Dinutuximab-beta after autologous peripheral blood stem cell transplantation improved event-free survival of newly diagnosed children with high-risk neuroblastoma but overall survival remains unchanged: Saudi Arabia's multi-institutional experiences

Background: Despite the use of multimodal therapy to treat high-risk neuroblastoma, the prognosis of this patient population remains poor. The addition of dinutuximab-beta to standard maintenance therapy after autologous peripheral blood stem cell transplantation (auto-PBSCT) has been found to improve survival rates. We present treatment outcome of high-risk neuroblastoma (HR NBL) before and after the introduction of dinutuximab-beta in comprehensive large cancer centers in Saudi Arabia. Materials and Methods: This is a multicenter retrospective chart review of all patients aged 1–14 years diagnosed with HR-NBL who received multimodal therapy including dinutuximab-beta during maintenance phase after auto-PBSCT compared with patients who did not receive between 2015 and 2020. Supportive therapy was administered to manage dinutuximab-beta-associated adverse events. Results: The treatment outcome was evaluated for 32 patients (21 received dinutuximab-beta and 11 patients did not receive it). Among 21 patients who received dinutuximab-beta, 12 (57.1%) patients received all planned five cycles of dinutuximab-beta (cumulative 100% of the dose) and 9 (42.9%) patients received less than 5 cycles of dinutuximab-beta maintenance mainly secondary to toxicities, which is reported in 11.1%, and progressive disease during dinutuximab-beta therapy, which is reported in 88.9%. The 5-year mean and median survival were 67.3 and 99 months, respectively, while the overall survival (OS) rate was approximately 57%. The mean and median disease-free survival (DFS) were 36.3 and 20 months, respectively, while the DFS rate was approximately 22%. There was nonsignificant difference in OS and DFS between patients who received dinutuximab-beta and patients who did not receive it ( P values 0.970 and 0.113). From all examined factors, there were no statistically significant differences between patients who received dinutuximab-beta and patients who did not receive it with the baseline characteristics, except for relapse status with P = 0.013, time from PBSCT to relapse with P = 0.023, and mortality with P=0.049. Dinutuximab-beta maintenance treatment was generally well tolerated with proper use of supportive therapy, with the most prevalent toxicities being nonhematological in nature and being reported in 52%. Conclusion: There is a noticeable improvement and reduction in disease progression-free survival with manageable adverse events in patients who received dinutuximab-beta maintenance therapy, but the overall survival rate remains unchanged.