No-carrier-added iodine-131-MIBG: evaluation of a therapeutic preparation.

Abstract

UNLABELLED:

Iodine-131-metaiodobenzylguanidine ([131I]MIBG) is a radiopharmaceutical for imaging as well as targeted radiotherapy of neuroblastoma. It is predicted that the use of no-carrier-added [131I]MIBG, rather than the conventional low specific activity preparation, will result in an enhanced therapeutic ratio because of different transport processes in neuroblastoma compared with most normal tissues.

METHODS:

The main aims of the study were: (1) to determine whether [131I]MIBG of substantially greater specific activity is transported into tumor cells by the same process as the existing compound; (2) to evaluate the effect of nonradiolabeled MIBG on the cytotoxicity of no-carrier-added [131I]MIBG; and (3) to compare the biodistribution of both preparations of the radiochemical in neuroblastoma xenografts.

RESULTS:

Active uptake of no-carrier-added [131I]MIBG was temperature-, sodium- and oxygen-dependent; ouabain- and desmethylimipramine-inhibitable; and could be blocked competitively by monoamine inhibitors of the noradrenaline transport mechanism. The rank order of specific uptake capacity in a panel of neuroblastoma cell lines was the same for both low and high specific activity drug. Neuroblastoma spheroid regrowth was 85% inhibited by no-carrier-added [131I]MIBG at 2 MBq.ml-1. Inhibitory potency was reduced in a dose-dependent manner by nonradiolabeled MIBG. The accumulation of no-carrier-added [131I]MIBG was significantly greater in tumor, adrenal, heart and skin of tumor-bearing mice than that of the conventional therapy preparation of [131I]MIBG.

CONCLUSION:

These data indicate that there may be clinical advantages in the use of no-carrier-added [131I]MIBG rather than conventional [131I]MIBG.

• Authors: R J Mairs, S H Cunningham, J Russell, A Armour, J Owens, K McKellar, M N Gaze
• Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine (J Nucl Med) Vol. 36 Issue 6 Pg. 1088-95 (Jun 1995) ISSN: 0161-5505 [Print] United States
• PMID: 7769433 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Iodine Radioisotopes
• Iodobenzenes
• 3-Iodobenzylguanidine

Topics

• 3-Iodobenzylguanidine
• Animals
• Female
• Humans
• Iodine Radioisotopes (pharmacokinetics, therapeutic use)
• Iodobenzenes (pharmacokinetics, therapeutic use)
• Male
• Mice
• Mice, Nude
• Neoplasm Transplantation
• Neuroblastoma (metabolism, radiotherapy)
• Ovarian Neoplasms (metabolism, radiotherapy)
• Tumor Cells, Cultured