Partial Remission in Pediatric Relapsed Neuroblastoma After Multiple Cycle Low-Dose 211At-MABG Therapy

An 11-year-old boy with relapsed, poorly differentiated left adrenal neuroblastoma presented with multiple bone metastases, demonstrated by an ¹⁸ F-MFBG PET/CT with a Curie score of 4, despite prior multimodal therapy. He was subsequently enrolled in a phase 1 dose-escalation trial of ²¹¹ At-MABG-targeted alpha therapy. Follow-up ¹⁸ F-MFBG PET/CT revealed the resolution of most lesions and markedly decreased tracer uptake at the residual site, reducing his posttreatment Curie score to 1. This case highlights the therapeutic potential, safety, and feasibility of repeated, low-dose ²¹¹ At-MABG-targeted alpha therapy for pediatric relapsed neuroblastoma.