Y-mAbs Therapeutics announces interim analysis of Phase 2 data for Naxitamab

Y-mAbs Therapeutics announced new interim data from the Phase 2 Trial 201 of naxitamab in combination with granulocyte-macrophage colony-stimulating factor in patients with relapsed or refractory high-risk neuroblastoma with residual disease limited to bone and/or bone marrow. The results are summarized in poster presentations at the 2024 American Society of Clinical Oncology Annual Meeting in Chicago, IL. A poster titled “Patterns of improvement following initial response in patients treated with naxitamab for relapsed/refractory high-risk neuroblastoma” demonstrates that continued treatment with naxitamab can further reduce disease following the initial response to naxitamab therapy. The Trial 201 prespecified interim analysis achieved a 50% overall response rate in 26 out of 52 patients. Nearly a quarter of patients achieved their first complete response or partial response after three or more cycles of naxitamab therapy. Among these patients, most had initial stable disease within specific bone or bone marrow compartments prior to achieving a CR or PR. These results support the rationale for extended naxitamab therapy in patients who do not achieve a CR or PR at first assessment. A poster titled “Naxitamab-related adverse events within and across treatment cycles in patients with relapsed/refractory high-risk neuroblastoma” demonstrates the frequency and patterns of adverse events based on the interim analysis of Trial 201. In this analysis, 81% of naxitamab-related AEs were Grade 1 or 2, while Grade greater than or equal to 3 AEs reported in greater than or equal to 10% of patients included hypotension, pain, urticaria, bronchospasm, and abdominal pain. None resulted in treatment discontinuation. Notably, the frequency of naxitamab-related pain Grade 3 AEs decreased from the first cycle to the second, generally stabilizing thereafter, with frequencies consistent across infusions. Similarly, the frequency of hypotension showed marked reductions across cycles and infusions.