The majority of neuroblastoma patients have tumors that initially respond to chemotherapy, but a large proportion of patients will experience therapy-resistant relapses. The molecular basis of this aggressive phenotype is unknown. Whole genome sequencing of 23 paired diagnostic and relapsed neuroblastomas showed clonal evolution from the diagnostic tumor with a median of 29 somatic mutations unique to the relapse sample. Eighteen of the 23 relapse tumors (78%) showed mutations predicted to activate the RAS-MAPK signaling pathway. Seven events were detected only in the relapse tumor while the others showed clonal enrichment. In neuroblastoma cell lines we also detected a high frequency of activating mutations in the RAS-MAPK pathway (11/18, 61%) and these lesions predicted for sensitivity to MEK inhibition in vitro and in vivo. Our findings provide the rationale for genetic characterization of relapse neuroblastoma and show that RAS-MAPK pathway mutations may function as a biomarker for new therapeutic approaches to refractory disease.

chemotherapy followed by high-dose therapy with autologous stem cell transplant and subsequent antidisialoganglioside antibody immunotherapy is standard of care for patients with high-risk neuroblastoma, but survival rate among these patients remains low. OBJECTIVE To determine if tandem autologous transplant improves event-free survival (EFS) compared with single transplant. DESIGN, SETTING, AND PARTICIPANTS Patients were enrolled in this randomized clinical trial from November 2007 to February 2012 at 142 Children's Oncology Group centers in the United States, Canada, Switzerland, Australia, and New Zealand. A total of 652 eligible patients aged 30 years or younger with protocol-defined high-risk neuroblastoma were enrolled and 355 were randomized. The final date of follow-up was June 29, 2017, and the data analyses cutoff date was June 30, 2017. INTERVENTIONS Patients were randomized to receive tandem transplant with thiotepa/cyclophosphamide followed by dose-reduced carboplatin/etoposide/melphalan (n = 176) or single transplant with carboplatin/etoposide/melphalan (n = 179). MAIN OUTCOMES AND MEASURES The primary outcome was EFS from randomization to the occurrence of the first event (relapse, progression, secondary malignancy, or death from any cause). The study was designed to test the 1-sided hypothesis of superiority of tandem transplant compared with single transplant. RESULTS Among the 652 eligible patients enrolled, 297 did not undergo randomization because they were nonrandomly assigned (n = 27), ineligible for randomization (n = 62), had no therapy (n = 1), or because of physician/parent preference (n = 207). Among 355 patients randomized (median diagnosis age, 36.1 months; 152 [42.8%] female), 297 patients (83.7%) completed the study and 21 (5.9%) were lost to follow-up after completing protocol therapy. Three-year EFS from the time of randomization was 61.6% (95% CI, 54.3%-68.9%) in the tandem transplant group and 48.4% (95% CI, 41.0%-55.7%) in the single transplant group (1-sided log-rank P=.006). The median (range) duration of follow-up after randomization for 181 patients without an event was 5.6 (0.6-8.9) years. The most common significant toxicities following tandem vs single transplant were mucosal (11.7% vs 15.4%) and infectious (17.9% vs 18.3%). CONCLUSIONS AND RELEVANCE Among patients aged 30 years or younger with high-risk neuroblastoma, tandem transplant resulted in a significantly better EFS than single transplant. However, because of the low randomization rate, the findings may not be representative of all patients with high-risk neuroblastoma.

Background Outcomes for children with relapsed and refractory neuroblastoma are dismal. The combination of irinotecan and temozolomide (I/T) has activity in these patients, and the toxicity profile of I/T makes it an excellent backbone for study of new agents. Temsirolimus (TEM) and dinutuximab (DIN) were selected for testing with I/T in subjects with relapsed or refractory neuroblastoma. Methods Children’s Oncology Group (COG) ANBL1221, a randomised Phase II selection design trial, compared response and toxicity in subjects treated with I/T and either temsirolimus (I/T/TEM) or dinutuximab with granulocyte-macrophage colony stimulating factor (I/T/DIN). Patients were eligible at first relapse/progression or first designation of refractory disease, provided organ function requirements were met. Patients had to have histologic verification of neuroblastoma and/or demonstration of tumour cells in bone marrow with increased urinary catecholamines at diagnosis. Patients were eligible at first designation of relapse (defined as recurrence after response to treatment), or first designation of refractory disease (defined as inadequate response to treatment that included at least 4 cycles of ≥2 chemotherapeutic agents, including an alkylator and a platinum-containing compound. Patients previously treated for refractory or relapsed disease were ineligible. Computer-based randomisation with sequence generation defined by permuted block randomisation, with blocks of size 2, was used to assign patients 1:1 to I/T/TEM or I/T/DIN. Randomisation was stratified to ensure equal distribution of disease category (measurable vs. evaluable), prior exposure to anti-GD2 antibody therapy, and tumour MYCN amplification status. Patients on both regimens received oral temozolomide (100 mg/m2/dose) and intravenous (IV) irinotecan (50 mg/m2/dose) on days 1–5 of 21-day cycles. TEM (35 mg/m2/dose IV) was given on days 1 and 8. DIN (17·5 or 25 mg/m2/day IV) was administered on days 2–5. The primary endpoint was objective (complete or partial) response; responses were centrally reviewed by an independent panel of radiologists. Response was analysed on an intent-to-treat basis. Toxicity was assessed in all participants who received at least one dose of protocol therapy. Follow up of the initial cohort is ongoing. This study is registered at ClinicalTrials.gov (NCT01767194). Findings Thirty-five eligible subjects were enrolled from February 22, 2013-March 23, 2015. Median age was 5.7 years (range 2·1–16·2 years; interquartile range (IQR) 4·5–9·1 years). Among 18 subjects randomised to I/T/TEM, 1 PR was observed (5·6%, 95% confidence interval (CI): [0·0%, 16·1%]). Among 17 patients randomised to I/T/DIN, 9 (53%, 95% CI: [29·2%, 76·7%]) had objective responses (4 PR, 5 CR), including responses in 5/10 patients with relapsed/progressive disease and 4/7 with refractory disease. I/T/DIN met protocol-defined criteria for selection as the combination meriting further study. The most common ≥Grade 3 toxicities among I/T/TEM patients were neutropenia ...