BACKGROUND Preclinical and preliminary clinical data indicate that ch14.18, a monoclonal antibody against the tumor-associated disialoganglioside GD2, has activity against neuroblastoma and that such activity is enhanced when ch14.18 is combined with granulocyte–macrophage colony-stimulating factor (GM-CSF) or interleukin-2. We conducted a study to determine whether adding ch14.18, GM-CSF, and interleukin-2 to standard isotretinoin therapy after intensive multimodal therapy would improve outcomes in high-risk neuroblastoma. METHODS Patients with high-risk neuroblastoma who had a response to induction therapy and stem-cell transplantation were randomly assigned, in a 1:1 ratio, to receive standard therapy (six cycles of isotretinoin) or immunotherapy (six cycles of isotretinoin and five concomitant cycles of ch14.18 in combination with alternating GM-CSF and interleukin-2). Event-free survival and overall survival were compared between the immunotherapy group and the standard-therapy group, on an intention-to-treat basis. RESULTS A total of 226 eligible patients were randomly assigned to a treatment group. In the immunotherapy group, a total of 52% of patients had pain of grade 3, 4, or 5, and 23% and 25% of patients had capillary leak syndrome and hypersensitivity reactions, respectively. With 61% of the number of expected events observed, the study met the criteria for early stopping owing to efficacy. The median duration of follow-up was 2.1 years. Immunotherapy was superior to standard therapy with regard to rates of event-free survival (66±5% vs. 46±5% at 2 years, P = 0.01) and overall survival (86±4% vs. 75±5% at 2 years, P = 0.02 without adjustment for interim analyses). CONCLUSIONS Immunotherapy with ch14.18, GM-CSF, and interleukin-2 was associated with a significantly improved outcome as compared with standard therapy in patients with high-risk neuroblastoma.

AlloHCT was associated with long-term survival in patients with advanced SM. Although alloHCT may be considered as a viable and potentially curative therapeutic option for advanced SM in the meantime, given that this is a retrospective analysis with no control group, the definitive role of alloHCT will need to be determined by a prospective trial.

Purpose: Previously our randomized phase III trial demonstrated that immunotherapy including dinutuximab, a chimeric anti-GD2 mAb, GM-CSF, and IL2 improved survival for children with high-risk neuroblastoma that had responded to induction and consolidation therapy. These results served as the basis for FDA approval of dinutuximab. We now present long-term follow-up results and evaluation of predictive biomarkers. Patients and Methods: Patients recieved six cycles of isotretinoin with or without five cycles of immunotherapy which consists of dinutuximab with GM-CSF alternating with IL2. Accrual was discontinued early due to meeting the protocol-defined stopping rule for efficacy, as assessed by 2-year event-free survival (EFS). Plasma levels of dinutuximab, soluble IL2 receptor (sIL2R), and human anti-chimeric antibody (HACA) were assessed by ELISA. Fcγ receptor 2A and 3A genotypes were determined by PCR and direct sequencing. Results: For 226 eligible randomized patients, 5-year EFS was 56.6 ± 4.7% for patients randomized to immunotherapy (n = 114) versus 46.1 ± 5.1% for those randomized to isotretinoin only (n = 112; P = 0.042). Five-year overall survival (OS) was 73.2 ± 4.2% versus 56.6 ± 5.1% for immunotherapy and isotretinoin only patients, respectively (P = 0.045). Thirteen of 122 patients receiving dinutuximab developed HACA. Plasma levels of dinutuximab, HACA, and sIL2R did not correlate with EFS/OS, or clinically significant toxicity. Fcγ receptor 2A and 3A genotypes did not correlate with EFS/OS. Conclusions: Immunotherapy with dinutuximab improved outcome for patients with high-risk neuroblastoma. Early stoppage for efficacy resulted in a smaller sample size than originally planned, yet clinically significant long-term differences in survival were observed.