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Supplementary Data from Bone Marrow Surveillance of Pediatric Cancer Survivors Identifies Clones that Predict Therapy-Related Leukemia

Supplementary Figure from Bone Marrow Surveillance of Pediatric Cancer Survivors Identifies Clones that Predict Therapy-Related Leukemia

PURPOSE The tyrosine kinase receptor anaplastic lymphoma kinase (ALK) can be abnormally activated in neuroblastoma, and somatic ALK mutations occur in 6%-10% of patients. The differential clinical impact of these mutations has not been clearly elucidated. METHODS Data on patients with neuroblastoma harboring ALK mutations were retrospectively analyzed. ALK sequencing was performed by whole-genome sequencing, hybrid-based capture of targeted exomes, or hotspot ALK mutation profiling. The differential impact of ALK mutation site on clinical characteristics, response to treatment, and survival was analyzed. In a subgroup of patients with locoregional neuroblastoma diagnosed after 2014, the impact of all ALK mutations was compared with wild-type ALK. RESULTS Of 641 patients with neuroblastoma with ALK status analyzed on at least one tumor sample, 103 (16%) had tumors harboring ALK mutations. Mutations existed across all ages (birth to 67.8 years), stages (30% locoregional and 70% metastatic), and risk groups (20%, 11%, and 69% with low-, intermediate-, and high-risk disease, respectively). Mutation sites included F1174 (51%), R1275 (29%), R1245 (10%), and others (10%). Mutation site was not prognostic for progression-free survival or overall survival in the entire cohort, high-risk subgroup, or locoregional subgroup. Locoregional tumors with any ALK mutation were generally invasive: L2 by International Neuroblastoma Research Group staging in 30/31 patients with a 2-year progression-free survival (59%, 95% CI, 37.4 to 80.5) that was inferior to historical controls. This observation was corroborated in the post-2014 subgroup in which gross total resection was less likely for ALK-mutated tumors. CONCLUSION Somatic ALK mutations are present across all stages and risk groups of neuroblastoma. No specific mutation carries differential prognostic significance. Locoregional neuroblastoma has an invasive phenotype when harboring somatic ALK mutations in this population.

In high-risk neuroblastoma, multimodality therapy including craniospinal irradiation (CSI) is effective for central nervous system (CNS) relapse. Management of post-CSI CNS relapse is not clearly defined.Pediatric patients with neuroblastoma treated with CSI between 2000 and 2019 were identified. Treatment of initial CNS disease (e.g., CSI, intraventricular compartmental radioimmunotherapy [cRIT] withOf 128 patients (65% male, median age 4 years), 19 (15%) received CSI with protons and 115 (90%) had a boost. Most (103, 81%) received cRIT, associated with improved OS (hazard ratio [HR] 0.3, 95% confidence interval [CI]: 0.1-0.5, p .001). Forty (31%) developed a second CNS relapse, associated with worse OS (1-year OS 32.5%, 95% CI: 19-47; HR 3.8; 95% CI: 2.4-6.0, p .001), and more likely if the leptomeninges were initially involved (HR 2.5, 95% CI: 1.3-4.9, p = .006). Median time to second CNS relapse was 6.8 months and 51% occurred outside the CSI boost field. Twenty-five (63%) patients underwent reirradiation, most peri-operatively (18, 45%) with focal hypofractionation. Eight (20%) patients with second CNS relapse received cRIT, associated with improved OS (HR 0.1; 95% CI: 0.1-0.4, p .001).CNS relapse after CSI for neuroblastoma portends a poor prognosis. Surgery with hypofractionated radiotherapy was the most common treatment. Acknowledging the potential for selection bias, receipt of cRIT both at first and second CNS relapse was associated with improved survival. This finding necessitates further investigation.

High-risk neuroblastoma is generally metastatic and often lethal. Using genomic profiling of 470 sequential and spatially separated samples from 283 patients, we characterize subtype-specific genetic evolutionary trajectories from diagnosis, through progression and end-stage metastatic disease. Clonal tracing timed disease initiation to embryogenesis. Continuous acquisition of structural variants at disease defining loci (MYCN, TERT, MDM2-CDK4) followed by convergent evolution of mutations targeting shared pathways emerged as the predominant feature of progression. At diagnosis metastatic clones were already established at distant sites where they could stay dormant, only to cause relapses years later and spread via metastasis-to-metastasis and polyclonal seeding after therapy.

Consensus criteria; Early phase; Neuroblastoma Criteris de consens; Fase inicial; Neuroblastoma Criterios de consenso; Fase inicial; Neuroblastoma Background International standardized criteria for eligibility, evaluable disease sites, and disease response assessment in patients with refractory, progressive, or relapsed high-risk neuroblastoma enrolled in early-phase clinical trials are lacking. Methods A National Cancer Institute–sponsored Clinical Trials Planning Meeting was convened to develop an international consensus to refine the tumor site eligibility criteria and evaluation of disease response for early-phase clinical trials in children with high-risk neuroblastoma. Results Standardized data collection of patient and disease characteristics (including specified genomic data), eligibility criteria, a definition of evaluable disease, and response evaluations for primary and metastatic sites of disease were developed. Eligibility included two distinct patient groups: progressive disease and refractory disease. The refractory disease group was subdivided into responding persistent disease and stable persistent disease to better capture the clinical heterogeneity of refractory neuroblastoma. Requirements for defining disease evaluable for a response assessment were provided; they included requirements for biopsy to confirm viable neuroblastoma and/or ganglioneuroblastoma in those patients with soft tissue or bone disease not avid for iodine-123 meta-iodobenzylguanidine. Standardized evaluations for response components and time intervals for response evaluations were established. Conclusions The use of international consensus eligibility, evaluability, and response criteria for early-phase clinical studies will facilitate the collection of comparable data across international trials and promote more rapid identification of effective treatment regimens for high-risk neuroblastoma. National Cancer Institute Pediatric and Adolescent Solid Tumor Steering Committee; Alex's Lemonade Stand Foundation for Childhood Cancer; Ben Towne Foundation; EVAN Foundation; Cancer Research UK Institute of Cancer Research, Grant/Award Number C347/A15403; National Institute for Health Research Research Methods Programme/Institute of Cancer Research Biomedical Research Centre.

Naxitamab is a humanized GD2-binding monoclonal antibody that received accelerated approval from the U.S. Food and Drug Administration for refractory or relapsed high-risk neuroblastoma limited to bone or bone marrow. Trial 201 (NCT03363373) is an ongoing global clinical trial to evaluate the efficacy and safety of naxitamab in combination with granulocyte-macrophage colony-stimulating factor in this population.Here, we review the safety profile and adverse event (AE) management associated with naxitamab administration in a pediatric population, based on Trial 201 protocol guidelines and clinical trial experience.At least 50% of patients experienced pain, hypotension, bronchospasm, cough, vomiting, diarrhea, nausea, and tachycardia, with the following reported at grade ≥3 AEs for at least 10% of patients: pain, hypotension, urticaria, and bronchospasm. These AEs were generally manageable in the outpatient setting using premedications, supportive therapies, and appropriate monitoring post-infusion. Algorithms were established for infusion-related AEs, including hypotension and bronchospasm, to provide guidance to investigators for early recognition and timely intervention, including medication and infusion rate modification or interruption, or treatment discontinuation, based on AE severity. Educating patients and caregivers on what to expect regarding premedication at home, experience during the infusion cycle, and post-infusion monitoring helps optimize naxitamab treatment and supportive therapies and may reduce treatment burden.This article highlights the protocol-based recommendations for the management of acute AEs associated with outpatient naxitamab treatment in Trial 201. The authors recommend close monitoring and timely implementation of measures to ensure that patients can remain on treatment and obtain maximum clinical benefit from naxitamab therapy.

Simple Summary Beta glucans, complex polysaccharides, can prime leukocyte dectin-1 and CR3-receptors and enhance anti-tumor cytotoxicity of monoclonal antibodies. In a phase I study (clinicaltrials.gov NCT00492167), we treated patients with intravenous 3F8 (fixed dose of 10 mg/m2/day × 10 days) and oral BG (dose-escalated from 10–200 mg/kg/day × 17 days in cohorts of 3–6 patients each). Forty-four patients completed 141 cycles of therapy with 3F8 + BG. One patient developed DLT: transient self-limiting hepatic transaminase elevation at a BG dose of 120 mg/kg/day. Overall, 1, 3, 12 and 24 evaluable patients had complete response, partial response, stable and progressive disease, respectively, at the end of treatment. Positive human anti-mouse antibody response and dectin-1 rs3901533 polymorphism were associated with better overall survival. BG dose level and serum BG levels did not correlate with response. BG lacked major toxicity and, in combination with 3F8, demonstrated anti-neuroblastoma activity against resistant disease. The recommended phase II dose was established at 40 mg/kg/day. Abstract Beta glucans, complex polysaccharides, prime leukocyte dectin-1 and CR3-receptors and enhance anti-tumor cytotoxicity of complement-activating monoclonal antibodies. We conducted a phase I study (clinicaltrials.gov NCT00492167) to determine the safety of the combination of yeast-derived beta glucan (BG) and anti-GD2 murine monoclonal antibody 3F8 in patients with relapsed or refractory high-risk neuroblastoma. Patients received intravenous 3F8 (fixed dose of 10 mg/m2/day × 10 days) and oral BG (dose-escalated from 10–200 mg/kg/day × 17 days in cohorts of 3–6 patients each). Forty-four patients completed 141 cycles. One patient developed DLT: transient self-limiting hepatic transaminase elevation 5 days after starting BG (120 mg/kg/day). Overall, 1, 3, 12 and 24 evaluable patients had complete response, partial response, stable and progressive disease, respectively, at the end of treatment. Positive human anti-mouse antibody response and dectin-1 rs3901533 polymorphism were associated with better overall survival. BG dose level and serum BG levels did not correlate with response. Progression-free and overall survival at 2 years were 28% and 61%, respectively. BG lacked major toxicity. Treatment with 3F8 plus BG was associated with anti-neuroblastoma responses in patients with resistant disease. Although the maximal tolerated dose for yeast BG was not reached, considering the large volume of oral BG, we recommended 40 mg/kg/day as the phase II dose.

Purpose: Therapy-related myelodysplastic syndrome and acute leukemias (t-MDS/AL) are a major cause of nonrelapse mortality among pediatric cancer survivors. Although the presence of clonal hematopoiesis (CH) in adult patients at cancer diagnosis has been implicated in t-MDS/AL, there is limited published literature describing t-MDS/AL development in children. Experimental Design: We performed molecular characterization of 199 serial bone marrow samples from 52 patients treated for high-risk neuroblastoma, including 17 with t-MDS/AL (transformation), 14 with transient cytogenetic abnormalities (transient), and 21 without t-MDS/AL or cytogenetic alterations (neuroblastoma-treated control). We also evaluated for CH in a cohort of 657 pediatric patients with solid tumor. Results: We detected at least one disease-defining alteration in all cases at t-MDS/AL diagnosis, most commonly TP53 mutations and KMT2A rearrangements, including involving two novel partner genes (PRDM10 and DDX6). Backtracking studies identified at least one t-MDS/AL-associated mutation in 13 of 17 patients at a median of 15 months before t-MDS/AL diagnosis (range, 1.3–32.4). In comparison, acquired mutations were infrequent in the transient and control groups (4/14 and 1/21, respectively). The relative risk for development of t-MDS/AL in the presence of an oncogenic mutation was 8.8 for transformation patients compared with transient. Unlike CH in adult oncology patients, TP53 mutations were only detectable after initiation of cancer therapy. Last, only 1% of pediatric patients with solid tumor evaluated had CH involving myeloid genes. Conclusions: These findings demonstrate the clinical relevance of identifying molecular abnormalities in predicting development of t-MDS/AL and should guide the formation of intervention protocols to prevent this complication in high-risk pediatric patients.

Very rarely, vasoactive intestinal peptide-related diarrhea (VIP-D) is observed in patients with high-risk neuroblastoma (HR-NB) where the associated fluid and electrolyte abnormalities can pose a major clinical challenge for administering the required aggressive multimodality treatment. Two patients with HR-NB developed VIP-D during induction and were found to have a somatic BRAF V600E mutation. Serum VIP levels and diarrhea promptly resolved in both patients after initiating treatment with BRAF and MEK inhibitors. This illustrates an association of VIP-D with BRAF V600E mutations and demonstrates a therapeutic strategy in the specific context of VIP-D and BRAF V600E mutations in HR-NB patients. The addition of BRAF and MEK inhibitors allows continued conventional tumor-directed treatment by decreasing the severity of symptoms caused by this life-threatening complication.

Background and Aim: Ganglioside GD2/GD3 vaccine stimulated robust antibody response among patients with high-risk metastatic neuroblastoma (HR-NB) who had prior disease progression (J Clin Oncol 39:215-226, 2020). High anti-GD2-IgG1antibody titer was associated with improved progression-free survival and overall survival in multivariable analyses. A gel formulation of yeast beta-glucan was used as an oral vaccine adjuvant, but its importance remained unproven. Patients and Methods: In a follow-up randomized Phase II trial (Clinicaltrials.gov identifier: NCT00911560), seven vaccine injections at 1, 2, 3, 8, 20, 32 and 52 weeks were administered to patients with HR-NB during their first or subsequent remissions. Each subcutaneous vaccine injection consisted of 30 ug each of GD2 and GD3, which was lactonized and conjugated to keyhole limpet hemocyanin and mixed with the subcutaneous saponin OPT-821 adjuvant at 150 µg/m2. No patients in this analysis received prior ganglioside vaccine. They were randomized to Arm 1 (n=54) receiving no glucan, or Arm 2 (n=53) receiving oral beta-glucan regimen (40 mg/kg/day, 14 days on/14 days off) starting at week 1. From week 6 onwards, all 107 patients received oral beta-glucan regimen through year end or up to disease progression. Serum IgG1 against GD2 and GD3, and IgM against GD2 were measured by ELISA at (right before) each vaccine injection. Wilcoxon rank sum test was used to compare antibody titers between the 2 arms. Results: In both arms, patients had comparable disease status at study entry, with 70% each in first remission. The remaining patients were in second remission after one prior disease progression. Consistently higher antibody response was observed among Arm 2 patients. The primary endpoint was met for anti-GD2-IgG1 titer at vaccine injection #6 at 32 weeks (p=0.08). Per protocol design, statistical significance (p Conclusion: Adding oral yeast beta-glucan as vaccine adjuvant during the first 6 weeks of immunization significantly enhanced the anti-GD2-IgG1 antibody response without added toxicities. Its impact on patient survival will require a longer clinical follow-up. Citation Format: Irene Y. Cheung, Audrey Mauguen, Yi Feng, Govind Ragupathi, Ellen Basu, Stephen S. Roberts, Shakeel Modak, Brian H. Kushner, Nai-Kong V. Cheung. Oral beta-glucan enhanced anti-ganglioside antibody titer after vaccination against high-risk neuroblastoma: Results of a randomized trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5218.

e22019 Background: Almost half of pts with NB present with high-risk disease, most of whom experience persistence of disease or disease progression. Further, residual disease in the bone/bone marrow (BM) can drive relapse. NAX is a humanized GD2-binding monoclonal antibody indicated under accelerated approval in the US with GM-CSF for the treatment of R/R HR-NB in the bone/BM in pts ≥1 year of age with a partial response (PR), minor response (MR), or stable disease (SD) to prior therapy. Here we characterize the response data of NAX overall and efficacy in pt subgroups. Methods: Trial 201 is an ongoing registrational phase II trial evaluating NAX in pts with R/R HR-NB. Pts with progressive or residual soft tissue disease were excluded. NAX was administered over 30-60 min in the outpatient setting on Days 1/3/5 at 3 mg/kg/day with GM-CSF at 250 µg/m2/day on Days –4 to 0 and 500 µg/m2/day on Days 1 to 5; cycles were every 4 wks. Efficacy was evaluated by independent pathology and radiology review per revised International Neuroblastoma Response Criteria. Results: Results presented here are from an ad hoc interim analysis (Aug 5, 2020) of 48 pts (safety population) and 36 (efficacy population). Pts in the efficacy population received a median of 7 cycles (range 1–11). Overall response rate (ORR; complete response [CR] + PR) was 58% (44% CR; Table). Of the 9 responders who had PR initially, 4 improved to CR. Median number of cycles before onset of response (CR or PR) was 2 (range 2–8) and median time to onset of response (CR or PR) was 7.3 wks (95% CI 6–17). Median duration of response was 24.9 wks (95% CI 25–not estimable). The most common adverse events (CTCAE graded) were infusion-related reactions including hypotension and pain, which occurred in 98% and 96% of pts, respectively. Adverse events were managed with established guidelines. Conclusions: NAX provided a clinically meaningful response in pts with R/R HR-NB limited to bone/BM – frequent sites of residual disease. Response rates were generally consistent across subgroups. These efficacy results combined with a manageable safety profile and use in the outpatient setting demonstrate that NAX addresses a significant unmet medical need. Clinical trial information: NCT03363373. [Table: see text]

10028 Background: Chemoresistant disease is an obstacle for cure of high-risk neuroblastoma (HR-NB). Anti-GD2 monoclonal antibodies (MoAb) dinutuximab and naxitamab in combination with cytokines are FDA-approved to consolidate remission and for chemorefractory osteomedullary HR-NB, but responses in progressive disease (PD) are rare. We investigated the combination of Humanized anti-GD2 MoAb naxitamab (Hu3F8), Irinotecan, Temozolomide and Sargramostim (GMCSF) in a phase II "HITS" protocol against resistant HR-NB (NCT03189706). Noteworthy differences between HITS and COG protocol ANBL 1221 included higher MoAb and temozolomide dosage and overlap of naxitamab with GMCSF. Methods: Patients were treated at Memorial Sloan Kettering (MSK) on protocol and at Hospital Sant Joan de Déu (HJSD) per protocol on compassionate basis. Salient eligibility criteria included evaluable or measurable chemoresistant disease. Prior anti-GD2 MoAb or irinotecan/temozolomide (IT) therapy was permitted. Each cycle, administered 3-5 weeks apart, comprised irinotecan 50 mg/m2/day intravenously (IV) plus temozolomide 150 mg/m2/day IV or orally (days 1-5); naxitamab 2.25 mg/kg/day IV, days 2,4,8 and 10, and GMCSF 250 mg/m2/day subcutaneously, days 6-10. Toxicity was measured by CTCAE v4.0 and responses by International Neuroblastoma Response Criteria. Objective responses (OR) were also noted. The primary endpoint of the phase II trial was complete (CR) and partial response (PR) after 4 cycles with a desirable rate of 40%; type I and II errors of 10% (undesirable=20%). Results: Of 90 heavily prior-treated patients (38 at MSK evaluated on trial, 52 at HJSD), 8 had HR-NB refractory to induction chemotherapy while 82 had up to 6 prior relapses (median=1). 503 cycles (median 5/patient) were administered. Toxicities included myelosuppression and diarrhea expected with IT, pain and hypertension expected with naxitamab, plus febrile neutropenia in 4%. No other >grade 2 unexpected toxicities occurred; treatment was outpatient. Primary endpoint was reached in the phase II trial: INRC response = 30.6%, lower boundary = 20.4%. In the entire cohort, best responses were CR (26%), PR (11%), mixed response (9%), stable disease (27%) and PD (27%). OR were noted in 64%, with soft tissue (48%) and skeletal MIBG uptake (66%). CR in BM was seen in 57%. OR occurred in patients with MYCN-amplified (25%), refractory (100%) and relapsed (61%) HR-NB; and patients who had previously received I/T (64%) or naxitamab (68%). In patients who had previously received dinutuximab/IT, OR rate to HITS was 42% (5/12). Human anti-human antibody did not develop in any patient (n=50). Conclusions: Naxitamab-based chemoimmunotherapy was safe without immunogenicity. It was effective against chemoresistant HR-NB in all disease compartments even in patients with multiple prior relapses, and in patients who previously received anti-GD2 MoAbs and/or IT.

Background Although metastatic involvement of bony sites including cranial bones is common in neuroblastoma (NB), mandibular metastases (MM) are uncommon, and specific outcomes have not been reported upon in the modern therapeutic era. Methods In this retrospective study, medical records on patients with MM from NB were reviewed. Statistical analysis was performed using the Kaplan-Meier method. Results Of 29 patients, nine (31%) had MM at diagnosis, whereas in 20 (69%) MM were first detected at NB relapse at a median time of 26 (6-89) months from diagnosis. Median maximal diameter of lesions was 3 (range 0.8-4.9) cm. MM were unilateral in 83% of patients, with ascending ramus (55%) and mandibular body (38%) being the two most common sites. All patients received systemic chemotherapy, and 26 (93%) patients received radiotherapy to MM. At a median follow-up of 37.3 (24.2-219.5) months, eight of nine patients with MM at diagnosis did not experience mandibular progressive disease. Eighteen of 20 patients with MM at relapse received therapeutic radiotherapy; objective responses were noted in 78%. Seventy-two percent (5/18) had not experienced relapse within the radiation field at a median of 12 (2-276) months postradiotherapy. Dental findings at follow-up after completion of NB therapy included hypodontia, hypocalcification of enamel, and trismus. Median 3-year overall survival in patients with relapsed MM was 51 ± 12% months from relapse. Conclusion MM when detected at diagnosis is associated with a prognosis similar to that for other skeletal metastases of NB. Radiotherapy is effective for control of MM detected both at diagnosis and relapse. Significant dental abnormalities posttherapy warrant regular dental evaluations and appropriate intervention.

PURPOSE Anti-GD2 monoclonal antibody (mAb) has proven efficacy in high-risk neuroblastoma (HR-NB). A small phase I GD2/GD3 vaccine trial (n = 15) described long-term survival and a favorable safety profile among patients with a history of disease progression (PD). The kinetics of mounting antibody response to vaccine and its prognostic impact on survival are now investigated in a phase II study (ClinicalTrials.gov identifier: NCT00911560 ). PATIENTS AND METHODS One hundred two patients with HR-NB who achieved remission after salvage therapies were enrolled in this trial. They received seven subcutaneous injections of GD2/GD3 vaccine spanning 1 year plus oral β-glucan starting at week 6 after the third dose of vaccine. Serum anti-vaccine antibody titers were quantified by enzyme-linked immunosorbent assay. Single nucleotide polymorphisms (SNPs) were determined by quantitative polymerase chain reaction. Kaplan-Meier and landmark Cox Regression models were used for survival estimates. RESULTS Patients had a history of one (63%), two (21%), or three to six (16%) episodes of PD. 82% of them progressed following anti-GD2 mAb (m3F8/dinutuximab/naxitamab) therapy. Vaccine-related toxicities were self-limited injection–associated local reactions and fever without any > grade 3 toxicities. The progression-free survival (PFS) was 32% ± 6%, and the overall survival (OS) was 71% ± 7% at 5 years. Serum anti-GD2 (immunoglobulin G1 [IgG1] and IgM) and anti-GD3 (IgG1) titers showed notable increases following the initiation of β-glucan at week 6. There was an association between IgG1 titer and SNP rs3901533 of dectin-1, the β-glucan receptor. Multivariable analyses showed that anti-GD2-IgG1 titer ≥ 150 ng/mL by week 8 was associated with favorable PFS and OS, while having prior episodes of PD and the time from last PD to vaccine were associated with PFS. CONCLUSION GD2/GD3 vaccine plus β-glucan elicited robust antibody responses in patients with HR-NB with prior PD. Higher anti-GD2-IgG1 titer was associated with improved survival.

Objective To review the treatment and revaccination of neuroblastoma-associated opsoclonus-myoclonus-ataxia syndrome (OMAS) patients at Memorial Sloan Kettering Cancer Center (MSK). Procedure Institutional Review Board approval was obtained for this retrospective study of patients with neuroblastoma-associated OMAS followed at MSK from 2000 to 2016. Results Fourteen patients (nine female) were 9-21 (median 17) months old at diagnosis of neuroblastoma and OMAS syndrome. They had stage 1 (n = 12), stage 2B, or intermediate-risk stage 4. Tumor histology was favorable in 11 patients, unfavorable in two, and unknown in one patient. No patient had amplified MYCN. All patients underwent tumor resection at diagnosis. Anti-neuroblastoma treatment was limited to chemotherapy in one patient. Overall survival is 100% at 3-16 (median 10) years. For OMAS, 13 patients received intravenous immune globulin (IVIg), adrenocorticotropic hormone (ACTH), and rituximab, and one received ACTH and IVIg. Seven patients experienced OMAS relapse. For these relapses, five patients received low-dose cyclophosphamide and two received rituximab. The mean total OMAS treatment was 20-96 (median 48) months. Seven patients started rituximab ≤3 months from diagnosis and did not relapse. The other six experienced OMAS relapse. To date, six patients have been revaccinated at a minimum of 2 years after completion of OMAS therapy without OMAS recurrence. Conclusions Patients with neuroblastoma-associated OMAS had excellent overall survival. Early initiation of rituximab, IVIg, and ACTH may reduce risks of OMAS relapse. Revaccination can be resumed without exacerbation of OMAS. Further investigation with a larger cohort of patients is needed.

PURPOSE: The tyrosine kinase receptor anaplastic lymphoma kinase (ALK) can be abnormally activated in neuroblastoma, and somatic ALK mutations occur in 6%-10% of patients. The differential clinical impact of these mutations has not been clearly elucidated. METHODS: Data on patients with neuroblastoma harboring ALK mutations were retrospectively analyzed. ALK sequencing was performed by whole-genome sequencing, hybrid-based capture of targeted exomes, or hotspot ALK mutation profiling. The differential impact of ALK mutation site on clinical characteristics, response to treatment, and survival was analyzed. In a subgroup of patients with locoregional neuroblastoma diagnosed after 2014, the impact of all ALK mutations was compared with wild-type ALK. RESULTS: Of 641 patients with neuroblastoma with ALK status analyzed on at least one tumor sample, 103 (16%) had tumors harboring ALK mutations. Mutations existed across all ages (birth to 67.8 years), stages (30% locoregional and 70% metastatic), and risk groups (20%, 11%, and 69% with low-, intermediate-, and high-risk disease, respectively). Mutation sites included F1174 (51%), R1275 (29%), R1245 (10%), and others (10%). Mutation site was not prognostic for progression-free survival or overall survival in the entire cohort, high-risk subgroup, or locoregional subgroup. Locoregional tumors with any ALK mutation were generally invasive: L2 by International Neuroblastoma Research Group staging in 30/31 patients with a 2-year progression-free survival (59%, 95% CI, 37.4 to 80.5) that was inferior to historical controls. This observation was corroborated in the post-2014 subgroup in which gross total resection was less likely for ALK-mutated tumors. CONCLUSION: Somatic ALK mutations are present across all stages and risk groups of neuroblastoma. No specific mutation carries differential prognostic significance. Locoregional neuroblastoma has an invasive phenotype when harboring somatic ALK mutations in this population.

Purpose Treatment strategies in palliation of pediatric cancer remain a significant challenge. In this study, we aimed to assess the efficacy and safety of a short course of hypofractionated radiation therapy (RT) for metastatic or recurrent childhood tumors. Methods and Materials A total of 104 lesions in 62 pediatric patients with metastatic or recurrent cancer were treated with a short hypofractionation schedule (>1 but ≤5 fractions; ≥3 Gy per fraction) between 2007 and 2017 in our institution. The primary endpoint was local control (LC). Other endpoints included treatment response, overall survival, progression-free survival, and toxicity. Toxicities were assessed using the Common Terminology Criteria for Adverse Events v.4.0. Results The most common histologies were neuroblastoma, comprising 50 of the 104 lesions (48.1%); osteosarcoma, 17 lesions (16.4%); and Ewing sarcoma, 13 lesions (12.5%). A median total dose of 24 Gy was delivered in a median of 5 fractions. Of 104 lesions, 26 (25.0%) were treated with stereotactic body radiation therapy, 24 (23.1%) with intensity modulated RT, and 48 (46.2%) with 2-dimensional RT or 3-dimensional conformal RT. A complete or partial response was observed in 63 (60.6%) of lesions, and stable disease was observed in 34 (32.7%). At a median follow-up of 8.7 months, 21 local failures occurred (20.2%). The 1- and 2-year LC rates were 74% and 68%, respectively. LC was better for tumors without previous irradiation (83% vs 57% with previous RT; P = .004). LC rates did not differ between RT techniques or total biologically effective dose with α/β ratio of 10 (BED10) (≤30 vs >30 Gy). At the time of analysis, 38 deaths in the cohort of 62 patients (61.3%) were recorded. The 1-year progression-free survival and overall survival rates were 31% and 44%, respectively. Incidence of any grade ≥3 toxicity was 6.7% (7 of 104). No grade 5 events occurred. Conclusions A short hypofractionation scheme yields effective disease control and treatment response with a favorable side effect profile. Select pediatric patients with symptomatic metastases or recurrent disease can be considered for a short course of palliative RT.

High-risk neuroblastoma (HR-NB) includes MYCN-amplified stage 2/3, but reports covering anti-GD2 immunotherapy, which recently became standard for HR-NB, do not provide details on this subset. We now report on all 20 MYCN-amplified stage 2/3 patients who received induction chemotherapy at our center during the era of consolidation with anti-GD2 antibody 3F8/ granulocyte-macrophage colony-stimulating factor (GM-CSF) (2000-2015). Early in this period, consolidation included autologous stem-cell transplantation (ASCT). Event-free survival (EFS) and overall survival (OS) were estimated using Kaplan-Meier analyses. With induction, 19/20 (95%) patients achieved complete/very good partial remission (CR/VGPR) but one had progressive disease with early death. One responder did not receive consolidation and died of relapse. Five-year post-diagnosis EFS/OS rates for all 20 patients were 72%/84%. The 18 CR/VGPR patients who received consolidation had EFS/OS 81%/94% at five years from starting 3F8/GM-CSF: 4/4 ASCT patients remained relapse-free, while 11/14 non-ASCT patients remained relapse-free and two of the three relapsed patients achieved 2nd CR (consolidated by retreatment with 3F8/GM-CSF) and remained in 2nd CR at 36+ and 95+ months post-relapse. The 14 non-ASCT patients had EFS/OS 73.5%/93% at five years from starting 3F8/GM-CSF. This subset appears to have a good prognosis with contemporary multi-modality therapy, possibly even without ASCT.

Purpose In patients with high-risk neuroblastoma, there is an increased recognition of relapse in the central nervous system (CNS). Craniospinal irradiation (CSI) has been an effective treatment but carries significant long-term complications. It is unclear whether reducing the CSI dose from 21 to 18 Gy can achieve similar CNS tumor control. Patients and methods A retrospective review of pediatric patients with CNS-relapsed neuroblastoma treated with CSI and boost to parenchymal lesions between 2003 and 2019 was performed. The goal was to assess CNS control comparing 18 Gy and 21 Gy regimens. Results Ninety-four patients with CNS-relapsed neuroblastoma were treated with CSI followed by intraventricular compartmental radioimmunotherapy. Median age at the time of CNS disease was 4 years (range 1-13 years). Forty-one patients (44%) received 21 Gy CSI prior to an institutional decision to lower the dose; 53 patients (56%) received 18 Gy CSI. Seventy-nine patients (84%) received additional boosts. With a median follow up of 4.1 years for surviving patients, 2-year CNS relapse-free survival was 74% for 18 Gy group versus 77% for 21 Gy group, and 5-year CNS relapse-free survival was 66% for 18 Gy versus 72% for 21 Gy group, respectively (P = .40). Five-year overall survival rate was 43% in 18 Gy group versus 47% in 21 Gy group (P = .72). Conclusion For patients with CNS-relapsed neuroblastoma, CNS disease control is comparable between 18 Gy and 21 Gy CSI dose regimens, in conjunction with radioimmunotherapy and CNS penetrating chemotherapy. More than 65% of the patients remain CNS disease free after 5 years. The findings support 18 Gy as the new standard CSI dose for CNS-relapsed neuroblastoma.

BACKGROUND/OBJECTIVES: Survivors of high-risk neuroblastoma (NB) are exposed to multimodality therapies early in life and confront late therapy-related toxicities. This study assessed respiratory symptoms, exercise capacity, and longitudinal changes in pulmonary function tests (PFTs) among survivors. DESIGN/METHODS: Survivors of high-risk NB followed in the Long-term Follow-up clinic at Memorial Sloan Kettering Cancer Center were enrolled. Symptom and physical activity questionnaires were completed. Medical records were reviewed for treatments and co-morbidities. Participants completed spirometry, plethysmography, diffusion capacity of the lung for carbon monoxide, 6 Minute Walk Tests (6MWTs), and cardiopulmonary exercise testing. Questionnaires and PFTs were repeated at least one year after enrollment. RESULTS: Sixty-two survivors participated (median age at study: 10.92years; median age at diagnosis: 2.75years; median time since completion of therapy: 5.29years). Thirty-two percent had chronic respiratory symptoms. Seventy-seven percent had PFT abnormalities, mostly mild to moderate severity. Thirty-three completed 6MWTs (median 634.3meters); eight completed cardiopulmonary exercise tests (mean VO(2) max: 63 percent predicted); twenty-three completed a second PFT revealing declines over a median 2.97years (mean percent predicted forced vital capacity: 79.9 to 70.0; mean forced expiratory volume in 1 second: 81.6 to 69.9). Risks for abnormalities included thoracic surgery, chest radiation therapy (RT), thoracic surgery plus chest RT, and hematopoietic stem cell transplant. CONCLUSIONS: In this cohort of survivors of high-risk NB, PFT abnormalities were common but mostly mild or moderate. Maximal exercise capacity may be affected by respiratory limitations and declines in lung function may occur over time. Continued pulmonary surveillance of this at-risk population is warranted.

2001 Background: Neuroblastoma (NB), a rare malignancy of the sympathetic nervous system, is a tumor of early childhood with > 90% of cases diagnosed before 5 years of age. Adult-onset NB (AON) is extremely rare and differs significantly from childhood disease. AON, while more indolent, is usually metastatic at diagnosis, generally chemotherapy-resistant, and almost invariably lethal. Additionally, standard therapies for NB such as dose-intensive chemotherapy and anti-GD2 antibody are poorly tolerated by adults. Prior studies have shown AON is enriched for genomic aberrations especially ALK (Suzuki et al 2018). Although ALK inhibitors (ALKi) are effective for therapy of lymphoma and non-small cell lung cancer, their use in AON has not previously been reported. Methods: Retrospective review of patients > 18 years old at diagnosis seen at Memorial Sloan Kettering Cancer Center (MSKCC) was performed after IRB approval. Response to ALKi was evaluated using International Neuroblastoma Response Criteria; objective responses were also noted. Progression-free (PFS) and overall survival (OS) was calculated using Kaplan-Meier methods. Results: Since 1979, 52 patients with AON were seen at MSKCC. Of 23 patients evaluated, 14 (61%), harbored somatic ALK mutations. Seven were treated with FDA-approved ALKi. One patient initially diagnosed at 12 years of age was treated with ALKi following a relapse 15 years later. Overall, all ALKi were well-tolerated; reported adverse events included grade 1-2 nausea and vomiting (n = 6), and neurologic symptoms including hallucinations, drowsiness, and dizziness (n = 1 patient each) which resolved after stopping ALKi. Four patients received > 1 ALKi either due to progressive disease or intolerance. Most patients responded to the first ALKi with objective though partial response (n = 5) while one had progressive disease (PD). Median time to progression for initial ALKi was 15.5 months (10-45). One patient with no evaluable disease after four prior relapses was treated with alectinib for 36 months without PD. Of the patients treated with a second ALKi (n = 4), 1 had CR and 2 had PR after not having progressed previously, while the other had stable disease. Median OS from beginning treatment with first ALKi was 46.5 (17-74) months. Conclusions: AON is a rare disease which is a therapeutic challenge. Enrichment of ALK mutations permits consideration of targeted therapy. ALKi were well tolerated, often associated with significant responses, and treatment with serial ALKi led to ongoing benefit. Given this, ALKi should be considered for treatment in future AON cases.

10022 Background: NB is the most common extracranial solid tumor in children and half of patients present with high-risk disease. Bone and BM are frequent sites of metastatic disease and can serve as a reservoir for residual disease driving relapse. Naxitamab, a GD2-binding monoclonal antibody, was recently approved in the United States in combination with GM-CSF for the treatment of pediatric patients ≥1 year of age and adult patients with R/R HR-NB in the bone/BM who have demonstrated a partial response (PR), minor response (MR), or stable disease (SD) to prior therapy. Here we describe outcomes from the registrational Trial 201 (NCT03363373) detailed by bone/BM involvement. Methods: HR-NB patients with primary refractory disease or incomplete response to salvage treatment following relapse or progressive disease (PD) (in both cases including SD, MR and PR) with disease limited to bone and/or BM were eligible. Naxitamab was administered over ≥30 min in the outpatient setting on Days 1, 3 and 5 at 3 mg/kg/infusion (9 mg/kg/cycle) in combination with GM-CSF at 250 µg/m2/day on Days -4 to 0 and at 500 µg/m2/day on days 1 to 5. Treatment cycles were repeated every 4 weeks. Response was assessed after Cycle 2 and then every 2-3 months by revised International Neuroblastoma Response Criteria (INRC) using BM biopsies/aspirates and 123I-MIBG scintigraphy or FDG-PET. Effectiveness was concluded if the lower limit of the Clopper-Pearson exact 95% confidence interval (CI) of overall response rate (ORR) was >20%. We report efficacy data on 22 patients and safety data on the first 25 patients enrolled. Results: 13 (59%) patients had NB in bone, 2 (9%) had NB in BM, and 7 (32%) had NB in both bone and BM. Summary of overall response and response by compartment. Conclusions: Naxitamab provided clinically meaningful activity in both bone and BM with ORR of 68% and had a manageable AE profile. Clinical trial information: NCT03363373. [Table: see text]

Purpose To evaluate local control after 21-Gy radiation therapy (RT) to the primary site in patients with high-risk neuroblastoma. Methods and Materials After receiving dose-intensive chemotherapy and gross total resection (GTR), 246 patients (aged 1.2-17.9 years, median 4.0 years) with high-risk neuroblastoma underwent RT to the primary site at Memorial Sloan Kettering from 2000 to 2014. Radiation therapy consisted of 21 Gy in twice-daily fractions of 1.5 Gy each. Local failure (LF) was correlated with biologic prognostic factors and clinical findings at the time of diagnosis and start of RT. Results Median follow-up of surviving patients was 6.4 years. Cumulative incidence of LF was 7.1% at 2 years after RT and 9.8% at 5 years after RT. The isolated LF rate was 3.0%. Eighty-six percent of all local failures were within the RT field. Local control was worse in patients who required more than 1 surgical resection to achieve GTR (22.4% vs 8.3%, P =.01). There was also a trend toward inferior local control with MYCN- amplified tumors or serum lactate dehydrogenase ≥1500 U/L ( P =.09 and P =.06, respectively). Conclusion After intensive chemotherapy and maximal surgical debulking, hyperfractionated RT with 21 Gy in high-risk neuroblastoma results in excellent local control. Given the young patient age, concern for late effects, and local control >90%, dose reduction may be appropriate for patients without MYCN amplification who achieve GTR.

AKT plays a pivotal role in driving the malignant phenotype of many cancers, including high-risk neuroblastoma (HR-NB). AKT signaling, however, is active in normal tissues, raising concern about excessive toxicity from its suppression. The oral AKT inhibitor perifosine showed tolerable toxicity in adults and in our phase I trial in children with solid tumors (clinicaltrials.gov NCT00776867). We now report on the HR-NB experience. HR-NB patients received perifosine 50-75mg/m2/day after a loading dose of 100-200mg/m2 on day 1, and continued on study until progressive disease. The 27 HR-NB patients included three treated for primary refractory disease and 24 with disease resistant to salvage therapy after 1-5 (median 2) relapses; only one had MYCN-amplified HR-NB. Pharmacokinetic studies showed μM concentrations consistent with cytotoxic levels in preclinical models. Nine patients (all MYCN-non-amplified) remained progression-free through 43+ to 74+ (median 54+) months from study entry, including the sole patient to show a complete response and eight patients who had persistence of abnormal 123I-metaiodobenzylguanidine skeletal uptake but never developed progressive disease. Toxicity was negligible in all 27 patients, even with the prolonged treatment (11-to-62 months, median 38) in the nine long-term progression-free survivors. The clinical findings 1) confirm the safety of therapeutic serum levels of an AKT inhibitor in children; 2) support perifosine for MYCN-non-amplified HR-NB as monotherapy after completion of standard treatment or combined with other agents (based on preclinical studies) to maximize antitumor effects; and 3) highlight the welcome possibility that refractory or relapsed MYCN-non-amplified HR-NB is potentially curable. This article is protected by copyright. All rights reserved.

Background and Aim: High-risk neuroblastoma (HR-NB) relapse carries a dismal prognosis. Recent experience, however, suggests that cure is possible when remission is achieved with salvage therapy that includes anti-GD2 monoclonal antibody (mAb). The long-term survival and the favorable safety profile of gangliosides GD2 and GD3 vaccine among these patients in a Phase I trial (n=15, Clinical Cancer Res 2014) need to be confirmed. Moreover, the kinetics of seroconversion (mounting anti-vaccine antibody response) and its prognostic impact on survival need to be explored. Patients and Methods: In this Phase II trial (Clinicaltrials.gov NCT00911560), 102 HR-NB patients who achieved complete remission after salvage therapy were enrolled. They received 7 subcutaneous vaccine injections (week 1-2-3-8-20-32-52) plus oral beta-glucan (starting in week 6 at 40 mg/kg/day, 14 days on/14 days off). Each subcutaneous vaccine injection consisted of 30 µg each of GD2 and GD3, lactonized and conjugated to keyhole limpet hemocyanin and mixed with the saponin OPT-821 adjuvant. Serum anti-vaccine antibody titers were quantified by ELISA. Kaplan-Meier statistics and landmark Cox Regression models were used for survival estimates and prognostic impact analyses. Results: Among 102 patients, 63% had one, 21% had 2, and 16% had 3-6 prior disease progressions. 83/101 patients had failed prior anti-GD2 mAb (m3F8, dinutuximab, or naxitamab) therapy before vaccine: one mAb (n=62), two mAbs (n=15), or all three (n=6). Common toxicities were self-limited injection-related local reactions and fever. No pain, neuropathy, or grade 3/4 toxicities occurred during or post treatment. Progression-free survival (PFS) was 44%±5% and overall survival (OS) was 88%±4% at 2 years, and 36%±7% and 70%±8% at 5 years, respectively. Serum anti-GD2 (IgG1 and IgM) and anti-GD3 (IgG1) titers had marked increases following the initiation of beta-glucan at week 6. In univariate analyses, favorable prognostic factors included: one versus ≥2 prior disease progressions (PFS p=0.005, OS p=0.04), none versus any prior anti-GD2 mAb failures (PFS p=0.004, OS p=0.01); and the induction of ≥150 ng/ml anti-GD2-IgG1 titers by week 8 (PFS p=0.02, OS p=0.06). Factors not prognostic included: time to first NB progression, MYCN amplification status, anti-GD2-IgM, anti-GD3-IgG1 or anti-KLH-IgG1 titers, and treatment with anti-GD2 mAb right before vaccine. In multivariate analyses, week 8 anti-GD2-IgG1 titer ≥150 ng/ml yielded a hazard ratio (HR) of 0.41 [0.20, 0.83], p=0.01 for PFS, and HR=0.15 [0.02, 1.12], p=0.06 for OS. The second independent prognostic variable was the number of prior disease progressions (≥2 vs 1), yielding HR of 2.12 [1.26, 3.58], p=0.005 for PFS, and HR=2.77 (1.03, 7.47), p=0.04 for OS. Conclusions: Even with prior disease progressions, anti-GD2 (though not anti-GD3) seroconversion was associated with notable long-term survival among HR-NB patients previously thought to be unsalvageable. A randomized trial to assess the role of beta-glucan in seroconversion is actively accruing patients. Citation Format: Irene Y. Cheung, Nai-Kong V. Cheung, Shakeel Modak, Audrey Mauguen, Ellen Basu, Stephen S. Roberts, Govind Ragupathi, Brian H. Kushner. Survival impact of anti-GD2 antibody response - A phase II ganglioside vaccine trial in relapsed neuroblastoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-092.

Purpose For patients with high-risk neuroblastoma (HR-NB), a dose of 21 Gy to the primary tumor site after gross total resection (GTR) provides excellent local control. However, no clinical trial has specifically evaluated the optimal dose of radiation therapy (RT), and RT-related long-term toxicities are of increasing concern. We sought to assess local control, survival outcomes, and toxicity after a reduction in dose to the primary site from 21 Gy to 18 Gy. Methods and Materials After induction chemotherapy and GTR, patients with HR-NB were enrolled and treated on an RT dose-reduction prospective trial with 18 Gy hyperfractionated RT given in twice-daily fractions of 1.5 Gy each. Results The 25 study subjects were 1.6 to 9.5 (median, 4.3) years old at enrollment and included 23 (92%) with stage IV and II (8%) with MYCN-amplified stage III disease. Eleven (44%) were in complete remission (CR), and 14 (56%) had persistence of osteomedullary disease postinduction. Three patients (12%) received proton therapy, and the rest received intensity modulated photon therapy. After a follow-up of 1.8 to 4.2 (median, 3.5) years from initiation of RT, no failures occurred within the RT field; 3 patients had marginal recurrences. The respective 3-year progression-free and overall survival rates were 54.5% and 90.9% for patients in first CR and 42.9% and 76.2% for patients not in metastatic CR. Acute toxicity was negligible. Conclusions Reduced-dose RT with 18 Gy did not compromise local control or survival outcomes in our cohort of patients with HR-NB after GTR. These findings support assessing further RT dose reduction and validation on a larger, multi-institutional trial.

The antivascular endothelial growth factor antibody, bevacizumab, is effective against several malignancies in adults but unproven in pediatric oncology. In early phase pediatric studies toxicities were similar to those in adults. Bowel perforation in adults is a rare but serious toxicity, but has not been hitherto reported in children. A 5-year-old boy with chemoresistant neuroblastoma treated with bevacizumab plus radioimmunotherapy developed acute abdominal pain. Computed tomography scan showed free abdominal air and pneumatosis coli. Emergency laparotomy and bowel diversion were performed leading to complete recovery and timely continuation of antineuroblastoma therapy. Early recognition and rapid intervention can prevent a catastrophic outcome in bevacizumab-related bowel perforation.

Arsenic trioxide has in vitro and in vivo radiosensitizing properties. We hypothesized that arsenic trioxide would enhance the efficacy of the targeted radiotherapeutic agent 131I-metaiodobenzylguanidine (131I-MIBG) and tested the combination in a phase II clinical trial. Methods: Patients with recurrent or refractory stage 4 neuroblastoma or metastatic paraganglioma/pheochromocytoma (MP) were treated using an institutional review board–approved protocol (Clinicaltrials.gov identifier NCT00107289). The planned treatment was 131I-MIBG (444 or 666 MBq/kg) intravenously on day 1 plus arsenic trioxide (0.15 or 0.25 mg/m2) intravenously on days 6–10 and 13–17. Toxicity was evaluated using National Cancer Institute Common Toxicity Criteria, version 3.0. Response was assessed by International Neuroblastoma Response Criteria or (for MP) by changes in 123I-MIBG or PET scans. Results: Twenty-one patients were treated: 19 with neuroblastoma and 2 with MP. Fourteen patients received 131I-MIBG and arsenic trioxide, both at maximal dosages; 2 patients received a 444 MBq/kg dose of 131I-MIBG plus a 0.15 mg/kg dose of arsenic trioxide; and 3 patients received a 666 MBq/kg dose of 131I-MIBG plus a 0.15 mg/kg dose of arsenic trioxide. One did not receive arsenic trioxide because of transient central line–induced cardiac arrhythmia, and another received only 6 of 10 planned doses of arsenic trioxide because of grade 3 diarrhea and vomiting with concurrent grade 3 hypokalemia and hyponatremia. Nineteen patients experienced myelosuppression higher than grade 2, most frequently thrombocytopenia (n = 18), though none required autologous stem cell rescue. Twelve of 13 evaluable patients experienced hyperamylasemia higher than grade 2 from transient sialoadenitis. By International Neuroblastoma Response Criteria, 12 neuroblastoma patients had no response and 7 had progressive disease, including 6 of 8 entering the study with progressive disease. Objective improvements in semiquantitative 131I-MIBG scores were observed in 6 patients. No response was seen in MP. Seventeen of 19 neuroblastoma patients continued on further chemotherapy or immunotherapy. Mean 5-year overall survival (±SD) for neuroblastoma was 37% ± 11%. Mean absorbed dose of 131I-MIBG to blood was 0.134 cGy/MBq, well below myeloablative levels in all patients. Conclusion:131I-MIBG plus arsenic trioxide was well tolerated, with an adverse event profile similar to that of 131I-MIBG therapy alone. The addition of arsenic trioxide to 131I-MIBG did not significantly improve response rates when compared with historical data with 131I-MIBG alone.

ABSTRACT Desmoplastic small round cell tumor (DSRCT) was proposed as a distinct disease entity by William L Gerald and Juan Rosai in 1991. Over 850 patients have been reported in the medical literature. A specific translocation, t(11;22)(p13;q12), is seen in almost all cases, juxtaposing the EWS gene to the WT1 tumor suppressor gene. DSRCT is composed of nests of small round cells with polyphenotypic differentiation, typically a mixture of epithelial, mesenchymal and neural features, surrounded by a prominent desmoplastic stroma. DSRCT has a predilection for adolescent and young adult males, and primarily involves the abdominal cavity and pelvis. Survival is low despite their initial response to multimodal treatment. Most patients relapse with disseminated disease that is unresponsive to further therapy.

PURPOSE: As part of consolidative therapy in high-risk neuroblastoma, modern protocols recommend radiation therapy (RT) both to the primary site and to sites of metastatic disease that persist after induction chemotherapy. Although there are abundant data showing excellent local control (LC) with 21 Gy directed at the primary site, there are few data describing the feasibility and efficacy of RT directed at metastatic sites of disease as part of consolidation. METHODS AND MATERIALS: All patients with neuroblastoma who received RT to metastatic sites of disease as a part of consolidative therapy at a single institution between 2000 and 2015 were reviewed. Among 159 patients, 244 metastases were irradiated. RESULTS: The median follow-up period among surviving patients was 7.4 years. Over 85% of the irradiated metastases were treated with 21 Gy (range, 10.5-36 Gy). Tumor recurrence occurred in 43 of 244 irradiated metastases (18%). The 5-year LC rate of treated metastatic sites was 81%. Metastatic sites that cleared with induction chemotherapy had improved LC compared with sites with persistent uptake on metaiodobenzylguanidine scans (LC rate, 92% vs 67%; P

Anti-G(D2) murine antibody 3F8 plus subcutaneously (sc) administered granulocyte-macrophage colony-stimulating factor (GM-CSF) was used against primary refractory neuroblastoma in metastatic osteomedullary sites. Large study size and long follow-up allowed assessment of prognostic factors in a multivariate analysis not reported with other anti-G(D2) antibodies. In a phase II trial, 79 patients without prior progressive disease were treated for persistent osteomedullary neuroblastoma documented by histology and/or metaiodobenzyl-guanidine (MIBG) scan. In the absence of human antimouse antibody, 3F8 + scGM-CSF cycles were repeated up to 24 months. Minimal residual disease (MRD) in bone marrow was measured by quantitative reverse transcription-polymerase chain reaction pre-enrollment and post-cycle #2, before initiation of 13-cis-retinoic acid. Study endpoints were: (i) progression-free survival (PFS) compared with the predecessor trial of 3F8 plus intravenously administered (iv) GM-CSF (26 patients) and (ii) impact of MRD on PFS. Using all 105 patients from the two consecutive 3F8 + GM-CSF trials, prognostic factors were analyzed by multivariate Cox regression model. Complete response rates to 3F8 + scGM-CSF were 87% by histology and 38% by MIBG. Five-year PFS was 24 ± 6%, which was significantly superior to 11 ± 7% with 3F8 + ivGM-CSF (p = 0.002). In the multivariate analysis, significantly better PFS was associated with R/R or H/R FCGR2A polymorphism, sc route of GM-CSF and early MRD response. MYCN amplification was not prognostic. Complement consumption was similar with either route of GM-CSF. Toxicities were manageable, allowing outpatient treatment. 3F8 + scGM-CSF is highly active against chemoresistant osteomedullary neuroblastoma. MRD response may be an indicator of tumor sensitivity to anti-G(D2) immunotherapy. Correlative studies highlight the antineoplastic potency of myeloid effectors.

BACKGROUND The authors exploited a large database to investigate the outcomes of patients with high-risk neuroblastoma in the contemporary era. METHODS All patients with high-risk neuroblastoma aged 18 months with MYCN-nonamplified [MYCN(−)] stage 4 disease. RESULTS A complete response/very good partial response (CR/VGPR) to induction was correlated with significantly superior event-free survival (EFS) (P

Purpose: To report on a phase I trial designed to find the maximally tolerated dose in children of the immunologic adjuvant OPT-821 in a vaccine containing neuroblastoma-associated antigens (GD2 and GD3; Clinicaltrials.gov NCT00911560). Secondary objectives were to obtain preliminary data on immune response and activity against minimal residual disease (MRD). Treatment also included the immunostimulant β-glucan. Experimental Design: Patients with neuroblastoma in ≥2nd complete/very good partial remission received vaccine subcutaneously (weeks 1–2–3–8–20–32–52). Vaccine contained 30 μg each of GD2 and GD3 stabilized as lactones and conjugated to the immunologic carrier protein keyhole limpet hemocyanin; and OPT-821, which was dose escalated as 50, 75, 100, and 150 μg/m2 per injection. Oral β-glucan (40 mg/kg/day, 14 days on/14 days off) started week 6. Results: The study was completed with 15 patients because there was no dose-limiting toxicity at 150 μg/m2 of OPT-821 (the dosing used in adults). Thirteen of fifteen patients received the entire protocol treatment, including 12 who remain relapse-free at 24+ to 39+ (median 32+) months and 1 who relapsed (single node) at 21 months. Relapse-free survival was 80% ± 10% at 24 months. Vaccine and β-glucan were well tolerated. Twelve of fifteen patients had antibody responses against GD2 and/or GD3. Disappearance of MRD was documented in 6 of 10 patients assessable for response. Conclusions: This immunotherapy program lacks major toxicity and is transportable to any outpatient clinic. Patient outcome is encouraging but the efficacy is uncertain because of the complexity and heterogeneity of prior therapies. A larger phase II trial is underway. Clin Cancer Res; 20(5); 1375–82. ©2014 AACR.

10025 Background: Chemoresistant and relapsed disease are major obstacles to curing high-risk neuroblastoma (HR-NB). Anti-GD2 monoclonal antibody (MoAb) is effective in preventing relapse after remission but responses in relapsed or progressive disease (PD) are rare. We investigated the combination of humanized anti-GD2 MoAb naxitamab, (previously termed Hu3F8), irinotecan, temozolomide and sargramostim (GM-CSF): a pilot HITS protocol against resistant HR-NB now expanded to a phase II study (NCT03189706). Methods: Salient eligibility criteria included evaluable or measurable chemoresistant disease. Prior anti-GD2 MoAb and/or irinotecan/temozolomide (I/T) therapy was permitted. Each cycle comprised of irinotecan 50 mg/m2/day intravenously (IV) plus temozolomide 150 mg/m2/day IV or orally (days 1-5); naxitamab 2.25 mg/kg/day IV over 30 minutes, days 2, 4, 8 and 10 (total 9 mg/kg or 270 mg/m2 per cycle), and GM-CSF 250 mg/m2/day subcutaneously, days 6-10. Toxicity was measured by CTCAE v4.0 and responses by modified International Neuroblastoma Response Criteria. Results: Forty-six (23 enrolled on protocol and 23 on compassionate-use basis) heavily prior-treated patients (median age at enrollment: 6.6 years; median number of prior relapses: 2) have received 175 (median 2; range 1-12) cycles to date. At enrollment, 7 patients had HR-NB refractory to induction chemotherapy while 39 had prior relapse. Toxicities included myelosuppression and diarrhea expected with I/T, and pain and hypertension expected with naxitamab. No other > grade 2 related toxicities occurred; treatment was outpatient. Early responses, assessed after 2 cycles, were documented in 18 (39%) patients and were complete (n = 9), partial (n = 8), and mixed (n = 1); 13 patients had stable disease. Responses were achieved in refractory (3/7;43%) and PD (15/39;38%) subgroups, in patients who had previously received I/T (12/34;35%) and/or anti-GD2 MoAb (14/36;39%), and in soft tissue (6/22; 27%) MIBG-avid skeletal sites (20/36;56%) and on bone marrow histology (9/12; 75%). Conclusions: High-dose naxitamab-based chemoimmunotherapy is safe and effective against chemoresistant HR-NB. This ongoing phase II study may define a broader role for naxitamab which was recently granted breakthrough designation by the FDA. Clinical trial information: NCT03189706.

We report a severe and not previously reported toxicity after short-interval retreatment with stereotactic body radiotherapy (SBRT) in a pediatric patient with neuroblastoma. This patient experienced Grade III radiation myositis after treatment with conventional radiation therapy followed by high-dose SBRT for persistent disease a short interval after the initial radiotherapy course. While SBRT shows outstanding rates of local control in adult disease, data in pediatric cancers are extremely limited. In this report, we discuss the rationale of SBRT in this patient's multimodality neuroblastoma treatment, management of the toxicity, and future perspectives on the use of SBRT in pediatric cancer.