Phase II Study of High-Dose [131I]Metaiodobenzylguanidine Therapy for Patients With Metastatic Pheochromocytoma and Paraganglioma

Purpose To evaluate the safety and efficacy of high-dose [131I]metaiodobenzylguanidine ([131I]MIBG) in the treatment of malignant pheochromocytoma (PHEO) and paraganglioma (PGL). Methods Fifty patients with metastatic PHEO or PGL, age 10 to 64 years, were treated with [131I]MIBG doses ranging from 492 to 1,160 mCi (median, 12 mCi/kg). Cumulative [131I]MIBG administered ranged from 492 to 3,191 mCi. Autologous hematopoietic stem cells were collected and cryopreserved before treatment with [131I]MIBG greater than 12 mCi/kg or with a total dose greater than 500 mCi. Sixty-nine [131I]MIBG infusions were given, which included infusions to 35 patients treated once and infusions to 15 patients who received two or three treatments. Response was evaluated by [123I]MIBG scans, computed tomography/magnetic resonance imaging, urinary catecholamines/metanephrines, and chromogranin A. Results The overall complete response (CR) plus partial response (PR) rate in 49 evaluable patients was 22%. Additionally, 35% of patien...