Phase II Study of Allogeneic Hematopoietic Stem Cell Transplantation for Children with High-Risk Neuroblastoma Using a Reduced-Intensity Conditioning Regimen: Results from the AIEOP trial.

Despite aggressive multimodal treatment, the outcome of pediatric patients affected by high-risk (HR) neuroblastoma (NB) remains poor. The rational of use of allogeneic hematopoietic stem cell transplantation (allo-HCT) for NB was based on the possible graft versus tumor effect; however, toxicity represents a limitation to its efficacy. We sought to prospectively assess the feasibility and efficacy of allo-HCT using a reduced intensity conditioning regimen in pediatric patients with HR NB in a multicenter phase II trial. Primary endpoints were the rate of neutrophil and platelet engraftment, the 5-year transplant-related mortality (TRM) and the disease-free survival (DFS). Secondary endpoint measures included the incidence of acute and chronic graft-versus-host disease (aGvHD and cGvHD). Fifty-one patients were enrolled in the study. Five-year cumulative incidence (CI) of TRM and DFS were 29.4%±6.4%, and 11.8%±4.5%, respectively. Patients receiving allo-HCT within 1 year from diagnosis or with bone marrow as cell source had higher DFS probability. CI of neutrophil engraftment, platelet engraftment, and grade II-IV aGvHD was 97.9%±2.1%, 93.8%±3.5%, and 47.1%±7.0%. The development of new therapeutic strategies could further improve the disease control.