What is MIBG?

Meta-iodo–benzylguanidine (“MIBG”) has a similar chemical structure than norepinephrine as illustrated here. Because norepinephrine is concentrated in sympathetic nervous tissue, MIBG molecules use the same transporter system to enter the cells and get “absorbed” into tumor tissue.

Approximately 85% of neuroblastomas will be MIBG avid.

There are really 2 ways in which the molecule MIBG is used in neuroblastoma. It is both a diagnostic and a therapeutic agent depending on the isotope attached to the molecule. You may be familiar with “MIBG scans” – in this case, the radioactive iodine isotope attached to the molecule is I¹²³. It is used for imaging of the disease (presence or absence of tumors). When used as a therapeutic agent, the radioactive iodine isotope attached to the molecule is I¹³¹. In this case, the I-¹³¹MIBG will be “absorbed” by the neuroblastoma cells and its radiation will break the cells’ DNA thereby destroying the tumor cells.

How does I-131 MIBG work?

The illustration shows the various mechanisms involved in I-¹³¹MIBG uptake, retention, cytotoxicity and how those mechanisms may enhance I-¹³¹MIBG’s activity. Certain drugs can be also used in conjunction with I-¹³¹MIBG to “sensitize” neuroblastoma cells to I-¹³¹MIBG. For example, Vorinostat (HDAC inhibitor) is used in combination with I-¹³¹MIBG in the OPTIMUM^TM study. Others drugs may directly increase NET expression or enhance its function.

I-¹³¹MIBG is retained in the neuroblastoma cells because those cells do not have secretory granules.

I-¹³¹ is a beta-particle and gamma radiation emitter, penetrating several millimeters in the tissue.

How does I-131 MIBG get to the treating facility?

Jubilant Radiopharma

Children’s Hospital system/ Pediatric Oncology

Isolated or Non-isolated Treatment room

MIBG Intravenous Infusion

The ß emission of I-131 deliver

targeted radiation

to the NB cells. I-131 MIBG is absorbed by the NB cells and breaks the cells’ DNA.

Child stays at the hospital until the radiation meets the discharge requirement, usually

3-5 days.

Jubilant Radiopharma is located near Montreal-Canada. Jubilant Radiopharma manufactures and distributes I-131 MIBG “on-demand” across all North America via its network of specialized radiopharmacies. The clinical investigator requests a dose to be manufactured specifically for the child. The ordering institution will select a date for the infusion, and Jubilant will manufacture and ship the dose accordingly. The receiving local radiopharmacy will deliver as soon as possible to the hospital. Meanwhile, the care team will have prepared the child and the family to receive the treatment. This will include radiation safety training.

Once the drug is at bedside, a nuclear medicine technologist will administer the infusion over approximately 90 minutes. The patient will be monitored over the next few days (3-5 days) depending on the dose received, the rate of elimination and until the level of radiation has declined to the institution’s discharge criteria.

The approach to therapy varies from institution to institution. Some institutions offer isolated rooms for the patient with adjacent parent suites and other institutions provide MIBG therapy from a regular hospital room equipped with portable shielding panels.

I-131 MIBG Clinical trials

Since 2007, Jubilant Radiopharma has supported clinical research in neuroblastoma by making I-131 MIBG available to treating physicians and researchers and remains the only manufacturer (supplier) in the USA for pediatric use. Jubilant Radiopharma is currently conducting its own registrational trial while participating in other studies such as COG ANBL-1531 in newly diagnosed high-risk neuroblastoma and supplying MIBG for NANT studies in relapse/refractory as well as other investigator led studies in the USA and Canada.

There are other clinical trials in neuroblastoma. It is important that parents and patients discuss with the clinical investigators the treatment regimen that is best for their situation in order to make an informed decision.

Please Note: Therapeutic I-131 MIBG is not approved for use in neuroblastoma by US FDA nor Health Canada

For more information, please consult www.clinicaltrials.gov .

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