Iodine-131 meta-iodobenzylguanidine (I-131 MIBG) is a radiopharmaceutical used for both imaging and treating certain types of neuroendocrine tumors. Neuroendocrine tumors that can be treated with I-131 MIBG include neuroblastomas, paragangliomas and pheochromocytomas.
This targeted radionuclide therapy is able to detect and treat these tumors because the compound MIBG is very similar to norepinephrine/noradrenaline, a neurotransmitter chemical that is taken up by certain neuroendocrine cells. I-131 MIBG is used to treat neuroendocrine tumors by selectively targeting and killing neuroendocrine tumors that take up MIBG.
I-131 MIBG is administered under the supervision of a nuclear medicine specialist. It is a procedure that is performed in the hospital. The radiopharmaceutical is injected into the patient's bloodstream, and the patient remains in the hospital for a few days during and after treatment until the radioactivity in the patient's body has decreased to a safe level for the patient to be around other people.
In July 2018, the U.S. Food and Drug Administration (FDA) approved iobenguane I-131, a form of I-131 MIBG, for the treatment of paragangliomas and pheochromocytomas. It is the first FDA approved radiopharmaceutical for the treatment of paragangliomas and pheochromocytomas in patients age 12 and older with tumors that are not surgically removable and have spread to other sites of the body. FDA approval was based on data from a clinical trial that demonstrated decreases in tumor-related high blood pressure, tumor size and tumor markers in patients who underwent treatment.
Similar to conventional I-131 MIBG, iobenguane I-131 treatment is performed in the hospital under the supervision of a nuclear medicine specialist. It is injected into the patient’s bloodstream, and the patient stays in the hospital for a few days during and after treatment.