title: Safety and efficacy of tandem 131I-metaiodobenzylguanidine infusions in relapsed/refractory neuroblastoma.
abstract: BACKGROUND
  Targeted radiotherapy with (131) I-Metaiodobenzylguanidine ((131) I-MIBG) is safe and effective therapy for patients with relapsed neuroblastoma, but anti-tumor activity is sometimes transient. The goal of this study was to determine the safety and efficacy of early (<100 days) second (131) I-MIBG treatment following an effective initial treatment.
  
  
  METHODS
  After an initial infusion of 18 mCi/kg (131) I-MIBG, patients with tumor response or stable disease (SD), and available hematopoietic stem cell product, were eligible for additional (131) I-MIBG therapy. Residual thrombocytopenia did not preclude patients from receiving additional treatment. Subsequent treatment was administered a minimum of 6 weeks and maximum 100 days from initial infusion, and subjects could receive subsequent therapy if the same criteria were met.
  
  
  RESULTS
  Seventy-six heavily pretreated patients (median 4 prior chemotherapy regimens, range 1-8) with relapsed neuroblastoma were treated with (131) I-MIBG. Response rate to the first infusion was 30%, with 49% showing SD. Response rate among the 41 patients receiving a subsequent second infusion was 29%. After two treatments, 39% of patients experienced a reduction in overall disease burden. Four of five complete responses (CRs) to the initial infusion were maintained, despite all five having disease readily apparent on immediate post-second treatment (131) I-MIBG scanning. Hematologic toxicity was managed with early PBSC support after the second therapy (median: 15 days).
  
  
  CONCLUSIONS
  Early second (131) I-MIBG safely reduces disease burden in patients with relapsed neuroblastoma. Patients with CR by conventional (123) I-MIBG scintigraphy may have substantial disease burden apparent on high-dose (131) I-MIBG scintigraphy, supporting consolidation with subsequent (131) I-MIBG therapy in cases of apparent complete remission. Pediatr Blood Cancer 2011; 57: 1124-1129. © 2011 Wiley Periodicals, Inc.
authors.affiliation: University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA. kelseyj@mail.med.upenn.edu
authors.forename: Kelsey
authors.initials: K
authors.lastname: Johnson
authors.forename: Barbara
authors.initials: B
authors.lastname: McGlynn
authors.forename: Jennifer
authors.initials: J
authors.lastname: Saggio
authors.forename: Diane
authors.initials: D
authors.lastname: Baniewicz
authors.forename: Hongming
authors.initials: H
authors.lastname: Zhuang
authors.forename: John M
authors.initials: JM
authors.lastname: Maris
authors.forename: Yael P
authors.initials: YP
authors.lastname: Mosse
mesh_terms: D019797:3-Iodobenzylguanidine / Q000008:administration & dosage* / Q000009:adverse effects; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000009:adverse effects; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007457:Iodine Radioisotopes / Q000008:administration & dosage* / Q000009:adverse effects; D053208:Kaplan-Meier Estimate; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy*; D009367:Neoplasm Staging; D009447:Neuroblastoma / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D007457:Iodine Radioisotopes; D019797:3-Iodobenzylguanidine