Search

PURPOSE In 2006, Children's Oncology Group (COG) reclassified subgroups of toddlers diagnosed with neuroblastoma from high-risk to intermediate-risk, when the age cutoff for high-risk assignment was raised from 365 days (12 months) to 547 days (18 months). The primary aim of this retrospective study was to determine if excellent outcome was maintained after assigned reduction of therapy. PATIENTS AND METHODS Children RESULTS For 12-18mo/Stage4/FavBiology, 5-year EFS/OS (± SE) before (≤2006; n = 40) versus after (>2006; n = 55) assigned reduction in therapy was similar: 89% ± 5.1%/89% ± 5.1% versus 87% ± 4.6%/94% ± 3.2% ( P = .7; P = .4, respectively). For 12-18mo/Stage3/ MYCN-NA/Unfav, the 5-year EFS and OS were both 100%, before (n = 6) and after (n = 4) 2006. The 12-18mo/Stage4/FavBiology plus 12-18mo/Stage3/ MYCN-NA/Unfav classified as high-risk ≤2006 had an EFS/OS of 91% ± 4.4%/91% ± 4.5% versus 38% ± 1.3%/43% ± 1.3% for all other high-risk patients 2006 had an EFS/OS of 88% ± 4.3%/95% ± 2.9% versus 88% ± 0.9%/95% ± 0.6% for all other intermediate-risk patients CONCLUSION Excellent outcome was maintained among subsets of toddlers with neuroblastoma assigned to reduced treatment after reclassification of risk group from high to intermediate on the basis of new age cutoffs. Importantly, as documented in prior trials, intermediate-risk therapy is not associated with the degree of acute toxicity and late effects commonly observed with high-risk regimens.

PURPOSE The combination of irinotecan, temozolomide, dintuximab, and granulocyte-macrophage colony-stimulating factor (I/T/DIN/GM-CSF) demonstrated activity in patients with relapsed/refractory neuroblastoma in the randomized Children’s Oncology Group ANBL1221 trial. To more accurately assess response rate and toxicity, an expanded cohort was nonrandomly assigned to I/T/DIN/GM-CSF. PATIENTS AND METHODS Patients were eligible at first relapse or first designation of refractory disease. Oral T and intravenous (IV) irinotecan were administered on days 1 to 5 of 21-day cycles. DIN was administered IV (days 2-5), and GM-CSF was administered subcutaneously (days 6-12). The primary end point was objective response, analyzed on an intent-to-treat basis per the International Neuroblastoma Response Criteria. RESULTS Seventeen eligible patients were randomly assigned to I/T/DIN/GM-CSF (February 2013 to March 2015); 36 additional patients were nonrandomly assigned to I/T/DIN/GM-CSF (August 2016 to May 2017). Objective (complete or partial) responses were observed in nine (52.9%) of 17 randomly assigned patients (95% CI, 29.2% to 76.7%) and 13 (36.1%) of 36 expansion patients (95% CI, 20.4% to 51.8%). Objective responses were seen in 22 (41.5%) of 53 patients overall (95% CI, 28.2% to 54.8%); stable disease was also observed in 22 of 53. One-year progression-free and overall survival for all patients receiving I/T/DIN/GM-CSF were 67.9% ± 6.4% (95% CI, 55.4% to 80.5%) and 84.9% ± 4.9% (95% CI, 75.3% to 94.6%), respectively. Two patients did not receive protocol therapy and were evaluable for response but not toxicity. Common grade ≥ 3 toxicities were fever/infection (18 [35.3%] of 51), neutropenia (17 [33.3%] of 51), pain (15 [29.4%] of 51), and diarrhea (10 [19.6%] of 51). One patient met protocol-defined criteria for unacceptable toxicity (grade 4 hypoxia). Higher DIN trough levels were associated with response. CONCLUSION I/T/DIN/GM-CSF has significant antitumor activity in patients with relapsed/refractory neuroblastoma. Study of chemoimmunotherapy in the frontline setting is indicated, as is further evaluation of predictive biomarkers.

PURPOSE The primary objective of the Children’s Oncology Group study ANBL0531 (ClinicalTrials.gov identifier: NCT00499616 ) was to reduce therapy for subsets of patients with intermediate-risk neuroblastoma using a biology- and response-based algorithm to assign treatment duration while maintaining a 3-year overall survival (OS) of 95% or more for the entire cohort. PATIENTS AND METHODS Children younger than age 12 years with intermediate-risk stage 2A/2B or stage 3 tumors with favorable histology; infants younger than age 365 days with stage 3, 4 or 4S disease; and toddlers from 365 to younger than 547 days with favorable histology, hyperdiploid stage 4, or unfavorable histology stage 3 tumors were eligible. Patients with MYCN-amplified tumors were excluded. Patients were assigned to initially receive two (group 2), four (group 3), or eight (group 4) cycles of chemotherapy with or without surgery on the basis of prognostic markers, including allelic status of chromosomes 1p and 11q; ultimate duration of therapy was determined by overall response. RESULTS Between 2007 and 2011, 404 evaluable patients were enrolled. Compared with legacy Children’s Oncology Group studies, subsets of patients had a reduction in treatment. The 3-year event-free survival and OS rates were 83.2% (95% CI, 79.4% to 87.0%) and 94.9% (95% CI, 92.7% to 97.2%), respectively. Infants with stage 4 tumors with favorable biology (n = 61) had superior 3-year event-free survival compared with patients with one or more unfavorable biologic features (n = 47; 86.9% [95% CI, 78.3% to 95.4%] v 66.8% [95% CI, 53.1% to 80.6%]; P = .02), with a trend toward OS advantage (95.0% [95% CI, 89.5% to 100%] v 86.7% [95% CI, 76.6% to 96.7%], respectively; P = .08). OS for patients with localized disease was 100%. CONCLUSION Excellent survival was achieved with this treatment algorithm, with reduction of therapy for subsets of patients. More-effective treatment strategies still are needed for infants with unfavorable biology stage 4 disease.

10013 Background: In 2006, COG reclassified subgroups of toddlers diagnosed with neuroblastoma from high-(HR) to intermediate-risk (IR), when the age cut-off for increased risk was raised from 365 days (12 mo) to 547 days (18 mo) (London, J Clin Onc 2005). The aim of this retrospective study was to determine if excellent outcome was maintained after a reduction of therapy. Methods: Children < 3 yrs old at diagnosis, enrolled on a COG biology study from 1990-2018, were eligible (n = 9,189). Therapy was reduced for two “cohorts of interest” based on the age cut-off change: 365-546 days old with INSS stage 4, MYCN not amplified, favorable INPC, hyperdiploid tumors (12-18mo/Stage4/FavBiology); and, 365-546 days old with INSS stage 3 tumors with non-amplified MYCN and unfavorable INPC (12-18mo/Stage3/NotAmp/UnfavINPC). Log rank tests compared event-free (EFS) and overall survival (OS) curves. Results: In the cohorts of interest, patient (pt) characteristics were similar for ≤2006 vs > 2006. For 12-18mo/Stage4/FavBiology, 5-year EFS and OS (± std error) before (≤2006; n = 40) versus after (> 2006; n = 55) the reduction in therapy were similar: 89±5.1% versus 87±4.6% (p = 0.7), and 89±5.1% versus 94±3.2% (p = 0.4), respectively (Table). For 12-18mo/Stage3/NotAmp/UnfavINPC, the 5-year EFS and OS were both 100%, before (n = 6) and after (n = 4) 2006. For the combined cohorts for ≤2006 versus > 2006, EFS and OS were 91±4.4% versus 88±4.3% (p = 0.6), and 91±4.5% versus 95±2.9% (p = 0.5), respectively. Within HR pts diagnosed ≤2006, EFS/OS were 91±4.4%/91±4.5% for (12-18mo/Stage4/FavBiology plus 12-18mo/Stage3/NotAmp/UnfavINPC) vs 38±1.3%/43±1.3% for all other HR pts < 3 yrs old (p < 0.0001; Table). Within IR pts diagnosed > 2006, EFS/OS were 88±4.3%/95±2.9% for (12-18mo/Stage4/FavBiology plus 12-18mo/Stage3/NotAmp/UnfavINPC) vs 88±0.9%/95±0.6% for all other IR pts < 3 yrs old (p = 0.9). Conclusions: Our 19 year study demonstrates that excellent outcome is maintained among toddlers with Stage4/FavBiology and Stage3/Not Amp/Unfav INPC neuroblastoma with a significant reduction of therapy from high- to intermediate-risk treatment. Importantly, pts were likely spared acute toxicity and late effects known to be associated with HR therapy. Efforts to identify additional pt cohorts who may not require HR therapy to achieve long-term survival are critical to improve the long-term health of children with neuroblastoma. [Table: see text]

10041 Background: Lorlatinib, a macrocyclic ATP-competitive ALK inhibitor, exerts potent activity against neuroblastoma (NB) xenograftsharboring the most common ALK mutations. We performed a first-in-child phase 1 study of lorlatinib for patients with refractory/relapsed (R/R) ALK aberrant high-risk NB. We previously reported on Part A of the study, where safety of single agent lorlatinib was determined, showing complete responses (CR) to lorlatinib at the recommended phase 2 dose (RP2D) of 115 mg/m2 in pts < 18 years and 150 mg in pts > 18 yrs. Part B of the study aimed to determine the safety, pharmacokinetics (PK), RP2D, and explore the anti-tumor activity of lorlatinib in combination with topotecan and cyclophosphamide in pts with R/R ALK-driven NB. Methods: Patients with R/R NB ages 1-17 years with ALK mutations or amplification were eligible; prior ALK inhibitor (ALKi) treatment was allowed. Lorlatinib was orally administered once daily on days 1-28 with topotecan (0.75 mg/m2/day) and cyclophosphamide (250 mg/m2/day) administered intravenously days 1-5 and GCSF starting day 6. Two lorlatinib dose levels (DL) of 95 mg/m2/day (DL4B) and 115 mg/m2/day (DL5B) were assessed using a 3+3 dose escalation design with the primary endpoint of dose limiting toxicity (DLT) in Course 1. We report lorlatinib safety, PK, and objective response rate (ORR) for patients enrolled on Part B. Results: Between 10FEB2020 and 03DEC2021,9 eligible pts enrolled on Part B with a median age of 6.7 years (3.7-12.7). Three pts were enrolled onto DL4B and six onto DL5B (2/3 pts on DL4B and 4/6 pts on DL5B had received prior ALKi therapy) with no DLT’s observed in course 1. One patient on DL5B experienced a neuropsychological DLT in Course 3. Most common treatment-related adverse events were hematological, febrile neutropenia, high cholesterol, hypertriglyceridemia, and neuropsychological effects. The median number of courses received was 6 with a range of 1-8 on DL4B and 1-7 on DL5B. Of the 8 patients evaluable for response, ORR was 50%: 2/3 pts on DL4B and 2/5 pts on DL5B. Preliminary PK data demonstrate comparable dose level-associated lorlatinib steady state exposure between Part B chemotherapy combination and Part A monotherapy cohorts, supporting that chemotherapy had no effect on lorlatinib exposure that there are no overlapping toxicities. Conclusions: Lorlatinib in combination with topotecan and cyclophosphamide is well tolerated, and early data suggest encouraging objective anti-tumor activity. These data support the current integration of lorlatinib into up-front high risk neuroblastoma therapy for patients with ALK-driven neuroblastoma. Clinical trial information: NCT03107988.

Purpose Infants with stage 4S neuroblastoma usually have favorable outcomes with observation or minimal chemotherapy. However, young infants with symptoms secondary to massive hepatomegaly or with unfavorable tumor biology are at high risk of death. Our aim was to improve outcomes for patients with symptomatic and/or unfavorable biology 4S neuroblastoma with a uniform treatment approach using a biology- and response-based algorithm. Patients and Methods The subset of patients with 4S disease with MYCN-not amplified tumors with impaired or impending organ dysfunction, or with unfavorable histology and/or diploid DNA index, were eligible. Patients were assigned to receive two, four, or eight cycles of chemotherapy on the basis of histology, diploid DNA index, chromosome arm 1p or 11q loss of heterozygosity (LOH) status, and symptoms. Results Forty-nine eligible patients were enrolled: 41 were symptomatic and 28 had unfavorable biology. Seventeen patients (symptomatic, favorable biology) were assigned two cycles, 21 patients (any unfavorable biologic feature without 1p or 11q LOH) were assigned four cycles, and 11 patients (unfavorable biology including 1p and/or 11q LOH [n = 7] or symptomatic with unknown biology [n = 4]), were assigned eight cycles. The 3-year overall survival was 81.4% ± 5.8%. Eight of nine deaths were in patients younger than 2 months of age at diagnosis (median, 9 days [range, 1 to 68 days]): five acute deaths were a result of hepatomegaly and associated toxicities; two were a result of late relapse in patients with unfavorable biology; and two were a result of treatment complications. No deaths occurred after protocol-mandated pre-emptive treatment of infants younger than 2 months with hepatomegaly, regardless of symptoms. A new scoring algorithm for emergent chemotherapy in patients with 4S disease was developed on the basis of this experience. Conclusion The outcome for 4S neuroblastoma can be improved with pre-emptive chemotherapy for evolving hepatomegaly or other baseline comorbidities in infants younger than 2 months of age.

10037 Background: B7-H3 (encoded by the CD276 gene) is an immunoregulatory molecule that is widely expressed in pediatric embryonal tumors and sarcomas, while expression is limited for normal tissues. Among PPTC models, osteosarcoma models showed highest CD276 transcript levels followed by Wilms tumor, neuroblastoma, rhabdomyosarcoma, and Ewing sarcoma. Protein expression by IHC generally followed expression at the RNA level, with high expression by IHC observed across a range of models. MGC018 is a duocarmycin-based humanized ADC targeting B7-H3 that shows selective cytotoxicity for B7-H3 expressing cancer cells, robust in vivo activity against a range of adult cancer preclinical models, a favorable pharmacokinetic and safety profile in cynomolgus monkeys, and has entered clinical testing for adults with cancer. Herein we report the in vivo antitumor activity of MGC018 against preclinical models of pediatric solid tumors. Methods: MGC018 was tested at 6 mg/kg administered intraperitoneally (IP) on Day 1. SYD988, an anti-CD20 ADC with the same linker and payload as MGC018, was used as a control arm at 6 mg/kg IP on Day 1. Osteosarcoma models, due to their slower growth kinetics and lower rates of tumor regression, were tested with n = 10 mice per arm, while the sarcoma and neuroblastoma models were tested with n of 1 or n of 2 designs, respectively. Activity was evaluated using response criteria mirroring clinical criteria (progressive disease (PD), stable disease (SD), partial response (PR), complete response (CR), and maintained CR (MCR)], by minimum relative tumor volume across all models, and by event-free survival (EFS) comparisons between treatment groups. Results: For neuroblastoma models (n = 9), 3 and 2 neuroblastoma models showed objective responses (PR/CR/MCR) or SD, respectively, to MGC018, while none showed an objective response or SD to SYD988. For osteosarcoma, results are mature for 1 of 5 models, with this model showing an MCR response to MGC018 and a PD response to SYD988. For Ewing sarcoma (n = 5), a PR and MCR were observed to MGC018 with the remaining models showing PD; for SYD988 a single CR was observed with the remaining 4 models showing PD. For rhabdomyosarcoma (n = 3) 2 MCR and 1 PD were noted for MGC018, while only PD was noted for SYD988. EFS duration exceeding 100 days to a single dose of MGC018 was observed for 2 rhabdomyosarcoma, 1 Ewing sarcoma, and 1 neuroblastoma model. Evaluation of the relationship between B7-H3 expression and response to MGC018 will be performed when results from all studies are completed. Conclusions: B7-H3 is an important target for immuno-oncology agents for childhood cancers. Our results provide proof-of-principle for the ability of MGC018 to produce profound antitumor activity in select pediatric solid tumor models in a B7-H3 specific manner.

TPS10561 Background: Aurora kinase A (AurA) has been implicated in high-risk neuroblastoma, including roles stabilizing and increasing expression of MYCN protein. AurA impacts the function of MYCN in mediating transcription in a cell cycle dependent manner, suggesting that neuroblastoma and other MYC/MYCN-driven tumors may be sensitive to AurA inhibition. LY3295668 is a selective AurA inhibitor. The lack of AurB inhibitory activity is hypothesized to minimize on-target hematologic toxicity associated with AurB inhibition. The molecule’s selectivity is intended to allow for continuous dosing at exposures associated with > 90% target inhibition at trough. In an analysis of LY3295668 antiproliferative effects in 560 cancer cell lines, neuroblastoma was among the most sensitive histologies tested. This screen also separately evaluated genomic predictors of response to LY3295668, with MYC/ MYCN amplification identified as among the strongest predictors of sensitivity to this agent. LY3295668 is currently being evaluated in early phase adult trials. The current trial (J10-MC-JZHD) was uniquely designed to hasten time to first-in-child oncology development for a rare unmet need of relapsed/refractory neuroblastoma patients. Methods: Study J1O-MC-JZHD (NCT04106219) is a multicenter, dual collaboration (NANT and ITCC), randomized, open-label, Phase 1 study of oral LY3295668 in children with relapsed/refractory neuroblastoma. A rolling 6 design will be followed for dose escalation in both a monotherapy cohort and a combination cohort testing LY3295668 together with cyclophosphamide and topotecan. The starting monotherapy dose will be equivalent to 80% of the adult maximum tolerated dose. Key eligibility criteria include recurrent/refractory neuroblastoma not amenable to curative treatment, age 2-21 years, mandatory archival tissue submission, ability to swallow capsules, and adequate hematologic and organ function. LY3295668 is administered in capsule form orally BID continuously. Primary objectives include assessments of safety and tolerability of study drug to identify RP2D as monotherapy and combination, and assess antitumor activity. Secondary objectives include assessment of the pharmacokinetic profile as monotherapy and in combination, and assessment of the relationship between study drug exposure and efficacy. Following determination of the RP2Ds, an expansion phase will randomize patients to monotherapy or to the combination arm. Enrollment began 16 Dec 2019 and is ongoing. Clinical trial information: NCT04106219.

e22521 Background: Relapsed and refractory neuroblastoma (NBL) is a prime target for novel therapies targeting specific mutations. The genomic landscape of NBL can change between time of initial diagnosis and relapse, necessitating subsequent biopsy and next generation sequencing (NGS) to detect mutations within the relapsed neoplasm. Tissue of insufficient quality and quantity leads to specimen failure during NGS. Thus the goal of this study is to review core needle biopsy for relapsed and refractory NBL in a pediatric interventional radiology department and explore factors that enhance biopsy adequacy. Methods: Retrospective review of clinical records and images for 66 patients (36M, 30F) with median age 8.7 years (range 0.9 – 49.3 y) who underwent 95 biopsies (55 bone, 40 soft tissue) over a 12-year period. Results: Biopsy yield for neuroblastic tissue from 123I mIBG-avid masses was 89.7% overall, 84.9% in bone, and 91.6% in soft tissue. 87/95 masses were mIBG-avid; 2 non-avid masses were NBL-positive (but also 18F-FDG avid). 48/59 samples sent for NGS were adequate for analysis (81.4%); bone and soft tissue biopsies did not differ in adequacy (77.1% vs 87.5%, p = 0.32). Tumor cell percent (TC%) for adequate samples was 49.9% vs 11.1% for NGS failures (p = 0.0003). Number of needle passes performed in bone and soft tissue lesions was positively correlated with NGS adequacy (Bone: r2= 0.68, Soft: r2= 0.33). In bone and soft tissue, adequate biopsies tended towards higher mean needle passes than inadequate ones (Bone: 5.1 vs 3.4, p = 0.0582) (Soft: 10.5 vs 4.7, p = 0.0428). Total needle volume passed into a soft tissue mass (calculated as inner needle cylindrical volume * # of passes) was higher in the “adequate” vs “inadequate” group (0.20 cm3 vs 0.05 cm3, p = 0.0004). Lesion mIBG avidity was quantified with a ratio of lesion:liver SUV; this mIBG SUV ratio was positively correlated with TC% (R2 = 0.55, N = 14). Using a linear regression line, a TC% of 50% (the mean value for samples adequate for NGS) corresponded to an SUV ratio of 2.89. The rate of minor complications (requiring only nominal therapy) was 7/95 (7.4%). The rate of major complications (requiring longer hospital stay) was 1/95 (1.5%). Conclusions: Image-guided core needle biopsy for relapsed and refractory NBL has a moderately high yield for procuring tumor samples adequate for NGS with a low rate of major complications. Adequate bone and soft tissue biopsies averaged >5 and >10 needle passes, respectively. An approximate lesion:liver mIBG SUV ratio of >3 may maximize specimen quality for NGS.

10523 Background: Immunotherapy with the anti-GD2 antibody dinutuximab plus sargramostim (GM-CSF), aldesleukin (IL-2) and isotretinoin following consolidation therapy improved outcome for high-risk neuroblastoma (HRNBL) pts enrolled on COG ANBL0032. Randomization was halted in 2009; subsequent pts were non-randomly assigned to immunotherapy. Toxicities and survival were evaluated. Methods: HRNBL pts < 31 years old with a pre-autologous stem cell transplant (ASCT) response of ≥ partial response (PR) were eligible. Demographics, INSS stage, tumor biology, 1993 INRC pre-ASCT response and toxicities were summarized using descriptive statistics. Five-year (yr) EFS and OS from time of study enrollment were estimated. Results: From 2009-2015, 1,183 pts were non-randomly assigned to immunotherapy. 96.7% (n = 1,144) were ≥18 months old and 83.1% (n = 765/921) had stage 4 disease. 45.1% (n = 363/805) of tumors with known biology were MYCN amplified, 94.5% (n = 749/793) had unfavorable histology, and 54.9% (n = 397/723) were diploid. Pre-ASCT, 352 (29.8%) pts had complete response (CR), 418 (35.3%) had very good partial response (VGPR), and 413 (34.9%) had PR. 1,042 (88.1%) pts underwent a single and 141 (11.9%) underwent tandem ASCT. For the entire cohort, 5-yr EFS was 61.1±1.9% and 5-yr OS was 71.9±1.7%. 5-yr EFS and OS for pts ≥18 months of age with stage 4 disease (n = 746) were 58.4±2.3% and 71.0±2.1%. 5-yr EFS and OS were 82.3±4.8% and 86.7±4.2% among pts with stage 3 disease (n = 110). EFS but not OS was superior for those with a CR/VGPR pre-ASCT vs. PR (5-yr EFS: 64.2±2.2% vs. 55.4±3.2%, p = 0.0133; OS: 72.7±2.1% vs. 70.5±2.9%, p = 0.3811). There was a trend toward improved OS for those treated with tandem vs. single transplant (5-yr EFS: 65.9±4.3% vs. 60.4±2.1%, p = 0.1282; OS: 76.5±3.8% vs. 71.2±1.9%, p = 0.0704). Grade ≥3 toxicities ( > 10% of pts) during GM-CSF and IL-2-containing cycles, respectively, included pain (15.6/11.4%), fever (15.1/32.7%), anemia (18.9/21.7%), thrombocytopenia (13.9/17.4%), lymphopenia (12.3/16.0%), and hypokalemia (13.3/25.2%). Additional Grade ≥3 toxicities ( > 10% of pts) included hypoxia (10.1%) during GM-CSF-containing cycles, and anaphylaxis (12.0%), neutropenia (16.1%), hyponatremia (16.5%), and hypotension (13.8%) during IL-2-containing cycles. Conclusions: In this large cohort of HRNBL pts treated with immunotherapy, 5-yr EFS was 61.1%. Superior EFS was observed for pts with stage 3 disease and for those with CR/VGPR pre-ASCT. IL-2-containing cycles were associated with increased toxicity. Clinical trial information: NCT00026312.

10504 Background: Lorlatinib, a potent ALK inhibitor, exerts unprecedented activity against neuroblastoma (NB) derived xenografts harboring common crizotinib-resistant ALK mutations, leading to a first in child phase I study. Methods: R/R NB patients (pts) > 12 months, with ALK mutations/amplification and prior ALK inhibitor (ALKi) treatment were eligible. Lorlatinib was administered in 28-day courses (C). For pts < 18 years, 5 dose levels (DL) (45, 60, 75, 95, 115 mg/m2/day) were assessed. DL5 (115 mg/m2/day) expansion is enrolling (cohort A1). For patients > 18 years, two DL (DL3a the adult RP2D of 100 mg/day and DL4a at 150mg/day) were assessed (cohort A2). Primary endpoint was dose-limiting toxicity (DLT) during C1 and neurocognitive toxicity through C2. Blood samples for circulating tumor DNA (ctDNA) were matched to radiologic restaging. Results: From 9/2017 to 1/2019, 33 eligible patients enrolled (13 with prior ALKi therapy), with median age (range) 5.5 years (2-17) on A1, 21.5 years (15-50) on A2. In A1, 3 pts each enrolled onto DL1-3, with no DLT’s. 5/10 pts enrolled on DL4, with no DLT’s. 1/3 on DL5 had a DLT of grade 3 diarrhea, with expansion ongoing. In cohort A2, 5 patients enrolled at 100 mg/day with no DLT’s; 6 enrolled at 150 mg/day, with one DLT (grade 4 reversible psychosis). Most common treatment-related adverse events were weight gain (90%, grade 1-3), hyperlipidemia (90%, grade 1-3), concentration/memory impairment (23%, grade 1-2), peripheral neuropathy (13%; grade 1-2, A2 only), and peripheral edema (10%; grade 1, A2 only). Lorlatinib steady state exposure at DL3 and DL4 was in the range of exposures seen in adult lung cancer patients at the 100 mg and 200 mg DLs. In A1, 1/18 had partial response (PR), 3/18 had minor responses (MR), and 4/18 had stable disease (SD). Of pts with MR, 2/3 had PR of soft tissue and 1/3 had complete response (CR) by MIBG. In A2 pts, 1/10 had CR, 3/10 PR, and 3/10 MR; Notably, 2/3 with PR had CR by MIBG. Of the pts with MR, one had PR and one CR by MIBG. Responses occurred across dose levels, ALK mutations, and in ALKi pre-treated pts with median courses of 2 (1-24) on A1 and 10.5 (2-28) on A2. Serial ctDNA results showed mutant ALK variant allele frequency trajectories that correlated with clinical response and emergence of novel ALK mutations in cis that corresponded with disease progression. Conclusions: Inhibition of ALK-driven NB with lorlatinib occurs with manageable toxicity and objective anti-tumor activity. Prospective ctDNA allows for monitoring of disease and evolution of resistance. Clinical trial information: NCT03107988.

e13666 Background: Molecular profiling using NGS technology is critical for tumor diagnosis, risk stratification, and treatment selection. There are limited data in childhood cancers regarding evolution of genomic changes under the selective pressure of chemoradiotherapy. Here we report on serial testing of hematologic and solid pediatric tumor specimens across the spectrum of diagnosis, during treatment and disease relapse. Methods: Since 2016, 2,144 somatic NGS assays from 1,727 unique cancer patients were performed using the Comprehensive Hematological Malignancy Panel (CHMP) or the Comprehensive Solid Tumor Panel (CSTP). Serial tumor analysis was performed on 155 patients. All tumors were profiled for SNVs/indels, copy number alterations (CNAs), and fusions. The clinical impact on diagnosis, prognosis, and therapy was assessed. Results: 85 and 70 patients were tested with CHMP and CSTP, respectively. 86.5% (134/155) of patients underwent 1 subsequent genetic testing, while 13.5% (21/155) were serially tested for 3 - 6 times. Relapsed or therapy-refractory tumor was the most common indication for repeat CHMP and CSTP analysis of tumor genomics (64.5%, 100/155), primarily to survey for new targetable cancer driver mutations. The second most common reason for serial testing with CHMP was to monitor clonal evolution for patients with bone marrow failure syndromes and/or myelodysplastic syndromes, which resulted in a new cancer diagnosis in 14.6% (6/41) patients. For CSTP, the second most common reason for serial testing was to test a different part of the same tumor for tumors with histologic and/or radiographic heterogeneity (27.1%, 19/70). Of all patients with serial testing, 70 had at least one clinically significant new SNV/indel, 44 had distinct CNAs, and 4 had new clinically actionable fusions. Overall, clinically significant new results were detected in 81 (52.3%) patients, including 53 patients with new clonal changes indicating disease evolution, 31 of diagnostic significance, 9 of prognostic significance, and 8 suggesting new treatment options. Conclusions: Taken together, these data highlight the clinical importance of serial testing of pediatric tumors for potential biomarkers that may impact patients’ care at various time points across the spectrum of their diseases.

Purpose The primary objective of Children's Oncology Group study P9641 was to demonstrate that surgery alone would achieve 3-year overall survival (OS) ≥ 95% for patients with asymptomatic International Neuroblastoma Staging System stages 2a and 2b neuroblastoma (NBL). Secondary objectives focused on other low-risk patients with NBL and on those who required chemotherapy according to protocol-defined criteria. Patients and Methods Patients underwent maximally safe resection of tumor. Chemotherapy was reserved for patients with, or at risk for, symptomatic disease, with less than 50% tumor resection at diagnosis, or with unresectable progressive disease after surgery alone. Results For all 915 eligible patients, 5-year event-free survival (EFS) and OS were 89% ± 1% and 97% ± 1%, respectively. For patients with asymptomatic stage 2a or 2b disease, 5-year EFS and OS were 87% ± 2% and 96% ± 1%, respectively. Among patients with stage 2b disease, EFS and OS were significantly lower for those with unfavorable histology or diploid tumors, and OS was significantly lower for those ≥ 18 months old. For patients with stage 1 and 4s NBL, 5-year OS rates were 99% ± 1% and 91% ± 1%, respectively. Patients who required chemotherapy at diagnosis achieved 5-year OS of 98% ± 1%. Of all patients observed after surgery, 11.1% experienced recurrence or progression of disease. Conclusion Excellent survival rates can be achieved in asymptomatic low-risk patients with stages 2a and 2b NBL after surgery alone. Immediate use of chemotherapy may be restricted to a minority of patients with low-risk NBL. Patients with stage 2b disease who are older or have diploid or unfavorable histology tumors fare less well. Future studies will seek to refine risk classification.

Purpose This phase II study was conducted to determine the response rate associated with use of irinotecan and temozolomide for children with relapsed/refractory neuroblastoma. Patients and Methods Patients with relapsed/refractory neuroblastoma measurable by cross-sectional imaging (stratum 1) or assessable by bone marrow aspirate/biopsy or metaiodobenzylguanidine (MIBG) scan (stratum 2) received irinotecan (10 mg/m2/dose 5 days a week for 2 weeks) and temozolomide (100 mg/m2/dose for 5 days) every 3 weeks. Response was assessed after three and six courses using International Neuroblastoma Response Criteria. Of the first 25 evaluable patients on a given stratum, five or more patients with complete or partial responses were required to conclude that further study would be merited. Results Fifty-five eligible patients were enrolled. The objective response rate was 15%. Fourteen patients (50%) on stratum 1 and 15 patients (56%) on stratum 2 had stable disease. Objective responses were observed in three of the first 25 evaluable patients on stratum 1 and five of the first 25 evaluable patients on stratum 2. Less than 6% of patients experienced ≥ grade 3 diarrhea. Although neutropenia was observed, less than 10% of patients developed evidence of infection while neutropenic. Conclusion The combination of irinotecan and temozolomide was well tolerated. The objective response rate of 19% in stratum 2 suggests that this combination may be effective for patients with neuroblastoma detectable by MIBG or marrow analysis. Although fewer objective responses were observed in patients with disease measurable by computed tomography/magnetic resonance imaging, patients in both strata seem to have derived clinical benefit from this therapy.

Purpose The hu14.18-IL2 fusion protein consists of interleukin-2 molecularly linked to a humanized monoclonal antibody that recognizes the GD2 disialoganglioside expressed on neuroblastoma cells. This phase II study assessed the antitumor activity of hu14.18-IL2 in two strata of patients with recurrent or refractory neuroblastoma. Patients and Methods Hu14.18-IL2 was given intravenously (12 mg/m2/daily) for 3 days every 4 weeks for patients with disease measurable by standard radiographic criteria (stratum 1) and for patients with disease evaluable only by [123I]metaiodobenzylguanidine (MIBG) scintigraphy and/or bone marrow (BM) histology (stratum 2). Response was established by independent radiology review as well as BM histology and immunocytology, and durability was assessed by repeat evaluation after more than 3 weeks. Results Thirty-nine patients were enrolled (36 evaluable). No responses were seen in stratum 1 (n = 13). Of 23 evaluable patients in stratum 2, five patients (21.7%) responded; all had a complete response (CR) of 9, 13, 20, 30, and 35+ months duration. Grade 3 and 4 nonhematologic toxicities included capillary leak, hypoxia, pain, rash, allergic reaction, elevated transaminases, and hyperbilirubinemia. Two patients required dopamine for hypotension, and one patient required ventilatory support for hypoxia. Most toxicities were reversible within a few days of completing a treatment course and were expected based on phase I results. Conclusion Patients with disease evaluable only by MIBG and/or BM histology had a 21.7% CR rate to hu14.8-IL2, whereas patients with bulky disease did not respond. Hu14.18-IL2 warrants further testing in children with nonbulky high-risk neuroblastoma.

10508Background: COG ANBL1221 was a randomized Phase II selection design trial for patients (pts) with relapsed/refractory NBL. Randomization was stopped early when I/T/DIN/GMCSF was shown be the o...

Purpose Iodine-131—metaiodobenzylguanidine (131I-MIBG) provides targeted radiotherapy with more than 30% response rate in refractory neuroblastoma, but activity infused is limited by radiation safety and hematologic toxicity. The goal was to determine the maximum-tolerated dose of 131I-MIBG in two consecutive infusions at a 2-week interval, supported by autologous stem-cell rescue (ASCR) 2 weeks after the second dose. Patients and Methods The 131I-MIBG dose was escalated using a 3 + 3 phase I trial design, with levels calculated by cumulative red marrow radiation index (RMI) from both infusions. Using dosimetry, the second infusion was adjusted to achieve the target RMI, except at level 4, where the second infusion was capped at 21 mCi/kg. Results Twenty-one patients were enrolled onto the study at levels 1 to 4, with 18 patients assessable for toxicity and 20 patients assessable for response. Cumulative 131I-MIBG given to achieve the target RMI ranged from 22 to 50 mCi/kg, with cumulative RMI of 3.2 to 8.92 Gy. No patient had a dose-limiting toxicity. Reversible grade 3 nonhematologic toxicity occurred in six patients at level 4, establishing the recommended cumulative dose as 36 mCi/kg. The median time to absolute neutrophil count more than 500/μL after ASCR was 13 days (4 to 27 days) and to platelet independence was 17 days (6 to 47 days). Responses included two partial responses, eight mixed responses, three stable disease, and seven progressive disease. Responses by semiquantitative MIBG score occurred in eight patients, soft tissue responses occurred in five of 11 patients, but bone marrow responses occurred in only two of 13 patients. Conclusion The lack of toxicity with this approach allowed dramatic dose intensification of 131I-MIBG, with minimal toxicity and promising activity.

Purpose To evaluate the effect of disease sites and prior therapy on response and toxicity after iodine-131-metaiodobenzylguanidine (131I-MIBG) treatment of patients with resistant neuroblastoma. Patients and Methods One hundred sixty-four patients with progressive, refractory or relapsed high-risk neuroblastoma, age 2 to 30 years, were treated in a limited institution phase II study. Patients with cryopreserved hematopoietic stem cells (n = 148) were treated with 18 mCi/kg of 131I-MIBG. Those without hematopoietic stem cells (n = 16) received 12 mCi/kg. Patients were stratified according to prior myeloablative therapy and whether they had measurable soft tissue involvement or only bone and/or bone marrow disease. Results Hematologic toxicity was common, with 33% of patients receiving autologous hematopoietic stem cell support. Nonhematologic grade 3 or 4 toxicity was rare, with 5% of patients experiencing hepatic, 3.6% pulmonary, 10.9% infectious toxicity, and 9.7% with febrile neutropenia. The overall complete plus partial response rate was 36%. The response rate was significantly higher for patients with disease limited either to bone and bone marrow, or to soft tissue (compared with patients with both) for patients with fewer than three prior treatment regimens and for patients older than 12 years. The event-free survival (EFS) and overall survival (OS) times were significantly longer for patients achieving response, for those older than 12 years and with fewer than three prior treatment regimens. The OS was 49% at 1 year and 29% at 2 years; EFS was 18% at 1 year. Conclusion The high response rate and low nonhematologic toxicity with 131I-MIBG suggest incorporation of this agent into initial multimodal therapy of neuroblastoma.

Purpose To determine the maximum-tolerated dose (MTD) and toxicity of iodine-131–metaiodobenzylguanidine (131I-MIBG) with carboplatin, etoposide, melphalan (CEM) and autologous stem-cell transplantation (ASCT) in refractory neuroblastoma. Patients and Methods Twenty-four children with primary refractory neuroblastoma and no prior ASCT were entered; 22 were assessable for toxicity and response. 131I-MIBG was administered on day −21, CEM was administered on days −7 to −4, and ASCT was performed on day 0, followed by 13-cis-retinoic acid. 131I-MIBG was escalated in groups of three to six patients, stratified by corrected glomerular filtration rate (GFR). Results The MTD for patients with normal GFR (≥ 100 mL/min/1.73 m2) was 131I-MIBG 12 mCi/kg, carboplatin 1,500 mg/m2, etoposide 1,200 mg/m2, and melphalan 210 mg/m2. In the low-GFR cohort, at the initial dose level using 12 mCi/kg of 131I-MIBG and reduced chemotherapy, one in six patients had dose limiting toxicity (DLT), including veno-occlusive disease (VOD). Three more patients in this group had grade 3 or 4 hepatotoxicity, and two had VOD, without meeting DLT criteria. There was only one death as a result of toxicity among all 24 patients. All assessable patients engrafted, with median time for neutrophils ≥ 500/μL of 10 days and median time for platelets ≥ 20,000/μL of 26 days. Six of 22 assessable patients had complete or partial response, and 15 patients had mixed response or stable disease. The estimated probability of event-free survival and survival from the day of MIBG infusion for all patients at 3 years was 0.31 ± 0.10 and 0.58 ± 0.10, respectively. Conclusion 131I-MIBG with myeloablative chemotherapy is feasible and effective for patients with neuroblastoma exhibiting de novo resistance to chemotherapy.

Purpose In the Children's Oncology Group, risk group assignment for neuroblastoma is critical for therapeutic decisions, and patients are stratified by International Neuroblastoma Staging System stage, MYCN status, ploidy, Shimada histopathology, and diagnosis age. Age less than 365 days has been associated with favorable outcome, but recent studies suggest that older age cutoff may improve prognostic precision. Methods To identify the optimal age cutoff, we retrospectively analyzed data from the Pediatric Oncology Group biology study 9047 and Children's Cancer Group studies 321p1-p4, 3881, 3891, and B973 on 3,666 patients (1986 to 2001) with documented ages and follow-up data. Twenty-seven separate analyses, one for each different age cutoff (adjusting for MYCN and stage), tested age influence on outcome. The cutoff that maximized outcome difference between younger and older patients was selected. Results Thirty-seven percent of patients were younger than 365 days, and 64% were ≥ 365 days old (4-year event-free survival [EFS] rate ± SE: 83% ± 1% [n = 1,339] and 45% ± 1% [n = 2,327], respectively; P < .0001). Graphical analyses revealed the continuous nature of the prognostic contribution of age to outcome. The optimal 460-day cutoff we selected maximized the outcome difference between younger and older patients. Forty-three percent were younger than 460 days, and 57% were ≥ 460 days old (4-year EFS rate ± SE: 82% ± 1% [n = 1,589] and 42% ± 1% [n = 2,077], respectively; P < .0001). Using a 460-day cutoff (assuming stage 4, MYCN-amplified patients remain high-risk), 5% of patients (365 to 460 days: 4-year EFS 92% ± 3%; n = 135) fell into a lower risk group. Conclusion The prognostic contribution of age to outcome is continuous in nature. Within clinically relevant risk stratification, statistical support exists for an age cutoff of 460 days.

Purpose The long-term survival of children between age 12 and 24 months with stage 4 neuroblastoma and nonamplified MYCN (MYCN-NA) has not been defined previously. Patients and Methods Survival for stage 4 MYCN-NA neuroblastoma patients enrolled onto Children's Cancer Group (CCG) protocols 321P2 (1986 to 1991) and 3891 (1991 to 1996) was analyzed. Treatment consisted of intensive alkylator-based induction chemotherapy with or without autologous bone marrow transplantation (ABMT) with or without 13 cis-retinoic acid. Survival was analyzed by age strata less than 12, 12 to 18, 18 to 24, and more than 24 months at diagnosis. Patients younger than 12 months were treated on the moderate-intensity CCG protocol 3881. Results Forty-three patients with stage 4 MYCN-NA disease enrolled onto CCG-321P2 (n = 17) or CCG-3891 (n = 26) were between 12 and 24 months of age at diagnosis. After a median follow-up of 94 months (range, 4 to 140 months), the 6-year event-free survival (EFS) for the 12- to 18-month age group was superior to that of the 18- to 24-month age group (74% ± 8% v 31% ± 12%; P = .008). The EFS for children older than 24 months with stage 4 MYCN-NA neuroblastoma was 23% ± 3%, and for children younger than 12 months was 92% ± 3%. Conclusion Children diagnosed with stage 4 MYCN-NA neuroblastoma in the second year of life form a transitional group between infants and older children in terms of prognosis. Patients between 12 and 18 months of age have significantly better long-term survival than that of older children treated with intensive chemotherapy with or without ABMT. These patients may not benefit from additional intensification of therapy beyond that provided in earlier clinical trials and may even maintain this high survival rate with less intensive therapy.

Purpose To determine predictive strength of tumor cell ploidy and MYCN gene amplification on survival of children older than 12 months with disseminated neuroblastoma (NB). Patients and Methods Of 648 children with stage D NB enrolled onto the Pediatric Oncology Group NB Biology Study 9047 (1990-2000), 560 children were assessable for ploidy and MYCN amplification. Treatment of patients older than 12 months varied; most receiving high-dose chemotherapy with stem-cell rescue. Infants received standard chemotherapy, depending on MYCN status and ploidy. Results Among stage D MYCN-amplified patients, 4-year event-free survival (EFS) ± SE had no prognostic significance for tumor cell ploidy for patients either younger than 12 months or ≥ 12 months old. However, among stage D nonamplified-MYCN patients, 4-year EFS for those with tumor hyperdiploidy (DNA index [DI] > 1) was clearly superior to those with diploidy (DI ≤ 1): younger than 12 months, 83.7% ± 4.4% (n = 87) versus 46.2% ± 13.8% (n = 13; P = .0003); and for 12- to 24-month-old children, 72.7% ± 10.2% (n = 22) versus 26.7% ± 13.2% (n = 16; P = .0092). Further analysis suggested better prognoses in the 12- to 18-month-old subgroup with hyperdiploid tumors (4-year EFS, 92.9% ± 7.2%) compared with the 19- to 24-month-old subgroup (4-year EFS, 37.5% ± 21.0%; P = .0037). In children older than 24 months, outcome was dire (< 20% long-term survival), regardless of ploidy or MYCN status. Conclusion Children 12 to 18 months old with metastatic NB had favorable outcomes with high-dose therapy if their tumors were hyperdiploid and lacked MYCN amplification. This subgroup may respond well to contemporary chemotherapy, and could be spared intensive myeloablative therapy with stem-cell rescue.

TPS2596 Background: Enoblituzumab, is an Fc optimized humanized IgG1 monoclonal antibody that binds to B7-H3 (CD276), a member of the B7 family. It is Fc-engineered to enhance effector function including antibody dependent cellular cytotoxicity (ADCC). IHC analyses with the parental anti-B7H3 mAb specificity incorporated in enoblituzmab revealed limited B7-H3 expression in normal tissues but high expression in many cancers (Loo et al., 2012). Among pediatric solid tumors, high expression of B7-H3 has been reported in neuroblastoma, rhabdomyosarcoma, osteosarcoma, Wilms tumor, Ewing’s sarcoma and desmoplastic small round cell tumor. B7-H3 overexpression correlates with poor prognosis in a broad range of cancers in adults suggesting a potential role in enabling tumor immune escape. ADCC and potential modulation of T cell function resulting in enhanced antitumor immune response are presumed mechanisms of action of enoblituzumab. Methods: This is an open-label, dose escalation / cohort expansion phase 1 study (NCT02982941) designed to characterize the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of enoblituzumab in children and young adults with B7-H3-expressing relapsed or refractory malignant solid tumors. A 3+3 design is used in escalating dose cohorts of weekly intravenous (IV) enoblituzumab starting at 10 mg/kg. Response is first determined at 8 weeks. irRECIST is used for response assessment for patient management. Enoblituzumab may continue up to 2 years based on response. Cohort expansion phase, to further define the safety and initial antitumor activity of enoblituzumab, will start after maximum tolerated dose is determined. The patients are assigned to 1 of 5 cohorts based on disease type as follows: 1) neuroblastoma - measurable disease, 2) neuroblastoma - non-measurable disease, 3) rhabdomyosarcoma, 4) osteosarcoma, and 5) Ewing’s sarcoma, Wilms’ tumor and desmoplastic small round cell tumors. Enrollment is ongoing. Ref : Development of an Fc-enhanced anti-B7-H3 monoclonal antibody with potent antitumor activity. Loo D, Alderson RF, Chen FZ, Huang L et al. Clin Cancer Res. 2012; 18:3834-45. Clinical trial information: NCT02982941.

PURPOSE: To determine the independent prognostic significance of 1p36 loss of heterozygosity (LOH) in a representative group of neuroblastoma patients. PATIENTS AND METHODS: Diagnostic tumor specimens from 238 patients registered onto the most recent Children’s Cancer Group phase III clinical trials were assayed for LOH with 13 microsatellite polymorphic markers spanning chromosome band 1p36. Allelic status at 1p36 was correlated with other prognostic variables and disease outcome. RESULTS: LOH at 1p36 was detected in 83 (35%) of 238 neuroblastomas. There was a correlation of 1p36 LOH with age at diagnosis greater than 1 year (P = .026), metastatic disease (P < .001), elevated serum ferritin level (P < .001), unfavorable histopathology (P < .001), and MYCN oncogene amplification (P < .001). LOH at 1p36 was associated with decreased event-free survival (EFS) and overall survival (OS) probabilities (P < .0001). For the 180 cases with single-copy MYCN, 1p36 LOH status was highly correlated with decreased EFS (P = .0002) but not OS (P = .1212). Entering 1p36 LOH into a multivariate regression model suggested a trend toward an independent association with decreased EFS (P = .0558) but not with decreased OS (P = .3687). Furthermore, allelic status at 1p36 was the only prognostic variable that was significantly associated with decreased EFS in low-risk neuroblastoma patients (P = .0148). CONCLUSION: LOH at 1p36 is independently associated with decreased EFS, but not OS, in neuroblastoma patients. Determination of 1p36 allelic status may be useful for predicting which neuroblastoma patients with otherwise favorable clinical and biologic features are more likely to have disease progression.

LBA3 Background: ASCT improves event-free survival (EFS) for HR-NB. Pilot studies suggest that intensification of myeloablative therapy using tandem ASCT further improves outcome for HR-NB. We conducted a multicenter RCT comparing tandem vs. single consolidation in patients with HR-NB. Methods: Between 11/2007 and 2/2012, 652 eligible patients (pts) with newly diagnosed HR-NB received induction therapy: 6 cycles of chemotherapy including initial 2 cycles of dose-intensive cyclophosphamide/topotecan followed by PBSC collection. Randomization occurred at end induction to single ASCT with carboplatin-etoposide-melphalan (CEM) or tandem ASCT with thiotepa–cyclophosphamide ASCT followed by a modified CEM (TC:CEM). HR pts with non-MYCN amplified Stage 3 (age>18mos) or Stage 4 (age 12-18 mos) tumors were non-randomly assigned to single ASCT (CEM). EFS and overall survival (OS) were analyzed as intent-to-treat. Results: Median age at study entry was 3.1 yrs, 88% (n=574 pts) had Stage 4 disease and 38.2% (n=249 tumors) had MYCN amplification. A total of 355 pts were randomized (CEM n=179 pts; TC:CEM n=176 pts) and 27 patients were non-randomly assigned to CEM. Of randomized pts, 249 patients received post-consolidation immunotherapy on COG trials. Treatment-related mortality was 2.6% (Induction n=7 [1%]; Consolidation n=10 [2.8%; n=8 CEM, n=2 TC:CEM]). Rates of severe mucosal, infectious or liver toxicities were similar between arms. 3-year EFS and OS from diagnosis were 51.1±2.0% and 68.2±1.9%, respectively. EFS and OS for randomized cohort are shown in the Table. Conclusions: Tandem myeloablative consolidation therapy improves survival probability in patients with high-risk neuroblastoma, especially in the setting in post-consolidative immunotherapy. Clinical trial information: NCT00567567. [Table: see text]

e14014Background: High-risk neuroblastoma (NBL) patients (pts) enrolled in a COG phase III clinical trial (ANBL0032) were randomized to isotretinoin (RA) alone or RA + immunotherapy (IM): dinutuxim...

10526Background: Prior investigations suggest that neuroblastomas (NBL) that do not accumulate MIBG (MIBG non-avid) may have more favorable features compared to MIBG avid tumors. We compared clinic...

10556Background: In phase I testing in 22 patients with neuroblastoma, the maximum tolerated dose of alisertib tablets with irinotecan/temozolomide was 60 mg/m2/dose. This combination showed signif...

11542Background: PD-1 signaling in the tumor microenvironment dampens immune responses to cancer and blocking this axis induces anti-tumor effects in several malignancies. Expression of PD-L1 has b...

10017 Background: Combining anti-GD2 (disialoganglioside) monoclonal antibody with GM-CSF, IL2 and isotretinoin is now standard of care for high-risk neuroblastoma (NB) minimal residual disease (MR...

10044 Background: In a Phase 3 randomized study (COG ANBL0032), we demonstrated that the addition of ImmRx to standard therapy isotretinoin for high-risk neuroblastoma (NB) patients in CR or VGPR a...

9533 Background: Patients with non-high-risk neuroblastoma (low- and intermediate-risk) generally have an excellent event free (EFS) and overall (OS) survival with current therapy. However, within this heterogeneous patient population, there are patients that may benefit from further therapy reduction and patients that may benefit from augmented therapy. Methods: Survival tree regression analysis was performed in patients enrolled on P9641 and A3961 with OS the primary endpoint. Univariate Cox proportional hazards models determined statistically significant prognostic factors. Secondary analysis of cases with MYCN non-amplified, non-high-risk neuroblastoma classified patients by age, INSS stage, Shimada histology and genomic features to determine 5-year EFS and OS. Favorable genomics were defined as hyperdiploid tumors without 1p or 11q loss of heterozygosity (LOH). Those with LOH at 1p or 11q or with a diploid DNA index were considered unfavorable. Patients without genomic data were excluded. Results: In the survival tree analysis, ploidy and genomic features were found to be statistically significant. In the secondary analysis, patients

9576 Background: The PK of ch14.18, a chimeric monoclonal antibody (cMoAb) that significantly improves survival in high-risk neuroblastoma, was previously reported to be highly variable in children, and its clearance (CL, 130 mL/h · m2) and volume of distribution (Vdss, 32 L/m2) were >10-fold higher than the CL and Vdss of other cMoAbs. Characterizing the PK of ch14.18 and the factors responsible for its variability could lead to alternative dosing strategies that reduce toxicity. Methods: Detailed PK sampling was performed prior to, during and for 25 d after 4 daily 10 h infusions of 25 mg/m2 of ch14.18 administered with sargramostim (ANBL0032) in children enrolled on an IRB-approved institutional correlative protocol supported by United Therapeutics Corp. Ch14.18 concentrations were measured with a validated ELISA with a lower limit of detection of 0.44 mcg/mL. PK parameters were derived using non-compartmental methods and reported as median (range). Results: 5 males and 4 females, median (range) age 3.5 (1-7) yrs, have been enrolled. Six were studied on cycle 1 (C1), 2 on C5 and 1 on C3; 3 of 6 patients studied on C1 were re-studied on C3. Data from 3 patients are not included because pre-treatment plasma samples contained a substance that interfered with the ELISA. The Cmax after the 4th daily infusion was 14 (10-24) mcg/mL, and ch14.8 was undetectable at day 25 in 3/6 patients. The half-life was 220 (120-390) h, and the CL was 11 (3.8-16) mL/h · m2, which is similar to the average CL of 4 other cMoAbs (11 mL/h · m2). The Vdss of 2.8 (1.2-3.9) L/m2 approximated blood volume and was similar to the Vdss of other cMoAbs (1.7 L/m2) and humanized MoAbs (2.8 L/m2). AUC0-∞ in 2 patients studied twice were 3440 and 1540 mcg · h/mL on C1 and 2760 and 2690 mcg · h/mL on C3. Conclusions: Ch14.18 CL, Vdss and half-life in children are similar to those in adults receiving ch14.18 at the same dose and similar to other cMoAbs. Ch14.18 PK in children was less variable than previously reported. The identity of the interfering substance in the plasma of some patients requires further investigation. A limited sampling strategy will be developed from these data for use in larger multi-institutional PK studies of ch14.18.

9516 Background: An increased prevalence of high-risk disease and worse outcome are observed in children with neuroblastoma who self-report as black versus white. We sought to determine whether genetic variation would explain this racial disparity. Methods: After quality control, we analyzed 511,836 germline genetic variants in 2,709 ethnically diverse children with neuroblastoma enrolled on Children’s Oncology Group study ANBL00B1 from 2001 to 2009. Genetic variation was summarized by conducting principal components analysis. The first principal component (PC1) separated patients with African ancestry from all others. PC1 was used as a continuous variable for ordinal regression with risk group and a Cox proportional hazard model of EFS. To identify genetic mechanisms for the observed disparities, we developed a method using genome-wide variation data applied to high-risk versus non-high risk samples. We identified a comprehensive list of loci with significant divergence between the ancestral populations. We then tested each such locus for association with high-risk phenotype using logistic regression with the proportion of African ancestry estimated by ADMIXTURE as covariate. Finally, top SNPs were added to multivariate models of both risk and event-free survival to determine if any top associations could abrogate observed disparities. Results: PC1 was associated with both risk (p = 0.007) and EFS (p = 0.037). We identified 72 population-divergent SNPs nominally associated with high-risk disease (p < 0.001). The risk allele for one of the top SNPs: rs9295536 (p = 9.2x10-8) was more common in the African ancestral population, was associated with high-risk phenotype and poor outcome in all patients and validated in a Caucasian-only subanalysis. In multivariate testing, this SNP abrogated the PC1 association with EFS (p = 0.18). Conclusions: A SNP with high divergence between ancestral populations on chromosome 6p22 accounts for the observed racial disparity in survival and is also a common genetic variant associated with survival in patients derived from either European or African ancestry (Bonferroni adjusted p < 0.05). Studies to elucidate the function of this SNP are underway.

9513 Background: 131I-metaiodobenzylguanidine (MIBG) is a targeted radiopharmaceutical with activity in neuroblastoma. Irinotecan is a radiosensitizer with activity in neuroblastoma. This phase I s...

9514 Background: Mutations in the ALK proto-oncogene are the major cause of hereditary neuroblastoma (NB), can be somatically acquired, and may offer a tractable therapeutic target for a subset of patients. Methods: We identified 1,604 paired constitutional and tumor DNA samples from patients representative of the natural spectrum of NB for comprehensive evaluation of ALK genomic status. This set has complete annotation of clinical covariates and patient outcome, and provides sufficient power to identify clinically relevant ALK aberrations within each NB risk group. We performed DNA sequencing of the ALK kinase domain and defined ALK copy number (CN) status using quantitative PCR. For each tumor where a somatic mutation was identified, we sequenced matched germline DNA, allowing us to understand the frequency of hereditary predisposition to NB. Results: Mutations were discovered in 126/1,604 (7.9%) primary NB tumor samples distributed across the spectrum of phenotypes. Mutations at R1275 were most common ...

9512 Background: 131I-MIBG is specifically taken up in neuroblastoma, with a response rate >30% in relapsed disease. The presence of non-radioactive “carrier” MIBG molecules increases risk of cardiovascular side effects and can inhibit tumor uptake of 131I-MIBG, reducing tumor radiation. Our primary aim was to establish the maximum tolerated dose (MTD) of no-carrier-added MIBG with autologous hematopoietic stem cell (AHSC) support. Methods: Eligible patients were age 1-30 years with resistant neuroblastoma, MIBG avid tumors, and cryopreserved AHSC. The nca-MIBG therapeutic dose was escalated in 3 mCi/kg increments from 12-21 mCi/kg using a 3+3 design. The administered dose was limited by gamma image-derived pretreatment organ dosimetry and normal tissue tolerance estimates of Emami (1991). AHSC were infused 14 days post therapy. Response and toxicity were evaluated day 60. Dose limiting toxicity (DLT) was failure to engraft or grade 3 or 4 non-hematologic toxicity except grade 3 pre-defined exclusions. Re...

9529 Background: MLN8237, a selective small molecule inhibitor of Aurora A Kinase, has activity in a broad range of in vitro and in vivo preclinical models of pediatric cancer. We performed a phase...

10593 Background: MLN8237 is a selective Aurora kinase A inhibitor undergoing early phase clinical evaluation, and has demonstrated significant activity in NB xenograft models (Maris et al, PBC 201...

9532 Background: TrkB acts as an oncogenic kinase in a subset of human NB. Lestaurtinib, a multi-kinase inhibitor with potent activity against Trk kinases, has demonstrated anti-tumor activity in p...

10008b Background: Mutations in the ALK oncogene are the major cause of hereditary neuroblastoma (NB), and may offer a tractable therapeutic target. Methods: We resequenced the ALK tyrosine kinase domain in 496 primary NBs. We integrated data from 76 primary tumors analyzed using Illumina HumanHap550 SNP and Human-6 mRNA expression arrays. We stained a tissue microarray (TMA) of 134 NBs with anti-ALK and anti-pALK antibodies. We evaluated the in vitro and in vivo activity of PF-02341066, a small molecule inhibitor of ALK. Computational chemistry was used to homology map ALK interaction with PF-02341066. Results: Mutations were discovered in 38/496 NBs (8%), across the spectrum of phenotypes. R1275Q substitutions were most common (45%), followed by F1174L (15%). Evaluation of matched constitutional DNAs demonstrated 10% carried occult germline mutations. Integration of primary tumor microarrays from 76 samples showed that ALK mRNA expression was highly correlated with ALK DNA copy number (p=0.0005). ALK protein was nearly universally expressed (129/134; 93%), and there was evidence for ALK activation in 15% of tumors (pALK moderate or strong staining in 20/134), suggesting an additional and alternative pathway to ALK activation. A panel of 18 NB cell lines showed differential in vitro sensitivity to PF-2341066 dependent on ALK mutation and copy number status. A wild type (WT) amplified line and 2 lines harboring R1275Q mutations were sensitive (IC50 145 - 301 nM). Lines harboring F1174L mutations were more resistant (IC50 >950nM) as were lines with no ALK aberrations. Inhibition of proliferation was associated with abolishing phosphorylation of ALK, STAT3 and AKT. PF-02341066 caused complete regression of R1275Q xenografts, but caused only minimal growth delay in F1174L and WT xenografts. Based on homology mapping to a crystal structure of PF-02341066 bound to c-Met, the F1174L mutation is predicted to destabilize the specific conformation of the kinase activation loop required for binding PF-02341066. Conclusions: ALK pathway activation occurs in at least 15% of human neuroblastomas. PF-02341066 is a potent inhibitor of the most common ALK mutation, but there is a structural basis for resistance to F1174L mutations. Co-crystallization studies are ongoing and a phase 1 study is planned. No significant financial relationships to disclose.

10011 Background: Treatment of children with relapsed or refractory neuroblastoma (NB) remains a challenge. Responses to irinotecan (IRN) + temozolomide (TEM) were seen in NB xenograft-bearing mice, and objective responses were observed in patients with NB treated on a phase I study of this combination. Methods: A phase II study of IRN (10 mg/m2/dose IV daily × 5 days times; 2 weeks) + TEM (100 mg/m2/dose PO daily × 5 days) for children with relapsed or refractory NB was conducted. A one-stage design (endpoint: best overall response) required 5 or more responders out of the first 25 evaluable patients on each of two strata: 1) patients with disease measurable by CT or MRI; and 2) patients with disease detected only by bone marrow aspirate/biopsy and/or MIBG scan. Patients with stable disease or better after 3 cycles could receive an additional 3 cycles of study therapy. International Neuroblastoma Response Criteria were used for response assessment. Radiographic responses were centrally reviewed. Results: Fifty-five eligible and evaluable patients were enrolled, 28 on stratum 1 and 27 on stratum 2. Four responses were observed in the first 25 evaluable stratum 1 patients, and five responses were observed in the first 25 evaluable stratum 2 patients. Three patients had complete responses, but the overall objective response rate (CR+PR) was 16% (9/55). Eleven (stratum 1) and 13 (stratum 2) patients had stable disease. Less than 5% of patients experienced Grade 3 or 4 diarrhea. Although 18% of patients on stratum 1 and 35% of patients on stratum 2 experienced Grade 3 or 4 neutropenia during the first 3 cycles of therapy, No significant financial relationships to disclose.

10009 Background: Fenretinide (4-HPR), a cytotoxic retinoid, achieved limited and variable plasma levels when tested in a corn oil-based capsule. 4HPR/Lym-X-Sorb (LXS) oral powder is a new formulation intended to increase bioavailability, especially in children. Methods: This trial sought to define the toxicities, dose limiting toxicities (DLTs), maximum tolerated dose (MTD), and pharmacokinetics of 4-HPR/LXS oral powder when given mixed in Slim-Fast nutritional shakes, twice a day for 7 days, every 21 days. Eligible patients had high-risk neuroblastoma with recurrent/progressive disease, or disease refractory or persistent after frontline therapy. Dose escalation was in 30% increments using the traditional 3 + 3 design. Plasma levels were measured by HPLC. Results: Thirty-two patients accrued to 8 Dose Levels (DL) (352 –2210 mg/m2/day); 30 patients were evaluable. No MTD was identified. There was a DLT elevation of alkaline phosphatase on DL1. No other DLT's were observed. Other toxicities included dry skin, elevated triglycerides, reversible nyctalopia, and transient transaminase elevation. Course 1 day 7 peak 4HPR plasma levels (Dose (mg/m2/day) - mean, (range)) were: 352 –6 μM (3.8–9.6); 458–11.5 μM (9.7–14.9); 595–17.6 μM (6–24.3); 774–15 μM (9.1–25.3); 1006–6.7 μM (5.2–9.2); 1308–13.9 μM (2.9–23.8); 1700–19.7 μM (17.3–24.3); and 2210–10.8 μM (4–16.5). Course 2 day 7 peak plasma levels trended higher than course 1 at DL5–8. Three patients with isolated bone marrow disease and one with MIBG avid bone lesions, had complete responses (DL4, DL4, DL7, DL8) receiving 10, 17, 18 and 10 courses of therapy, respectively. Six patients had stable disease for 4–27 courses (median 5.5) (DL3, DL4, DL4, DL5, DL6, DL8). Twenty patients had progressive disease. Central review of responses is pending. Conclusions: 4-HPR/LXS oral powder was well tolerated, obtained 2 - 5 fold higher 4HPR plasma levels than fenretinide capsules on the same dose and schedule (P < 0.01), and showed anti-tumor activity (complete responses in 4/15 patients at DL4–8). Based on pharmacokinetic data, a recommended Phase II dose and schedule is 1700 mg/m2/day × 7days every 3 weeks. No significant financial relationships to disclose.

3002 Background: The hu14.18-IL2 fusion protein consists of IL2 linked to a humanized mAb that recognizes the GD2 disialoganglioside expressed on neuroblastoma (NB) cells. Hu14.18-IL2 has preclinical activity in mouse models of NB and melanoma, particularly when given to mice with a smaller tumor burden. Using the dosing and schedule developed in our phase I study, we determined the antitumor activity of hu14.18-IL2 in two strata of patients with recurrent or refractory NB. Methods: Hu14.18-IL2 was given intravenously at a dose of 12 mg/m2/day over 4 hours for three consecutive days every 28 days. Responses were evaluated every 2 cycles for patients with disease measurable by standard radiographical criteria (stratum 1) and for patients with disease evaluable only by MIBG and/or bone marrow histology (stratum 2). In each stratum, a one-stage design was powered to conclude efficacy with 4 or more responders (CR or PR) out of 20. Response was established by independent radiology review as well as bone marro...

10009 Background: There is lack of consensus on prognostic markers other than age and tumor MYCN amplification for children with INSS stage 3 NB. Methods: The INRG database (n=8800 patients) was utilized to assess whether age, elevated ferritin (≥ 96 ng/ml), tumor histology or somatically acquired chromosomes (ch) 1p or 11q aberrations impact EFS and OS from INSS stage 3, MYCN not amplified (NA) NB. Due to the confounding of Shimada histology with age, only tumor differentiation grade and MKI were tested in multivariate models. Results: Of 1,483 patients with INSS stage 3 tumors, 1,013 had MYCN-NA tumors. Among these, 654 (64.6%) patients were age

10010 Background: A subset of neuroblastomas show inheritance as an autosomal dominant trait with incomplete penetrance. Familial neuroblastoma is often lethal during childhood, resulting in very few pedigrees of sufficient size for linkage analysis. Low-resolution genetic approaches have not been successful in identifying a narrow genomic region consistent with linkage, a critical first step in identifying the causal gene. Methods: We performed a genome-wide scan for linkage in eighteen neuroblastoma pedigrees at ∼6000 single nucleotide polymorphisms. Parametric and non-parametric analyses were used to identify and refine candidate regions. Candidate genes were resequenced in a panel of 15 probands using Sanger-based or 454 technology. Results: We discovered a highly significant linkage signal covering a 34 Mb region on chromosome 2p with a maximum non-parametric LOD score of 4.23 (p=0.00001), and 13/18 families screened were consistent with linkage to this locus. No other genomic region was suggestive o...

10011 Background: ASCT improves outcome for HR-NB, but potential risk of reinfusion of viable tumor in PBSC could affect event-free survival (EFS). We assessed the impact of ASCT with immunomagnetic purging of PBSC, compared to UP product, on EFS, PBSC tumor content, engraftment, and ASCT toxicity. Methods: Between 2/2001 and 3/2006, 489 eligible newly diagnosed HR-NB pts were randomized at study entry to have P or UP PBSC obtained and cryopreserved after 2 cycles of induction chemotherapy. Purging was performed centrally using carbonyl iron depletion of phagocytes followed by 2 cycles of magnetic beads with 5 anti-NB monoclonal antibodies. After 6 chemotherapy cycles, pts received melphalan (180–210 mg/m2), carboplatin (AUC 4.1 to max 1700 mg/m2), and etoposide (800–1352 mg/m2) based on GFR followed by PBSC support. Post-ASCT pts had radiation to primary and MIBG+ sites, then 6 cycles of 13-cis-retinoic acid. EFS and overall survival (OS) from enrollment [primary endpoint] were analyzed as intent-to- tre...

10611 Background: Tumor blood vessels are disorganized and vascular endothelial cell proliferation (VEP) has been identified as a poor prognosticator in many adult cancers. To determine the clinical significance of VEP in neuroblastoma (NB), we evaluated blood vessel architecture in tumor sections from 51 children diagnosed at Children's Memorial Hospital, Chicago (CMH) and in 154 NB tumors on a Tissue Microarray (TMA) constructed at Children's Hospital of Philadelphia (CHOP). Methods: H&E-stained tumor sections were examined for the presence of structurally abnormal vessels and further characterized by immunostaining with anti-CD31 and von Willebrand factor (vWF) antibody to highlight endothelial cells. Tumors that contained vessels with disorganized walls and more than one endothelial cell layer were classified as VEP positive. Tumor sections that contained only thin walled vessels with no more than one layer of endothelial cells were classified as VEP negative. Associations between VEP and established clinico-pathologic features and outcome were assessed. Results: In the CHOP series, VEP was associated with high-risk group classification and MYCN amplification (p No significant financial relationships to disclose.

9505 Background: Myeloablative consolidation improves outcome for HR-NB pts, especially for pts in CR prior to consolidation. We assessed the toxicity and CR+VGPR rate of a dose-intensive multi-agent chemotherapy induction based upon the N7 regimen (JCO 22:4888, 2004) prior to myeloablative consolidation and peripheral blood autologous stem cell transplant (ASCT). Methods: Between 2/2001 and 3/2006, 489 eligible newly diagnosed HR- NB pts received the following induction consisting of 6 cycles of chemotherapy q 21 days. Cycles 1, 2, 4 & 6: cyclophosphamide 4.2 g/m2, doxorubicin 75 mg/m2, and vincristine 2 mg/m2 and Cycles 3 &5: cisplatin 200 mg/m2 and etoposide 600 mg/m2. Surgical resection of primary occurred after cycle 5. Following induction pts received purged or unpurged ASCT (as randomized), radiation, and then 13-cis-retinoic acid (13-cis-RA). Response was assessed after cycles 2 & 6 using the International Neuroblastoma Response Criteria and analyzed as intent-to-treat. Results: Median age was 3.1 yrs, 44% of 392 tumors tested had MYCN amplification. Fourteen pts (3%) died during induction (5 infection, 4 bleed into tumor, 4 compromised organ function from tumor, 1 unrelated to tumor/therapy). Patients experienced the following grade 3 & 4 toxicities at least once during induction: neutropenia 70%, thrombocytopenia 71%, hearing loss 6%, cardiac function 2% and renal function 3%. Documented infection occurred in 24% of cycles (90% bacterial, 3% viral, 7% fungal). Responses among the 489 pts at end of induction were CR 24%, VGPR 28%, PR 26%, SD 7%, and PD15%, with morphologically detectable bone marrow (BM) disease cleared in 87% and no disease remaining by MIBG scan in 55% of pts MIBG positive at baseline. Conclusions: Despite increased dose intensity of this regimen, toxicity was not excessive compared to prior HR-NB regimens. In a multi-center setting, the A3973 induction chemotherapy achieved morphologic BM clearance in 87% of pts prior to consolidation. The CR/VGPR rate of 52% is similar to that of prior less intensive regimens. The impact of this induction response on survival within the context of ASCT and 13-cis-RA on COG A3973 will be determined with longer follow-up. No significant financial relationships to disclose.