Long-term, continuous infusion of single-agent dinutuximab beta for relapsed/refractory neuroblastoma: an open-label, single-arm, Phase 2 study

BACKGROUND: Short-term infusions of dinutuximab beta plus isotretinoin and cytokines administered in previous immunotherapy studies in neuroblastoma were associated with severe pain. Here, long-term, continuous infusion of single-agent dinutuximab beta was evaluated in patients with relapsed/refractory neuroblastoma. METHODS: In this open-label, single-arm, Phase 2 study, patients with either refractory or relapsed high-risk neuroblastoma received dinutuximab beta by continuous infusion over 10 days of each cycle, for up to five cycles. The primary endpoint was objective response rate 24 weeks after the end of cycle 5. Secondary endpoints included adverse events, intravenous morphine use, best response, duration of response, and three-year progression-free and overall survival. RESULTS: Of the 40 patients included, 38 had evaluable response. Objective response rate was 26% and best response rate 37%. Median duration of response was 238 days (IQR 108–290). Three-year progression-free and overall survival rates were 31% (95% CI 17–47) and 66% (95% CI 47–79), respectively. Prophylactic intravenous morphine use and duration of use decreased with increasing cycles. The most common grade 3 treatment-related adverse events were pain, diarrhea, and hypokalemia. CONCLUSION: Long-term continuous infusion of single-agent dinutuximab beta is tolerable and associated with clinically meaningful responses in patients with relapsed/refractory high-risk neuroblastoma. CLINICAL TRIAL REGISTRATION: The study is registered with ClinicalTrials.gov (NCT02743429) and EudraCT (2014-000588-42).