Engraftment after myeloablative doses of 131I-metaiodobenzylguanidine followed by autologous bone marrow transplantation for treatment of refractory neuroblastoma

Background. Metaiodobenzylguanidine (MIBG) labeled with I-131 has been used for targeted radiotherapy of neural crest tumors, with bone marrow suppression being the primary dose-limiting toxicity. The purpose of this study was to examine the engraftment and toxicity of higher myeloablative doses of I-131-MIBG with autologous bone marrow support. Procedure. Twelve patients with refractory neuroblastoma were given infusions of their autologous, cryopreserved bone marrow following 1-4 doses of I-131-MIBG. The median cumulative administered activity per kilogram of I-131-MIBG was 18.0 mCi/kg (range 14.1-50.2 mCi/kg), the median total activity was 594 mCi (range 195-1,353 mCi), and the median cumulative whole body irradiation from I-131-MIBG was 426 cGy (range 256-800 coy). A median of 2.5 x 10(8) viable cells/kg (range 0.9-4.7 x 10(8) cells/kg) was given in the bone marrow infusion. Results, All 12 patients achieved an absolute neutrophil count >500/mu l with a median of 19 days, but only 5/11 evaluable patients achieved red cell transfusion independence, in a median of 44 days; and 4/11 evaluable patients achieved platelet count >20,000/mu l without transfusion, in a median of 27 days. Conclusions. Autologous bone marrow transplantation may allow complete hematopoietic reconstitution following ablative I-131-MIBG radiotherapy in patients with neuroblastoma. Risk factors for lack of red cell or platelet recovery include extensive prior chemotherapy, progressive disease at the time of transplant, especially in the bone marrow, and a history of prior myeloablative therapy with stem cell support. (C) 1998 Wiley-Liss, Inc.