 8.02 × 10 –10 ; St Jude Children's Research Hospital validation cohort: OR, 0.22 [95% CI, 0.05 to 0.80]; P = .009), and disomy of chromosomes 10 and 17 with gain of chromosome 6 was associated with relapse (OR, 7.16 [95% CI, 2.63 to 21.51]; P = 2.19 × 10 –5 ; validation cohort: OR, 21.32 [95% CI, 3.62 to 119.30]; P = .0004). Genomic alterations were associated with relapse in a subtype-dependent manner, including alterations of INO80 in ETV6::RUNX1 ALL, IKZF1 , and CREBBP in high-hyperdiploid ALL and FHIT in BCR::ABL1 -like ALL. Genomic alterations were also associated with the presence of minimal residual disease, including NRAS and CREBBP in high-hyperdiploid ALL. CONCLUSION Genetic subtype, patterns of aneuploidy, and secondary genomic alterations determine risk of relapse in childhood ALL. Comprehensive genomic analysis is required for optimal risk stratification.

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.

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Pediatric Aggressive Mature B-Cell Lymphomas include recommendations for the diagnosis and management of pediatric patients with primary mediastinal large B-cell lymphoma (PMBL) and sporadic variants of Burkitt lymphoma and diffuse large B-cell lymphoma. PMBL is now considered as a distinct entity arising from mature thymic B-cells accounting for 2% of mature B-cell lymphomas in children and adolescents. This discussion section includes the recommendations outlined in the NCCN Guidelines for the diagnosis and management of pediatric patients with PMBL.

Pediatric aggressive mature B-cell lymphomas are the most common types of non-Hodgkin lymphoma in children, and they include Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). These diseases are highly aggressive but curable, the treatment is complex, and patients may have many complicated supportive care issues. The NCCN Guidelines for Pediatric Aggressive Mature B-Cell Lymphomas provide guidance regarding pathology and diagnosis, staging, initial treatment, disease reassessment, surveillance, therapy for relapsed/refractory disease, and supportive care for clinicians who treat sporadic pediatric BL and DLBCL.

Abstract Introduction B progenitor acute lymphoblastic leukemia (B-ALL) is a leading cause of childhood cancer death. Many chimeric genes have been identified and led to a refined classification of B-ALL and tailored therapies. Still, up to 30% of B-ALL cannot be classified into established subtypes, and the outcome for many is poor. Methods To identify novel subtypes of B-ALL, we performed integrative genomic analysis including transcriptome sequencing (RNA-seq) of 1,988 cases from St. Jude, Children's Oncology Group and adult cooperative group studies and analyzed chromosomal rearrangements, gene-expression profiles (GEP), somatic mutations and chromosome-level copy-number alterations. Cases lacking known or putative subtype-defining alterations underwent whole genome sequencing. Effects on proliferation and transformation of novel lesions were assessed by retroviral expression in cell lines and point-mutation knock-in mice using CRISPR/Cas9 genome editing. Results Using integrated genetic alterations and gene expression profiling, we classified 23 B-ALL subtypes (Table and Figure). Three groups included cases with similar GEP as canonical subtypes (ETV6-RUNX1, KMT2A-rearranged, and ZNF384-rearranged), but lacking the expected drivers (e.g., ETV6-RUNX1-like, n=42). Eighteen cases (0.9%) had rearrangements of BCL2, MYC and/or BCL6 showing a distinct GEP; they were mostly adults (n=16) with very poor outcome. These alterations, rarely seen in ALL, are identical to those observed in "double/triple hit" lymphoma, and are of pre-B immunophenotype. Eight cases with tightly clustered GEP comprised a novel subtype defined by IKZF1 N159Y missense mutation. N159Y is in the DNA-binding domain of IKZF1, and is known to perturb IKZF1 function, with distinct nuclear mislocalization and induction of aberrant intercellular adhesion. We identified two subtypes with distinct GEP characterized by PAX5 alterations. One, herein termed PAX5 altered (PAX5alt), comprised 148 (7.4%) cases, was characterized by diverse PAX5 alterations including rearrangements (n=57), sequence mutations (n=46) and/or focal intragenic amplifications (n=8). These PAX5 alterations were found in 73.6% of PAX5alt cases and different alteration types were mutually exclusive. Other PAX5 alterations, including deletions and large-scale amplifications were also assessed using SNP array, but were not enriched in the PAX5alt group. Clinically, PAX5alt pediatric and adult patients had favorable (96.8±3.2%) and intermediate (42.1±10.2%) 5-year overall survival (OS), respectively. The other GEP distinct subtype comprised 44 cases, all with PAX5 P80R missense mutations. In 30 of these cases, PAX5 P80R was homozygous due to deletion of the wild-type (WT) PAX5 allele or copy-neutral loss of heterozygosity. Of the other 14 cases with heterozygous PAX5 P80R mutations, 13 had a second frameshift (n=7), nonsense (n=2) or deleterious missense (n=4) PAX5 mutation. Four of the remaining 1,944 cases also had the PAX5 P80R mutation, but all were heterozygous with preservation of a WT PAX5 allele, consistent with the notion that homozygous or compound heterozygous PAX5 P80R mutation is the hallmark of this subtype. Adult PAX5 P80R cases (n=14) showed better 5-year OS (61.9±13.4%) than those in PAX5alt subtype (42.1±10.2%). To examine the effects of PAX5 P80R on B-cell maturation, WT PAX5, PAX5 P80R, V26G and P34Q were expressed in Pax5-/- lineage-depleted bone marrow cells. Expression of WT PAX5, PAX5 V26G and P34Q resulted in near complete rescue of B cell differentiation; however, expression of PAX5 P80R blocked the differentiation at the pre-pro-B stage of B-cell maturation. Further, Pax5 P80R heterozygous or homozygous mice developed pre-B-ALL with a median latency of 166 and 87 days, respectively, with heterozygous mice acquiring alterations on the second allele. In contrast, Pax5+/- mice, and those harboring G183S mutation observed in familial leukemia, do not spontaneously develop B-ALL. Conclusions These results show the utility of transcriptome sequencing in defining subtypes and founding genetic alterations in B-ALL, provide a revised taxonomy of the disease across the age spectrum, and reinforce the central role of PAX5 as a checkpoint in B lymphoid maturation and leukemogenesis. Disclosures McKay: ImmunoGen Inc.: Employment. Tallman:Orsenix: Other: Advisory board; AROG: Research Funding; BioSight: Other: Advisory board; Cellerant: Research Funding; AbbVie: Research Funding; Daiichi-Sankyo: Other: Advisory board; ADC Therapeutics: Research Funding. Stock:Jazz Pharmaceuticals: Consultancy. Konopleva:Stemline Therapeutics: Research Funding. Relling:Shire Pharmaceuticals: Research Funding. Mullighan:Cancer Prevention and Research Institute of Texas: Consultancy; Amgen: Honoraria, Speakers Bureau; Abbvie: Research Funding; Loxo Oncology: Research Funding; Pfizer: Honoraria, Research Funding, Speakers Bureau.

Abstract Background: Children with DS and B-ALL have historically experienced excessive TRM, primarily from infection. Here we provide an interim report on TRM in children with DS and newly diagnosed B-ALL enrolled on Children's Oncology Group (COG) trials for NCI standard risk (SR) (AALL0932) and high risk (HR) B-ALL (AALL1131). Methods: As of 06/30/2015, 203 SR DS-ALL patients have completed Induction on AALL0932 with 146 receiving post-Induction treatment on AALL0932. Eighty-eight HR DS patients have completed Induction on AALL1131, with 80 receiving post-Induction treatment on AALL1131. An additional 26 SR DS patients with poor early response received post-Induction therapy on AALL1131. Adverse events were graded according to NCI CTCAE v4.0, with enhanced data collection for targeted toxicities including infectious toxicities, and enhanced supportive care recommendations. Results: Patient characteristics are summarized in Table 1. TRM on AALL0932 occurred during Induction in 2/203 (1.0%) and post-Induction in 3/146 (2.1%), compared to 17/5528 (0.3%) and 12/3119 (0.4%) in non-DS SR patients (Fisher exact p=0.14 for Induction and p=0.03 for post-Induction). TRM on AALL1131 occurred during Induction in 4/88 (4.5%) and post-Induction in 5/106 (4.7%), compared to 34/2116 (1.6%) and 13/1258 (1.0%) in non-DS AALL1131 patients (p=0.06 for Induction and p=0.01 for post-Induction). Timing, cause, and other circumstances surrounding TRM are provided in Table 2. Gram-negative organisms accounted for the majority of fatal bacterial infections in patients with HR DS-ALL. Conclusion: TRM continues to be higher on current COG trials for patients with DS-ALL compared to non-DS patients. Most of the toxic deaths occur during intensive treatment phases due to infection in the context of profound neutropenia. Patients with HR B-ALL have a higher incidence of toxic death, notably in patients over 15 years of age. Based on our findings, hospitalization and antimicrobial prophylaxis during intensive treatment phases should be considered in children with DS-ALL due to their increased risk of infection-related mortality. Table 1. Patient Characteristics AALL1131 AALL0932 DS-ALL Non-DS ALL DS-ALL Non-DS ALL N 117 2689 207 5619 Median Age at Diagnosis (Years) 10.5 10.3 4.8 4.5 Gender Male 62 1511 117 2981 Female 55 1178 90 2637 Table 2. Treatment-Related Mortality Case Characteristics Case Age Gender Treatment Phase Site of Infection Organism AALL1131 (High Risk) 1 15 F Induction D#29 (RER) Pneumonia, ARDS HMPV (pre-treatment) 2 21 F Induction D#29 (SER) Sepsis 3 17 F Induction D#22 (SER) Sepsis, typhlitis Escherichia coli 4 12 M Induction D#16 (RER) Sepsis, pneumonia (+baseline CHD, AV canal s/p repair 2003) Influenza B 5 19 M Consolidation D#18 Sepsis Citrobacter 6 2 F Delayed Intensification D#101 ARDS/capillary leak (+baseline CHD) Rhinovirus 7 15 F Delayed Intensification D#45 Sepsis, pneumonia Klebsiella, enterovirus, rhinovirus 8 27 M Delayed Intensification D#52 Sepsis Gram negative bacillus 9 14 M Delayed Intensification D#22 Sepsis AALL0932 (Standard Risk) 1 7.3 M Induction Febrile neutropenia, hypotension, cardiorespiratory failure None reported 2 3.0 F Induction Febrile neutropenia, sepsis, liver failure Viridans group Strepococcus coagulase negative staphylococcus HSV, EBV and HHV 3 3.4 M Consolidation Meningitis, brainstem infarction None reported 4 9.7 F Interim Maintenance I Sepsis, Stevens Johnson syndrome/TEN None reported 5 7.2 M Interim Maintenance II Death NOS None reported RER, rapid early responder; SER, slow early responder; CHD, congenital heart disease; AV, atrioventricular; ARDS, acute respiratory distress syndrome; HMPV, human metapneumovirus; TEN, toxic epidermal necrolysis; HSV, herpes simplex virus; EBV, Epstein-Barr virus; HHV, human herpesvirus. Disclosures Hunger: Sigma Tau: Consultancy; Jazz Pharmaceuticals: Consultancy; Merck: Equity Ownership; Spectrum Pharmaceuticals: Consultancy.