Thyroid and hepatic function after high-dose 131 I-metaiodobenzylguanidine (131 I-MIBG) therapy for neuroblastoma.

BACKGROUND: (131) I-Metaiodobenzylguanidine ((131) I-MIBG) provides targeted radiotherapy for children with neuroblastoma, a malignancy of the sympathetic nervous system. Dissociated radioactive iodide may concentrate in the thyroid, and (131) I-MIBG is concentrated in the liver after (131) I-MIBG therapy. The aim of our study was to analyze the effects of (131) I-MIBG therapy on thyroid and liver function. PROCEDURE: Pre- and post-therapy thyroid and liver functions were reviewed in a total of 194 neuroblastoma patients treated with (131) I-MIBG therapy. The cumulative incidence over time was estimated for both thyroid and liver toxicities. The relationship to cumulative dose/kg, number of treatments, time from treatment to follow-up, sex, and patient age was examined. RESULTS: In patients who presented with Grade 0 or 1 thyroid toxicity at baseline, 12 ± 4% experienced onset of or worsening to Grade 2 hypothyroidism and one patient developed Grade 2 hyperthyroidism by 2 years after (131) I-MIBG therapy. At 2 years post-(131) I-MIBG therapy, 76 ± 4% patients experienced onset or worsening of hepatic toxicity to any grade, and 23 ± 5% experienced onset of or worsening to Grade 3 or 4 liver toxicity. Liver toxicity was usually transient asymptomatic transaminase elevation, frequently confounded by disease progression and other therapies. CONCLUSION: The prophylactic regimen of potassium iodide and potassium perchlorate with (131) I-MIBG therapy resulted in a low rate of significant hypothyroidism. Liver abnormalities following (131) I-MIBG therapy were primarily reversible and did not result in late toxicity. (131) I-MIBG therapy is a promising treatment for children with relapsed neuroblastoma with a relatively low rate of symptomatic thyroid or hepatic dysfunction.

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 [(131)I]metaiodobenzylguanidine ([(131)I]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 [(131)I]MIBG doses ranging from 492 to 1,160 mCi (median, 12 mCi/kg). Cumulative [(131)I]MIBG administered ranged from 492 to 3,191 mCi. Autologous hematopoietic stem cells were collected and cryopreserved before treatment with [(131)I]MIBG greater than 12 mCi/kg or with a total dose greater than 500 mCi. Sixty-nine [(131)I]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 [(123)I]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 patients achieved a CR or PR in at least one measure of response without progressive disease, and 8% of patients maintained stable disease for greater than 12 months. Thirty-five percent of patients experienced progressive disease within 1 year after therapy. The estimated 5-year overall survival rate was 64%. Toxicities included grades 3 to 4 neutropenia (87%) and thrombocytopenia (83%). Grades 3 to 4 nonhematologic toxicity included acute respiratory distress syndrome (n = 2), bronchiolitis obliterans organizing pneumonia (n = 2), pulmonary embolism (n = 1), fever with neutropenia (n = 7), acute hypertension (n = 10), infection (n = 2), myelodysplastic syndrome (n = 2), and hypogonadism (n = 4). CONCLUSION: Although serious toxicity may occur, the survival and response rates achieved with high-dose [(131)I]MIBG suggest its utility in the management of selected patients with metastatic PHEO and PGL.

Malignant pheochromocytomas and paragangliomas: a phase II study of therapy with high-dose 131I-metaiodobenzylguanidine (131I-MIBG).

Thirty patients with malignant pheochromocytoma (PHEO) or paraganglioma (PGL) were treated with high-dose 131I-MIBG. Patients were 11-62 (mean 39) years old: 19 patients males and 11 females. Nineteen patients had PGL, three of which were multifocal. Six PGLs were nonsecretory. Eleven patients had PHEO. All 30 patients had prior surgery. Fourteen patients were refractory to prior radiation or chemotherapy before 131I-MIBG. Peripheral blood stem cells (PBSCs) were collected and cryopreserved. 131I-MIBG was synthesized on-site, by exchange-labeling 131I with 127I-MIBG in a solid-phase Cu2+-catalyzed exchange reaction. 131I-MIBG was infused over 2 h via a peripheral IV. Doses ranged from 557 mCi to 1185 mCi (7.4 mCi/kg to 18.75 mCi/kg). Median dose was 833 mCi (12.55 mCi/kg). Marrow hypoplasia commenced 3 weeks after 131I-MIBG therapy. After the first 131I-MIBG therapy, 19 patients required platelet transfusions; 19 received GCSF; 12 received epoeitin or RBCs. Four patients received a PBSC infusion. High-dose 131I-MIBG resulted in the following overall tumor responses in 30 patients: 4 sustained complete remissions (CRs); 15 sustained partial remissions (PRs); 1 sustained stable disease (SD); 5 progressive disease (PD); 5 initial PRs or SD but relapsed to PD. Twenty-three of the 30 patients remain alive; deaths were from PD (5), myelodysplasia (1), and unrelated cause (1). Overall predicted survival at 5 years is 75% (Kaplan Meier estimate). For patients with metastatic PHEO or PGL, who have good *I-MIBG uptake on diagnostic scanning, high-dose 131I-MIBG therapy was effective in producing a sustained CR, PR, or SD in 67% of patients, with tolerable toxicity.

Tumor response and toxicity with multiple infusions of high dose 131I-MIBG for refractory neuroblastoma.

BACKGROUND: (131)I Metaiodobenzylguanidine ((131)I-MIBG) is an effective targeted radiotherapeutic for neuroblastoma with response rates greater than 30% in refractory disease. Toxicity is mainly limited to myelosuppression. The aim of this study was to determine the response rate and hematologic toxicity of multiple infusions of (131)I-MIBG. PROCEDURE: Patients received two to four infusions of (131)I-MIBG at activity levels of 3-19 mCi/kg per infusion. Criteria for subsequent infusions were neutrophil recovery without stem cell support and lack of disease progression after the first infusion. RESULTS: Sixty-two infusions were administered to 28 patients, with 24 patients receiving two infusions, two patients receiving three infusions, and two patients receiving four infusions. All patients were heavily pre-treated, including 16 with prior myeloablative therapy. Eleven patients (39%) had overall disease response to multiple therapies, including eight patients with measurable responses to each of two or three infusions, and three with a partial response (PR) after the first infusion and stable disease after the second. The main toxicity was myelosuppression, with 78% and 82% of patients requiring platelet transfusion support after the first and second infusion, respectively, while only 50% had grade 4 neutropenia, usually transient. Thirteen patients did not recover platelet transfusion independence after their final MIBG infusion; stem cell support was given in ten patients. CONCLUSIONS: Multiple therapies with (131)I-MIBG achieved increasing responses, but hematologic toxicity, especially to platelets, was dose limiting. More effective therapy might be given using consecutive doses in rapid succession with early stem cell support.

Hematologic toxicity of high-dose iodine-131-metaiodobenzylguanidine therapy for advanced neuroblastoma.

PURPOSE: Iodine-131-metaiodobenzylguanidine ((131)I-MIBG) has been shown to be active against refractory neuroblastoma. The primary toxicity of (131)I-MIBG is myelosuppression, which might necessitate autologous hematopoietic stem-cell transplantation (AHSCT). The goal of this study was to determine risk factors for myelosuppression and the need for AHSCT after (131)I-MIBG treatment. PATIENTS AND METHODS: Fifty-three patients with refractory or relapsed neuroblastoma were treated with 18 mCi/kg (131)I-MIBG on a phase I/II protocol. The median whole-body radiation dose was 2.92 Gy. RESULTS: Almost all patients required at least one platelet (96%) or red cell (91%) transfusion and most patients (79%) developed neutropenia (< 0.5 x 10(3)/microL). Patients reached platelet nadir earlier than neutrophil nadir (P <.0001). Earlier platelet nadir correlated with bone marrow tumor, more extensive bone involvement, higher whole-body radiation dose, and longer time from diagnosis to (131)I-MIBG therapy (P