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BackgroundNeuroblastoma is the most common extra-cranial pediatric solid tumor. 131I-metaiodobenzylguanidine (MIBG) is a targeted radiopharmaceutical highly specific for neuroblastoma tumors, providing potent radiotherapy to widely metastatic disease. Aurora kinase A (AURKA) plays a role in mitosis and stabilization of the MYCN protein in neuroblastoma. We aimed to study the impact of AURKA inhibitors on DNA damage and tumor cell death in combination with 131I-MIBG therapy in a pre-clinical model of high-risk neuroblastoma.ResultsUsing an in vivo model of high-risk neuroblastoma, we demonstrated a marked combinatorial effect of 131I-MIBG and alisertib on tumor growth. In MYCN amplified cell lines, the combination of radiation and an AURKA A inhibitor increased DNA damage and apoptosis and decreased MYCN protein levels.ConclusionThe combination of AURKA inhibition with 131I-MIBG treatment is active in resistant neuroblastoma models.

PurposeWe sought to analyze biologic, clinical, and prognostic differences according to pattern of failure at the time of first relapse in neuroblastoma.Patients and methodsChildren

131I-metaiodobenzylguanidine (131I-mIBG) is a targeted radiation therapy developed for the treatment of advanced neuroblastoma. We have previously shown that this patient cohort can be used to predict absorbed dose associated with early 131I exposure, 72 h after treatment. We now expand these studies to identify gene expression differences associated with 131I-mIBG exposure 15 days after treatment. Total RNA from peripheral blood lymphocytes was isolated from 288 whole blood samples representing 59 relapsed or refractory neuroblastoma patients before and after 131I-mIBG treatment. We found that several transcripts predictive of early exposure returned to baseline levels by day 15, however, selected transcripts did not return to baseline. At 72 h, all 17 selected pathway-specific transcripts were differentially expressed. Transcripts CDKN1A (P < 0.000001), FDXR (P < 0.000001), DDB2 (P < 0.000001), and BBC3 (P < 0.000001) showed the highest up-regulation at 72 h after 131I-mIBG exposure, with mean log2 fold changes of 2.55, 2.93, 1.86 and 1.85, respectively. At day 15 after 131I-mIBG, 11 of the 17 selected transcripts were differentially expressed, with XPC, STAT5B, PRKDC, MDM2, POLH, IGF1R, and SGK1 displaying significant up-regulation at 72 h and significant down-regulation at day 15. Interestingly, transcripts FDXR (P = 0.01), DDB2 (P = 0.03), BCL2 (P = 0.003), and SESN1 (P < 0.0003) maintained differential expression 15 days after 131I-mIBG treatment. These results suggest that transcript levels for DNA repair, apoptosis, and ionizing radiation-induced cellular stress are still changing by 15 days after 131I-mIBG treatment. Our studies showcase the use of biodosimetry gene expression panels as predictive biomarkers following early (72 h) and late (15 days) internal 131I exposure. Our findings also demonstrate the utility of our transcript panel to differentiate exposed from non-exposed individuals up to 15 days after exposure from internal 131I.

PurposeThe primary aim of this phase III randomized trial was to test whether the addition of vincristine, topotecan, and cyclophosphamide (VTC) to interval compressed chemotherapy improved survival outcomes for patients with previously untreated nonmetastatic Ewing sarcoma.MethodsPatients were randomly assigned to receive standard five-drug interval compressed chemotherapy (regimen A) for 17 cycles or experimental therapy with five cycles of VTC within the 17 cycles (regimen B). Patients were stratified by age at diagnosis (< 18 years and ≥18 years) and tumor site (pelvic bone, nonpelvic bone, and extraosseous). Tumor volume at diagnosis was categorized as < 200 mL or ≥ 200 mL. Local control occurred following six cycles. Histologic response was categorized as no viable or any viable tumor. Event-free survival (EFS) and overall survival (OS) were compared between randomized groups with stratified log-rank tests.ResultsOf 642 enrolled patients, 309 eligible patients received standard and 320 received experimental therapy. The 5-year EFS and OS were 78% and 87%, respectively. There was no difference in survival outcomes between randomized groups (5-year EFS regimen A v regimen B, 78% v 79%; P = .192; 5-year OS 86% v 88%; P = .159). Age and primary site did not affect the risk of an EFS event. However, age ≥ 18 years was associated with an increased risk of death at 5 years (hazard ratio 1.84; 95% CI, 1.15 to 2.96; P = .009). The 5-year EFS rates for patients with pelvic, nonpelvic bone, and extraosseous primary tumors were 75%, 78%, and 85%, respectively. Tumor volume ≥ 200 mL was significantly associated with lower EFS.ConclusionWhile VTC added to five-drug interval compressed chemotherapy did not improve survival, these outcomes represent the best survival estimates to date for patients with previously untreated nonmetastatic Ewing sarcoma.

PurposeThe use of stereotactic body radiation therapy (SBRT) in pediatric patients has been underreported. We reviewed practice patterns, outcomes, and toxicity of SBRT in this population.Methods and materialsIn this multi-institutional study, 55 patients with 107 non-central nervous system lesions treated with SBRT between 2010 and 2016 were reviewed. Treatment response was evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 and modified RECIST v1.1 criteria for soft-tissue and bone lesions, respectively. Patterns of local failure (LF) were assessed dosimetrically. The cumulative incidence of LF and toxicity were estimated accounting for the competing risk event of death. Predictors of LF were identified through joint frailty models for clustered competing risks.ResultsThe median (range) dose/fraction was 7 (4.5-25) Gy, the total (range) dose/site was 35 (12-45), and the median (range) number of fractions was 5 (1-9). The radiographic response rates of bone and soft-tissue lesions were 90.6% and 76.7%, respectively. Symptom improvement was observed for 62% of symptomatic sites. A total of 27 LFs were documented, with 14 in-field, 9 marginal, and 4 out-of-field LFs. The 1-year estimated cumulative LF rate, progression-free survival, and overall survival were 25.2% (95% confidence interval [CI], 17.2%-36.1%), 17.5% (95% CI, 9.0%-34.1%), and 61% (95% CI, 48.9%-76.1%), respectively. Lesion type (soft tissue vs bone) was the only significant predictor of LF on multivariable analysis (P = .04), with increased hazard for soft-tissue lesions. No acute or late toxicity of grade 4 or higher was observed; the estimated 1-year cumulative incidence of late toxicity of any grade was 7.5% (95% CI, 3.6%-12.1%).ConclusionsThe SBRT was well tolerated and resulted in radiographic response and symptom palliation in most pediatric patients with advanced disease. The 1-year cumulative LF rate of 25% will serve as a benchmark for further modifications to radiation therapy indications, parameters, and combination therapy.

PurposeA primary objective of the Children's Oncology Group (COG) ANBL0532 phase III study was to assess the effect of increasing local dose of radiation to a residual primary tumor on the cumulative incidence of local progression (CILP) in patients with high-risk neuroblastoma.Patients and methodsNewly diagnosed patients with high-risk neuroblastoma were randomly assigned or assigned to receive single or tandem autologous stem-cell transplantation (SCT) after induction chemotherapy. Local control consisted of surgical resection during induction chemotherapy and radiotherapy after last SCT. Patients received 21.6 Gy to the preoperative primary tumor volume. For patients with incomplete surgical resection, an additional boost of 14.4 Gy was delivered to the gross residual tumor, for a total dose of 36 Gy. CILP (primary end point) and event-free (EFS) and overall survival (OS; secondary end points) were compared with the COG A3973 historical cohort, in which all patients received single SCT and 21.6 Gy without a boost.ResultsFor all patients in ANBL0532 receiving radiotherapy (n = 323), 5-year CILP, EFS, and OS rates were 11.2% ± 1.8%, 56.2% ± 3.4%, and 68.4% ± 3.2% compared with 7.1% ± 1.4% (P = .0590), 47.0% ± 3.5% (P = .0090), and 57.4% ± 3.5% (P = .0088) for all patients in A3973 receiving radiotherapy (n = 328), respectively. Five-year CILP, EFS, and OS rates for patients in A3973 with incomplete resection and radiotherapy (n = 47) were 10.6% ± 4.6%, 48.9% ± 10.1%, and 56.9% ± 10.0%, respectively. In comparison, 5-year CILP, EFS, and OS rates for patients in ANBL0532 who were randomly assigned or assigned to single SCT and received boost radiotherapy (n = 74) were 16.3% ± 4.3% (P = .4126), 50.9% ± 7.0% (P = .5084), and 68.1% ± 6.7% (P = .2835), respectively.ConclusionBoost radiotherapy to gross residual tumor present at the end of induction did not significantly improve 5-year CILP. These results highlight the need for new strategies to decrease the risk of locoregional failure.

PurposeTreatment failure from drug resistance is the primary reason for relapse in acute lymphoblastic leukemia (ALL). Improving outcomes by targeting mechanisms of drug resistance is a potential solution.Patients and methodsWe report results investigating the epigenetic modulators decitabine and vorinostat with vincristine, dexamethasone, mitoxantrone, and PEG-asparaginase for pediatric patients with relapsed or refractory B-cell ALL (B-ALL). Twenty-three patients, median age 12 years (range, 1-21) were treated in this trial.ResultsThe most common grade 3-4 toxicities included hypokalemia (65%), anemia (78%), febrile neutropenia (57%), hypophosphatemia (43%), leukopenia (61%), hyperbilirubinemia (39%), thrombocytopenia (87%), neutropenia (91%), and hypocalcemia (39%). Three subjects experienced dose-limiting toxicities, which included cholestasis, steatosis, and hyperbilirubinemia (n = 1); seizure, somnolence, and delirium (n = 1); and pneumonitis, hypoxia, and hyperbilirubinemia (n = 1). Infectious complications were common with 17 of 23 (74%) subjects experiencing grade ≥3 infections including invasive fungal infections in 35% (8/23). Nine subjects (39%) achieved a complete response (CR + CR without platelet recovery + CR without neutrophil recovery) and five had stable disease (22%). Nine (39%) subjects were not evaluable for response, primarily due to treatment-related toxicities. Correlative pharmacodynamics demonstrated potent in vivo modulation of epigenetic marks, and modulation of biologic pathways associated with functional antileukemic effects.ConclusionsDespite encouraging response rates and pharmacodynamics, the combination of decitabine and vorinostat on this intensive chemotherapy backbone was determined not feasible in B-ALL due to the high incidence of significant infectious toxicities. This study is registered at http://www.clinicaltrials.gov as NCT01483690.

BackgroundThe selective TRK inhibitor larotrectinib was approved for paediatric and adult patients with advanced TRK fusion-positive solid tumours based on a primary analysis set of 55 patients. The aim of our analysis was to explore the efficacy and long-term safety of larotrectinib in a larger population of patients with TRK fusion-positive solid tumours.MethodsPatients were enrolled and treated in a phase 1 adult, a phase 1/2 paediatric, or a phase 2 adolescent and adult trial. Some eligibility criteria differed between these studies. For this pooled analysis, eligible patients were aged 1 month or older, with a locally advanced or metastatic non-CNS primary, TRK fusion-positive solid tumour, who had received standard therapy previously if available. This analysis set includes the 55 patients on which approval of larotrectinib was based. Larotrectinib was administered orally (capsule or liquid formulation), on a continuous 28-day schedule, to adults mostly at a dose of 100 mg twice daily, and to paediatric patients mostly at a dose of 100 mg/m2 (maximum of 100 mg) twice daily. The primary endpoint was objective response as assessed by local investigators in an intention-to-treat analysis. Contributing trials are registered with ClinicalTrials.gov, NCT02122913 (active not recruiting), NCT02637687 (recruiting), and NCT02576431 (recruiting).FindingsBetween May 1, 2014, and Feb 19, 2019, 159 patients with TRK fusion-positive cancer were enrolled and treated with larotrectinib. Ages ranged from less than 1 month to 84 years. The proportion of patients with an objective response according to investigator assessment was 121 (79%, 95% CI 72-85) of 153 evaluable patients, with 24 (16%) having complete responses. In a safety population of 260 patients treated regardless of TRK fusion status, the most common grade 3 or 4 larotrectinib-related adverse events were increased alanine aminotransferase (eight [3%] of 260 patients), anaemia (six, 2%), and decreased neutrophil count (five [2%]). The most common larotrectinib-related serious adverse events were increased alanine aminotransferase (two [

BACKGROUND:MYCN amplification (MYCN-A) is an established adverse prognostic factor in neuroblastoma. The extent to which the prognostic impact of MYCN-A depends on other factors has not been fully characterized. PATIENTS AND METHODS:Using the International Neuroblastoma Risk Group database, we constructed Cox models of overall survival (OS) to obtain hazard ratios of the effect of MYCN-A within subgroups defined by other prognostic factors. Cox models assessed the degree to which the prognostic impact of MYCN-A was modulated by each other covariate. We used absolute hazard ratio (HR) differences to construct classification trees to identify subgroups with greatest differential prognostic effect of MYCN-A. RESULTS:In a cohort of 6223 patients with known MYCN status, the OS hazard ratio associated with MYCN-A was 6.3 (95% confidence interval 5.7-7.0, P

The authors have noticed that the final paragraph of the Results section contains errors in the number of patients involved. The correct number of patients is included in the text below. These errors do not affect the Figure referenced.In osteosarcoma, we focused on 8q gain as a specific biological feature of interest. Among the 41 patients with detectable ctDNA in the osteosarcoma cohort, 8q gain was detected in 73.2% (30/41). The 3-year EFS for patients with 8q gain (n = 30) in ctDNA was 60.0% (95% CI 40.5-75.0) compared to 80.8 (95% CI 42.4-94.9) in patients without 8q gain (n = 11) in ctDNA (p = 0.18; Fig. 3).

Osteosarcoma is a highly aggressive cancer for which treatment has remained essentially unchanged for more than 30 years. Osteosarcoma is characterized by widespread and recurrent somatic copy-number alterations (SCNA) and structural rearrangements. In contrast, few recurrent point mutations in protein-coding genes have been identified, suggesting that genes within SCNAs are key oncogenic drivers in this disease. SCNAs and structural rearrangements are highly heterogeneous across osteosarcoma cases, suggesting the need for a genome-informed approach to targeted therapy. To identify patient-specific candidate drivers, we used a simple heuristic based on degree and rank order of copy-number amplification (identified by whole-genome sequencing) and changes in gene expression as identified by RNA sequencing. Using patient-derived tumor xenografts, we demonstrate that targeting of patient-specific SCNAs leads to significant decrease in tumor burden, providing a road map for genome-informed treatment of osteosarcoma. SIGNIFICANCE: Osteosarcoma is treated with a chemotherapy regimen established 30 years ago. Although osteosarcoma is genomically complex, we hypothesized that tumor-specific dependencies could be identified within SCNAs. Using patient-derived tumor xenografts, we found a high degree of response for "genome-matched" therapies, demonstrating the utility of a targeted genome-informed approach.This article is highlighted in the In This Issue feature, p. 1.

PurposeIn phase I testing, alisertib tablets with irinotecan and temozolomide showed significant antitumor activity in patients with neuroblastoma. This study sought to confirm activity of this regimen; evaluate an alisertib oral solution; and evaluate biomarkers of clinical outcomes.Patients and methodsWe conducted a two-stage phase II trial of alisertib tablets (60 mg/m2/dose × 7 days), irinotecan (50 mg/m2/dose i.v. × 5 days), and temozolomide (100 mg/m2/dose orally × 5 days) in patients with relapsed or refractory neuroblastoma. The primary endpoint was best objective response. A separate cohort was treated with alisertib at 45 mg/m2 using oral solution instead of tablets. Exploratory analyses sought to identify predictors of toxicity, response, and progression-free survival (PFS) using pooled data from phase I, phase II, and oral solution cohorts.ResultsTwenty and 12 eligible patients were treated in the phase II and oral solution cohorts, respectively. Hematologic toxicities were the most common adverse events. In phase II, partial responses were observed in 19 evaluable patients (21%). The estimated PFS at 1 year was 34%. In the oral solution cohort, 3 patients (25%) had first cycle dose-limiting toxicity (DLT). Alisertib oral solution at 45 mg/m2 had significantly higher median C max and exposure compared with tablets at 60 mg/m2. Higher alisertib trough concentration was associated with first cycle DLT, whereas MYCN amplification was associated with inferior PFS.ConclusionsThis combination shows antitumor activity, particularly in patients with MYCN nonamplified tumors. Data on an alisertib oral solution expand the population able to be treated with this agent.

Background Children living in poverty and those of marginalized race or ethnicity experience inferior disease outcomes across many cancers. Whether survival disparities exist in osteosarcoma is poorly defined. We investigated the association between race, ethnicity, and proxied poverty exposures and event-free and overall survival for children with nonmetastatic osteosarcoma receiving care on a cooperative group trial. Methods We conducted a retrospective cohort study of US patients with nonmetastatic, osteosarcoma aged 5-21 years enrolled on the Children's Oncology Group trial AOST0331. Race and ethnicity were categorized to reflect historically marginalized populations, as Hispanic, non-Hispanic Black, non-Hispanic Other, and non-Hispanic White. Poverty was proxied at the household and neighborhood levels. Overall survival and event-free survival functions of time from trial enrollment were estimated using the Kaplan–Meier method. Hypotheses of associations between risks for event-free survival, death, and postrelapse death with race and ethnicity were assessed using log-rank tests. Results Among 758 patients, 25.6% were household-poverty and 28.5% neighborhood-poverty exposed. Of the patients, 21% of children identified as Hispanic, 15.4% non-Hispanic Black, 5.3% non-Hispanic Other, and 54.0% non-Hispanic White. Neither household or neighborhood poverty nor race and ethnicity were statistically significantly associated with risks for event-free survival or death. Postrelapse risk for death differed statistically significantly across race and ethnicity with non-Hispanic Black patients at greatest risk (4-year postrelapse survival 35.7% Hispanic vs 13.0% non-Hispanic Black vs 43.8% non-Hispanic Other vs 38.9% non-Hispanic White; P  = .0046). Conclusions Neither proxied poverty exposures or race and ethnicity were associated with event-free survival or overall survival, suggesting equitable outcomes following frontline osteosarcoma trial-delivered therapy. Non-Hispanic Black children experienced statistically significant inferior postrelapse survival. Investigation of mechanisms underlying postrelapse disparities are paramount. [ABSTRACT FROM AUTHOR]

* Context.--Molecular diagnostics play an increasing role in the diagnosis of Ewing sarcoma. The type of molecular testing used in clinical practice has been poorly described. Objective.--To describe patterns of translocation testing for newly diagnosed Ewing sarcoma. Design.--Children's Oncology Group (COG) trial AEWS1221 was a phase III randomized trial enrolling patients with newly diagnosed metastatic Ewing sarcoma from 2014 to 2019. Patients were required to have a histologic diagnosis of Ewing sarcoma, but translocation testing was not required. Sites provided types and results of any molecular diagnostics performed. Results.--Data from 305 enrolled patients were available. The most common type of molecular testing was fluorescence in situ hybridization (FISH) performed on the primary tumor (236 of 305 patients; 77.4%), with positive testing for an EWSR1 or FUS translocation in 211 (89.4%). Reverse transcription-polymerase chain reaction (RT-PCR) on the primary tumor was performed in 61 of 305 patients (20%), with positive results in 48 of 61 patients (78.7%). Next-generation sequencing was reported in 7 patients for the primary tumor and in 3 patients for metastatic sites. For all types of testing on either primary or metastatic tumor, 16 of 305 patients (5.2%) had no reported translocation testing. When evaluating all results from all testing, 44 of 305 patients (14.4%) lacked documentation of an abnormality consistent with a molecular diagnosis of Ewing sarcoma. Conclusions.--COG sites enrolling in a Ewing sarcoma trial have high rates of testing by FISH or PCR. A small proportion of patients have no translocation testing on either primary or metastatic sites. Next-generation sequencing techniques are not yet commonly used in this context., Ewing sarcoma is a translocation-associated sarcoma mainly affecting children, adolescents, and young adults. The most common translocation is EWSR1/FLI1, although any translocation of EWSR1 or FUS with a member of [...]

BackgroundThe highly selective oral tropomyosin receptor kinase (TRK) inhibitor larotrectinib has demonstrated significant activity in adult and pediatric TRK fusion cancers. In the current study, the authors describe the clinical course of children with locally advanced TRK fusion sarcoma who were treated preoperatively with larotrectinib and underwent subsequent surgical resection.MethodsA total of 24 children were treated on a pediatric phase 1 trial of larotrectinib (ClinicalTrials.gov identifier NCT02637687). Five children who had a documented TRK fusion sarcoma and underwent surgical resection were included in the current analysis. Tumor response (Response Evaluation Criteria In Solid Tumors [RECIST] version 1.1) and surgical outcomes were collected prospectively.ResultsA total of 5 patients (median age, 2 years; range, 0.4-12 years) had locally advanced infantile fibrosarcoma (3 patients) or soft-tissue sarcoma (2 patients). Four patients had disease that was refractory to standard therapy. All 5 patients achieved a partial response to larotrectinib by version 1.1 of RECIST and underwent surgical resection after a median of 6 cycles (range, 4-9 cycles) of treatment. Surgical resections were R0 (negative resection margins with no tumor at the inked resection margin) in 3 patients, R1 (microscopic residual tumor at the resection margin) in 1 patient, and R2 (macroscopic residual tumor at the resection margin) in 1 patient. Three patients achieved complete (2 patients) or near-complete (>98% treatment effect; 1 patient) pathologic responses. These patients remained in follow-up and were no longer receiving larotrectinib for a minimum of 7 to 15 months postoperatively. Two patients had viable tumor at the time of surgical resection and positive resection margins and continued to receive adjuvant larotrectinib. No patients experienced postoperative complications or wound healing issues.ConclusionsChildren with locally advanced TRK fusion sarcomas may proceed to surgical resection after treatment with the selective TRK inhibitor larotrectinib, thereby sparing them the potentially significant morbidity noted with current approaches. These results support the evaluation of larotrectinib as presurgical therapy in children with newly diagnosed TRK fusion sarcomas.

BackgroundNew prognostic markers are needed to identify patients with Ewing sarcoma (EWS) and osteosarcoma unlikely to benefit from standard therapy. We describe the incidence and association with outcome of circulating tumour DNA (ctDNA) using next-generation sequencing (NGS) assays.MethodsA NGS hybrid capture assay and an ultra-low-pass whole-genome sequencing assay were used to detect ctDNA in banked plasma from patients with EWS and osteosarcoma, respectively. Patients were coded as positive or negative for ctDNA and tested for association with clinical features and outcome.ResultsThe analytic cohort included 94 patients with EWS (82% from initial diagnosis) and 72 patients with primary localised osteosarcoma (100% from initial diagnosis). ctDNA was detectable in 53% and 57% of newly diagnosed patients with EWS and osteosarcoma, respectively. Among patients with newly diagnosed localised EWS, detectable ctDNA was associated with inferior 3-year event-free survival (48.6% vs. 82.1%; p = 0.006) and overall survival (79.8% vs. 92.6%; p = 0.01). In both EWS and osteosarcoma, risk of event and death increased with ctDNA levels.ConclusionsNGS assays agnostic of primary tumour sequencing results detect ctDNA in half of the plasma samples from patients with newly diagnosed EWS and osteosarcoma. Detectable ctDNA is associated with inferior outcomes.

Aberrant chromatin remodeling and activation of the PI3K pathway have been identified as important mediators of pediatric high-grade glioma (pHGG) and diffuse intrinsic pontine glioma (DIPG) pathogenesis. As inhibition of these pathways are promising therapeutic avenues and radiation is the only modality to prolong survival of patients with DIPG, we sought to explore radiosensitizing functions of such inhibition and to explore mechanisms of action of such agents. Here, we demonstrate that combined treatment with radiotherapy and CUDC-907, a novel first-in-class dual inhibitor of histone deacetylases (HDAC) and PI3K, evokes a potent cytotoxic response in pHGG and DIPG models. CUDC-907 modulated DNA damage response by inhibiting radiation-induced DNA repair pathways including homologous recombination and nonhomologous end joining. The radiosensitizing effects of CUDC-907 were mediated by decreased NFκB/Forkhead box M1 (FOXM1) recruitment to promoters of genes involved in the DNA damage response; exogenous expression of NFκB/FOXM1 protected from CUDC-907-induced cytotoxicity. Together, these findings reveal CUDC-907 as a novel radiosensitizer with potent antitumor activity in pHGG and DIPG and provide a preclinical rationale for the combination of CUDC-907 with radiotherapy as a novel therapeutic strategy against pHGG and DIPG. More globally, we have identified NFκB and FOXM1 and their downstream transcriptional elements as critical targets for new treatments for pHGG and DIPG.Significance: These findings describe the radiosensitizing effect of a novel agent in pediatric high-grade gliomas, addressing a critical unmet need of increasing the radiation sensitivity of these highly aggressive tumors. Cancer Res; 78(14); 4007-21. ©2018 AACR.

BackgroundGene fusions involving NTRK1, NTRK2, or NTRK3 (TRK fusions) are found in a broad range of paediatric and adult malignancies. Larotrectinib, a highly selective small-molecule inhibitor of the TRK kinases, had shown activity in preclinical models and in adults with tumours harbouring TRK fusions. This study aimed to assess the safety of larotrectinib in paediatric patients.MethodsThis multicentre, open-label, phase 1/2 study was done at eight sites in the USA and enrolled infants, children, and adolescents aged 1 month to 21 years with locally advanced or metastatic solid tumours or CNS tumours that had relapsed, progressed, or were non-responsive to available therapies regardless of TRK fusion status; had a Karnofsky (≥16 years of age) or Lansky (

BackgroundFusions involving one of three tropomyosin receptor kinases (TRK) occur in diverse cancers in children and adults. We evaluated the efficacy and safety of larotrectinib, a highly selective TRK inhibitor, in adults and children who had tumors with these fusions.MethodsWe enrolled patients with consecutively and prospectively identified TRK fusion-positive cancers, detected by molecular profiling as routinely performed at each site, into one of three protocols: a phase 1 study involving adults, a phase 1-2 study involving children, or a phase 2 study involving adolescents and adults. The primary end point for the combined analysis was the overall response rate according to independent review. Secondary end points included duration of response, progression-free survival, and safety.ResultsA total of 55 patients, ranging in age from 4 months to 76 years, were enrolled and treated. Patients had 17 unique TRK fusion-positive tumor types. The overall response rate was 75% (95% confidence interval [CI], 61 to 85) according to independent review and 80% (95% CI, 67 to 90) according to investigator assessment. At 1 year, 71% of the responses were ongoing and 55% of the patients remained progression-free. The median duration of response and progression-free survival had not been reached. At a median follow-up of 9.4 months, 86% of the patients with a response (38 of 44 patients) were continuing treatment or had undergone surgery that was intended to be curative. Adverse events were predominantly of grade 1, and no adverse event of grade 3 or 4 that was considered by the investigators to be related to larotrectinib occurred in more than 5% of patients. No patient discontinued larotrectinib owing to drug-related adverse events.ConclusionsLarotrectinib had marked and durable antitumor activity in patients with TRK fusion-positive cancer, regardless of the age of the patient or of the tumor type. (Funded by Loxo Oncology and others; ClinicalTrials.gov numbers, NCT02122913 , NCT02637687 , and NCT02576431 .).

PurposeTo identify clinical and treatment variables associated with a higher risk of local failure in Ewing sarcoma patients treated on recent Children's Oncology Group protocols.Methods and materialsData for 956 patients treated with ifosfamide and etoposide-based chemotherapy on INT-0091, INT-0154, and AEWS0031 were analyzed. Local treatment modalities were defined as surgery, definitive radiation therapy (RT), or surgery plus radiation (S+RT). Five-year cumulative incidence of local failure was determined.ResultsThe local failure rate for the entire cohort was 7.3%, with a 3.9% rate for surgery, 15.3% for RT (P

PurposeTo determine the maximum tolerated dose (MTD), toxicities, and pharmacodynamics effects of sirolimus combined with oral metronomic topotecan and cyclophosphamide in a pediatric population.Materials and methodsPatients who were 1 to 30 years of age with relapsed/refractory solid tumors (including CNS) were eligible. Patients received daily oral sirolimus and cyclophosphamide (25-50 mg/m2/dose) on days 1-21 and oral topotecan (0.8 mg/m2/dose) on days 1-14 in 28-day cycles. Sirolimus steady-state plasma trough concentrations of 3-7.9 ng/mL and 8-12.0 ng/mL were evaluated, with dose escalation based on a 3+3 phase 1 design. Biomarkers of angiogenesis were also evaluated.ResultsTwenty-one patients were treated (median age 18 years; range 9-30). Dose-limiting toxicities included myelosuppression, ALT elevation, stomatitis, and hypertriglyceridemia. The MTD was sirolimus with trough goal of 8-12.0 ng/mL; cyclophosphamide 25 mg/m2/dose; and topotecan 0.8 mg/m2/dose. No objective responses were observed. Four patients had prolonged stable disease > 4 cycles (range 4-12). Correlative biomarker analyses demonstrated reductions in thrombospondin-1 (p=0.043) and soluble vascular endothelial growth factor receptor-2 plasma concentrations at 21 days compared to baseline.ConclusionsThe combination of oral sirolimus, topotecan, and cyclophosphamide was well tolerated and biomarker studies demonstrated modulation of angiogenic pathways with this regimen.

Purpose: Second malignant neoplasms (SMNs) are severe late complications that occur in pediatric cancer survivors exposed to radiotherapy and other genotoxic treatments. To characterize the mutational landscape of treatment-induced sarcomas and to identify candidate SMN-predisposing variants, we analyzed germline and SMN samples from pediatric cancer survivors.Experimental Design: We performed whole-exome sequencing (WES) and RNA sequencing on radiation-induced sarcomas arising from two pediatric cancer survivors. To assess the frequency of germline TP53 variants in SMNs, Sanger sequencing was performed to analyze germline TP53 in 37 pediatric cancer survivors from the Childhood Cancer Survivor Study (CCSS) without any history of a familial cancer predisposition syndrome but known to have developed SMNs.Results: WES revealed TP53 mutations involving p53's DNA-binding domain in both index cases, one of which was also present in the germline. The germline and somatic TP53-mutant variants were enriched in the transcriptomes for both sarcomas. Analysis of TP53-coding exons in germline specimens from the CCSS survivor cohort identified a G215C variant encoding an R72P amino acid substitution in 6 patients and a synonymous SNP A639G in 4 others, resulting in 10 of 37 evaluable patients (27%) harboring a germline TP53 variant.Conclusions: Currently, germline TP53 is not routinely assessed in patients with pediatric cancer. These data support the concept that identifying germline TP53 variants at the time a primary cancer is diagnosed may identify patients at high risk for SMN development, who could benefit from modified therapeutic strategies and/or intensive posttreatment monitoring. Clin Cancer Res; 23(7); 1852-61. ©2016 AACR.

Ewing sarcoma (ES) is a malignant tumor of bone and soft tissue that most often occurs in children, adolescents, and young adults. Debate and controversy remain in the management of relapsed/refractory ES (RR‐ES). The authors leveraged the expertise assembled by the National Ewing Sarcoma Tumor Board, a multidisciplinary virtual tumor board that meets monthly to discuss challenging cases of ES. In this review, they focus on select topics that apply to the management of patients with RR‐ES. The specific topics covered include the initial approach of such patients and discussion of the goals of care, the role of molecular testing, chemotherapy regimens and novel agents to consider, the role of maintenance therapy, and the use of high‐dose chemotherapy with autologous stem cell rescue. The data referenced are often limited to subgroup analyses and/or compiled from multiple sources. Although not intended to replace the clinical judgement of treating physicians, these guidelines are intended to support clinicians and provide some clarity and recommendations for the management of patients with RR‐ES. Plain Language Summary: Ewing sarcoma (ES) is a bone and soft tissue cancer that most often occurs in teenagers and young adults.This article uses the experience of the National Ewing Sarcoma Tumor Board, a multi‐institution, multidisciplinary virtual tumor board that meets monthly to discuss challenging cases of ES and to address questions related to the treatment of patients with relapsed ES.Although not intended to replace the clinical judgement of treating physicians and limited by available data, these consensus recommendations will support clinicians who treat patients with this challenging malignancy, made even more difficult when it recurs. Debates remain in defining the standard of care for treating patients with relapsed Ewing sarcoma. This set of consensus recommendations from the National Ewing Sarcoma Tumor Board are intended to provide some clarity and recommendations for the management of patients with recurrent disease. [ABSTRACT FROM AUTHOR]

Sarcomas are a heterogeneous group of mesenchymal malignancies. In recent years, studies have demonstrated that inhibition of angiogenic pathways or disruption of established vasculature can attenuate the growth of sarcomas. However, when used as monotherapy in the clinical setting, these targeted antiangiogenic agents have only provided modest survival benefits in some sarcoma subtypes, and have not been efficacious in others. Preclinical and early clinical data suggest that the addition of conventional chemotherapy to antiangiogenic agents may lead to more effective therapies for patients with these tumors. In the current review, the authors summarize the available evidence and possible mechanisms supporting this approach.

Several reports of second malignant neoplasm (SMN) in patients with relapsed neuroblastoma after treatment with (131)I-MIBG suggest the possibility of increased risk. Incidence of and risk factors for SMN after (131)I-MIBG have not been defined. This is a multi-institutional retrospective review of patients with neuroblastoma treated with (131)I-MIBG therapy. A competing risk approach was used to calculate the cumulative incidence of SMN from time of first exposure to (131)I-MIBG. A competing risk regression was used to identify potential risk factors for SMN. The analytical cohort included 644 patients treated with (131)I-MIBG. The cumulative incidence of SMN was 7.6% (95% confidence interval [CI], 4.4-13.0%) and 14.3% (95% CI, 8.3-23.9%) at 5 and 10 years from first (131)I-MIBG, respectively. No increase in SMN risk was found with increased number of (131)I-MIBG treatments or higher cumulative activity per kilogram of (131)I-MIBG received (p = 0.72 and p = 0.84, respectively). Thirteen of the 19 reported SMN were haematologic. In a multivariate analysis controlling for variables with p

Calculating internal dose from therapeutic radionuclides currently relies on estimates made from multiple radiation exposure measurements, converted to absorbed dose in specific organs using the Medical Internal Radiation Dose (MIRD) schema. As an alternative biodosimetric approach, we utilized gene expression analysis of whole blood from patients receiving targeted radiotherapy. Collected blood from patients with relapsed or refractory neuroblastoma who received (131)I-labeled metaiodobenzylguanidine ((131)I-mIBG) at the University of California San Francisco (UCSF) was used to compare calculated internal dose with the modulation of chosen gene expression. A total of 40 patients, median age 9 years, had blood drawn at baseline, 72 and 96 h after (131)I-mIBG infusion. Whole-body absorbed dose was calculated for each patient based on the cumulated activity determined from injected mIBG activity and patient-specific time-activity curves combined with (131)I whole-body S factors. We then assessed transcripts that were the most significant for describing the mixed therapeutic treatments over time using real-time polymerase chain reaction (RT-PCR). Modulation was evaluated statistically using multiple regression analysis for data at 0, 72 and 96 h. A total of 10 genes were analyzed across 40 patients: CDKN1A; FDXR; GADD45A; BCLXL; STAT5B; BAX; BCL2; DDB2; XPC; and MDM2. Six genes were significantly modulated upon exposure to (131)I-mIBG at 72 h, as well as at 96 h. Four genes varied significantly with absorbed dose when controlling for time. A gene expression biodosimetry model was developed to predict absorbed dose based on modulation of gene transcripts within whole blood. Three transcripts explained over 98% of the variance in the modulation of gene expression over the 96 h (CDKN1A, BAX and DDB2). To our knowledge, this is a novel study, which uses whole blood collected from patients treated with a radiopharmaceutical, to characterize biomarkers that may be useful for biodosimetry. Our data indicate that transcripts, which have been previously identified as biomarkers of external exposures in ex vivo whole blood and in vivo radiotherapy patients, are also good early indicators of internal exposure. However, for internal sources of radiation, the biokinetics and physical decay of the radionuclide strongly influence the gene expression.

PurposeFlow cytometry and RT-PCR can detect occult Ewing sarcoma cells in the blood and bone marrow. These techniques were used to evaluate the prognostic significance of micrometastatic disease in Ewing sarcoma.Experimental designNewly diagnosed patients with Ewing sarcoma were enrolled on two prospective multicenter studies. In the flow cytometry cohort, patients were defined as "positive" for bone marrow micrometastatic disease if their CD99(+)/CD45(-) values were above the upper limit in 22 control patients. In the PCR cohort, RT-PCR on blood or bone marrow samples classified the patients as "positive" or "negative" for EWSR1/FLI1 translocations. The association between micrometastatic disease burden with clinical features and outcome was assessed. Coexpression of insulin-like growth factor-1 receptor (IGF-1R) on detected tumor cells was performed in a subset of flow cytometry samples.ResultsThe median total bone marrow CD99(+)CD45(-) percent was 0.0012% (range 0%-1.10%) in the flow cytometry cohort, with 14 of 109 (12.8%) of Ewing sarcoma patients defined as "positive." In the PCR cohort, 19.6% (44/225) patients were "positive" for any EWSR1/FLI1 translocation in blood or bone marrow. There were no differences in baseline clinical features or event-free or overall survival between patients classified as "positive" versus "negative" by either method. CD99(+)CD45(-) cells had significantly higher IGF-1R expression compared with CD45(+) hematopoietic cells (mean geometric mean fluorescence intensity 982.7 vs. 190.9; P < 0.001).ConclusionsThe detection of micrometastatic disease at initial diagnosis by flow cytometry or RT-PCR is not associated with outcome in newly diagnosed patients with Ewing sarcoma. Flow cytometry provides a tool to characterize occult micrometastatic tumor cells for proteins of interest. Clin Cancer Res; 22(14); 3643-50. ©2016 AACR.

Sarcomas are a rare subgroup of pediatric cancers comprised of a variety of bone and soft-tissue tumors. While significant advances have been made in improving outcomes of patients with localized pediatric sarcomas since the addition of systemic chemotherapy to local control many decades ago, outcomes for patients with metastatic and relapsed sarcoma remain poor with few novel therapeutics identified to date. With the advent of new technologies to study cancer genomes, transcriptomes and epigenomes, our understanding of sarcoma biology has improved tremendously in a relatively short period of time. However, much remains to be accomplished in this arena especially with regard to translating all of this new knowledge to the bedside. To this end, a meeting was convened in Philadelphia, PA, on April 18, 2015 sponsored by the QuadW foundation, Children's Oncology Group and CureSearch for Children's Cancer that brought together sarcoma clinicians and scientists from North America to review the current state of pediatric sarcoma biology and ongoing/planned genomics based clinical trials in an effort to identify and bridge knowledge gaps that continue to exist at present. At the conclusion of the workshop, three key objectives that would significantly further our understanding of sarcoma were identified and a proposal was put forward to develop an all-encompassing pediatric sarcoma biology protocol that would address these specific needs. This review summarizes the proceedings of the workshop.

PurposeAlisertib is an oral Aurora A kinase inhibitor with preclinical activity in neuroblastoma. Irinotecan and temozolomide have activity in patients with advanced neuroblastoma. The goal of this phase I study was to determine the maximum tolerated dose (MTD) of alisertib with irinotecan and temozolomide in this population.Patients and methodsPatients age 1 to 30 years with relapsed or refractory neuroblastoma were eligible. Patients received alisertib tablets at dose levels of 45, 60, and 80 mg/m(2) per day on days 1 to 7 along with irinotecan 50 mg/m(2) intravenously and temozolomide 100 mg/m(2) orally on days 1 to 5. Dose escalation of alisertib followed the rolling six design. Samples for pharmacokinetic and pharmacogenomic testing were obtained.ResultsTwenty-three patients enrolled, and 22 were eligible and evaluable for dose escalation. A total of 244 courses were administered. The MTD for alisertib was 60 mg/m(2), with mandatory myeloid growth factor support and cephalosporin prophylaxis for diarrhea. Thrombocytopenia and neutropenia of any grade were seen in the majority of courses (84% and 69%, respectively). Diarrhea in 55% of courses and nausea in 54% of courses were the most common nonhematologic toxicities. The overall response rate was 31.8%, with a 50% response rate observed at the MTD. The median number of courses per patient was eight (range, two to 32). Progression-free survival rate at 2 years was 52.4%. Pharmacokinetic testing did not show evidence of drug-drug interaction between irinotecan and alisertib.ConclusionAlisertib 60 mg/m(2) per dose for 7 days is tolerable with a standard irinotecan and temozolomide backbone and has promising response and progression-free survival rates. A phase II trial of this regimen is ongoing.