Single Stem Cell Rescue Supports Sequential MIBG Treatment in Resistant Neuroblastoma

Myelosuppression is the principal toxicity of iodine-131 metaiodobenzylguanidine (MIBG) therapy for neuroblastoma. Researchers retrospectively analyzed 96 patients who completed a single-arm expanded-access study (NCT00107289) at Memorial Sloan Kettering Cancer Center between 2008 and 2020. The analysis assessed whether single or tandem MIBG treatment, with or without subsequent chemotherapy, could be supported by one autologous stem cell rescue (ASCR), alongside toxicity and tumor response.

Of the 96 patients, 53 received single MIBG treatment and 43 received tandem treatment. Subsequent chemotherapy was given to 61 patients: 33 after single and 28 after tandem MIBG. ASCR was required in 11 patients after single MIBG, eight after tandem MIBG, and 58 after chemotherapy. With a single ASCR, neutrophil and platelet engraftment occurred in 100% and 90% of patients, respectively. The reported objective response rate, which included complete, partial, and minor responses, was 15% after initial MIBG, 21% with tandem MIBG, and 35% with chemotherapy after single MIBG.

These findings suggest that one ASCR may support sequential treatment in selected patients, potentially conserving stored stem cell aliquots. However, the retrospective, single-center analysis of study completers and nonrandomized treatment groups limit comparisons. Responses were modest, and the abstract does not detail nonhematologic toxicities or survival outcomes. The authors favor evaluating novel agents to optimize MIBG therapy rather than relying on tandem treatment or subsequent chemotherapy.