Impact of ¹³¹I-MIBG dose escalation (12 vs. 18 mCi/kg) during conditioning for autologous hematopoietic stem cell transplantation in pediatric neuroblastoma: a retrospective cohort study.

Authors

Amirali Kalantari, Maryam Behfar, Zahra Karimizadeh, Atieh Karimzadeh, Zeinab Paymani, Saeed Farzanehfar, Mehrshad Abbasi, Arghavan Tajalli, Sarina Ansari, Pooya Ashkevari, Rashin Mohseni, Najibe Karami, Amir Ali Hamidieh

Published in

European journal of pediatrics. Volume 185. Issue 11. Oct 20, 2026. Epub Oct 20, 2026.

Abstract

This study aimed to evaluate whether dose escalation of ¹³¹I-meta-iodobenzylguanidine (¹³¹I-MIBG) from 12 to 18 mCi/kg improves survival, engraftment, or toxicity profiles in children with high-risk neuroblastoma undergoing autologous HSCT. We retrospectively analyzed 56 pediatric patients under 18 years of age with high-risk, MIBG-avid neuroblastoma who underwent autologous HSCT between 2016 and 2025. Patients received either 12 mCi/kg (n = 17) or 18 mCi/kg (n = 39) of ¹³¹I-MIBG as part of a myeloablative chemotherapy conditioning regimen. Outcomes included engraftment, overall survival (OS), and event-free survival (EFS). Twenty-one deaths had occurred (8/17 [47.1%] in the 12 mCi/kg group; 13/39 [33.3%] in the 18 mCi/kg group). OS at 1 and 5 years was 76.5% and 59.5% for the 12 mCi/kg group, compared with 76.6% and 58.2% for the 18 mCi/kg group (log-rank p = 0.786). EFS at 1 and 5 years was 45.3% and 38.8% for the 12 mCi/kg group, compared with 69.1% and 36.2% for the 18 mCi/kg group (log-rank p = 0.656). Furthermore, at 1-year post-HSCT, the 18 mCi/kg group demonstrated a significantly higher rate of normal MIBG scans (83.3% vs. 46.2%, p = 0.024). Neutrophil engraftment was faster in the 18 mCi/kg group (median 10 vs 12 days; p = 0.001). Platelet engraftment was also more frequent in the 18 mCi/kg group (92.3% vs 70.6%; p = 0.047), with similar time to engraftment (16 vs 16.5 days).
 In this retrospective cohort, escalation from 12 to 18 mCi/kg was associated with faster neutrophil engraftment and a higher rate of normal MIBG scans at 1 year, without a significant difference in OS or EFS. The study was underpowered, and did not demonstrate a significant benefit of either the lower or the higher dose; the optimal dose remains undetermined and requires prospective evaluation.
• ¹³¹I-MIBG is incorporated into conditioning regimens prior to autologous HSCT for high-risk pediatric neuroblastoma, with doses up to 18 mCi/kg being tolerable, but the optimal dose and its impact on long-term survival remain unclear.
• In this direct retrospective comparison (12 vs. 18 mCi/kg), the higher dose was associated with faster neutrophil engraftment and a higher platelet engraftment rate and a higher rate of normal MIBG scans at year, but without a significant difference in OS or EFS, and with a non-significant trend toward more renal and thyroid toxicity. The study was underpowered and did not demonstrate a significant benefit of either dose; the optimal MIBG dose remains undetermined.

PMID:
42897384
Bibliographic data and abstract were imported from PubMed on 20 Oct 2026.

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