Radiolabeled metaiodobenzylguanidine for the treatment of neuroblastoma.

INTRODUCTION: Neuroblastoma is the most common pediatric extracranial solid cancer. This tumor is characterized by metaiodobenzylguanidine (MIBG) avidity in 90% of cases, prompting the use of radiolabeled MIBG for targeted radiotherapy in these tumors.
METHODS: The available English language literature was reviewed for original research investigating in vitro, in vivo and clinical applications of radiolabeled MIBG for neuroblastoma.
RESULTS: MIBG is actively transported into neuroblastoma cells by the norepinephrine transporter. Preclinical studies demonstrate substantial activity of radiolabeled MIBG in neuroblastoma models, with (131)I-MIBG showing enhanced activity in larger tumors compared to (125)I-MIBG. Clinical studies of (131)I-MIBG in patients with relapsed or refractory neuroblastoma have identified myelosuppression as the main dose-limiting toxicity, necessitating stem cell reinfusion at higher doses. Most studies report a response rate of 30-40% with (131)I-MIBG in this population. More recent studies have focused on the use of (131)I-MIBG in combination with chemotherapy or myeloablative regimens.
CONCLUSIONS: (131)I-MIBG is an active agent for the treatment of patients with neuroblastoma. Future studies will need to define the optimal role of this targeted radiopharmaceutical in the therapy of this disease.