 | |
| Clinical data | |
|---|---|
| Trade names | Adreview, Azedra |
| Other names | meta-iodobenzylguanidine mIBG, MIBG |
| License data | |
| Routes of administration | Intravenous |
| ATC code | |
| Legal status | |
| Legal status | |
| Identifiers | |
| |
| CAS Number |
|
| PubChemCID | |
| DrugBank |
|
| ChemSpider |
|
| UNII | |
| KEGG | |
| ChEBI | |
| ChEMBL | |
| CompTox Dashboard(EPA) | |
| Chemical and physical data | |
| Formula | C8H10IN3 |
| Molar mass | 275.093 g·mol−1 |
| 3D model (JSmol) | |
| |
| |
 N Y (what is this?) (verify) | |
Iobenguane, orMIBG, is an aralkylguanidine analog of theadrenergic neurotransmitternorepinephrine (noradrenaline), typically used as aradiopharmaceutical.[3] It acts as a blocking agent foradrenergic neurons. Whenradiolabeled, it can be used innuclear medicinal diagnostic and therapy techniques as well as inneuroendocrinechemotherapy treatments.
It localizes to adrenergic tissue and thus can be used to identify the location oftumors such aspheochromocytomas andneuroblastomas.[4] Withiodine-131 it can also be used to treat tumor cells that take up and metabolize norepinephrine.
MIBG is absorbed by and accumulated in granules of adrenal medullarychromaffin cells, as well as in pre-synaptic adrenergic neurongranules. The process in which this occurs is closely related to the mechanism employed by norepinephrine and its transporterin vivo.[5][6] Thenorepinephrine transporter (NET) functions to provide norepinephrineuptake at thesynaptic terminals and adrenal chromaffin cells. MIBG, by bonding to NET, finds its roles in imaging and therapy.
Less than 10% of the administered MIBG getsmetabolized into m-iodohippuric acid (MIHA), and the mechanism for how this metabolite is produced is unknown.[7]
MIBG concentrates inendocrine tumors, most commonly neuroblastoma,paraganglioma, andpheochromocytoma. It also accumulates in norepinephrine transporters in adrenergic nerves in theheart,lungs,adrenal medulla,salivary glands,liver, andspleen, as well as in tumors that originate in theneural crest. When labelled withiodine-123 it serves as a whole-body, non-invasivescintigraphic screening forgerm-line,somatic, benign, and malignantneoplasms originating in the adrenal glands. It can detect both intra and extra-adrenal disease. The imaging is highly sensitive and specific.[8][9]
Iobenguane concentrates in presynaptic terminals of the heart and otherautonomically innervated organs. This enables the possiblenon-invasive use as an in vivo probe to study these systems.[10][11]
Alternatives to imaging with123I-MIBG, for certain indications and under clinical and research use, include thepositron-emitting isotopeiodine-124, and other radiopharmaceuticals such as68Ga-DOTA and18F-FDOPA forpositron emission tomography (PET).[9][12][13]123I-MIBG imaging on agamma camera can offer significantly higher cost-effectiveness and availability compared to PET imaging, and is particularly effective where131I-MIBG therapy is subsequently planned, due to their directly comparable uptake.[14][9][15]
Side effects post imaging are rare but can includetachycardia,pallor, vomiting, and abdominal pain.[9]
MIBG can be radiolabelled with thebeta emitting radionuclide131I for the treatment of certain pheochromocytomas, paragangliomas,carcinoid tumors, neuroblastomas, andmedullary thyroid cancer.[16]
Thyroid blockade with (nonradioactive) potassium iodide is indicated for nuclear medicine scintigraphy with iobenguane/mIBG. This competitively inhibits radioiodine uptake, preventing excessive radioiodine levels in the thyroid and minimizing risk of thyroid ablation (in treatment with131I). The minimal risk of thyroid cancer is also reduced as a result.[9][17]
The dosing regime for theFDA-approved commercial123I-MIBG product Adreview ispotassium iodide orLugol's solution containing 100 mg iodide, weight adjusted for children and given an hour before injection.[18]EANM guidelines, endorsed by theSNMMI, suggest a variety of regimes in clinical use, for both children and adults.[9][12]
Product labeling for diagnostic131I iobenguane recommends giving potassium iodide one day before injection and continuing five to seven days following.[19]131I iobenguane used for therapeutic purposes requires a different pre-medication duration, beginning 24–48 hours before iobenguane injection and continuing 10–15 days after injection.[16]
Iobenguane I 131, marketed under the trade nameAzedra, has had a clinical trial as a treatment for malignant, recurrent or unresectable pheochromocytoma and paraganglioma, and theFDAapproved it on July 30, 2018. The drug is developed by Progenics Pharmaceuticals.[20][21]
Metaiodobenzylguanidine (MIBG) is a radiolabeled analogue of guanethidine that enters the cells via the norepinephrine transporter and is either stored in the cytoplasm or in secretory granules
{{cite book}}: CS1 maint: location missing publisher (link)Metaiodobenzylguanidine (MIBG) is transported to and stored in the distal storage granules of chromaffin cells in the same way as norepinephrine.
