Long-Term Follow-up of a Phase III Study of ch14.18 (Dinutuximab) + Cytokine Immunotherapy in Children with High-Risk Neuroblastoma: COG Study ANBL0032

Yu AL, Gilman AL, Ozkaynak MF, Naranjo A, Diccianni MB, Gan J, Hank JA, Batova A, London WB, Tenney SC, Smith M, Shulkin BL, Parisi M, Matthay KK, Cohn SL, Maris JM, Bagatell R, Park JR, Sondel PM. Long-Term Follow-up of a Phase III Study of ch14.18 (Dinutuximab) + Cytokine Immunotherapy in Children with High-Risk Neuroblastoma: COG Study ANBL0032. Clin Cancer Res. 2021 Apr 15;27(8):2179-2189. doi: 10.1158/1078-0432.CCR-20-3909. Epub 2021 Jan 27. PubMed PMID: 33504555; PubMed Central PMCID: PMC8046731.

Previously our randomized Phase III trial demonstrated that immunotherapy including dinutuximab, a chimeric anti-GD2 monoclonal antibody, granulocyte macrophage-colony stimulating factor (GM-CSF), and interleukin-2 (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 recieved 6 cycles of isotretinoin with or without 5 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. 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. 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.