Search

Although outcomes for patients with high-risk neuroblastoma improved after the addition of a chimeric anti-GD2 monoclonal antibody (dinutuximab) as treatment for minimal residual disease, nearly half of these patients die of disease. Recent studies demonstrated efficacy of the combination of chemotherapy with anti-GD2 mAb in patients with relapsed or newly diagnosed disease. This retrospective case series describes 6 patients treated at St Jude Children's Research Hospital with an induction regimen containing dinutuximab and chemotherapy, followed by consolidation and postconsolidation therapy. The treatment was well tolerated with expected toxicities. All patients completed induction therapy and demonstrated a clinical response. Further studies are warranted.

Background Talazoparib combined with irinotecan and temozolomide demonstrated efficacy in a murine Ewing sarcoma model. Based on these data, we conducted a phase I trial of talazoparib and irinotecan with/without temozolomide in paediatric patients with recurrent/refractory solid malignancies. Patients and methods Cohorts of 3–6 patients with recurrent/refractory solid malignancies received escalating doses of oral talazoparib and intravenous irinotecan (arm A) and oral talazoparib, oral temozolomide and intravenous irinotecan (arm B) in a 3 + 3 design. Talazoparib was administered on days 1–6, and intravenous irinotecan and oral temozolomide were administered on days 2–6, of a 21-day course. Serum for talazoparib and irinotecan pharmacokinetics was obtained during course 1. UGT1A1 polymorphism and Schlafen family member 11 (SLFN11) immunohistochemical staining were performed. Results Forty-one patients (20 males; median age, 14.6 years; 24 with recurrent disease) were evaluable for dose escalation. Twenty-nine and 12 patients were treated on arm A and arm B, respectively, for a total of 208 courses. The most common diagnosis was Ewing sarcoma (53%). The most common ≥grade III haematologic toxicities in arms A and B included neutropenia (78% and 31%, respectively) and thrombocytopenia (42% and 31%, respectively). In arms A and B, febrile neutropenia (24% and 14%, respectively) and diarrhoea (21% and 7%, respectively) were the most common ≥grade III non-hematologic toxicities. Six patients (Ewing sarcoma [5 patients] and synovial sarcoma [1 patient]) had a response (1 with a complete response, 5 with a partial response). The objective response rates were 10.3% (arm A) and 25% (arm B). Pharmacokinetic testing demonstrated no evidence of drug-drug interaction between talazoparib and irinotecan. UGT1A1 was not related to response. SLFN11 positivity was associated with best response to therapy. Conclusions The combination of talazoparib and irinotecan with/without temozolomide is feasible and active in Ewing sarcoma, and further investigation is warranted.

Background Angiogenesis is critical for tumour growth and metastasis. Dual inhibition of vascular endothelial growth factors and platelet-derived growth factor receptors suppresses angiogenesis. This expansion cohort of a phase I study targeted angiogenesis with sorafenib, bevacizumab and low-dose cyclophosphamide in children and young adults with recurrent solid tumours. Methods An expansion cohort including patients with refractory or recurrent solid tumours was enrolled and received bevacizumab (15 mg/kg IV, day 1), sorafenib (90 mg/m2 po twice daily, days 1–21) and low-dose cyclophosphamide (50 mg/m2 po daily, days 1–21). Each course was 21 days. Toxicities were assessed using Common Terminology Criteria for Adverse Events, v3.0, and responses were evaluated by Response Evaluation Criteria in Solid Tumors criteria. Serial bevacizumab pharmacokinetic (PK) studies were performed during course 1. Results Twenty-four patients (15 males; median age 14.5 yrs; range 1–22 yr) received a median of 6 courses (range 1–18). Twelve patients had a bone or soft tissue sarcoma. The most common grade III/IV non-haematologic toxicities were hypertension (N = 4), hand/foot rash (N = 3) and elevated lipase (N = 3). The most common grade III/IV haematologic toxicities were neutropenia (N = 7) and lymphopenia (N = 17). Three patients (2 synovial sarcoma, 1 rhabdoid tumour) achieved a partial response and 18 had stable disease. The progression-free survival at 3 and 6 months were 78.1% (95% confidence interval [CI] 60.6–95.6%) and 54% (95% CI 30.2–78.2%), respectively. Bevacizumab PKs in 15 patients was similar to published adult PK results. Conclusions Intravenous bevacizumab combined with oral sorafenib and low-dose cyclophosphamide was tolerated and demonstrated promising activity in a subset of childhood solid tumours.

Background/Purpose MYCN-amplification in neuroblastoma is associated with an aggressive clinical phenotype. We evaluated the association of MYCN amplification with tumor response to neoadjuvant chemotherapy. Methods Primary tumor response, assessed by percentage volume change on CT scan and degree of tumor resection, assessed by the operating surgeon, were retrospectively compared in 84 high-risk neuroblastoma patients. There were thirty-four (40%) with MYCN-amplified tumors and fifty (60%) with non-amplified tumors treated at our institution from 1999 to 2016. Metastatic disease response was assessed on MIBG scan by change in Curie score. Results MYCN-amplification was associated with a greater mean percentage reduction in primary tumor volume after neoadjuvant chemotherapy (72.27% versus 46.83% [non-amplified tumors], p = 0.001). The percentage of patients with a Curie score > 2 at diagnosis who then had a score ≤ 2 after neoadjuvant chemotherapy was not significantly different (8 [61.5%] and 8 [34.8%], respectively, p = 0.37). Twenty-eight (85.7%) patients with MYCN-amplification had ≥ 90% surgical resection compared to 45 (91.84%) patients with non-amplified tumors (p = 0.303). Conclusions MYCN-amplification in high-risk neuroblastoma was associated with a better response of the primary tumor to neoadjuvant chemotherapy, but not metastatic sites, than in patients with non-amplified tumors. This did not significantly impact the ability to resect ≥ 90% of the primary tumor/locoregional disease. Type of Study Treatment Study Level of Evidence Level III

Purpose: To determine the pharmacokinetics and skin toxicity profile of sorafenib in children with refractory/relapsed malignancies. Patients and Methods: Sorafenib was administered concurrently or sequentially with clofarabine and cytarabine to patients with leukemia or with bevacizumab and cyclophosphamide to patients with solid tumor malignancies. The population pharmacokinetics (PPK) of sorafenib and its metabolites and skin toxicities were evaluated. Results: In PPK analysis, older age, bevacizumab and cyclophosphamide regimen, and higher creatinine were associated with decreased sorafenib apparent clearance (CL/f; P < 0.0001 for all), and concurrent clofarabine and cytarabine administration was associated with decreased sorafenib N-oxide CL/f (P = 7e−4). Higher bilirubin was associated with decreased sorafenib N-oxide and glucuronide CL/f (P = 1e−4). Concurrent use of organic anion-transporting polypeptide 1B1 inhibitors was associated with increased sorafenib and decreased sorafenib glucuronide CL/f (P < 0.003). In exposure–toxicity analysis, a shorter time to development of grade 2–3 hand–foot skin reaction (HFSR) was associated with concurrent (P = 0.0015) but not with sequential (P = 0.59) clofarabine and cytarabine administration, compared with bevacizumab and cyclophosphamide, and with higher steady-state concentrations of sorafenib (P = 0.0004) and sorafenib N-oxide (P = 0.0275). In the Bayes information criterion model selection, concurrent clofarabine and cytarabine administration, higher sorafenib steady-state concentrations, larger body surface area, and previous occurrence of rash appeared in the four best two-predictor models of HFSR. Pharmacokinetic simulations showed that once-daily and every-other-day sorafenib schedules would minimize exposure to sorafenib steady-state concentrations associated with HFSR. Conclusions: Sorafenib skin toxicities can be affected by concurrent medications and sorafenib steady-state concentrations. The described PPK model can be used to refine exposure–response relations for alternative dosing strategies to minimize skin toxicity.

Purpose: We sought to evaluate whether combining a humanized antidisialoganglioside mAb (hu14.18K322A) with induction chemotherapy improves early responses and outcomes in children with newly diagnosed high-risk neuroblastoma. Patients and Methods: We conducted a prospective nonrandomized, single-arm, two-stage, phase II clinical trial. Six courses of induction chemotherapy were coadministered with hu14.18K322A and followed with granulocyte–macrophage colony-stimulating factor (GM-CSF) and low-dose IL2. Consolidation was performed with a busulfan/melphalan preparative regimen. An additional course of hu14.18K322A was administered with parent-derived natural killer cells, when available, during consolidation. Hu14.18K322A, GM-CSF, IL2, and isotretinoin were then administered. Secondary outcomes included reduced tumor volume and semiquantitative 123I-metaiodobenzylguanidine scoring [i.e., Curie scores (CS)] at the end of induction. Results: Forty-two patients received hu14.18K322A and induction chemotherapy. This regimen was well tolerated, with continuous-infusion narcotics adjusted to patient tolerance. Partial responses (PR) or better after the first two chemoimmunotherapy courses occurred in 32 patients [76.2%; 95% confidence interval (CI), 60.6–88.0]. This was accompanied by primary tumor volume reductions (median, –76%; range, –100% to 5%). Of 35 patients with stage IV disease who completed induction, 31 had end-of-induction CSs of 2 or less. No patients experienced progression during induction. Two-year event-free survival (EFS) was 85.7% (95% CI, 70.9–93.3). Conclusions: Adding hu14.18K322A to induction chemotherapy produced early PR or better in most patients, reduced tumor volumes, improved CSs at the end of induction, and yielded an encouraging 2-year EFS. These results, if validated in a larger study, may change the standard of care for children with high-risk neuroblastoma.

Introduction: Diffuse alveolar hemorrhage (DAH) is an early pulmonary complication of hematopoietic cell transplantation (HCT) associated with severe hypoxemic respiratory failure and mortality. Extracorporeal membrane oxygenation (ECMO) support is often used for respiratory failure refractory to conventional interventions; however, its use has been limited in HCT patients with DAH due to potential for worsening alveolar hemorrhage and reported high mortality.Case Presentation: We report two cases of DAH following HCT who developed refractory hypoxemic respiratory failure despite cessation of bleeding and were successfully supported with ECMO.Conclusion: DAH after HCT should not automatically preclude ECMO support; rather, these patients must be evaluated individually for ECMO within the context of their overall clinical picture.

For children with neuroblastoma, the likelihood of cure varies widely according to age at diagnosis, disease stage, and tumor biology. Treatments are tailored for children with this clinically heterogeneous malignancy on the basis of a combination of markers that are predictive of risk of relapse and death. Sequential risk-based, cooperative-group clinical trials conducted during the past 4 decades have led to improved outcome for children with neuroblastoma. Increasingly accurate risk classification and refinements in treatment stratification strategies have been achieved with the more recent discovery of robust genomic and molecular biomarkers. In this review, we discuss the history of neuroblastoma risk classification in North America and Europe and highlight efforts by the International Neuroblastoma Risk Group (INRG) Task Force to develop a consensus approach for pretreatment stratification using seven risk criteria including an image-based staging system—the INRG Staging System. We also update readers on the current Children’s Oncology Group risk classifier and outline plans for the development of a revised 2021 Children’s Oncology Group classifier that will incorporate INRG Staging System criteria to facilitate harmonization of risk-based frontline treatment strategies conducted around the globe. In addition, we discuss new approaches to establish increasingly robust, future risk classification algorithms that will further refine treatment stratification using machine learning tools and expanded data from electronic health records and the INRG Data Commons.

Aggressive cancers often have activating mutations in growth-controlling oncogenes and inactivating mutations in tumor-suppressor genes. In neuroblastoma, amplification of the MYCN oncogene and inactivation of the ATRX tumor-suppressor gene correlate with high-risk disease and poor prognosis. Here we show that ATRX mutations and MYCN amplification are mutually exclusive across all ages and stages in neuroblastoma. Using human cell lines and mouse models, we found that elevated MYCN expression and ATRX mutations are incompatible. Elevated MYCN levels promote metabolic reprogramming, mitochondrial dysfunction, reactive-oxygen species generation, and DNA-replicative stress. The combination of replicative stress caused by defects in the ATRX–histone chaperone complex, and that induced by MYCN-mediated metabolic reprogramming, leads to synthetic lethality. Therefore, ATRX and MYCN represent an unusual example, where inactivation of a tumor-suppressor gene and activation of an oncogene are incompatible. This synthetic lethality may eventually be exploited to improve outcomes for patients with high-risk neuroblastoma., In most cancers, mutations that lead to oncogene activation and tumor suppressor inactivation synergize to promote tumorigenesis. However, in neuroblastomas, MYCN amplification and ATRX mutations are mutually exclusive and incompatible.

BACKGROUND Patients with metastatic Ewing sarcoma experience poor outcomes despite intensive systemic and local therapy. Early chemotherapy response of pulmonary metastases has been associated with prognosis in other pediatric malignancies. We reviewed the outcomes of patients with Ewing sarcoma and pulmonary metastases treated at our institution based on therapy received and early pulmonary response. MATERIALS AND METHODS We retrospectively reviewed patients with newly diagnosed Ewing sarcoma and pulmonary metastases at St. Jude Children's Research Hospital between 1979 and 2015. Data obtained included demographic and treatment characteristics including chemotherapy, local control measures, whole lung irradiation (WLI) administration, autologous stem cell transplantation, and outcomes. Patients were evaluated for radiographic post-induction pulmonary complete response (CR). We estimated event-free survival (EFS) and overall survival (OS) and used Cox proportional hazards regression to examine the effects of clinical and treatment factors on outcomes. RESULTS Fifty-four patients (median age, 12.9 years) were evaluated. Post-induction pulmonary CR was observed in 33 (61%) patients. WLI was delivered to 16 patients (4/33 with pulmonary CR and 12/21 with non-CR). At median 3.6 years follow-up, five-year EFS and OS were 30.8% ± 6.4% and 49.6% ± 7.1%, respectively. Post-induction pulmonary CR was associated with prolonged EFS (P

Purpose: Anti-GD2 mAbs, acting via antibody-dependent cell-mediated cytotoxicity, may enhance the effects of chemotherapy. This pilot trial investigated a fixed dose of a unique anti-GD2 mAb, hu14.18K322A, combined with chemotherapy, cytokines, and haploidentical natural killer (NK) cells. Experimental Design: Children with recurrent/refractory neuroblastoma received up to six courses of hu14.18K322A (40 mg/m2/dose, days 2–5), GM-CSF, and IL2 with chemotherapy: cyclophosphamide/topotecan (courses 1,2), irinotecan/temozolomide (courses 3,4), and ifosfamide/carboplatin/etoposide (courses 5,6). Parentally derived NK cells were administered with courses 2, 4, and 6. Serum for pharmacokinetic studies of hu14.18K322A, soluble IL2 receptor alpha (sIL2Rα) levels, and human antihuman antibodies (HAHA) were obtained. Results: Thirteen heavily pretreated patients (9 with prior anti-GD2 therapy) completed 65 courses. One patient developed an unacceptable toxicity (grade 4 thrombocytopenia >35 days). Four patients discontinued treatment for adverse events (hu14.18K322A allergic reaction, viral infection, surgical death, second malignancy). Common toxicities included grade 3/4 myelosuppression (13/13 patients) and grade 1/2 pain (13/13 patients). Eleven patients received 29 NK-cell infusions. The response rate was 61.5% (4 complete responses, 1 very good partial response, 3 partial responses) and five had stable disease. The median time to progression was 274 days (range, 239–568 days); 10 of 13 patients (77%) survived 1 year. Hu14.18K322A pharmacokinetics was not affected by chemotherapy or HAHA. All patients had increased sIL2Rα levels, indicating immune activation. Conclusions: Chemotherapy plus hu14.18K322A, cytokines, and NK cells is feasible and resulted in clinically meaningful responses in patients with refractory/recurrent neuroblastoma. Further studies of this approach are warranted in patients with relapsed and newly diagnosed neuroblastoma. Clin Cancer Res; 23(21); 6441–9. ©2017 AACR.

Paediatric solid tumours arise from endodermal, ectodermal, or mesodermal lineages. Although the overall survival of children with solid tumours is 75%, that of children with recurrent disease is below 30%. To capture the complexity and diversity of paediatric solid tumours and establish new models of recurrent disease, here we develop a protocol to produce orthotopic patient-derived xenografts at diagnosis, recurrence, and autopsy. Tumour specimens were received from 168 patients, and 67 orthotopic patient-derived xenografts were established for 12 types of cancer. The origins of the patient-derived xenograft tumours were reflected in their gene-expression profiles and epigenomes. Genomic profiling of the tumours, including detailed clonal analysis, was performed to determine whether the clonal population in the xenograft recapitulated the patient's tumour. We identified several drug vulnerabilities and showed that the combination of a WEE1 inhibitor (AZD1775), irinotecan, and vincristine can lead to complete response in multiple rhabdomyosarcoma orthotopic patient-derived xenografts tumours in vivo.

Secondary hemophagocytic syndrome (HPS) has been described after autologous hematopoietic cell transplant (AutoHCT). We report two cases of secondary HPS after novel consolidation therapy for high-risk neuroblastoma as part of an institutional phase 2 trial incorporating immunotherapy into a "standard" AutoHCT regimen. Both patients developed liver dysfunction beyond expected course of hepatic veno-occlusive disease, coagulopathy, hyperferritinemia, and when evaluated, elevated soluble interleukin-2 receptor and hemophagocytosis. These cases highlight the need for clinicians to have a high index of suspicion for immune-related complications in patients receiving immune therapies.

// Andrew D.J. Pearson 1 , Sara M. Federico 2 , Isabelle Aerts 3 , Darren R. Hargrave 4 , Steven G. DuBois 5 , Robert Iannone 6 , Ryan D. Geschwindt 6 , Ruixue Wang 7 , Frank G. Haluska 8 , Tanya M. Trippett 9 , Birgit Geoerger 10 1 Paediatric Drug Development Unit, Children and Young People’s Unit, Institute of Cancer Research, The Royal Marsden NHS Foundation Trust, Sutton, United Kingdom (Retired) 2 Department of Pediatric Oncology, St. Jude Children’s Research Hospital, Memphis, TN, USA 3 Department of Pediatric, Adolescent and Young Adult Oncology, Institut Curie, Paris, France 4 Haematology and Oncology Department, Great Ormond Street Hospital for Children, London, United Kingdom 5 Department of Pediatrics, University of California San Francisco School of Medicine, and Benioff Children’s Hospital, San Francisco, CA, USA (current affiliation: Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and Harvard Medical School, Boston, MA, USA) 6 Clinical Research, Merck & Co., Inc., North Wales, PA, USA 7 BARDS, MSD RD 18 were evaluable for dose-limiting toxicities. One dose-limiting toxicity (grade 3 increased alanine aminotransferase) occurred in 1 patient at 33 mg/m 2 . Dose escalation concluded at 33 mg/m 2 ; the maximum tolerated dose was not determined. The most common treatment-related adverse events (frequency ≥40%) were manageable grade 1–2 stomatitis, thrombocytopenia, hypertriglyceridemia, increased alanine aminotransferase, fatigue, hypercholesterolemia, anemia, and increased aspartate aminotransferase. Ridaforolimus exposure at 28 mg/m 2 and 33 mg/m 2 exceeded adult target levels. The RP2D for oral ridaforolimus in children was defined as 33 mg/m 2 . Four patients received at least 4 cycles; 2 with pineoblastoma and diffuse intrinsic pontine glioma had stable disease for 12 and 46 cycles, respectively. Conclusions: Ridaforolimus is orally bioavailable and well tolerated in children with advanced solid tumors. The RP2D (33 mg/m 2 , 5 days/week) exceeds the adult RP2D. The favorable toxicity and pharmacokinetic profiles may allow for combination therapy, a promising therapeutic option in pediatric malignancies.

Significant advances have been made over the past 25 years in our understanding of the most common adult solid tumors such as breast, colon, lung and prostate cancer. Much less is known about childhood solid tumors because they are rare and because they originate in developing organs during fetal development, childhood and adolescence. It can be very difficult to study the cellular origins of pediatric solid tumors in developing organs characterized by rapid proliferative expansion, growth factor signaling, developmental angiogenesis, programmed cell death, tissue reorganization and cell migration. Not only has the etiology of pediatric cancer remained elusive because of their developmental origins, but it also makes it more difficult to treat. Molecular targeted therapeutics that alter developmental pathway signaling may have devastating effects on normal organ development. Therefore, basic research focused on the mechanisms of development provides an essential foundation for pediatric solid tumor translational research. In this article, we describe new resources available for the developmental biology and oncology research communities. In a companion paper, we present the detailed characterization of an orthotopic xenograft of a pediatric solid tumor derived from sympathoadrenal lineage during development.

ATRX alterations occur at high frequency in neuroblastoma of adolescents and young adults. Particularly intriguing are the large N-terminal deletions of ATRX (Alpha Thalassemia/Mental Retardation, X-linked) that generate in-frame fusion (IFF) proteins devoid of key chromatin interaction domains, while retaining the SWI/SNF-like helicase region. We demonstrate that ATRX IFF proteins are redistributed from H3K9me3-enriched chromatin to promoters of active genes and identify REST as an ATRX IFF target whose activation promotes silencing of neuronal differentiation genes. We further show that ATRX IFF cells display sensitivity to EZH2 inhibitors, due to derepression of neurogenesis genes, including a subset of REST targets. Taken together, we demonstrate that ATRX structural alterations are not loss-of-function and put forward EZH2 inhibitors as a potential therapy for ATRX IFF neuroblastoma.

Purpose: The use of celiac plexus block (CPB) for abdominal pain has been extensively reported in adults. However, pediatric literature is limited to three single case reports and a series of three cases. This study evaluated the effectiveness of CPB in children and young adults (aged 8–20 years) with abdominal malignancies. Methods: Pain outcomes after CPB were evaluated in four children and young adults with cancer. Mean daily pain score (PS, 0–10) and morphine consumption (intravenous morphine equivalent daily [MED], mg/kg/day) before and after CPB were used to assess effectiveness. Results: Mean daily PS reduced after CPB in all patients. In one patient, this reduction was sustained up to 6 months of follow-up, and analgesics were discontinued 1 week after CPB. The other three patients had limited survival (6, 16, and 37 days) after CPB. One patient had a PS of 0 over the last few days of life, but the MED was escalated from 0.74 before the block to 5.4 mg/kg/day at the end of life. In the other two patients, MED was lower during the first week after CPB than that before CPB (4.55 vs. 1.59 and 2.88 vs. 1.51 mg/kg/day, respectively). As these two patients had disease progression during their last days of life, the MED was increased to 4.75 and 263.9 mg/kg/day, respectively. Conclusions: Our results suggest that CPB may contribute to reducing PS and MED. We observed the use of CPB rather late in the disease trajectory.

Background Approximately 30% of patients with metastatic (stage M) neuroblastoma present with periorbital ecchymosis from orbital osseous disease. Though locoregional disease is staged by imaging, the prognostic significance of metastatic site in stage M disease is unknown. We hypothesize that, compared to nonorbital metastasis, orbital metastasis is associated with decreased survival in patients with stage M neuroblastoma, and that periorbital ecchymosis reflects location and extent of orbital disease. Procedure Medical records and imaging from 222 patients with stage M neuroblastoma seen at St. Jude Children's Research Hospital between January 1995 and May 2009 were reviewed. Thirty-seven patients were

Neuroblastoma is a pediatric cancer of the developing sympathoadrenal lineage. The tumors are known to develop from the adrenal gland or paraspinal ganglia and have molecular and cellular features of sympathetic neurons such as dense core vesicles and catecholamine production. Here we present the detailed molecular, cellular, genetic and epigenetic characterization of an orthotopic xenograft derived from a high-risk stage 4 neuroblastoma patient. Overall, the xenografted tumor retained the high risk features of the primary tumor and showed aggressive growth and metastasis in the mouse. Also, the genome was preserved with no additional copy number variations, structural variations or aneuploidy. There were 13 missense mutations identified in the xenograft that were not present in the patient׳s primary tumor and there were no new nonsense mutations. None of the missense mutations acquired in the xenograft were in known cancer genes. We also demonstrate the feasibility of using the orthotopic neuroblastoma xenograft to test standard of care chemotherapy and molecular targeted therapeutics. Finally, we optimized a new approach to produce primary cultures of the neuroblastoma xenografts for high-throughput drug screening which can be used to test new combinations of therapeutic agents for neuroblastoma.

Identification of FDGavid- neoplasms may be obscured by high-uptake normal tissues, thus limiting inferences about the natural history of disease. We introduce a FDG-PET radiomics tissue classifier for differentiating FDGavid- normal tissues from tumor. Thirty-three scans from 15 patients with Hodgkin lymphoma and 68 scans from 23 patients with Ewing sarcoma treated on two prospective clinical trials were retrospectively analyzed. Disease volumes were manually segmented on FDG-PET and CT scans. Brain, heart, kidneys and bladder and tumor volumes were automatically segmented on PET images. Standard-uptake-value (SUV) derived shape and first order radiomics features were computed to build a random forest classifier. Manually segmented volumes were compared to automatically segmented tumor volumes. Classifier accuracy for normal tissues was 90%. Classifier performance was varied across normal tissue types (brain, left kidney and bladder, hear and right kidney were 100%, 96%, 97%, 83% and 87% respectively). Automatically segmented tumor volumes showed high concordance with the manually segmented tumor volumes (R2 = 0.97). Inclusion of texture-based radiomics features minimally contributed to classifier performance. Accurate normal tissue segmentation and classification facilitates accurate identification of FDGavid tissues and classification of those tissues as either tumor or normal tissue.

Purpose Primary pancreatic carcinoma and pancreatic metastases are rare in the pediatric population. Pancreatoblastoma is the most common pancreatic malignant tumor in young children and solid-pseudopapillary tumor in teenagers. Pancreatic adenocarcinoma is extremely rare under the age of 40 and is usually associated with underlying genetic abnormalities. Secondary malignancies of the pancreas occur more frequently than primary pancreatic malignancies in children and are most commonly seen with non-Hodgkin lymphomas (NHL) and mesenchymal sarcomas. The purpose of this study was to characterize the metabolism of primary and secondary tumors of the pancreas in pediatric patients. Materials and methods A retrospective analysis of all primary and secondary pancreatic malignancies imaged with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) computed tomography (CT) was conducted. Results Three patients with primary pancreatic cancers were identified, one each with pancreatoblastoma, solid-pseudopapillary tumor, and adenocarcinoma. Each tumor showed elevated uptake of FDG. Metastatic disease in the pancreas was identified in 12 patients-five NHL (including three Burkitt lymphomas), six sarcomas (three osteosarcomas, two rhabdomyosarcomas, and one Ewing sarcoma family tumor), and one malignant rhabdoid tumor. Elevated but variable uptake of FDG was found in each of the tumors of patients with metastatic disease within the pancreas. Conclusion Both primary malignancies and metastatic disease within the pancreas, though very rare in children, adolescents, and young adults, are metabolically active and can be functionally characterized using FDG-PET CT.

The treatment of pediatric high-risk neuroblastoma is intensive and multimodal. Despite the introduction of immunotherapy for minimal residual disease, survival rates remain suboptimal and new therapies are needed. As part of a phase 2 trial, we are using a consolidation therapy regimen that combines a busulfan/melphalan conditioning schema, autologous hematopoietic cell transplantation (AHCT), and experimental immunotherapy with hu14.18K322A (a humanized anti-GD2 monoclonal antibody), granulocyte-macrophage colony–stimulating factor (GM-CSF), and IL-2, with or without the adoptive transfer of haploidentical natural killer cells (NKs). Here we report on 30 patients who have undergone AHCT with this experimental immunotherapy regimen, 21 of whom received haploidentical NKs. The median time to neutrophil engraftment was 13 days (range, 10 to 28 days) and to platelet engraftment of at least 20 × 103/mm3 was 36.5 days (range, 0 to 102 days); no clinical difference was seen in those who did or did not receive NKs. Eight patients developed veno-occlusive disease, with 3 having multiorgan dysfunction. Toxicities were similar for patients who did or did not receive NKs. We conclude that this consolidation regimen is feasible and has an acceptable acute toxicity profile.

SummaryRhabdomyosarcoma is a soft-tissue sarcoma with molecular and cellular features of developing skeletal muscle. Rhabdomyosarcoma has two major histologic subtypes, embryonal and alveolar, each with distinct clinical, molecular, and genetic features. Genomic analysis shows that embryonal tumors have more structural and copy number variations than alveolar tumors. Mutations in the RAS/NF1 pathway are significantly associated with intermediate- and high-risk embryonal rhabdomyosarcomas (ERMS). In contrast, alveolar rhabdomyosarcomas (ARMS) have fewer genetic lesions overall and no known recurrently mutated cancer consensus genes. To identify therapeutics for ERMS, we developed and characterized orthotopic xenografts of tumors that were sequenced in our study. High-throughput screening of primary cultures derived from those xenografts identified oxidative stress as a pathway of therapeutic relevance for ERMS.

Aim Dalotuzumab is a highly specific, humanised immunoglobulin G1 monoclonal antibody against insulin-like growth factor receptor 1. This multicenter phase 1 study (NCT01431547) explored the safety and pharmacokinetics of dalotuzumab monotherapy (part 1) and the combination of dalotuzumab with the mammalian target of rapamycin inhibitor ridaforolimus (part 2) in paediatric patients with advanced solid tumours. Methods Dalotuzumab was administered intravenously every 3 weeks starting at 900 mg/m 2 and escalating to 1200 and 1500 mg/m 2 . Combination therapy included intravenous dalotuzumab at the defined single-agent recommended phase 2 dose (RP2D) and oral ridaforolimus 28 mg/m 2 daily (days 1–5), repeated weekly. Pharmacokinetic studies were performed to evaluate the mean serum trough dalotuzumab concentration, which guided the RP2D. Results Twenty-four patients were enrolled (part 1, n = 20; part 2, n = 4). No dose-limiting toxicities were observed in patients receiving dalotuzumab alone. One patient experienced dose-limiting stomatitis in the combination arm. Pharmacokinetic data showed dose-dependent increases in exposure (area under the curve from zero to infinity [AUC 0–∞ ]) (87,900, 164,000, and 186,000 h*mg/ml for the 900, 1200, and 1500 mg/m 2 dose levels, respectively), maximum serum concentration (C max ) (392, 643, and 870 mg/ml), and serum trough concentration (C trough ) (67.1, 71.6, and 101 mg/ml). The mean half-life was 265, 394, and 310 h, respectively. Dalotuzumab pharmacokinetics were not affected by coadministration with ridaforolimus. One of six patients with Ewing sarcoma had confirmed partial response to dalotuzumab monotherapy at 900 mg/m 2 . Time to response was 41 d, and progression occurred at 126 d. Conclusion Dalotuzumab was well tolerated in paediatric patients with advanced solid malignancies. The RP2D of dalotuzumab is 900 mg/m 2 (ClinicalTrials.gov identifier: NCT01431547, Protocol PN062).

The most significant oncologic concern with finding new pulmonary nodules on imaging in a pediatric patient who has anaplastic Wilms tumor is progressive disease with new pulmonary metastases. This case emphasizes the importance of employing a creative clinical differential diagnosis, even for patients with known underlying oncologic disease.

In 1971 president Richard Nixon declared a war on cancer and announced his goal to cure cancer by 1976, the bicentennial year. Thirty nine years and more than 100 billion dollars later, the cumulative adult death rate from cancer adjusted for the size and age of the population has improved by less than 5% [1]. In comparison, the death rate for heart disease over this time period has improved by more than 64% [1]. In 2009, the NY Times published a series on the “war on cancer” specifically highlighting some of the suspected causes for these disappointing results. The primary aim of the series was to investigate and discuss the translational research efforts over the past several decades and to explore some of the strategic decisions made by funding agencies as it relates to basic science and clinical research in order to move new therapies into the clinic quickly and safely. There is no simple explanation for why the death rate due to cancer hasn’t improved more than 5% over the past 4 decades. However, the progress made in treating pediatric cancer over the same time period may shed some light on ways to improve our approach to translational research in coming years. Today, the overall cure rate for pediatric cancers approaches 80%; this is a 30% improvement since 1971. This is remarkable when we consider the rarity of pediatric cancer, the limited research funding and lack of investment by the pharmaceutical industry. Most of the progress in improving outcome for pediatric cancer has come from clinical research. Indeed, the majority (>90%) of pediatric cancer patients are enrolled on treatment protocols and there is now abundant evidence that research protocols have helped optimize treatment intensification, drug dosing and timing, chemotherapeutic drug combination, and the identification of prognostic features of disease in relation to treatment plans. In sharp contrast, only 3% of adult cancer patients are enrolled on research protocols [2]. These numbers suggest that the advances in patient outcome for pediatric cancer since the beginning of the war on cancer can be attributed in part to the coordinated participation in clinical research protocols.

e23212 Background: Desmoplastic small round cell tumor (DSRCT) is a rare but pernicious mesenchymal neoplasm that expresses the EWS-WT1 gene fusion transcript. It has similar histopathology to Ewing sarcoma (EWS). In previous work, we showed that addition of Poly (ADP-ribose) polymerase 1 and 2 inhibitors (PARPi) to the existing standard of care (SOC) therapy of irinotecan (IRN) and temozolomide (TMZ) was remarkably successful at treating mouse models of EWS, resulting in > 80% complete response compared to 100% mortality with SOC alone. EWS has high levels of the protein Schlafen-11 (SLFN11), a putative biomarker for defective DNA damage repair. The goal of this study is to determine whether DSCRT also expresses SLFN11, and whether high levels of the protein sensitize the tumor to PARPi as single-agent or in combination with other drugs and ionizing radiation. Methods: SLFN11 mRNA and protein levels were assessed by immunohistochemistry, quantitative PCR, Western blot, and immunofluorescence microscopy. Viability of the DSRCT cell line, JN-DSCRT-1, was measured using CellTiterGlo and the colony forming assay. Ionizing radiation (IR) was delivered using an orthovoltage irradiator calibrated to deliver graded doses of 0-16 Gy. Results: We found that SLFN11 was detected at high levels in several DSRCT patient tumor samples, and we confirmed that SLFN11 transcript and protein levels in JN-DSCRT-1were comparable to EWS cell lines. JN-DSCRT-1 demonstrated sensitivity to PARPi as single-agent or in combination with either the topoisomerase I inhibitor irinotecan or ionizing radiation comparable to EWS cell lines. To supplement our in vitro studies and to utilize more accurate models of the clinical disease, we developed orthotopic patient derived xenograft models (O-PDX) from three patients with DSCRT. Preliminary findings suggest that these O-PDX models maintain SLFN11 expression and recapitulate important aspects of DSRCT biology, including widespread dissemination of tumor in the abdominal cavity and characteristic cellular phenotype. Preclinical in vivo efficacy studies with PARPi combinations are in progress. Conclusions: Our work suggests that DSCRT expresses the SLFN11 biomarker and is sensitive to PARPi combination therapy.

10542 Background: Poly (ADP-ribose) Polymerase inhibitors (PARPi) target tumors with deficiencies in DNA repair mechanisms. Talazoparib (TAL), a potent PARP inhibitor, demonstrated significant efficacy in a Ewing sarcoma model when combined with DNA-damaging irinotecan (IRN). We performed a phase I trial to determine the maximum tolerated doses (MTDs) of TAL and IRN in pediatric patients with solid tumors. Methods: Cohorts of 3-6 eligible patients (pts) with recurrent/refractory solid tumors received escalating doses of oral (PO) TAL and intravenous (IV) IRN in a 3+3 design (Table 1). Each course was 21 days. Serum for TAL and IRN pharmacokinetics (PK) were obtained. Toxicities were assessed using CTCAE v.4 and responses were evaluated by RECIST v.1.1. Results: Twenty-four pts (9 male; median age, 11 years; 18 recurrent) received a median of 2 courses (range, 1-18). Fifteen pts had prior exposure to IRN. Table 1 summarizes the dose-limiting toxicities (DLTs) in course 1. The most common grade 3 or higher non-hematologic and hematologic toxicities in 82 evaluable courses were febrile neutropenia (5), elevated gamma-glutamyltransferase (GGT, 4), neutropenia (22) and lymphopenia (17). Two of 22 evaluable patients had a response (CR Ewing sarcoma, 18 courses; PR synovial sarcoma, 10 courses) and 9 had disease stabilization, median 4 courses (range, 4-10). Results of PK tests will be presented. Conclusions: The recommended phase II doses are TAL 600mcg/m2 (max 1000mcg/dose) days 1-6 and IRN 40mg/m2/day days 2-6. This regimen is feasible with evidence of anti-tumor activity and warrants further investigation. Clinical trial information: NCT02392793. [Table: see text]

10534 Background: We are conducting a Phase II trial of the anti-GD2 mAb hu14.18K322A given concomitantly with CT in newly diagnosed pts with HR NB. Our primary objective is to compare the response rate (RR; defined as ≥ PR) after two courses of CT with cyclophosphamide (CTX)/topotecan (TPT) and hu14.18K322A with GM-CSF and IL-2 to the RR reported by Park et al. (JCO 29:4351, 2011), using identical CT with GCSF only, in a two-stage group sequential design. Semiquantitative MIBG scoring (Curie; CS) has been shown to be a prognostic indicator of outcome in pts with HR NB (Yanik et al, J Nucl Med, 2013), particularly, those with CS > 2 at end of induction (EoI) CT have inferior outcomes. Here we update the RR and report the CS at EoI CT. Methods: Pts received induction CT (6 cycles) as described by Park et al, with the addition of hu14.18K332A (on d 2-5; 40mg/m2/d x 4d), daily sc GM-CSF and sc IL-2 (1 x 106 IU/m2/dose) qod x 6. 123I-MIBG scans and scoring (CS) were obtained on all pts at diagnosis, after second course of CT and at EoI. Results: 42 evaluable pts completed the first two courses of CT (24 male, median age 2.9 yrs (range 6 m -15.2 yrs), 36 INSS 4, 19 MYCNamplified); 40/42 evaluable pts had measurable reductions in primary tumor volume after two courses of CT (median 79%, average 69%, range +5 – 100%). Responses (≥ PR) after two courses were seen in 32/42 (76.2%; 95% CI 61.3 – 87.9%); No mAb dose-reductions were made but 20/43 (47%) pts had infusion times extended. The development of human anti-human antibody reactivity (HAHA) to hu14.18K322A in the first 22 pts is minimal. Of the 36 INSS 4 pts, 1 withdrew prior to EoI and 2 are too early. The median CS at diagnosis for the 33 stage 4 pts who have completed induction CT was 18 (range 1 – 28). At EoI the median CS was 0 (range 0 -23); 29/33 INSS 4 pts had EoI CS ≤ 2. Conclusions: The addition of hu14.18K322A to two courses of CTX/TPT significantly improves the RR compared to two courses of CTX/TPT alone (32/42 vs 12/30 as reported by Park et al,; P = 0.000004). The improved median CS of the stage 4 patients from 18 at diagnosis to 0 at EoI suggest the improvement in early RR may translate into improved EFS as well. Clinical trial information: NCT01857934.

10501Background: The chimeric anti-GD2 mAb dinutuximab improves EFS in HR NB when administered in the setting of minimal residual disease following intensive chemotherapy (CT) (Yu et al. NEJM 2010)...

10525Background: Older age at diagnosis is associated with poor outcome in neuroblastoma (NB). A recent study identified ATRX mutations in older patients with stage 4 NB (JAMA 307:1062, 2012). We p...

Background Preclinical models of pediatric cancers are essential for testing new chemotherapeutic combinations for clinical trials. The most widely used genetic model for preclinical testing of neuroblastoma is the TH-MYCN mouse. This neuroblastoma-prone mouse recapitulates many of the features of human neuroblastoma. Limitations of this model include the low frequency of bone marrow metastasis, the lack of information on whether the gene expression patterns in this system parallels human neuroblastomas, the relatively slow rate of tumor formation and variability in tumor penetrance on different genetic backgrounds. As an alternative, preclinical studies are frequently performed using human cell lines xenografted into immunocompromised mice, either as flank implant or orthtotopically. Drawbacks of this system include the use of cell lines that have been in culture for years, the inappropriate microenvironment of the flank or difficult, time consuming surgery for orthotopic transplants and the absence of an intact immune system. Principal Findings Here we characterize and optimize both systems to increase their utility for preclinical studies. We show that TH-MYCN mice develop tumors in the paraspinal ganglia, but not in the adrenal, with cellular and gene expression patterns similar to human NB. In addition, we present a new ultrasound guided, minimally invasive orthotopic xenograft method. This injection technique is rapid, provides accurate targeting of the injected cells and leads to efficient engraftment. We also demonstrate that tumors can be detected, monitored and quantified prior to visualization using ultrasound, MRI and bioluminescence. Finally we develop and test a “standard of care” chemotherapy regimen. This protocol, which is based on current treatments for neuroblastoma, provides a baseline for comparison of new therapeutic agents. Significance The studies suggest that use of both the TH-NMYC model of neuroblastoma and the orthotopic xenograft model provide the optimal combination for testing new chemotherapies for this devastating childhood cancer.