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Diffuse midline gliomas (DMG), including diffuse intrinsic pontine gliomas (DIPG), are the most lethal of childhood cancers. Palliative radiotherapy is the only established treatment, with median patient survival of 9 to 11 months. ONC201 is a DRD2 antagonist and ClpP agonist that has shown preclinical and emerging clinical efficacy in DMG. However, further work is needed to identify the mechanisms of response of DIPGs to ONC201 treatment and to determine whether recurring genomic features influence response. Using a systems-biological approach, we showed that ONC201 elicits potent agonism of the mitochondrial protease ClpP to drive proteolysis of electron transport chain and tricarboxylic acid cycle proteins. DIPGs harboring PIK3CA mutations showed increased sensitivity to ONC201, whereas those harboring TP53 mutations were more resistant. Metabolic adaptation and reduced sensitivity to ONC201 was promoted by redox-activated PI3K/Akt signaling, which could be counteracted using the brain penetrant PI3K/Akt inhibitor, paxalisib. Together, these discoveries coupled with the powerful anti-DIPG/DMG pharmacokinetic and pharmacodynamic properties of ONC201 and paxalisib have provided the rationale for the ongoing DIPG/DMG phase II combination clinical trial NCT05009992. Significance: PI3K/Akt signaling promotes metabolic adaptation to ONC201-mediated disruption of mitochondrial energy homeostasis in diffuse intrinsic pontine glioma, highlighting the utility of a combination treatment strategy using ONC201 and the PI3K/Akt inhibitor paxalisib.

The mitogen-activated protein kinase (MAPK) pathway signaling pathway is one of the most commonly mutated pathways in human cancers. In particular, BRAF alterations result in constitutive activation of the rapidly accelerating fibrosarcoma–extracellular signal–regulated kinase–MAPK significant pathway, leading to cellular proliferation, survival, and dedifferentiation. The role of BRAF mutations in oncogenesis and tumorigenesis has spurred the development of targeted agents, which have been successful in treating many adult cancers. Despite advances in other cancer types, the morbidity and survival outcomes of patients with glioma have remained relatively stagnant. Recently, there has been recognition that MAPK dysregulation is almost universally present in paediatric and adult gliomas. These findings, accompanying broad molecular characterization of gliomas, has aided prognostication and offered opportunities for clinical trials testing targeted agents. The use of targeted therapies in this disease represents a paradigm shift, although the biochemical complexities has resulted in unexpected challenges in the development of effective BRAF inhibitors. Despite these challenges, there are promising data to support the use of BRAF inhibitors alone and in combination with MEK inhibitors for patients with both low-grade and high-grade glioma across age groups. Safety and efficacy data demonstrate that many of the toxicities of these targeted agents are tolerable while offering objective responses. Newer clinical trials will examine the use of these therapies in the upfront setting. Appropriate duration of therapy and durability of response remains unclear in the glioma patient cohort. Longitudinal efficacy and toxicity data are needed. Furthermore, access to these medications remains challenging outside of clinical trials in Australia and New Zealand. Compassionate access is limited, and advocacy for mechanism of action-based drug approval is ongoing.

Pediatric high-grade gliomas (pHGG) are the leading cause of cancer-related death in children and young adults. Current treatment strategies are centered on maximal safe resection, followed by radiotherapy, and interrogation of the tumor genome to identify targetable mutations. Unfortunately, we are yet to see an improvement in patient outcomes with a median overall survival remaining 15-months. To improve patient outcomes, we have begun to characterize the genome, proteome, and phosphoproteome of 168 pHGGs to better understand the functional consequences of their somatic alterations as well as their influence of the tumor microenvironment. Employing a novel ‘pharmaco-phospho-proteo-genomics’ pipeline, we have analyzed pHGG cell lines and tumor tissue specimens at diagnosis, relapse (partial resection congenital glioblastoma), and autopsy. Genomic profiling was conducted utilizing the 523-gene TruSight Oncology 500 (TSO500) next-generation sequencing panel. Simultaneously, tumor proteomes and phosphoproteomes were characterized using our high-throughput global phospho-proteomic profiling technique termed pHASED (phospho Heavy-labelled-spiketide FAIMS StEpped-CV DDA). High-fidelity tumor proteomic and phospho-proteomic data were identified and compared to normal control brain samples. Across 40 pHGG samples, we identified 290 unique somatic alterations with a high predicted impact severity and quantified 7,345 unique proteins and 3,327 phosphoproteins. Gene panel sequencing of a critical pediatric glioblastoma patient sample identified 18 somatic alterations, eight of which had a high predicted impact severity, however, none were targetable. Conversely, phosphoproteomic profiling identified enriched MAPK and PRKCB signaling, relative to normal brain tissues, thereby encouraging the use of the TGA/FDA approved therapies trametinib (MAPKs) and enzastaurin (PRKCB). In vitro investigations confirmed the utility of these treatment approaches and in vivo patient derives xenograft mouse models for this sample are under investigation. This pilot study provides critical data to support the benefit of interrogating the genome, proteome, and phospho-proteome of these devastating tumours to aid in the selection/development of effective treatment strategies.

Diffuse midline glioma (DMG), including those of the brainstem (diffuse intrinsic pontine glioma), are pediatric tumors of the central nervous system (CNS). Recognized as the most lethal of all childhood cancers, palliative radiotherapy remains the only proven treatment option, however, even for those that respond, survival is only temporarily extended. DMG harbor an immunologically “cold” tumor microenvironment (TME) with few infiltrating immune cells. The mechanisms underpinning the cold TME are not well understood. Low expression levels of immune checkpoint proteins, including PD-1, PD-L1, and CTLA-4, are recurring features of DMG and likely contribute to the lack of response to immune checkpoint inhibitors (ICIs). The unique epigenetic signatures (including stem cell-like methylation patterns), a low tumor mutational burden, and recurring somatic mutations (H3K27M, TP53, ACVR1, MYC, and PIK3CA), possibly play a role in the reduced efficacy of traditional immunotherapies. Therefore, to circumvent the lack of efficacy thus far seen for the use of ICIs, adoptive cell transfer (including chimeric antigen receptor T cells) and the use of oncolytic viruses, are currently being evaluated for the treatment of DMG. It remains an absolute imperative that we improve our understanding of DMG’s intrinsic and TME features if patients are to realize the potential benefits offered by these sophisticated treatments. Herein, we summarize the limitations of immunotherapeutic approaches, highlight the emerging safety and clinical efficacy shown for sophisticated cell-based therapies, as well as the evolving knowledge underpinning the DMG-immune axis, to guide the development of immunotherapies that we hope will improve outcomes.

Background Pediatric acute lymphoblastic leukemia (ALL) therapy is accompanied by treatment-related toxicities (TRTs) and impaired quality of life. In Australia and New Zealand, children with ALL are treated with either Children’s Oncology Group (COG) or international Berlin-Frankfurt-Munster (iBFM) Study Group-based therapy. We conducted a prospective registry study to document symptomatic TRTs (venous thrombosis, neurotoxicity, pancreatitis and bone toxicity), compare TRT outcomes to retrospective TRT data, and measure the impact of TRTs on children’s general and cancer-related health-related quality of life (HRQoL) and parents’ emotional well-being. Methods Parents of children with newly diagnosed ALL were invited to participate in the ASSET (Acute Lymphoblastic Leukaemia Subtypes and Side Effects from Treatment) study and a prospective, longitudinal HRQoL study. TRTs were reported prospectively and families completed questionnaires for general (Healthy Utility Index Mark 3) and cancer specific (Pediatric Quality of Life Inventory (PedsQL)-Cancer Module) health related quality of life as well the Emotion Thermometer to assess emotional well-being. Results Beginning in 2016, 260 pediatric patients with ALL were enrolled on the TRT registry with a median age at diagnosis of 59 months (range 1–213 months), 144 males (55.4%), majority with Pre-B cell immunophenotype, n = 226 (86.9%), 173 patients (66.5%) treated according to COG platform with relatively equal distribution across risk classification sub-groups. From 2018, 79 families participated in the HRQoL study through the first year of treatment. There were 74 TRT recorded, reflecting a 28.5% risk of developing a TRT. Individual TRT incidence was consistent with previous studies, being 7.7% for symptomatic VTE, 11.9% neurotoxicity, 5.4% bone toxicity and 5.0% pancreatitis. Children’s HRQoL was significantly lower than population norms throughout the first year of treatment. An improvement in general HRQoL, measured by the HUI3, contrasted with the lack of improvement in cancer-related HRQoL measured by the PedsQL Cancer Module over the first 12 months. There were no persisting differences in the HRQoL impact of COG compared to iBFM therapy. Conclusions It is feasible to prospectively monitor TRT incidence and longitudinal HRQoL impacts during ALL therapy. Early phases of ALL therapy, regardless of treatment platform, result in prolonged reductions in cancer-related HRQoL.

Diffuse midline gliomas (DMG), including those of the brainstem (diffuse intrinsic pontine glioma - DIPG), are pediatric CNS tumors recognized as the most lethal of all children’s cancers. Palliative radiotherapy is the only approved treatment, with survival just 9-11–months post-diagnosis. ONC201 shows preclinical and emerging clinical efficacy in early-stage clinical trials, extending survival of DIPG patients by ~9-11–months compared to historic controls. However, patients invariably develop resistance, with some patients completely refractory to treatment. Using a multi-omics approach, including pharmacology, proteomics, genomics, epigenetics, in vitro and in vivo modeling, across ten international laboratories, we have uncovered the inherent mechanisms of resistance to ONC201. We find ONC201 elicits antagonism of the Dopamine receptor D2 (DRD2), whilst also causing mitochondrial degradation through potent agonism of the Mitochondrial protease CLPP, that drives proteolysis of the electron transport chain (ETC) protein Succinate dehydrogenase A (SDHA) and degradation of critical mitochondrial tricarboxylic acid (TCA) cycle regulator Isocitrate dehydrogenase 3B (IDH3B). Loss mitochondrial respiration increased hypoxia and reduced α-ketoglutarate, inhibiting lysine demethylation, increasing methylation of H3K4me3 and H3K27me3, thus altering the epigenome of primary DIPG cells. Loss of SDHA caused oxidation of succinate forming superoxide driving redox regulated PI3K/AKT signaling, counteracted using the PI3K/AKT inhibitor paxalisib. The combination of ONC201 and paxalisib synergically extended survival of two aggressive DIPG PDX models (SU-SIPG-VI vehicle=73 vs. combination=100-days, p=0.0027; SF8626 vehicle=36 vs. combination=43-days, p=0.0002). Compassionate access to this combination (n=2 patients; immediately post-RT and following re-RT) resulted in reductions in tumor volume and complete resolution of disease symptoms, extending overall survival (e.g., diagnosis patient MR axial scan=1554 mm2 , following eight months on the combination, current tumor volume=464 mm2 (

PURPOSE Few studies have investigated the health-related quality of life (HRQoL) of young childhood cancer survivors and their parents. This study describes parent and child cancer survivor HRQoL compared to population norms and identifies factors influencing child and parent HRQoL. METHODS We recruited parents of survivors who were currently 5 years postdiagnosis. Parents reported on their child's HRQoL (Kidscreen-10), and their own HRQoL (EQ-5D-5L). Parents rated their resilience and fear of cancer recurrence and listed their child's cancer-related late effects. RESULTS One hundred eighty-two parents of survivors (mean age = 12.4 years old and 9.7 years postdiagnosis) participated. Parent-reported child HRQoL was significantly lower than population norms (48.4 vs. 50.7, p

Diffuse midline gliomas (DMGs), including those of the pons (diffuse intrinsic pontine glioma - DIPG), are pediatric CNS tumors recognized as the most lethal of all children’s cancers. Palliative radiotherapy remains the only approved treatment, with survival just 9-11 months post-diagnosis. The brain-penetrant small molecule therapy, ONC201, shows preclinical and emerging efficacy in early-stage clinical trials. However, patients invariably develop resistance, with some patients and models completely refractory to treatment. Using a powerful combination of pharmacology, proteomics, genomics, epigenetics, in vitro and in vivo modeling, across ten international laboratories, we have uncovered mechanisms underpinning resistance to ONC201. We find ONC201 elicits antagonism of the Dopamine receptor D2 (DRD2), whilst also causing mitochondrial degradation through potent agonism of the mitochondrial protease CLPP. This drives proteolysis of the electron transport chain (ETC) proteins including Succinate dehydrogenase A (SDHA) and the critical mitochondrial tricarboxylic acid (TCA) cycle regulator, Isocitrate dehydrogenase 3B (IDH3B). Loss of TCA activity reduces α-ketoglutarate and inhibits lysine demethylation, increasing methylation of H3K4me3 and H3K27me3, thus, altering the epigenome of DIPG. Mitochondrial disruption elicited redox-activated RAS-PI3K/AKT signaling, counteracted using the PI3K/AKT inhibitor paxalisib. The combination of ONC201 and paxalisib synergistically extended survival of two aggressive DIPG PDX models (SU-DIPG-VI vehicle=73 vs. combination=100-days, p=0.0027; SF8626 vehicle=36 vs. combination=43-days, p=0.0002). Compassionate access to this combination (n=2 patients; immediately post-RT and following re-RT) resulted in dramatic reductions in tumor volume, extending overall survival for the patient at diagnosis and the patient at progression (e.g., MR axial diagnosis scan = 1554 mm2, following twelve months on the combination, current tumor volume = 464 mm2 (~70% reduction), patient remains in progression free survival, 15 months since diagnosis). The clinical utility of our preclinical data is currently under investigation in the PNOC022 clinical trial (NCT05009992).

ObjectivesUnlike adults, malignant melanoma in children and adolescents is rare. In adult melanoma, significant progress in understanding tumor biology and new treatments, including targeted therapies and immunotherapy have markedly improved overall survival. In sharp contrast, there is a paucity of data on the biology and clinical behavior of pediatric melanoma. We report a national case series of all pediatric and adolescent malignant melanoma presenting to ANZCHOG Childhood Cancer Centers in Australia and New Zealand.MethodsA retrospective, descriptive, multi-center study was undertaken to identify patients less than 18 years of age treated for cutaneous malignant melanoma over a twenty-year period (1994 to 2014). Data on clinical characteristics, histopathology, and extent of disease, treatment and follow-up are described.ResultsA total of 37 cases of malignant melanoma were identified from all of the Australasian tertiary Childhood Cancer Centers. The median age was 10 years (range 1 month – 17 years). Clinically, the most common type of lesion was pigmented, occurring in sixteen (57%) patients, whilst amelanotic was seen in 7 patients (25%). In 11 (27.9%) the Breslow thickness was greater than 4mm. A total of 11 (29.7%) patients relapsed and 90% of these died of disease. Five-year event free survival (EFS) and overall survival were 63.2 (95% CI: 40.6 – 79.1) and 67.7% (95% CI: 45.1 – 82.6) respectively.ConclusionOur data confirms that melanoma is a rare presentation of cancer to tertiary Australasian Childhood Cancer Centers with only 37 cases identified over two decades. Notably, melanoma managed in Childhood Cancer Centers is frequently at an advanced stage, with a high percentage of patients relapsing and the majority of these patients who relapsed died of disease. This study confirms previous clinical and prognostic information to support the early multidisciplinary management in Childhood Cancer Centers, in conjunction with expert adult melanoma centers, of this rare and challenging patient group.

Symptomatic methotrexate-related central neurotoxicity (MTX neurotoxicity) is a severe toxicity experienced during acute lymphoblastic leukemia (ALL) therapy with potential long-term neurologic complications. Risk factors and long-term outcomes require further study. We conducted a systematic, retrospective review of 1,251 consecutive Australian children enrolled on Berlin-Frankfurt-Münster or Children's Oncology Group-based protocols between 1998-2013. Clinical risk predictors for MTX neurotoxicity were analyzed using regression. A genome-wide association study (GWAS) was performed on 48 cases and 537 controls. The incidence of MTX neurotoxicity was 7.6% (n=95 of 1,251), at a median of 4 months from ALL diagnosis and 8 days after intravenous or intrathecal MTX. Grade 3 elevation of serum aspartate aminotransferase (P=0.005, odds ratio 2.31 [range, 1.28–4.16]) in induction/consolidation was associated with MTX neurotoxicity, after accounting for the only established risk factor, age ≥10 years. Cumulative incidence of CNS relapse was increased in children where intrathecal MTX was omitted following symptomatic MTX neurotoxicity (n=48) compared to where intrathecal MTX was continued throughout therapy (n=1,174) (P=0.047). Five-year central nervous system relapse-free survival was 89.2 4.6% when intrathecal MTX was ceased compared to 95.4 0.6% when intrathecal MTX was continued. Recurrence of MTX neurotoxicity was low (12.9%) for patients whose intrathecal MTX was continued after their first episode. The GWAS identified single-nucletide polymorphism associated with MTX neurotoxicity near genes regulating neuronal growth, neuronal differentiation and cytoskeletal organization (P

To prevent relapse, high risk paediatric acute lymphoblastic leukaemia (ALL) is treated very intensively. However, most patients who eventually relapse have standard or medium risk ALL with low minimal residual disease (MRD) levels. We analysed recurrent microdeletions and other clinical prognostic factors in a cohort of 475 uniformly treated non-high risk precursor B-cell ALL patients with the aim of better predicting relapse and refining risk stratification. Lower relapse-free survival at 7 years (RFS) was associated with IKZF1 intragenic deletions (P 5 × 10-5 (P

Recurring somatic mutations and gene amplifications to members of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) signaling axis are overarching contributors to the aggressive growth and survival of diffuse intrinsic pontine gliomas (DIPG). However, targeting PI3K has thus far failed to improve outcomes for patients in the clinic. To identify the mechanisms underpinning PI3K/AKT/mTOR treatment failure in DIPG, we have employed high-resolution quantitative phosphoproteomic profiling in patient-derived DIPG cell lines harboring H3K27M and PI3K mutations, +/- the blood-brain barrier permeable PI3K inhibitor, paxalisib (previously “GDC-0084”, currently in Phase I trials - NCT03696355) and rapamycin. Paxalisib was significantly more potent than rapamycin at inducing PI3K/AKT/mTOR inhibition, however, both simultaneously activated protein kinase C signaling (pT500PKCβ +8.2 and +4.5 fold, respectively). PKC lies directly upstream of myristoylated alanine-rich C-kinase substrate (MARCKs), which was phosphorylated at Ser170 by +9.4 and +4.7 fold, respectively; promoting actin cytoskeletal remodeling and cellular migration. Indeed, activation of PKC signaling using phorbol 12-myristate 13-acetate (PMA), increased DIPG cell growth and migration by >3 fold. Targeting PKC using midostaurin (FDA-approved for acute myeloid leukemia), and enzastaurin (blood-brain barrier penetrant inhibitor of PKCβ), in combination with paxalisib was highly synergistic (CI=

BackgroundDecitabine is a deoxycytidine nucleoside derivative inhibitor of DNA-methyltransferases, which has been studied extensively and is approved for myelodysplastic syndrome in adults but with less focus in children. Accordingly, we conducted a phase 1 multicenter, randomized, open-label study to evaluate decitabine pre-treatment before standard induction therapy in children with newly diagnosed AML to assess safety and tolerability and explore a number of biologic endpoints.ResultsTwenty-four patients were fully assessable for all study objectives per protocol (10 in Arm A, 14 in Arm B). All patients experienced neutropenia and thrombocytopenia. The most common grade 3 and 4 non-hematologic adverse events observed were gastrointestinal toxicities and hypophosphatemia. Plasma decitabine PK were similar to previously reported adult data. Overall CR/CRi was similar for the two arms. MRD negativity at end-induction was 85% in Arm A versus 67% in Arm B patients. DNA methylation measured in peripheral blood over the course of treatment tracked with blast clearance and matched marrow aspirates at day 0 and day 21. Unlike end-point marrow analyses, promoter methylation in blood identified an apparent reversal of response in the lone treatment failure, one week prior to the patient’s marrow aspirate confirming non-response. Decitabine-induced effects of end-induction marrows in Arm A were reflected by changes in DNA methylation and gene expression comparison with matched paired marrow diagnostic aspirates.ConclusionsThis first-in-pediatrics trial demonstrates that decitabine prior to standard combination chemotherapy is feasible and well tolerated in children with newly diagnosed AML. Pre-treatment with decitabine may represent a newer therapeutic option for pediatric AML, especially as it appears to induce important epigenetic alterations. The novel biological correlates studied in this trial offer a clinically relevant window into disease progression and remission. Additional studies are needed to definitively assess whether decitabine can enhance durability responses in children with AML. This trial was registered at www.clinicaltrials.gov as NCT01177540.

BACKGROUND: Diffuse Intrinsic Pontine Glioma (DIPG) is a devastating, incurable childhood brain cancer. 80% of patients harbour a genetic lesion to Histone-H3 with a substitution of lysine 27 for a methionine (K27M) (H3F3A/H3.3 and HIST1H3B/H3.1) which results in the loss of methylation, interfering with chromatin function, activating oncogenic transcription. Unfortunately, H3 mutations are not directly targetable. RTK-RAS-PI3Kpathway alterations occur in more than half of these patients (69%), and may represent a more promising therapeutic target. However, PI3K inhibitors have been notoriously ineffective due to their inability to cross the blood-brain-barrier (BBB). Targeting downstream components of the PI3K-AKT-mTOR signalling axis is a promising paradigm for PI3K mutant patients. This project aims to overcome the limitations of targeting downstream effectors of the PI3K pathway by utilising a novel PIK3CA specific, BBB permeable inhibitor, GDC-0084, currently in clinical trials for Glioblastoma (GBM) and DIPG. METHODS: Utilising DIPG patient derived (PDX) cells harboringH3K27M mutations (n=6), and +/- PI3Kmutations, we examined the in-vitroefficacy of GDC-0084 on cell proliferation compared to Rapamycin. Phosphoproteomic profiling is currently underway investigating the role GDC-0084 has on inhibition of downstream oncogenic signalling pathways. Assessment of efficacy in a PDX in-vivo model is currently in progress. RESULTS: GDC-0084 significantly reduced the growth of all DIPG cell lines regardless of whether they harboredPI3K mutations (p=

Approximately one-third of children with acute myeloid leukemia (AML) relapse, requiring re-treatment and allogeneic hematopoietic stem cell transplantation (HSCT). Although achieving second complete remission (CR2) prior to HSCT is desirable, once CR2 is attained, it is unclear if there is any benefit from further chemotherapy prior to HSCT. Moreover, although pre-HSCT minimal residual disease (MRD) has prognostic value in acute lymphoblastic leukemia, the benefit of MRD reduction after achieving CR prior to HSCT is less clear for AML. To address these questions, we analyzed data from pediatric transplant centers in Australia and New Zealand concerning relapsed childhood AML cases occurring between 1998 and 2013. Given the retrospective nature of our analysis and assay data available, we analyzed patients on the basis of measurable residual disease (MeRD) by any methodology, rather than MRD in the conventional sense. We observed improved overall survival (OS) in children receiving two chemotherapy cycles, compared to one cycle or three or more cycles pre-HSCT. Improved OS with two cycles remained significant for patients without MeRD after cycle 1. These data suggest that a second chemotherapy cycle pre-HSCT may improve survival by lowering disease burden. Prospective trials assessing strategies to reduce pre-HSCT MRD in relapsed childhood AML are warranted.

Diffuse intrinsic pontine glioma (DIPG) is a highly aggressive, childhood brainstem cancer with a median overall survival of 10 months post diagnosis. Remarkably, 80–90% of patients harbor recurring point mutation in histone H3, which induces a lysine for methionine substitution at amino acid 27 (H3K27M) in either H3.1 (HIST1H3B ~25%) or H3.3 (H3F3A ~65%) variants. Using the blood-brain barrier (BBB) permeable DRD2 antagonist, ONC201 (in clinical trials for DIPG and H3K27M-mutant gliomas – NCT03416530), we hypothesized that DRD2 antagonism would induce TRAIL expression via indirect inhibition of AKT and ERK signaling, to drive apoptosis in both H3.1K27M and H3.3K27M patient-derived DIPG cell lines alike. For the first time, we reveal that ONC201 shows efficacy in 100% of WT-H3 and H3.1K27M mutant DIPG cell lines (n=5), compared to 50% of H3.3K27M mutant DIPGs (n=6). Investigations to identify the mechanisms of resistance to ONC201, revealed that cell lines with decreased sensitivity upregulated the PI3K/AKT/MTOR signaling axis to drive phosphorylation of AKT and increase metabolic activity. Combined administration of ONC201 and the BBB-permeable PI3K/AKT inhibitor, paxalisib (previously GDC-0084, in clinical trials for newly diagnosed DIPG – NCT03696355), showed synergistic cytotoxicity, reduced PI3K/AKT signaling and metabolic reprogramming to drive apoptosis in all DIPG cell lines tested. This combination was used to treat a 3-year-old DIPG patient, commencing 14 weeks post disease progression, completing 40 weeks of therapy prior to her passing, December 2019. These studies highlight the potential of combined administration of two safe, BBB penetrant, oral targeted therapies and supports testing under clinical trial conditions.

Symptomatic venous thromboembolism (VTE) occurs in five percent of children treated for acute lymphoblastic leukemia (ALL), but whether a genetic predisposition exists across different ALL treatment regimens has not been well studied. Methods: We undertook a genome-wide association study (GWAS) meta-analysis for VTE in consecutively treated children in the Nordic/Baltic acute lymphoblastic leukemia 2008 (ALL2008) cohort and the Australian Evaluation of Risk of ALL Treatment-Related Side-Effects (ERASE) cohort. A total of 92 cases and 1481 controls of European ancestry were included. Results: No SNPs reached genome-wide significance (p &lt, 5 &times, 10&minus, 8) in either cohort. Among the top 34 single-nucleotide polymorphisms (SNPs) (p &lt, 1 &times, 6), two loci had concordant effects in both cohorts: ALOX15B (rs1804772) (MAF: 1%, p = 3.95 &times, 7) that influences arachidonic acid metabolism and thus platelet aggregation, and KALRN (rs570684) (MAF: 1%, p = 4.34 &times, 7) that has been previously associated with risk of ischemic stroke, atherosclerosis, and early-onset coronary artery disease. Conclusion: This represents the largest GWAS meta-analysis conducted to date associating SNPs to VTE in children and adolescents treated on childhood ALL protocols. Validation of these findings is needed and may then lead to patient stratification for VTE preventive interventions. As VTE hemostasis involves multiple pathways, a more powerful GWAS is needed to detect combination of variants associated with VTE.

BACKGROUND There is growing impetus for increased genetic screening in childhood cancer survivors. Family history-taking is a critical first step in determining survivors' suitability. However, the family history-taking practices of providers of pediatric oncology survivorship care and the confidence of these providers to discuss cancer risks to relatives are unknown. PROCEDURE Fifty-four providers completed semistructured interviews in total, which included eight tertiary providers representing nine hospitals across two countries (63% male, 63% oncologists, 37% nurses) and 46 primary care providers (PCPs) nominated by a survivor (59% male, 35% regional practice). We used content analysis and descriptive statistics/regression to analyze the data. RESULTS Few tertiary (38%) or primary (35%) providers regularly collected survivors' family histories, often relying on survivors/parents to initiate discussions. Providers mostly took two-generation pedigrees (63% tertiary and 81% primary). Primary providers focused on adult cancers. Lack of time, alternative priorities, and perceived lack of relevance were common barriers. Half of all tertiary providers felt moderately comfortable discussing genetic cancer risk to children of survivors (88% felt similarly discussing risks to other relatives). Most primary providers lacked confidence: 41% felt confident regarding risks to survivors' children and 48% regarding risks to other relatives. CONCLUSIONS While family history-taking will not identify all survivors suitable for genetics assessment, recommendations for regular history-taking are not being implemented in tertiary or primary care. Additional PCP-targeted genetic education is warranted given that they are well placed to review family histories of pediatric cancer survivors.

Minimal residual disease (MRD) during early chemotherapy is a powerful predictor of relapse in acute lymphoblastic leukaemia (ALL) and is used in children to determine eligibility for allogeneic haematopoietic stem cell transplantation (HSCT) in first (CR1) or later complete remission (CR2/CR3). Variables affecting HSCT outcome were analysed in 81 children from the ANZCHOG ALL8 trial. The major cause of treatment failure was relapse, with a cumulative incidence of relapse at 5 years (CIR) of 32% and treatment-related mortality of 8%. Leukaemia-free survival (LFS) and overall survival (OS) were similar for HSCT in CR1 (LFS 62%, OS 83%, n = 41) or CR2/CR3 (LFS 60%, OS 72%, n = 40). Patients achieving bone marrow MRD negativity pre-HSCT had better outcomes (LFS 83%, OS 92%) than those with persistent MRD pre-HSCT (LFS 41%, OS 64%, P 0·0001) or post-HSCT (LFS 35%, OS 55%, P 0·0001). Patients with B-other ALL had more relapses (CIR 50%, LFS 41%) than T-ALL and the main precursor-B subtypes including BCR-ABL1, KMT2A (MLL), ETV6-RUNX1 (TEL-AML1) and hyperdiploidy50. A Cox multivariate regression model for LFS retained both B-other ALL subtype (hazard ratio 4·1, P = 0·0062) and MRD persistence post-HSCT (hazard ratio 3·9, P = 0·0070) as independent adverse prognostic variables. Persistent MRD could be used to direct post-HSCT therapy.

Previous research has suggested positive associations between parental or childhood exposure to pesticides and risk of childhood brain tumors (CBT). This Australian case–control study of CBT investigated whether exposures to pesticides before pregnancy, during pregnancy and during childhood, were associated with an increased risk. Cases were recruited from 10 pediatric oncology centers, and controls by random-digit dialing, frequency matched on age, sex, and State of residence. Exposure data were collected by written questionnaires and telephone interviews. Data were analyzed by unconditional logistic regression. The odds ratios (ORs) for professional pest control treatments in the home in the year before the index pregnancy, during the pregnancy, and after the child’s birth were 1.54 (95 % confidence interval (CI): 1.07, 2.22), 1.52 (95 % CI: 0.99, 2.34) and 1.04 (95 % CI: 0.75, 1.43), respectively. ORs for treatments exclusively before pregnancy and during pregnancy were 1.90 (95 % CI: 1.08, 3.36) and 1.02 (95 % CI: 0.35, 3.00), respectively. The OR for the father being home during the treatment was 1.79 (95 % CI: 0.85, 3.80). The OR for paternal occupational exposure in the year before the child’s conception was 1.36 (95 % CI: 0.66, 2.80). ORs for prenatal home pesticide exposure were elevated for low- and high-grade gliomas; effect estimates for other CBT subtypes varied and lacked precision. These results suggest that preconception pesticide exposure, and possibly exposure during pregnancy, is associated with an increased CBT risk. It may be advisable for both parents to avoid pesticide exposure during this time.

We performed a retrospective analysis on the outcomes of 135 hematopoietic stem cell transplantations (HSCTs) for primary immunodeficiency disorders in Australian and New Zealand Children's Haematology Oncology Group transplantation centers between 1992 and 2008. The most common indications for HSCT were severe combined immunodeficiency, Wiskott-Aldrich syndrome, and chronic granulomatous disease. Five-year overall survival (OS) was 72% for the entire cohort. Disease-specific 5-year OS was 70% for severe combined immunodeficiency, 81% for Wiskott-Aldrich syndrome, and 69% for chronic granulomatous disease. Transplantation-related mortality (TRM) was 10% at day +100. TRM and OS were equivalent in recipients of related and unrelated donor transplants. Source of stem cells had no impact on TRM or OS with outcomes following unrelated umbilical cord blood similar to unrelated bone marrow. The presence of interstitial pneumonitis, active cytomegalovirus infection, or veno-occlusive disease were all independent variables that significantly decreased OS. This large series supports the use of HSCT as curative therapy for a range of primary immunodeficiency disorders, demonstrating excellent survival after both related and unrelated donor transplantation.

Item does not contain fulltext Children with acute lymphoblastic leukemia (ALL) and high minimal residual disease (MRD) levels after initial chemotherapy have a poor clinical outcome. In this prospective, single arm, Phase 2 trial, 111 Dutch and Australian children aged 1-18 years with newly diagnosed, t(9;22)-negative ALL, were identified among 1041 consecutively enrolled patients as high risk (HR) based on clinical features or high MRD. The HR cohort received the AIEOP-BFM (Associazione Italiana di Ematologia ed Oncologia Pediatrica (Italy)-Berlin-Frankfurt-Munster ALL Study Group) 2000 ALL Protocol I, then three novel HR chemotherapy blocks, followed by allogeneic transplant or chemotherapy. Of the 111 HR patients, 91 began HR treatment blocks, while 79 completed the protocol. There were 3 remission failures, 12 relapses, 7 toxic deaths in remission and 10 patients who changed protocol due to toxicity or clinician/parent preference. For the 111 HR patients, 5-year event-free survival (EFS) was 66.8% (+/-5.5) and overall survival (OS) was 75.6% (+/-4.3). The 30 patients treated as HR solely on the basis of high MRD levels had a 5-year EFS of 63% (+/-9.4%). All patients experienced grade 3 or 4 toxicities during HR block therapy. Although cure rates were improved compared with previous studies, high treatment toxicity suggested that novel agents are needed to achieve further improvement.

Purpose To develop an evidence-based guideline for the empiric management of pediatric fever and neutropenia (FN). Methods The International Pediatric Fever and Neutropenia Guideline Panel is a multidisciplinary and multinational group composed of experts in pediatric oncology and infectious disease as well as a patient advocate. The Panel was convened for the purpose of creating this guideline. We followed previously validated procedures for creating evidence-based guidelines. Working groups focused on initial presentation, ongoing management, and empiric antifungal therapy. Each working group developed key clinical questions, conducted systematic reviews of the published literature, and compiled evidence summaries. The Grades of Recommendation Assessment, Development, and Evaluation approach was used to generate summaries, and evidence was classified as high, moderate, low, or very low based on methodologic considerations. Results Recommendations were made related to initial presentation (risk stratification, initial evaluation, and treatment), ongoing management (modification and cessation of empiric antibiotics), and empiric antifungal treatment (risk stratification, evaluation, and treatment) of pediatric FN. For each recommendation, the strength of the recommendation and level of evidence are presented. Conclusion This guideline represents an evidence-based approach to FN specific to children with cancer. Although some recommendations are similar to adult-based guidelines, there are key distinctions in multiple areas. Implementation will require adaptation to the local context.

The objective of this study was to assess the efficacy of the VETOPEC regimen, a regimen of vincristine and etoposide with escalating doses of cyclophosphamide (CPA), in pediatric patients with high-risk brain tumors. Three consecutive studies by the Australia and New Zealand Children’s Cancer Study Group—VETOPEC I, Baby Brain 91, and VETOPEC II—have used a specific chemotherapy regimen of vincristine (VCR), etoposide (VP-16) and escalating CPA in patients with relapsed, refractory, or high-risk solid tumors. Patients in the VETOPEC II cohort were treated with very high dose CPA with peripheral blood stem cell (PBSC) rescue. We analyzed the subset of patients with high-risk brain tumors treated with these intensive VETOPEC-based protocols to assess the response, toxicity, and survival. We also assessed whether the use of very high dose chemotherapy with stem cell rescue improved the response rate or affected toxicity. Seventy-one brain tumor patients were treated with VETOPEC-based protocols. Of the 54 patients evaluable for tumor response, 17 had a complete response (CR) and 20 a partial response (PR) to treatment, which yielded an overall response rate of 69%. The CR + PR was 83% (19/23) for medulloblastomas, 56% (5/9) for primitive neuroectodermal tumors, 55% (6/11) for grade 3 and 4 astrocytomas, and 80% (6/8) for ependymomas. At a median follow-up of 36 months, overall survival for the entire cohort of 71 patients was 32%, with event-free survival of 13%. There were no toxic deaths within the PBSC-supported VETOPEC II cohort, despite higher CPA doses, compared with 7% among the non-PBSC patients. This regimen produces high response rates in a variety of very poor prognosis pediatric brain tumors. The maximum tolerated dose of CPA was not reached. Higher escalation in doses of CPA did not deliver a further improvement in response. With PBSC rescue in the VETOPEC II study, hematologic toxicity was no longer a limiting factor. The response rates observed support further development of this chemotherapy regimen.

Background and Purpose Improved radiotherapy techniques in pediatric craniospinal therapy (CSRT) strive to reduce risks of late morbidity. Using a pediatric anthropomorphic phantom, this research correlated measured target and normal tissue dose to that predicted from a 3D planning system (3D-RTP). Patients and Methods A pediatric anthropomorphic phantom was planned following French Society of Pediatric Oncology (SFOP) protocols. Thermoluminescent detectors (TLDs) were used to perform dosimetric measurements during treatment. 4 and 6 MV photon fields with multi leaf collimation (MLC) or custom blocks were compared to 3D-RTP computer (ADAC Pinnacle) predictions for cranial fields. Spinal dosimetry was studied using photons (4 and 6 MV) and electrons (9 and 12 MeV). Results 3D-RTP predictions generally concurred with dose received in cranial and spinal sites. The measured dose was over-predicted significantly by the 3D-RTP in the anterior cranial fossa. Normal tissue doses were reduced when treating the spine using megavoltage electron beams instead of photons. Conclusions Treating the spinal field with electrons minimises the risk of pulmonary sequelae, however electron energy selection is critical to achieve adequate spinal field coverage. Despite adhering to a major trial protocol guideline, dose at the floor of the anterior cranial fossa remains a potential clinical problem and 3D-RTP do not predict this well.

After publication, it was noted by the authors that the dataset used for the analyses of occupational exposures in this study accidentally used incomplete occupational histories collected for 94 control fathers and 104 control mothers recruited in 2006, and these control parents were all treated as unexposed to occupational pesticides. Results in Tables 1–3 and Supplemental Tables 1 and 2 (and the first three rows of Supplemental Table 3) of our published paper were unaffected by this error as they concerned household, rather than occupational pesticide exposure. The conclusions regarding the association with household exposure to professional pest control treatments are consequently unchanged. However, for occupational exposure, 18 control fathers and 2 control mothers were mistakenly classified as being unexposed to pesticides when they should have been classified as exposed (any time before the child’s birth). The analyses presented in Table 4 and parts of Supplemental Table 3 in the published manuscript were re-run using the full dataset to ensure correct exposure assignment (5 case fathers and 4 control fathers were additionally excluded from revised occupational analysis due to genuinely missing data). The updated Table 4 and Supplemental Table 3 (occupational estimates only) are presented in this erratum. The online version of the original article can be found under doi:10. 1007/s10552-013-0205-1.

Abstract 1517 Purpose: Decitabine, a deoxycytidine nucleoside derivative, is an inhibitor of DNA-methyltransferases indicated for treatment of myelodysplastic syndrome (MDS) including previously treated and untreated, de novo or secondary MDS of all French-American-British (FAB) subtypes, Intermediate-1, Intermediate-2, and High-Risk International Prognostic Scoring System (IPSS) groups. Laboratory evidence shows that pretreatment of AML cell lines can sensitize leukemia cells to chemotherapy as well as inhibit clonogenic potential. The purpose of this study is to evaluate the safety, pharmacokinetics, and efficacy of decitabine when used as priming before induction therapy in children with newly diagnosed AML. Exploratory analyses of genomic methylation and RNA expression patterns and minimal residual disease (MRD) are embedded correlative studies. Methods: This multicenter, randomized, two-arm, open-label study enrolls pediatric pts ages 1–16 with newly diagnosed AML to either Arm A: daunorubicin, cytarabine, etoposide (D-ADE) preceded by a 5-day course of decitabine (experimental arm) or Arm B: daunorubicin, cytarabine, etoposide (ADE; control arm). Following completion of induction on study, post-induction therapy is at the treating physician's discretion. To date, 20 pts, 10 in each arm (1–16 yrs, median 9.4 yrs in both arms) have been enrolled. Results: At the protocol-specified bone marrow sampling time 3 weeks post-induction, there were 2 CRs, 6 CRi (CR with incomplete hematopoietic recovery), 1 leukemia not in remission and 1 pt who discontinued due to an AE in Arm A. In Arm B, 6 CRs, 2CRi, 1 PR and 1 pt with marrow aplasia have been confirmed. Decitabine PK in all arm A pts (100%) were characterized by mean+SD Cmax, 297+109 ng/mL, AUC0-t, 216+73.7 ng*h/mL, CL, 136+93.9L/h, Vdss 93.1+70.7 L, t1/2 0.456+0.073 h, and median tmax0.925 h. All pts had at least one AE. Grade 3 and 4 non-hematologic AEs in Arm A that were not seen in Arm B were caecitis in 2 (20%), anorexia in 3 (30%), and hypophosphatemia in 2 (20%) of pts. All pts experienced neutropenia and thrombocytopenia as expected. One pt in Arm A had appendicitis and colon perforation on Day 6 that led to study discontinuation, later determined to have been leukemic infiltrate. Two pts have died to date (both in Arm A), one of necrotic bowel, Pseudomonas sepsis and multisystem organ failure 6 months after completing study induction therapy. One pt died 5 months following study treatment from multisystem organ failure after stem cell transplant. Epigenetic changes associated with decitabine pretreatment were analyzed and will be presented. Conclusions: Decitabine in combination with ADE chemotherapy is well tolerated in children with newly diagnosed AML. There were no AEs that had not been previously identified in adults with MDS or AML. No differences have been observed between treatment arms in hematologic toxicities based on the current sample size. To date, the decitabine-treated pts in this study may have more gastrointestinal toxicity and hypophosphatemia. Decitabine-treated pts achieved PK exposures that were similar to those observed in adults treated with decitabine. Preliminary responses by CR/CRi were similar between treatment arms; expected adverse events of neutropenia and thrombocytopenia were similar between both Arms. Molecular changes associated with decitabine pretreatment may be important in the sensitization of clonogenic AML cells. Total accrual of 40 subjects is planned. Disclosures: Off Label Use: AC220 in relapsed/refractory pediatric acute leukemia. Tarassoff:Eisai, Inc.: Employment. Jones:Eisai Inc: Employment.