Anti-GD2 based immunotherapy prevents late events in high-risk neuroblastoma patients over 18 months at diagnosis

Abstract

Background: Anti-GD2 based immunotherapy has improved overall (OS) and event free survival (EFS) for high-risk neuroblastoma (HR-NBL) patients. Here, we evaluate the long-term efficacy of anti-GD2 immunotherapy in combination with isotretinoin, GM-CSF, and IL-2. Methods: Dutch HR-NBL patients treated with immunotherapy according to the COG-ANBL0032 protocol (n = 47) were included and compared to historical controls (n = 37) treated with single-agent isotret-inoin maintenance therapy. Survival time was calculated from start of the maintenance therapy. Results: The study and control group were similar concerning baseline characteristics. In the com-plete cohort, 5 year OS was 64±7% and 49±8% for the immunotherapy group and the control group, respectively (p = 0.16). Five year EFS was 57±7% and 41±8%, respectively (p = 0.16). In the subgroup of patients ≥ 18 months, 5-yr OS was 63±8% and 39±9, respectively (p = 0.04) and EFS 54±8% and 29±8%, respectively (p = 0.05). Landmark analysis for EFS with landmark point at 6 months after start of maintenance suggests a larger effect on the prevention of late than early events. Conclusions: This study is the first to confirm the results of the COG-ANBL0032 study in a cohort treated with a different induction regimen. Anti-GD2 immunotherapy prevents late events, most significantly in patients older than 18 months of age at diagnosis.