Predictors of differential response to induction therapy in high-risk neuroblastoma: A report from the Children's Oncology Group (COG)

A 2035 Clinical Research Vision and Roadmap for High-Risk Neuroblastoma

Despite the introduction of anti-GD2 antibody therapy, outcomes for children with high-risk neuroblastoma remain poor, with low cure rates and a high proportion of survivors facing long-term sequelae. In this report, leaders from international cooperative groups and patient advocacy organizations review lessons learnt, identify current challenges, and provide a vision to bring new agents into frontline therapy to increase cure rates and reduce long-term toxicities over the next decade. The implementation of this vision requires improved global collaboration, incorporation of novel biomarkers, and a strengthened interaction with the regulatory landscape.

Characteristics, treatments, and outcomes of adolescents and adults with neuroblastoma: a retrospective study in China

Background

Neuroblastoma (NB) is rare in adolescents and adults, resulting in limited availability of data.

Objectives

We comprehensively investigated the characteristics, treatments, and outcomes of adolescent and adult patients with NB, aiming to provide a more in-depth insight into this disease.

Design

A retrospective, single-center study.

Methods

We retrieved and analyzed the medical data of patients with NB aged 10 years or older at diagnosis who were treated at Sun Yat-sen University Cancer Center between June 2005 and January 2024.

Results

Sixty-five patients (30 males and 35 females) were enrolled, with a median age of 20 years (interquartile range, 14-26 years), including 27 patients aged 10-18 years and 38 patients aged >18 years. Most patients were classified as M-stage disease (n = 40, 61.5%), high-risk (n = 42, 64.6%), and poorly differentiated NB (n = 27, 41.5%). Additionally, 3 (6.7%) patients had MYCN amplification, and 5 (25%) had ALK mutations. The genomic landscape revealed that mutations in the cell cycle and DNA repair pathways are related to chemotherapy sensitivity. After induction therapy, 34 (52.3%) patients achieved complete response (CR). The 5-year progression-free survival (PFS) and overall survival (OS) rates were 33.1% ± 6.9% and 55.1% ± 7.6%, respectively. Patients who achieved CR after induction therapy had superior PFS (p = 0.009), with 5-year PFS rates of 44.0% ± 10.6% compared to 18.5% ± 8.5% in non-CR patients.

Conclusion

Adolescent and adult patients with NB exhibit distinct characteristics, less chemotherapy sensitivity, and poorer outcomes compared to pediatric patients. Achieving CR after induction therapy is associated with better outcomes. Further investigation for new therapies is required.

Mechanisms and molecular characterization of relapsed/refractory neuroblastomas

Relapsed/refractory neuroblastoma is a type of malignant solid tumor with a very poor prognosis in children. Its pathogenesis is complex, involving multiple molecular pathways and genetic alterations. Recent studies have shown that MYCN amplification, ALK mutation, TERT promoter mutation, p53 pathway inactivation, and chromosomal instability are the key mechanisms and molecular characteristics of relapsed/refractory neuroblastoma. Precision treatment strategies targeting these molecular mechanisms have shown certain prospects in preclinical studies and clinical practice. This review focuses on the relevant mechanisms and molecular characteristics of relapsed/refractory neuroblastoma, explores its relationship with treatment response and clinical prognosis, and briefly introduces the current treatment strategies to provide a theoretical basis for the development of novel and personalized therapeutic regimens to improve the prognosis of children.

Management and outcome of children with high-risk neuroblastoma: insights from the Spanish Society of Pediatric Hematology and Oncology (SEHOP) neuroblastoma group on refractory and relapse/progressive disease

PURPOSE

Outcome for children with refractory and relapse/progressive high-risk neuroblastoma (HR-NB) remains poor, without an internationally agreed standard second-line approach. Heterogeneity in patients' disease and treatment strategies challenges clinical management. The survival rate for patients with resistant disease does not exceed 20% at 5 years. The study's aim was to analyze refractory and progressive HR-NB patients in a real-world setting to evaluate current clinical practices and optimize future approaches.

METHODS

Data from patients diagnosed with refractory and relapse/progressive (R/R-P) HR-NB between January 2019 and December 2021 at six of the major Spanish neuroblastoma treating hospitals were collected and analyzed.

RESULTS

A total of 67 episodes of R/R-P HR-NB were included. Treatments applied included chemotherapy (97%), immunotherapy (48%), consolidation (21%), local treatment (surgery and/or radiotherapy) (45%) and maintenance (16%), and were administered within a clinical trial (CT) in 34% of the episodes. Biopsy was performed in 37% of the tumors and 30% were profiled. Event-free survival (EFS) in our cohort was 20.9% and overall survival (OS) 32%. Significant survival advantage (in both OS and EFS) was observed in refractory episodes compared to relapse/progressive, in first events compared to successive, and when response or disease stabilization was achieved. MYCN status, presence of lymph node metastases, use of irinotecan or topotecan, and radiotherapy were also univariate predictors of OS.

CONCLUSIONS

Treatment of refractory and relapse/progressive HR-NB is highly heterogeneous. We confirm a poor outcome, although certain epidemiological and treatment-related factors have prognostic value. Molecular profiling and inclusion in CTs should be improved.

The anti-GD2 monoclonal antibody naxitamab plus GM-CSF for relapsed or refractory high-risk neuroblastoma: a phase 2 clinical trial

In this single-arm, non-randomized, phase 2 trial (NCT03363373), 74 patients with relapsed/refractory high-risk neuroblastoma and residual disease in bone/bone marrow (BM) received naxitamab on Days 1, 3, and 5 (3 mg/kg/day) with granulocyte-macrophage colony-stimulating factor (Days -4 to 5) every 4 weeks, until complete response (CR) or partial response (PR) followed by 5 additional cycles every 4 weeks. Primary endpoint in the prespecified interim analysis was overall response (2017 International Neuroblastoma Response Criteria). Among 26 responders (CR + PR) in the efficacy population (N = 52), 58% had refractory disease, and 42% had relapsed disease. Overall response rate (ORR) was 50% (95% CI: 36-64%), and CR and PR were observed in 38% and 12%, respectively. With the 95% CI lower limit for ORR exceeding 20%, the primary endpoint of overall response was met. Patients with evaluable bone disease had a 58% (29/50) bone compartment response (CR, 40%; PR, 18%). BM compartment response was 74% (17/23; CR, 74%). One-year overall survival and progression-free survival (secondary endpoints) were 93% (95% CI: 80-98%) and 35% (95% CI: 16-54%), respectively. Naxitamab-related Grade 3 adverse events included hypotension (58%) and pain (54%). Overall, naxitamab demonstrated clinically meaningful efficacy with manageable safety in patients with residual neuroblastoma in bone/BM.

Response to induction chemotherapy modifies the effect of conventional prognostic factors in high-risk neuroblastoma: A report from the Children's Oncology Group

Background

Response to induction chemotherapy has been shown to predict outcome in patients with high-risk neuroblastoma (HR-NB), with those achieving a complete response (CR) having superior outcomes.

Methods

We evaluated whether conventional prognostic factors remain prognostic in subsets of patients defined by response to induction. 1244 Patients from four COG high-risk trials were included. End-induction response was coded as CR, partial response (PR) or better, less than PR without progressive disease (PD), and PD. Cox regression models were performed to calculate event-free and overall survival (EFS, OS) hazard ratios, including interaction terms between induction response and prognostic factors including sex, age, stage, primary tumor location, LDH, ferritin, ploidy, MYCN status, ALK status, histology, MKI, grade, and study era.

Results

Among patients who achieved a CR after induction, INSS stage 4 disease and trial era were the only factors that remained significantly associated with inferior OS. For those who achieved less than a PR, adrenal primary site, MYCN amplification, and 1p LOH were associated with inferior outcomes. Multivariable models showed that end-induction response remained prognostic of EFS and OS even after controlling for other factors. Multiple significant statistical interactions were observed between end-induction response and other prognostic factors.

Conclusion

The impact of conventional prognostic factors is not static in patients with HR-NB. Instead, response to induction chemotherapy modifies the effect of conventional prognostic factors. These data can help to further refine prognosis for patients with variable responses to induction and help to identify candidates who might benefit from treatment other than standard post-induction therapy.

Mechanism of Drug Resistance to First-Line Chemotherapeutics Mediated by TXNDC17 in Neuroblastomas

BACKGROUND

The prognosis of high-risk neuroblastomas (NB) that are resistant to first-line induction chemotherapy is relatively poor. This study explored the mechanism of resistance to first-line chemotherapeutics mediated by TXNDC17 and its potential solutions in NB.

METHODS

The genetic and clinical data of patients with NB were obtained from the Therapeutically Applicable Research to Generate Effective Treatments dataset. TXNDC17 and BECN1 expressions in NB cells were up- and downregulated by transfection with plasmids and shRNA, respectively. Autophagy-related proteins were detected by western blot. Cell viability was determined using cell proliferation and toxicity experiments. Apoptotic cells were detected using flow cytometry.

RESULTS

Overall, 1076 pediatric and adolescent patients with NB were enrolled in this study. The 10-year overall survival (OS) rates and event-free survival (EFS) rates for the patients with a mutation of BECN1 were 37.4 ± 9.1% and 34.5 ± 8.8%, respectively. For patients with a mutation of TXNDC17, the 10-year OS and EFS were 41.4 ± 5.9% and 24.3 ± 5.1%, respectively, which were significantly lower than those in the unaltered group. The overexpression of BECN1 and TXNDC17 reduced NB sensitivity to cisplatin (DDP), etoposide (VP16), and cyclophosphamide (CTX). Autophagy mediated by BECN1 was regulated by TXNDC17, and this process was involved in the resistance to DDP, VP16, and CTX in NB. Suberoylanilide hydroxamic acid (SAHA) can enhance the sensitivity and apoptosis of NB cells to chemotherapeutics by inhibiting TXNDC17, ultimately decreasing autophagy-mediated chemoresistance.

CONCLUSIONS

Acquired resistance to first-line chemotherapeutics was associated with autophagy mediated by BECN1 and regulated by TXNDC17, which can be reversed by SAHA.

A subset of image-defined risk factors predict completeness of resection in children with high-risk neuroblastoma: An international multicenter study

BACKGROUND

Image-defined risk factors (IDRFs) were promulgated for predicting the feasibility and safety of complete primary tumor resection in children with neuroblastoma (NB). There is limited understanding of the impact of individual IDRFs on resectability of the primary tumor or patient outcomes. A multicenter database of patients with high-risk NB was interrogated to answer this question.

DESIGN/METHODS

Patients with high-risk NB (age <20 years) were eligible if cross-sectional imaging was performed at least twice prior to resection. IDRFs and primary tumor measurements were recorded for each imaging study. Extent of resection was determined from operative reports.

RESULTS

There were 211 of 229 patients with IDRFs at diagnosis, and 171 patients with IDRFs present pre-surgery. A ≥90% resection was significantly more likely in the absence of tumor invading or encasing the porta hepatis, hepatoduodenal ligament, superior mesenteric artery (SMA), renal pedicles, abdominal aorta/inferior vena cava (IVC), iliac vessels, and/or diaphragm at diagnosis or an overlapping subset of IDRFs (except diaphragm) at pre-surgery. There were no significant differences in event-free survival (EFS) and overall survival (OS) when patients were stratified by the presence versus absence of any IDRF either at diagnosis or pre-surgery.

CONCLUSION

Two distinct but overlapping subsets of IDRFs present either at diagnosis or after induction chemotherapy significantly influence the probability of a complete resection in children with high-risk NB. The presence of IDRFs was not associated with significant differences in OS or EFS in this cohort.

Long-term follow-up of patients with intermediate-risk neuroblastoma treated with response- and biology-based therapy: A report from the Children's Oncology Group study ANBL0531

BACKGROUND

We previously reported excellent three-year overall survival (OS) for patients with newly diagnosed intermediate-risk neuroblastoma treated with a biology- and response-based algorithm on the Children's Oncology Group study ANBL0531. We now present the long-term follow-up results.

METHODS

All patients who met the age, stage, and tumor biology criteria for intermediate-risk neuroblastoma were eligible. Treatment was based on prognostic biomarkers and overall response. Event-free survival (EFS) and OS were estimated by the Kaplan-Meier method.

RESULTS

The 10-year EFS and OS for the entire study cohort (n = 404) were 82.0% (95% confidence interval (CI), 77.2%-86.9%) and 94.7% (95% CI, 91.8%-97.5%), respectively. International Neuroblastoma Staging System stage 4 patients (n = 133) had inferior OS compared with non-stage 4 patients (n = 271; 10-year OS: 90.8% [95% CI, 84.5%-97.0%] vs 96.6% [95% CI, 93.9%-99.4%], p = .02). Infants with stage 4 tumors with ≥1 unfavorable biological feature (n = 47) had inferior EFS compared with those with favorable biology (n = 61; 10-year EFS: 66.8% [95% CI, 50.4%-83.3%] vs 86.9% [95% CI, 76.0%-97.8%], p = .02); OS did not differ (10-year OS: 84.4% [95% CI, 71.8%-97.0%] vs 95.0% [95% CI, 87.7%-100.0%], p = .08). Inferior EFS but not OS was observed among patients with tumors with (n = 26) versus without (n = 314) 11q loss of heterozygosity (10-year EFS: 68.4% [95% CI, 44.5%-92.2%] vs 83.9% [95% CI, 78.7%-89.2%], p = .03; 10-year OS: 88.0% [95% CI, 72.0%-100.0%] vs 95.7% [95% CI, 92.8%-98.6%], p = .09).

CONCLUSIONS

The ANBL0531 trial treatment algorithm resulted in excellent long-term survival. More effective treatments are needed for subsets of patients with unfavorable biology tumors.

Distinct Expression Profiles of Neuroblastoma-Associated mRNAs in Peripheral Blood and Bone Marrow of Non-High-Risk and High-Risk Neuroblastoma Patients

Non-high-risk (non-HR) neuroblastoma (NB) patients have excellent outcomes, with more than a 90% survival rate, whereas HR NB patients expect less than a 50% survival rate. Metastatic disease is the principal cause of death among both non-HR and HR NB patients. Previous studies have reported the significant but limited prognostic value of quantitative PCR (qPCR)-based assays, measuring overlapping but different sets of neuroblastoma-associated mRNAs (NB-mRNAs), to detect metastatic disease in both non-HR and HR patient samples. A droplet digital PCR (ddPCR)-based assay measuring seven NB-mRNAs (CRMP1, DBH, DDC, GAP43, ISL1, PHOX2B, and TH mRNAs) was recently developed and exhibited a better prognostic value for HR patient samples than qPCR-based assays. However, it remained to be tested on non-HR patient samples. In the present study, we employed the ddPCR-based assay to study peripheral blood (PB) and bone marrow (BM) samples collected at diagnosis from eight non-HR and eleven HR cases and characterized the expression profiles of NB-mRNAs. The most highly expressed NB-mRNAs in PB and BM differed between non-HR and HR cases, with the CRMP1 mRNA being predominant in non-HR cases and the GAP43 mRNA in HR cases. The levels of NB-mRNAs in PB and BM were 5 to 1000 times lower in non-HR cases than in HR cases. The PB to BM ratio of NB-mRNAs was 10 to 100 times higher in non-HR cases compared to HR cases. The present case series suggests that non-HR and HR NB patients have the distinct expression profiles of NB-mRNAs in their PB and BM.

Management of High-Risk Neuroblastoma with Soft-Tissue-Only Disease in the Era of Anti-GD2 Immunotherapy

Neuroblastoma presents with two patterns of disease: locoregional or systemic. The poor prognostic risk factors of locoregional neuroblastoma (LR-NB) include age, MYCN or MDM2-CDK4 amplification, 11q, histology, diploidy with ALK or TERT mutations, and ATRX aberrations. Anti-GD2 immunotherapy has significantly improved the outcome of high-risk (HR) NB and is mostly effective against osteomedullary minimal residual disease (MRD), but less so against soft tissue disease. The question is whether adding anti-GD2 monoclonal antibodies (mAbs) benefits patients with HR-NB compounded by only soft tissue. We reviewed 31 patients treated at SJD for HR-NB with no osteomedullary involvement at diagnosis. All tumors had molecular genetic features of HR-NB. The outcome after first-line treatment showed 25 (80.6%) patients achieving CR. Thirteen patients remain in continued CR, median follow-up 3.9 years. We analyzed whether adding anti-GD2 immunotherapy to first-line treatment had any prognostic significance. The EFS analysis using Cox models showed a HR of 0.20, p = 0.0054, and an 80% decrease in the risk of relapse in patients treated with anti-GD2 immunotherapy in the first line. Neither EFS nor OS were significantly different by CR status after first-line treatment. In conclusion, adding treatment with anti-GD2 mAbs at the stage of MRD helps prevent relapse that unequivocally portends poor survival.

Bevacizumab, Irinotecan, or Topotecan Added to Temozolomide for Children With Relapsed and Refractory Neuroblastoma: Results of the ITCC-SIOPEN BEACON-Neuroblastoma Trial

PURPOSE

Outcomes for children with relapsed and refractory high-risk neuroblastoma (RR-HRNB) remain dismal. The BEACON Neuroblastoma trial (EudraCT 2012-000072-42) evaluated three backbone chemotherapy regimens and the addition of the antiangiogenic agent bevacizumab (B).

MATERIALS AND METHODS

Patients age 1-21 years with RR-HRNB with adequate organ function and performance status were randomly assigned in a 3 × 2 factorial design to temozolomide (T), irinotecan-temozolomide (IT), or topotecan-temozolomide (TTo) with or without B. The primary end point was best overall response (complete or partial) rate (ORR) during the first six courses, by RECIST or International Neuroblastoma Response Criteria for patients with measurable or evaluable disease, respectively. Safety, progression-free survival (PFS), and overall survival (OS) time were secondary end points.

RESULTS

One hundred sixty patients with RR-HRNB were included. For B random assignment (n = 160), the ORR was 26% (95% CI, 17 to 37) with B and 18% (95% CI, 10 to 28) without B (risk ratio [RR], 1.52 [95% CI, 0.83 to 2.77]; P = .17). Adjusted hazard ratio for PFS and OS were 0.89 (95% CI, 0.63 to 1.27) and 1.01 (95% CI, 0.70 to 1.45), respectively. For irinotecan ([I]; n = 121) and topotecan (n = 60) random assignments, RRs for ORR were 0.94 and 1.22, respectively. A potential interaction between I and B was identified. For patients in the bevacizumab-irinotecan-temozolomide (BIT) arm, the ORR was 23% (95% CI, 10 to 42), and the 1-year PFS estimate was 0.67 (95% CI, 0.47 to 0.80).

CONCLUSION

The addition of B met protocol-defined success criteria for ORR and appeared to improve PFS. Within this phase II trial, BIT showed signals of antitumor activity with acceptable tolerability. Future trials will confirm these results in the chemoimmunotherapy era.

Integrated machine learning-driven disulfidptosis profiling: CYFIP1 and EMILIN1 as therapeutic nodes in neuroblastoma

BACKGROUND

Neuroblastoma (NB), a prevalent pediatric solid tumor, presents formidable challenges due to its high malignancy and intricate pathogenesis. The role of disulfidptosis, a novel form of programmed cell death, remains poorly understood in the context of NB.

METHODS

Gaussian mixture model (GMM)-identified disulfidptosis-related molecular subtypes in NB, differential gene analysis, survival analysis, and gene set variation analysis were conducted subsequently. Weighted gene co-expression network analysis (WGCNA) selected modular genes most relevant to the disulfidptosis core pathways. Integration of machine learning approaches revealed the combination of the Least absolute shrinkage and selection operator (LASSO) and Random Survival Forest (RSF) provided optimal dimensionality reduction of the modular genes. The resulting model was validated, and a nomogram assessed disulfidptosis characteristics in NB. Core genes were filtered and subjected to tumor phenotype and disulfidptosis-related experiments.

RESULTS

GMM clustering revealed three distinct subtypes with diverse prognoses, showing significant variations in glucose metabolism, cytoskeletal structure, and tumor-related pathways. WGCNA highlighted the red module of genes highly correlated with disulfide isomerase activity, cytoskeleton formation, and glucose metabolism. The LASSO and RSF combination yielded the most accurate and stable prognostic model, with a significantly worse prognosis for high-scoring patients. Cytological experiments targeting core genes (CYFIP1, EMILIN1) revealed decreased cell proliferation, migration, invasion abilities, and evident cytoskeletal deformation upon core gene knockdown.

CONCLUSIONS

This study showcases the utility of disulfidptosis-related gene scores for predicting prognosis and molecular subtypes of NB. The identified core genes, CYFIP1 and EMILIN1, hold promise as potential therapeutic targets and diagnostic markers for NB.

Guidelines for outpatient administration of naxitamab: Experience from Atrium Health Levine Children's Hospital

AIM

In this publication, we will share our experience of AE management, provide guidance for appropriate staffing, and the discuss the importance of patient education when treating patients with R/R HR neuroblastoma using naxitamab.

BACKGROUND

Approved treatments for patients with refractory and/or relapsed (R/R) high-risk (HR) neuroblastoma are limited, and there is a high unmet need for new treatment combinations. Naxitamab is a disialoganglioside 2 (GD2)-binding antibody that was approved by the United States Food and Drug Administration in 2020 for use in combination with granulocyte-macrophage colony-stimulating factor for the treatment of patients with R/R HR neuroblastoma in the bone and/or bone marrow and who have demonstrated a partial response, minor response, or stable disease with prior therapy.

METHODS

The pediatric oncology team at Atrium Health Levine Children's Hospital has successfully treated several patients with naxitamab both alone and in combination with chemotherapy, with no patients requiring unplanned overnight hospitalization and few severe adverse events (AEs). To accomplish this, the team at Levine Children's Hospital established standard operating procedures for naxitamab, a therapy defined as high acuity due to the potential for acute AEs with rapid onset and that benefits from continuous monitoring by a nursing team and a dedicated provider.

CONCLUSIONS

This will provide a practical guide for institutions offering naxitamab to their patients, and ensure successful administration of this high acuity treatment in the outpatient setting.

Risk factors and novel predictive models for metastatic neuroblastoma in children

INTRODUCTION

Neuroblastoma (NB) with distant metastasis (DM) is a high-risk condition with a poor prognosis. Early identify the risk and prognostic differences of DM in children, which is helpful for the development of clinical diagnosis and treatment.

METHODS

The study cohort included patients with NB in surveillance, epidemiological, and final outcome databases between 2010 and 2018. To identify the risk and prognostic factors for DM, both univariate and multivariate logistic and Cox regression analyses were conducted. In addition, we created and verified three online clinical prediction models. Finally, we assess the performance of the proposed predictive model.

RESULTS

Among the 1224 children with NB included in the study, 599 developed DM. Primary site is the most important factor affecting metastasis and prognosis. The training and validation groups of the diagnostic nomograms had area under curves (AUC) values of 0.872 and 0.824, respectively. In addition, in the training group, the AUC values at 12, 36, and 60 months were 0.68, 0.71, and 0.75 for the OS nomogram and 0.70, 0.72, and 0.75 for the CSS nomogram. In the validation group, the AUC values at 12, 36, and 60 months were 0.68, 0.72, and 0.70 for the OS nomogram and 0.67, 0.71, and 0.69 for the CSS nomogram, respectively. Calibration curve and decision curve analyses revealed good performance of the nomogram.

CONCLUSIONS

The nomogram developed in this study could appropriately predict DM and assess its prognosis in patients with NB.

Early Salvage Chemo-Immunotherapy with Irinotecan, Temozolomide and Naxitamab Plus GM-CSF (HITS) for Patients with Primary Refractory High-Risk Neuroblastoma Provide the Best Chance for Long-Term Outcomes

Patients with high-risk neuroblastoma (HR-NB) who are unable to achieve a complete response (CR) to induction therapy have worse outcomes. We investigated the combination of humanized anti-GD2 mAb naxitamab (Hu3F8), irinotecan (I), temozolomide (T), and sargramostim (GM-CSF)-HITS-against primary resistant HR-NB. Eligibility criteria included having a measurable chemo-resistant disease at the end of induction (EOI) treatment. Patients were excluded if they had progressive disease (PD) during induction. Prior anti-GD2 mAb and/or I/T therapy was permitted. Each cycle, administered four weeks apart, comprised Irinotecan 50 mg/m2/day intravenously (IV) plus Temozolomide 150 mg/m2/day orally (days 1-5); naxitamab 2.25 mg/kg/day IV on days 2, 4, 8 and 10, (total 9 mg/kg or 270 mg/m2 per cycle), and GM-CSF 250 mg/m2/day subcutaneously was used (days 6-10). Toxicity was measured using CTCAE v4.0 and responses through the modified International Neuroblastoma Response Criteria (INRC). Thirty-four patients (median age at treatment initiation, 4.9 years) received 164 (median 4; 1-12) HITS cycles. Toxicities included myelosuppression and diarrhea, which was expected with I/T, and pain and hypertension, expected with naxitamab. Grade ≥3-related toxicities occurred in 29 (85%) of the 34 patients; treatment was outpatient. The best responses were CR = 29% (n = 10); PR = 3% (n = 1); SD = 53% (n = 18); PD = 5% (n = 5). For cohort 1 (early treatment), the best responses were CR = 47% (n = 8) and SD = 53% (n = 9). In cohort 2 (late treatment), the best responses were CR = 12% (n = 2); PR = 6% (n = 1); SD = 53% (n = 9); and PD = 29% (n = 5). Cohort 1 had a 3-year OS of 84.8% and EFS 54.4%, which are statistically significant improvements (EFS p = 0.0041 and OS p = 0.0037) compared to cohort 2. In conclusion, naxitamab-based chemo-immunotherapy is effective against primary chemo-resistant HR-NB, increasing long-term outcomes when administered early during the course of treatment.

Treatment of High-Risk Neuroblastoma with Dinutuximab and Chemotherapy Administered in all Cycles of Induction

Administration of chemoimmunotherapy using concurrent chemotherapy and an anti-GD2 monoclonal antibody (mAb), dinutuximab (DIN), demonstrated efficacy for the treatment of relapsed and refractory neuroblastoma. Chemoimmunotherapy, using a humanized anti-GD2 mAb, demonstrated a signal of activity in a phase 2 study for the treatment of patients with newly diagnosed high-risk neuroblastoma (HRNBL). In this single-institution retrospective study, patients with HRNBL received an Induction chemotherapy regimen plus DIN in all Induction cycles. Toxicity and response data were abstracted from the electronic medical record. Toxicities were graded by CTCAE v.5.0. The end of Induction (EOI) objective response rate was determined using the Revised International Neuroblastoma Response Criteria. Twenty-seven patients with HRNBL (23 newly diagnosed, 16 females, median age 3.9 years) started Induction chemoimmunotherapy from 27 January 2017 to 28 December 2022. All patients received DIN with all cycles of Induction therapy, and all but one patient completed Induction therapy. The most common non-hematologic grade ≥ 3 toxicities included fever (44%), hypoxemia (20%), and hypoalbuminemia (11%). End of Induction responses included eighteen with a complete response (CR), seven with a partial response (PR), one with progressive disease (PD), and zero with a minor response or stable disease. Twenty-six of twenty-seven patients (96%) completed all Induction cycles and were evaluable for a response. The EOI response of PR or better in the evaluable cohort was 96%. Dinutuximab was well tolerated with all Induction cycles, demonstrated an encouraging EOI response rate, and should be evaluated in a randomized study.

Target Genes of c-MYC and MYCN with Prognostic Power in Neuroblastoma Exhibit Different Expressions during Sympathoadrenal Development

Deregulation of the MYC family of transcription factors c-MYC (encoded by MYC), MYCN, and MYCL is prevalent in most human cancers, with an impact on tumor initiation and progression, as well as response to therapy. In neuroblastoma (NB), amplification of the MYCN oncogene and over-expression of MYC characterize approximately 40% and 10% of all high-risk NB cases, respectively. However, the mechanism and stage of neural crest development in which MYCN and c-MYC contribute to the onset and/or progression of NB are not yet fully understood. Here, we hypothesized that subtle differences in the expression of MYCN and/or c-MYC targets could more accurately stratify NB patients in different risk groups rather than using the expression of either MYC gene alone. We employed an integrative approach using the transcriptome of 498 NB patients from the SEQC cohort and previously defined c-MYC and MYCN target genes to model a multigene transcriptional risk score. Our findings demonstrate that defined sets of c-MYC and MYCN targets with significant prognostic value, effectively stratify NB patients into different groups with varying overall survival probabilities. In particular, patients exhibiting a high-risk signature score present unfavorable clinical parameters, including increased clinical risk, higher INSS stage, MYCN amplification, and disease progression. Notably, target genes with prognostic value differ between c-MYC and MYCN, exhibiting distinct expression patterns in the developing sympathoadrenal system. Genes associated with poor outcomes are mainly found in sympathoblasts rather than in chromaffin cells during the sympathoadrenal development.

Children's Oncology Group's 2023 blueprint for research: Neuroblastoma

Neuroblastoma is the most common extra-cranial solid tumor in children and is known for its clinical heterogeneity. A greater understanding of the biology of this disease has led to both improved risk stratification and new approaches to therapy. Outcomes for children with low and intermediate risk disease are excellent overall, and efforts to decrease therapy for such patients have been largely successful. Although survival has improved over time for patients with high-risk disease and treatments evaluated in the relapse setting are now being moved into earlier phases of treatment, much work remains to improve survival and decrease therapy-related toxicities. Studies of highly annotated biobanked samples continue to lead to important insights regarding neuroblastoma biology. Such studies, along with correlative biology studies incorporated into therapeutic trials, are expected to continue to provide insights that lead to new and more effective therapies. A focus on translational science is accompanied by an emphasis on new agent development, optimized risk stratification, and international collaboration to address questions relevant to molecularly defined subsets of patients. In addition, the COG Neuroblastoma Committee is committed to addressing the patient/family experience, mitigating late effects of therapy, and studying social determinants of health in patients with neuroblastoma.

Impact of diagnostic and end-of-induction Curie scores with tandem high-dose chemotherapy and autologous transplants for metastatic high-risk neuroblastoma: A report from the Children's Oncology Group

BACKGROUND

Diagnostic mIBG (meta-iodobenzylguanidine) scans are an integral component of response assessment in children with high-risk neuroblastoma. The role of end-of-induction (EOI) Curie scores (CS) was previously described in patients undergoing a single course of high-dose chemotherapy (HDC) and autologous hematopoietic cell transplant (AHCT) as consolidation therapy.

OBJECTIVE

We now examine the prognostic significance of CS in patients randomized to tandem HDC and AHCT on the Children's Oncology Group (COG) trial ANBL0532.

STUDY DESIGN

A retrospective analysis of mIBG scans obtained from patients enrolled in COG ANBL0532 was performed. Evaluable patients had mIBG-avid, International Neuroblastoma Staging System (INSS) stage 4 disease, did not progress during induction therapy, consented to consolidation randomization, and received either single or tandem HDC (n = 80). Optimal CS cut points maximized the outcome difference (≤CS vs. >CS cut-off) according to the Youden index.

RESULTS

For recipients of tandem HDC, the optimal cut point at diagnosis was CS = 12, with superior event-free survival (EFS) from study enrollment for patients with CS ≤ 12 (3-year EFS 74.2% ± 7.9%) versus CS > 12 (59.2% ± 7.1%) (p = .002). At EOI, the optimal cut point was CS = 0, with superior EOI EFS for patients with CS = 0 (72.9% ± 6.4%) versus CS > 0 (46.5% ± 9.1%) (p = .002).

CONCLUSION

In the setting of tandem transplantation for children with high-risk neuroblastoma, CS at diagnosis and EOI may identify a more favorable patient group. Patients treated with tandem HDC who exhibited a CS ≤ 12 at diagnosis or CS = 0 at EOI had superior EFS compared to those with CS above these cut points.

T-cell inflammation is prognostic of survival in patients with high-risk neuroblastoma enriched for an adrenergic signature

Purpose

T-cell inflammation (TCI) has been shown to be a prognostic marker in neuroblastoma, a tumor comprised of cells that can exist in two epigenetic states, adrenergic (ADRN) and mesenchymal (MES). We hypothesized that elucidating unique and overlapping aspects of these biologic features could serve as novel biomarkers.

Patients and Methods

We detected lineage-specific, single-stranded super-enhancers defining ADRN and MES specific genes. Publicly available neuroblastoma RNA-seq data from GSE49711 (Cohort 1) and TARGET (Cohort 2) were assigned MES, ADRN, and TCI scores. Tumors were characterized as MES (top 33%) or ADRN (bottom 33%), and TCI (top 67% TCI score) or non-inflamed (bottom 33% TCI score). Overall survival (OS) was assessed using the Kaplan-Meier method, and differences were assessed by the log-rank test.

Results

We identified 159 MES genes and 373 ADRN genes. TCI scores were correlated with MES scores (R=0.56, p<0.001 and R=0.38, p<0.001) and anticorrelated with MYCN -amplification (R=-0.29, p<0.001 and -0.18, p=0.03) in both cohorts. Among Cohort 1 patients with high-risk, ADRN tumors (n=59), those with TCI tumors (n=22) had superior OS to those with non-inflammed tumors (n=37) (p=0.01), though this comparison did not reach significance in Cohort 2. TCI status was not associated with survival in patients with high-risk MES tumors in either cohort.

Conclusions

High inflammation scores were correlated with improved survival in some high-risk patients with, ADRN but not MES neuroblastoma. These findings have implications for approaches to treating high-risk neuroblastoma.

MYCN Amplification Is Associated with Reduced Expression of Genes Encoding γ-Secretase Complex and NOTCH Signaling Components in Neuroblastoma

Amplification of the MYCN oncogene is found in ~20% of neuroblastoma (NB) cases and correlates with high-risk disease and poor prognosis. Despite the plethora of studies describing the role of MYCN in NB, the exact molecular mechanisms underlying MYCN's contribution to high-risk disease are not completely understood. Herein, we implemented an integrative approach combining publicly available RNA-Seq and MYCN ChIP-Seq datasets derived from human NB cell lines to define biological processes directly regulated by MYCN in NB. Our approach revealed that MYCN-amplified NB cell lines, when compared to non-MYCN-amplified cell lines, are characterized by reduced expression of genes involved in NOTCH receptor processing, axoneme assembly, and membrane protein proteolysis. More specifically, we found genes encoding members of the γ-secretase complex, which is known for its ability to liberate several intracellular signaling molecules from membrane-bound proteins such as NOTCH receptors, to be down-regulated in MYCN-amplified NB cell lines. Analysis of MYCN ChIP-Seq data revealed an enrichment of MYCN binding at the transcription start sites of genes encoding γ-secretase complex subunits. Notably, using publicly available gene expression data from NB primary tumors, we revealed that the expression of γ-secretase subunits encoding genes and other components of the NOTCH signaling pathway was also reduced in MYCN-amplified tumors and correlated with worse overall survival in NB patients. Genetic or pharmacological depletion of MYCN in NB cell lines induced the expression of γ-secretase genes and NOTCH-target genes. Chemical inhibition of γ-secretase activity dampened the expression of NOTCH-target genes upon MYCN depletion in NB cells. In conclusion, this study defines a set of MYCN-regulated pathways that are specific to MYCN-amplified NB tumors, and it suggests a novel role for MYCN in the suppression of genes of the γ-secretase complex, with an impact on the NOTCH-target gene expression in MYCN-amplified NB.

Impact of Genomic and Clinical Factors on Outcome of Children ≥18 Months of Age with Stage 3 Neuroblastoma with Unfavorable Histology and without MYCN Amplification: A Children's Oncology Group (COG) Report

PURPOSE

Patients ≥18 months of age with International Neuroblastoma Staging System (INSS) stage 3 unfavorable histology (UH), MYCN-nonamplified (MYCN-NA) tumors have favorable survival rates compared with other high-risk neuroblastoma populations. The impact of select clinical and biological factors on overall survival (OS) and event-free survival (EFS) were evaluated.

EXPERIMENTAL DESIGN

Patients enrolled on Children's Oncology Group (COG) A3973 (n = 34), ANBL0532 (n = 27), and/or biology protocol ANBL00B1 (n = 72) were analyzed. Tumors with available DNA (n = 65) and RNA (n = 42) were subjected to whole-exome sequencing (WES) and RNA sequencing. WES analyses and gene expression profiling were evaluated for their impact on survival. Multivariate analyses of EFS/OS using significant factors from univariate analyses were performed.

RESULTS

5-year EFS/OS for patients treated with high-risk therapy on A3973 and ANBL0532 were 73.0% ± 8.1%/87.9% ± 5.9% and 61.4% ± 10.2%/73.0% ± 9.2%, respectively (P = 0.1286 and P = 0.2180). In the A3973/ANBL0532 cohort, patients with less than partial response (PR; n = 5) at end-induction had poor outcomes (5-year EFS/OS: 0%/20.0% ± 17.9%. Univariate analyses of WES data revealed that subjects whose tumors had chromosome 1p or 11q loss/LOH and chromosome 5 or 9 segmental chromosomal aberrations had inferior EFS compared with those with tumors without these aberrations. Multivariate analysis revealed that 11q loss/LOH was an independent predictor of inferior OS [HR, 3.116 (95% confidence interval, 1.034-9.389), P = 0.0435].

CONCLUSIONS

Patients ≥18 months of age at diagnosis who had tumors with UH and MYCN-NA INSS stage 3 neuroblastoma assigned to high-risk therapy had an 81.6% ± 5.3% 5-year OS. Less than PR to induction therapy and chromosome 11q loss/LOH are independent predictors of inferior outcome and identify patients who should be eligible for future high-risk clinical trials.

Arsenic Trioxide inhibits Activation of Hedgehog Pathway in Human Neuroblastoma Cell Line SK-N-BE(2) Independent of Itraconazole

BACKGROUND

Neuroblastoma (NB) remains associated with a low overall survival rate over the long term. Abnormal activation of the Hedgehog (HH) signaling pathway can activate the transcription of various downstream target genes that promote NB. Both arsenic trioxide (ATO) and itraconazole (ITRA) can inhibit tumor growth.

OBJECTIVE

To determine whether ATO combined with ITRA can be used to treat NB with HH pathway activation, we examined the effects of ATO and ITRA monotherapy or combined inhibition of the HH pathway in NB.

METHODS

Analysis of CCK8 and flow cytometry showed cell inhibition and cell cycle, respectively. Real-time PCR analysis was conducted to assess the mRNA expression of HH pathway.

RESULTS

We revealed that as concentrations of ATO and ITRA increased, the killing effects of both agents on SK-N-BE(2) cells became more apparent. During G2/M, the cell cycle was largely arrested by ATO alone and combined with ITRA, and in the G0/G1 phase by ITRA alone. In the HH pathway, ATO inhibited the transcription of the SHH, PTCH1, SMO and GLI2 genes, however, ITRA did not. Instead of showing synergistic effects in a combined mode, ITRA decreased ATO inhibitory effects.

CONCLUSION

We showed that ATO is an important inhibitor of HH pathway but ITRA can weaken the inhibitory effect of ATO. This study provides an experimental evidence for the clinical use of ATO and ITRA in the treatment of NB with HH pathway activation in cytology.

Investigation of chemoresistance to first-line chemotherapy and its possible association with autophagy in high-risk neuroblastoma

High-risk neuroblastoma (NB) is sensitive to chemotherapy but susceptible to chemoresistance. In this study, we aimed to analyze the incidence of chemoresistance in high-risk NB patients and to explore the role of autophagy in NB chemoresistance. We retrospectively analyzed the incidence of changing the chemotherapy regimen due to disease stabilization or disease progression during induction chemotherapy in high-risk NB patients, which was expressed as the chemoresistance rate. The autophagy levels were probed in tumor cells exposed to first-line chemotherapy agents. The sensitivity of tumor cells to chemotherapy agents and apoptosis rate were observed after inhibiting autophagy by transfection of shRNA or chloroquine (CQ). This study included 247 patients with high-risk NB. The chemoresistance rates of patients treated with cyclophosphamide + adriamycin + vincristine (CAV) alternating with etoposide + cisplatin (EP) (Group 1) and CAV alternating with etoposide + ifosfamide + cisplatin (VIP) (Group 2) was 61.5% and 39.9% (P = 0.0009), respectively. Group 2 had better survival rates than group 1. After exposure to cisplatin, cyclophosphamide, and etoposide, the autophagy-related proteins LC3-I, LC3-II, and Beclin-1 were upregulated, and the incidence of autophagy vesicle formation and the expression of P62 were increased. Chemotherapeutic agents combined with CQ significantly increased the chemotherapeutic sensitivity of tumor cells and increased the cell apoptosis. The downregulated expression of Beclin-1 increased the sensitivity of tumor cells to chemotherapeutics. Our results suggest that increasing the chemotherapy intensity can overcome resistance to NB. Inhibition of autophagy is beneficial to increase the sensitivity of NB to chemotherapy agents.

Treatment outcomes among high-risk neuroblastoma patients receiving non-immunotherapy regimen: Multicenter study on behalf of the Thai Pediatric Oncology Group

BACKGROUND

Neuroblastoma is the most common extracranial malignant solid tumor during childhood. Despite intensified treatment, patients with high-risk neuroblastoma (HR-NBL) still carry a dismal prognosis. The Thai Pediatric Oncology Group (ThaiPOG) proposed the use of a multimodality treatment to improve outcomes of HR-NBL in non-immunotherapy settings.

METHODS

Patients with HR-NBL undergoing ThaiPOG protocols (ThaiPOG-NB-13HR or -18HR) between 2013 and 2019 were retrospectively reviewed. Patient demographic data, treatment modalities, outcomes, and prognostic factors were evaluated and analyzed.

RESULTS

A total of 183 patients with HR-NBL undergoing a topotecan containing induction regimen were enrolled in this study. During the consolidation phase (n = 169), 116 patients (68.6%) received conventional chemotherapy, while 53 patients (31.4%) underwent hematopoietic stem cell transplantation (HSCT). The 5-year overall survival (OS) and event-free survival (EFS) were 41.2% and 22.8%, respectively. Patients who underwent HSCT had more superior 5-year EFS (36%) than those who received chemotherapy (17.1%) (p = .041), although they both performed similarly in 5-year OS (48.7% vs. 39.8%, p = .17). The variation of survival outcomes was observed depending on the number of treatment modalities. HSCT combined with metaiodobenzylguanidine (MIBG) treatment and maintenance with 13-cis-retinoic acid (cis-RA) demonstrated a desirable 5-year OS and EFS of 65.6% and 58.3%, respectively. Poorly or undifferentiated tumor histology and cis-RA administration were independent factors associated with relapse and survival outcomes, respectively (p < .05).

CONCLUSION

A combination of HSCT and cis-RA successfully improved the outcomes of patients with HR-NBL in immunotherapy inaccessible settings.

Efficacy of post-induction therapy for high-risk neuroblastoma patients with end-induction residual disease

BACKGROUND

High-risk neuroblastoma patients with end-induction residual disease commonly receive post-induction therapy in an effort to increase survival by improving the response before autologous stem cell transplantation (ASCT). The authors conducted a multicenter, retrospective study to investigate the efficacy of this approach.

METHODS

Patients diagnosed between 2008 and 2018 without progressive disease with a partial response or worse at end-induction were stratified according to the post-induction treatment: 1) no additional therapy before ASCT (cohort 1), 2) post-induction "bridge" therapy before ASCT (cohort 2), and 3) post-induction therapy without ASCT (cohort 3). χ2 tests were used to compare patient characteristics. Three-year event-free survival (EFS) and overall survival (OS) were estimated by the Kaplan-Meier method and survival curves were compared by log-rank test.

RESULTS

The study cohort consisted of 201 patients: cohort 1 (n = 123), cohort 2 (n = 51), and cohort 3 (n = 27). Although the end-induction response was better for cohort 1 than cohorts 2 and 3, the outcomes for cohorts 1 and 2 were not significantly different (P = .77 for EFS and P = .85 for OS). Inferior outcomes were observed for cohort 3 (P < .001 for EFS and P = .06 for OS). Among patients with end-induction stable metastatic disease, 3-year EFS was significantly improved for cohort 2 versus cohort 1 (P = .04). Cohort 3 patients with a complete response at metastatic sites after post-induction therapy had significantly better 3-year EFS than those with residual metastatic disease (P = .01).

CONCLUSIONS

Prospective studies to confirm the benefits of bridge treatment and the prognostic significance of metastatic response observed in this study are warranted.

Advancing therapy for neuroblastoma

Neuroblastomas are tumours of sympathetic origin, with a heterogeneous clinical course ranging from localized or spontaneously regressing to widely metastatic disease. Neuroblastomas recapitulate many of the features of sympathoadrenal development, which have been directly targeted to improve the survival outcomes in patients with high-risk disease. Over the past few decades, improvements in the 5-year survival of patients with metastatic neuroblastomas, from <20% to >50%, have resulted from clinical trials incorporating high-dose chemotherapy with autologous stem cell transplantation, differentiating agents and immunotherapy with anti-GD2 monoclonal antibodies. The next generation of trials are designed to improve the initial response rates in patients with high-risk neuroblastomas via the addition of immunotherapies, targeted therapies (such as ALK inhibitors) and radiopharmaceuticals to standard induction regimens. Other trials are focused on testing precision medicine strategies for patients with relapsed and/or refractory disease, enhancing the antitumour immune response and improving the effectiveness of maintenance regimens, in order to prolong disease remission. In this Review, we describe advances in delineating the pathogenesis of neuroblastoma and in identifying the drivers of high-risk disease. We then discuss how this knowledge has informed improvements in risk stratification, risk-adapted therapy and the development of novel therapies.

To transplant, or not to transplant? That is the question. A patient advocate evaluation of autologous stem cell transplant in neuroblastoma

High-dose chemotherapy with autologous stem cell transplant (ASCT) has been a mainstay of high-risk neuroblastoma treatment for several decades, demonstrating improvements in event-free survival but with risks of serious or even life-threatening acute toxicities, severe long-term adverse health effects for survivors, and ongoing contention regarding overall survival benefit. The merits of ASCT in the modern era of immunotherapy are a source of debate among parents, advocates, and some physicians. Here we examine evidence for and against ASCT, explore parent attitudes and their turmoil over decision-making, and strongly encourage international research consortia to develop a coordinated strategy to accelerate progress toward a future that avoids the routine use of ASCT in high-risk neuroblastoma.

High-Risk and Relapsed Neuroblastoma: Toward More Cures and Better Outcomes

Approximately half of the patients diagnosed with neuroblastoma are classified as having high-risk disease. This group continues to have inadequate cure rates despite multiagent chemotherapy, surgery, high-dose chemotherapy with autologous stem cell rescue, and immunotherapy directed against GD2. We review current efforts to try to improve outcomes in patients with newly diagnosed disease by integrating novel targeted therapies earlier in the course of the disease. We further examine a growing list of options available for patients with relapsed or refractory high-risk disease, with an eye toward graduating successful strategies from a relapsed/refractory setting to the frontline setting. Last, we review efforts to study and potentially mitigate the array of late effects faced by survivors of high-risk neuroblastoma.

How we approach the treatment of patients with high-risk neuroblastoma with naxitamab: experience from the Hospital Sant Joan de Déu in Barcelona, Spain

Naxitamab [humanized 3f8 (hu3F8)] is a humanized monoclonal antibody (mAb) targeting the disialoganglioside GD2. It was approved in 2020 by the United States Food and Drug Administration (FDA) in combination with granulocyte–macrophage colony-stimulating factor (GM-CSF) for treatment of pediatric and adult patients with relapsed/refractory high-risk neuroblastoma, limited to the bone or bone marrow (BM). The team at Sant Joan de Déu Children’s Hospital in Barcelona, Spain, have been using naxitamab to treat neuroblastoma under clinical trial protocols [e.g. Trial 201, and hu3F8, irinotecan, temozolomide, and sargramostim (GM-CSF) (HITS) study] and compassionate use since 2017. The team has experience with two primary regimens: naxitamab with GM-CSF only, or naxitamab in combination with irinotecan, temozolomide, and GM-CSF (chemoimmunotherapy). This article aims to provide a practical overview of the team’s experience with naxitamab to date, including preparing the treatment room and selecting the team. Adverse event management, including the use of ketamine to manage pain during anti-GD2 mAb infusions, is also discussed. We hope this will provide practical information for other health care providers considering offering this treatment.

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Immunotherapy with anti-GD2 antibodies has revolutionized the treatment of patients with high-risk neuroblastoma.

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In 2020, FDA approved naxitamab + GM-CSF for treatment of patients with R/R neuroblastoma in the bone and/or BM.

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Outpatient treatment with naxitamab-based immunotherapy may improve health-related quality of life.

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Naxitamab infusions require specific training and teamwork to prevent and efficiently manage most frequent adverse events.

A pilot study of genomic-guided induction therapy followed by immunotherapy with difluoromethylornithine maintenance for high-risk neuroblastoma

BACKGROUND

Survival for patients with high-risk neuroblastoma (HRNB) remains poor despite aggressive multimodal therapies.

AIMS

To study the feasibility and safety of incorporating a genomic-based targeted agent to induction therapy for HRNB as well as the feasibility and safety of adding difluoromethylornithine (DFMO) to anti-GD2 immunotherapy.

METHODS

Twenty newly diagnosed HRNB patients were treated on this multicenter pilot trial. Molecular tumor boards selected one of six targeted agents based on tumor-normal whole exome sequencing and tumor RNA-sequencing results. Treatment followed standard upfront HRNB chemotherapy with the addition of the selected targeted agent to cycles 3-6 of induction. Following consolidation, DFMO (750 mg/m² twice daily) was added to maintenance with dinutuximab and isotretinoin, followed by continuation of DFMO alone for 2 years. DNA methylation analysis was performed retrospectively and compared to RNA expression.

RESULTS

Of the 20 subjects enrolled, 19 started targeted therapy during cycle 3 and 1 started during cycle 5. Eighty-five percent of subjects met feasibility criteria (receiving 75% of targeted agent doses). Addition of targeted agents did not result in toxicities requiring dose reduction of chemotherapy or permanent discontinuation of targeted agent. Following standard consolidation, 15 subjects continued onto immunotherapy with DFMO. This combination was well-tolerated and resulted in no unexpected adverse events related to DFMO.

CONCLUSION

This study demonstrates the safety and feasibility of adding targeted agents to standard induction therapy and adding DFMO to immunotherapy for HRNB. This treatment regimen has been expanded to a Phase II trial to evaluate efficacy.

Characterization of m6A-related lncRNA signature in neuroblastoma

N6-methyladenosine (m6A) constitutes one of the most common modifications in mRNA, rRNA, tRNA, microRNA, and long-chain noncoding RNA. The influence of modifications of m6A on the stability of RNA depends upon the expression of methyltransferase ("writer") and demethylase ("eraser") and m6A binding protein ("reader"). In this study, we identified a set of m6A-related lncRNA expression profiles in neuroblastoma (NBL) based on the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) program. Thereupon, we identified two subgroups of neuroblastoma (high-risk group and low-risk group) by applying consensus clustering to m6A RNA methylation regulators ("Readers,", "Writer," and "Erase"). Relative to the low-risk group, the high-risk group correlates with a poorer prognosis. Moreover, the present study also revealed that the high-risk group proves to be significantly positively enriched in the tumor-related signaling pathways, including the P53 signaling pathway, cell cycle, and DNA repair. This finding indicates that these molecular prognostic markers may also be potentially valuable in early diagnosis, which provides a new research direction for the study of molecular mechanisms underlying the development of NBL. In conclusion, this study constructed a new model of NBL prognosis based on m6a-associated lncRNAs. Ultimately, this model is helpful for stratification of prognosis and development of treatment strategies.

Impact of 11q Loss of Heterozygosity Status on the Response of High-Risk Neuroblastoma With MYCN Amplification to Neoadjuvant Chemotherapy

PURPOSE

The aim of this study was to investigate whether 11q loss of heterozygosity (LOH) aberration would impact the response of the primary tumor to neoadjuvant chemotherapy or to the degree of surgical resection in neuroblastoma (NB) patients with MYCN amplification.

METHODS

The clinical data of 42 NB patients with MYCN amplification who were newly diagnosed and received treatments at our hospital from 2011 to 2020 were retrospectively analyzed. According to the results of the segmental chromosome aberration analysis, the patients enrolled were assigned to an 11qLOH positive group and an 11qLOH negative group.

RESULTS

There was no significant difference in the mean number of chemotherapy courses completed before surgery between the 11qLOH positive and 11qLOH negative groups (p = 0.242). Each of the 42 patients had metaiodobenzylguanidine (MIBG) scans both before and after neoadjuvant chemotherapy. The percentage of patients who had a clinical MIBG change in the 11qLOH positive group was lower than the percentage in the 11qLOH negative group (27.27 vs. 66.67%, p = 0.030). The 11qLOH negative group seemed to have a higher rate of surgical resection (≥90%); however, the difference between the two groups was not statistically significant (p = 0.088). Furthermore, the 11qLOH negative group did not show significantly superior event-free survival and overall survival rates compared with the 11qLOH positive group.

CONCLUSIONS

This study showed that patients with NB and MYCN amplification in combination with 11qLOH might be less likely to respond to neoadjuvant chemotherapy when compared with patients with NB and MYCN amplification without 11qLOH.

Predicting Response to Chemotherapy in Patients With Newly Diagnosed High-Risk Neuroblastoma: A Report From the International Neuroblastoma Risk Group

PURPOSE

Metaiodobenzylguanidine (MIBG) scans are a radionucleotide imaging modality that undergo Curie scoring to semiquantitatively assess neuroblastoma burden, which can be used as a marker of therapy response. We hypothesized that a convolutional neural network (CNN) could be developed that uses diagnostic MIBG scans to predict response to induction chemotherapy.

METHODS

We analyzed MIBG scans housed in the International Neuroblastoma Risk Group Data Commons from patients enrolled in the Children's Oncology Group high-risk neuroblastoma study ANBL12P1. The primary outcome was response to upfront chemotherapy, defined as a Curie score ≤ 2 after four cycles of induction chemotherapy. We derived and validated a CNN using two-dimensional whole-body MIBG scans from diagnosis and evaluated model performance using area under the receiver operating characteristic curve (AUC). We also developed a clinical classification model to predict response on the basis of age, stage, and MYCN amplification.

RESULTS

Among 103 patients with high-risk neuroblastoma included in the final cohort, 67 (65%) were responders. Performance in predicting response to upfront chemotherapy was equivalent using the CNN and the clinical model. Class-activation heatmaps verified that the CNN used areas of disease within the MIBG scans to make predictions. Furthermore, integrating predictions using a geometric mean approach improved detection of responders to upfront chemotherapy (geometric mean AUC 0.73 v CNN AUC 0.63, P < .05; v clinical model AUC 0.65, P < .05).

CONCLUSION

We demonstrate feasibility in using machine learning of diagnostic MIBG scans to predict response to induction chemotherapy for patients with high-risk neuroblastoma. We highlight improvements when clinical risk factors are also integrated, laying the foundation for using a multimodal approach to guiding treatment decisions for patients with high-risk neuroblastoma.

Residual meta-iodobenzyl guanidine (MIBG) positivity following therapy for metastatic neuroblastoma: Patient characteristics, imaging, and outcome

BACKGROUND

Meta-iodobenzylguanidine(MIBG) scans are used to detect neuroblastoma metastatic lesions at diagnosis and during posttreatment surveillance. MIBG positivity following induction chemotherapy correlates with poor outcome; however, there are reports of patients with progression-free survival despite MIBG positivity at the end of therapy. The factors distinguishing these survivors from patients who progress or relapse are unclear. FDG-positron-emission tomography (PET) scans can also detect metastatic lesions at diagnosis; however, their role in posttherapy surveillance is less well studied.

METHODS

We performed a retrospective analysis of International Neuroblastoma Staging System (INSS) stage 4 patients to identify those with residual MIBG-avid metastatic lesions on end-of-therapy scans without prior progression. Data collected included age, disease sites, histopathology, biomarkers, treatment, imaging studies, and response.

RESULTS

Eleven of 265 patients met inclusion criteria. At diagnosis three of 11 patients were classified as intermediate and eight of 11 high risk; nine of 11 had documented marrow involvement. Histologic classification was favorable for four of 10 and MYCN amplification was detected in zero of 11 cases. The median time with persistent MIBG positivity following treatment was 1.5 years. Seven patients had at least one PET scan with low or background activity. Biopsies of three of three MIBG-avid residual lesions showed differentiation. All patients remain alive with no disease progression at a median of 4.0 years since end of therapy.

CONCLUSION

Persistently MIBG-avid metastatic lesions in subsets of patients following completion of therapy may not represent active disease that will progress. Further studies are needed to determine whether MYCN status or other biomarkers, and/or PET scans, may help identify patients with residual inactive MIBG lesions who require no further therapy.

A safety and feasibility trial of 131 I-MIBG in newly diagnosed high-risk neuroblastoma: A Children's Oncology Group study

INTRODUCTION

¹³¹ I-meta-iodobenzylguanidine (¹³¹ I-MIBG) is effective in relapsed neuroblastoma. The Children's Oncology Group (COG) conducted a pilot study (NCT01175356) to assess tolerability and feasibility of induction chemotherapy followed by ¹³¹ I^- MIBG therapy and myeloablative busulfan/melphalan (Bu/Mel) in patients with newly diagnosed high-risk neuroblastoma.

METHODS

Patients with MIBG-avid high-risk neuroblastoma were eligible. After the first two patients to receive protocol therapy developed severe sinusoidal obstruction syndrome (SOS), the trial was re-designed to include an ¹³¹ I-MIBG dose escalation (12, 15, and 18 mCi/kg), with a required 10-week gap before Bu/Mel administration. Patients who completed induction chemotherapy were evaluable for assessment of ¹³¹ I-MIBG feasibility; those who completed ¹³¹ I-MIBG therapy were evaluable for assessment of ¹³¹ I-MIBG + Bu/Mel feasibility.

RESULTS

Fifty-nine of 68 patients (86.8%) who completed induction chemotherapy received ¹³¹ I-MIBG. Thirty-seven of 45 patients (82.2%) evaluable for ¹³¹ I-MIBG + Bu/Mel received this combination. Among those who received ¹³¹ I-MIBG after revision of the study design, one patient per dose level developed severe SOS. Rates of moderate to severe SOS at 12, 15, and 18 mCi/kg were 33.3%, 23.5%, and 25.0%, respectively. There was one toxic death. The ¹³¹ I-MIBG and ¹³¹ I-MIBG+Bu/Mel feasibility rates at the 15 mCi/kg dose level designated for further study were 96.7% (95% CI: 83.3%-99.4%) and 81.0% (95% CI: 60.0%-92.3%).

CONCLUSION

This pilot trial demonstrated feasibility and tolerability of administering ¹³¹ I-MIBG followed by myeloablative therapy with Bu/Mel to newly diagnosed children with high-risk neuroblastoma in a cooperative group setting, laying the groundwork for a cooperative randomized trial (NCT03126916) testing the addition of ¹³¹ I-MIBG during induction therapy.

Excellent Early Outcomes of Combined Chemotherapy With Arsenic Trioxide for Stage 4/M Neuroblastoma in Children: A Multicenter Nonrandomized Controlled Trial

This nonrandomized, multicenter cohort, open-label clinical trial evaluated the efficacy and safety of combined chemotherapy with arsenic trioxide (ATO) in children with stage 4/M neuroblastoma (NB). We enrolled patients who were newly diagnosed with NB and assessed as stage 4/M and received either traditional chemotherapy or ATO combined with chemotherapy according to their own wishes. Twenty-two patients were enrolled in the trial group (ATO combined with chemotherapy), and 13 patients were enrolled in the control group (traditional chemotherapy). Objective response rate (ORR) at 4 weeks after completing induction chemotherapy was defined as the main outcome, and adverse events were monitored and graded in the meantime. Data cutoff date was December 31, 2019. Finally, we found that patients who received ATO combined with chemotherapy had a significantly higher response rate than those who were treated with traditional chemotherapy (ORR: 86.36% vs. 46.16%, p=0.020). Reversible cardiotoxicity was just observed in three patients who were treated with ATO, and no other differential adverse events were observed between the two groups. ATO combined with chemotherapy can significantly improve end-induction response in high-risk NB, and our novel regimen is well tolerated in pediatric patients. These results highlight the superiority of chemotherapy with ATO, which creates new opportunity for prolonging survival. In addition, this treatment protocol minimizes therapeutic costs compared with anti-GD2 therapy, MIBG, and proton therapy and can decrease the burden to families and society. However, we also need to evaluate more cases to consolidate our conclusion.

Early Use of Dinutuximab Beta in Patients with High-Risk Neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in children, accounting for 15% of all pediatric cancer deaths. High-risk neuroblastoma (HRNB) is a particularly difficult-to-treat form of the disease that requires aggressive multimodality therapy, including induction chemotherapy, consolidation therapy with high-dose chemotherapy and autologous stem cell transplant, and maintenance therapy with dinutuximab beta. Despite treatment advances, the prognosis of these patients remains poor. As a better response to induction therapy has been associated with prolonged survival in patients with HRNB, we hypothesized that early use of dinutuximab beta-post-induction chemotherapy-may improve patient outcomes. We describe here our experience of administering at least one cycle of dinutuximab beta post-induction and prior to surgery in three children with HRNB who did not demonstrate a complete response to induction chemotherapy. All three patients achieved complete remission. Early use of dinutuximab beta may therefore have the potential to improve outcomes in patients with HRNB.

Frequency and Prognostic Impact of ALK Amplifications and Mutations in the European Neuroblastoma Study Group (SIOPEN) High-Risk Neuroblastoma Trial (HR-NBL1)

PURPOSE

In neuroblastoma (NB), the ALK receptor tyrosine kinase can be constitutively activated through activating point mutations or genomic amplification. We studied ALK genetic alterations in high-risk (HR) patients on the HR-NBL1/SIOPEN trial to determine their frequency, correlation with clinical parameters, and prognostic impact.

MATERIALS AND METHODS

Diagnostic tumor samples were available from 1,092 HR-NBL1/SIOPEN patients to determine ALK amplification status (n = 330), ALK mutational profile (n = 191), or both (n = 571).

RESULTS

Genomic ALK amplification (ALKa) was detected in 4.5% of cases (41 out of 901), all except one with MYCN amplification (MNA). ALKa was associated with a significantly poorer overall survival (OS) (5-year OS: ALKa [n = 41] 28% [95% CI, 15 to 42]; no-ALKa [n = 860] 51% [95% CI, 47 to 54], [P < .001]), particularly in cases with metastatic disease. ALK mutations (ALKm) were detected at a clonal level (> 20% mutated allele fraction) in 10% of cases (76 out of 762) and at a subclonal level (mutated allele fraction 0.1%-20%) in 3.9% of patients (30 out of 762), with a strong correlation between the presence of ALKm and MNA (P < .001). Among 571 cases with known ALKa and ALKm status, a statistically significant difference in OS was observed between cases with ALKa or clonal ALKm versus subclonal ALKm or no ALK alterations (5-year OS: ALKa [n = 19], 26% [95% CI, 10 to 47], clonal ALKm [n = 65] 33% [95% CI, 21 to 44], subclonal ALKm (n = 22) 48% [95% CI, 26 to 67], and no alteration [n = 465], 51% [95% CI, 46 to 55], respectively; P = .001). Importantly, in a multivariate model, involvement of more than one metastatic compartment (hazard ratio [HR], 2.87; P < .001), ALKa (HR, 2.38; P = .004), and clonal ALKm (HR, 1.77; P = .001) were independent predictors of poor outcome.

CONCLUSION

Genetic alterations of ALK (clonal mutations and amplifications) in HR-NB are independent predictors of poorer survival. These data provide a rationale for integration of ALK inhibitors in upfront treatment of HR-NB with ALK alterations.

Intratumoral immunosuppression profiles in 11q-deleted neuroblastomas provide new potential therapeutic targets

High‐risk neuroblastoma (NB) patients with 11q deletion frequently undergo late but consecutive relapse cycles with fatal outcome. To date, no actionable targets to improve current multimodal treatment have been identified. We analyzed immune microenvironment and genetic profiles of high‐risk NB correlating with 11q immune status. We show in two independent cohorts that 11q‐deleted NB exhibits various immune inhibitory mechanisms, including increased CD4+ resting T cells and M2 macrophages, higher expression of programmed death‐ligand 1, interleukin‐10, transforming growth factor‐beta‐1, and indoleamine 2,3‐dioxygenase 1 (P < 0.05), and also higher chromosomal breakages (P ≤ 0.02) and hemizygosity of immunosuppressive miRNAs than MYCN‐amplified and other 11q‐nondeleted high‐risk NB. We also analyzed benefits of maintenance treatment in 83 high‐risk stage M NB patients focusing on 11q status, either with standard anti‐GD2 immunotherapy (n = 50) or previous retinoic acid‐based therapy alone (n = 33). Immunotherapy associated with higher EFS (50 vs. 30, P = 0.028) and OS (72 vs. 52, P = 0.047) at 3 years in the overall population. Despite benefits from standard anti‐GD2 immunotherapy in high‐risk NB patients, those with 11q deletion still face poor outcome. This NB subgroup displays intratumoral immune suppression profiles, revealing a potential therapeutic strategy with combination immunotherapy to circumvent this immune checkpoint blockade.

Upfront consolidation treatment with 131I-mIbG followed by myeloablative chemotherapy and hematopoietic stem cell transplantation in high-risk neuroblastoma

Importance

¹³¹I‐metaiodobenzylguanidine (¹³¹I‐mIBG) has a significant targeted antitumor effect for neuroblastoma. However, currently there is a paucity of data for the use of ¹³¹I‐mIBG as a “front‐line” therapeutic agent in those patients with newly diagnosed high‐risk neuroblastoma as part of the conditioning regimen for myeloablative chemotherapy (MAC).

Objective

To evaluate the feasibility of upfront consolidation treatment with ¹³¹I‐mIBG plus MAC and hematopoietic stem cell transplantation (HSCT) in high‐risk neuroblastoma patients.

Methods

A retrospective, single‐center study was conducted from 2003–2019 on newly diagnosed high‐risk neuroblastoma patients without progressive disease (PD) after the completion of induction therapy. They received ¹³¹I‐mIBG infusion and MAC followed by HSCT.

Results

A total of 24 high‐risk neuroblastoma patients were enrolled with a median age of 3.0 years at diagnosis. After receiving this sequential consolidation treatment, 3 of 13 patients who were in partial response (PR) before ¹³¹I‐mIBG treatment achieved either complete response (CR) (n = 1) or very good partial response (VGPR) (n = 2) after HSCT. With a median follow‐up duration of 13.0 months after ¹³¹I‐mIBG therapy, the 5‐year event‐free survival and overall survival rates estimated were 29% and 38% for the entire cohort, and 53% and 67% for the patients who were in CR/VGPR at the time of ¹³¹I‐mIBG treatment.

Interpretation

Upfront consolidation treatment with ¹³¹I‐mIBG plus MAC and HSCT is feasible and tolerable in high‐risk neuroblastoma patients, however the survival benefit of this ¹³¹I‐mIBG regimen is only observed in the patients who were in CR/VGPR at the time of ¹³¹I‐mIBG treatment.

Association between end-induction response according to the revised International Neuroblastoma Response Criteria (INRC) and outcome in high-risk neuroblastoma patients

BACKGROUND

The 1993 International Neuroblastoma Response Criteria (INRC) were revised in 2017 to include modern functional imaging studies and methods for quantifying disease in bone marrow. We hypothesized the 2017 INRC would enable more precise assessment of response to treatment and provide superior prognostic information compared with the 1993 criteria.

METHODS

High-risk (HR) neuroblastoma patients from two institutions in Chicago diagnosed between 2006 and 2016 were identified. Patients were assessed post induction chemotherapy via the 1993 and 2017 INRC and classified as responder (≥ mixed response [MXR] or ≥ minor response [MR], respectively) or nonresponder (< MXR or < MR). Event-free survival (EFS) and overall survival (OS) for responders versus nonresponders were determined from end induction and stratified by Cox regression. Patients with progressive disease at end induction were eliminated from the EFS analyses but included in the OS analysis.

RESULTS

The 1993 criteria classified 52 of the 60 HR patients as responders, whereas 54 responders were identified using the 2017 criteria (Spearman correlation r = 0.82, P < 0.001). No statistically significant difference in EFS was observed for responders versus nonresponders using either criteria (P = 0.48 and P = 0.08). However, superior OS was observed for responders (P = 0.01) using either criteria. Both criteria were sensitive in identifying responders among those with good outcomes. The specificity to identify nonresponders among those with poor outcomes was poor.

CONCLUSIONS

In HR neuroblastoma, end-induction response defined by the 1993 or 2017 INRC is associated with survival. Larger cohorts are needed to determine if the 2017 INRC provides more precise prognostication.

Trends in conditional survival and predictors of late death in neuroblastoma

PURPOSE

Significant advances in the treatment of neuroblastoma have been made in the past several decades. There are scant data examining how these improvements have changed over time and differentially affected conditional survival among high-risk and non-high-risk patient groups.

METHODS

We conducted a retrospective cohort study using the Surveillance, Epidemiology, and End Results database. We analyzed clinical characteristics and survival outcomes for 4717 neuroblastoma patients. Kaplan-Meier methods were used to estimate overall survival (OS) and conditional overall survival (COS) with estimates compared between groups using log-rank tests.

RESULTS

Five-year OS was 41.46% (95% CI 38.77-44.13) for the high-risk group and 91.13% (95% CI 89.49-92.53) for the non-high-risk group. Both groups saw significant improvements in OS by decade (P < .001). Five-year COS among 1-year survivors was 52.69% (CI 49.54-55.73) for the high-risk group and 96.75% (95% CI 95.57-97.62) for the non-high-risk group. One-year survivors in the high-risk group showed a statistically significant improvement in COS over time. No difference in COS was observed among 5-year high-risk survivors. In the high-risk and non-high-risk groups, 82% and 32% of late deaths were attributable to cancer, respectively. Statistically significant adverse prognostic factors for late death were age ≥ 1 year at diagnosis, metastatic disease, and nonthoracic primary site (P = .001).

CONCLUSIONS

Improvements in COS over time have largely benefited high-risk patients, though they are still at higher risk for late death due to cancer when compared to non-high-risk patients. Age, stage, and primary site, but not treatment decade, influence outcomes among 5-year survivors.

Factors Impacting Time to Engraftment in Patients With High-risk Neuroblastoma Following Autologous Stem Cell Transplant

BACKGROUND

Despite advances in supportive measures, myeloablative chemotherapy with stem cell rescue remains limited by toxicity and treatment-related mortality. The purpose of this study was to identify factors influencing the rate of hematopoietic recovery following autologous stem cell transplant in high-risk neuroblastoma.

PROCEDURE

We retrospectively studied 54 patients with high-risk neuroblastoma who received a single autologous stem cell transplant between 2006 and 2016. Race, sex, conditioning regimen, chemotherapy delays and bone marrow involvement were analyzed using Kaplan-Meier Log-Rank test while the amount of cells infused, age, and length of hospital stay were analyzed using univariate Cox Proportional Hazards Regression.

RESULTS

The conditioning regimen administered was significant (P=0.016) for time to engraftment of neutrophils, with busulfan/melphalan (Bu/Mel) at 16.6 days, and carboplatin/etoposide/melphalan at 12.1 days. A delay of chemotherapy during induction (n=24) was significant (P<0.001) for time to platelet engraftment of >75,000/µL. Female patients had a longer time to engraftment (P=0.029).

CONCLUSION

Patients receiving Bu/Mel as a conditioning regimen, patients who had a delay in induction chemotherapy and patients of female sex were found to be significant for delayed engraftment of neutrophils, platelets, and hemoglobin, respectively, in patients with high-risk neuroblastoma undergoing autologous stem cell transplant. Knowing these factors may lead to new expectations and possible interventions to decrease the morbidity and mortality of treatment and recovery.

Epigenome-wide association study reveals CpG sites related to COG of neuroblastoma

Background. Neuroblastoma (NB) is the most common extracranial solid tumor in infants and children. Its variable location and complex pathogenesis make NB hard for early diagnosis and risk classification. Methodology. We analyzed the methylation data of 236 samples from patients with NB in Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. Kaplan–Meier survival analysis was used for comparing overall survival of NB patients in different groups. Epigenome-wide association study (EWAS) was conducted to screen CpGs significantly associated with NB patients’ Children’s Oncology Group (COG). Logistic regression method was used for constructing a model to predict NB patients’ COG. Results. NB patients in low COG showed significantly superior prognosis than those in high COG. A total of seven CpG sites were found closely related to COG. Logistic regression model based on those CpGs showed superior performance in separating NB patients in different COGs. Conclusions. The present study highlights the important role of DNA methylation in NB development, which might provide evidence for treatment decisions for children NB.

MTHFR and VDR Polymorphisms Improve the Prognostic Value of MYCN Status on Overall Survival in Neuroblastoma Patients

Single nucleotide polymorphisms (SNPs) in Pharmacogenetics can play an important role in the outcomes of the chemotherapy treatment in Neuroblastoma, helping doctors maximize efficacy and minimize toxicity. Employing AgenaBioscience MassArray, 96 SNPs were genotyped in 95 patients looking for associations of SNP with response to induction therapy (RIT) and grade 3-4 toxicities, in High Risk patients. Associations of SNPs with overall (OS) and event-free (EFS) survival in the whole cohort were also explored. Cox and logistic regression models with Elastic net penalty were employed. Association with grade 3-4 gastrointestinal and infectious toxicities was found for 8 different SNPs. Better RIT was correlated with rs726501 AG, rs3740066 GG, rs2010963 GG and rs1143684 TT (OR = 2.87, 1.79, 1.23, 1.14, respectively). EFS was affected by rs2032582, rs4880, rs3814058, rs45511401, rs1544410 and rs6539870. OS was influenced by rs 1801133, rs7186128 and rs1544410. Remarkably, rs1801133 in MTHFR (p = 0.02) and rs1544410 in VDR (p = 0.006) also added an important predictive value for OS to the MYCN status, with a more accurate substratification of the patients. Although validation studies in independent cohorts will be required, the data obtained supports the utility of Pharmacogenetics for predicting Neuroblastoma treatment outcomes.