FDA Approves First Domestic Source of Medical Isotope

Roxanne Nelson, RN, BSN


February 09, 2018

The US Food and Drug Administration (FDA) has approved a high-tech isotope separation platform, the RadioGenix System (NorthStar Medical Radioisotopes), to be used in producing the isotope technetium-99m (Tc-99m) from non-uranium-based molybdenum-99 (Mo-99).

NorthStar is the first US company in 30 years to produce Mo-99 domestically for patient use.

The most innovative aspect of the approval, commented Libero (Louis) Marzella, MD, PhD, director, Division of Medical Imaging Products, Center for Drug Evaluation and Research at the FDA, "is that this is a totally nonfission process for producing Mo99."

Speaking during a press briefing held to discuss the approval, Dr Marzella noted that the US government had put an emphasis and a premium on "shifting from highly enriched uranium because of concerns of diversion with this highly fissionable material."

Tc-99m is the most widely used radioisotope in medical imaging. It is used in more than 80% of routine medical imaging procedures performed in the United States. When used with the appropriate diagnostic scanning device, such as a SPECT imaging system, Tc-99m emits signals that produce an image of internal organs. But its shelf life is limited, and a stable supply chain is critically needed.

The Nuclear Regulatory Commission (NRC), the regulatory authority responsible for overseeing the production, distribution, possession, and use of radioactive materials and products containing radioactive materials, will be issuing guidance for medical and commercial nuclear pharmacy users on the license amendments they will need in order to use the RadioGenix System.

Domestic Source Needed

Prior to this FDA clearance, Tc-99m had to be acquired through a complicated supply chain, which has led to unexpected shortages or disruptions in supply. Mo-99 could only be produced from enriched uranium by facilities outside the United States; thus, enriched uranium had to first be shipped from the United States, then processed into medically useful Mo-99, and then shipped back again.

"A severe shortage of Mo-99 occurred in 2010 and had a major impact on the ability to conduct standard nuclear imaging," said Janet Woodcock, MD, director of the FDA's Center for Drug Evaluation and Research.

Because of the shortage, practitioners had to switch to alternative isotopes, and patients had to either wait for imaging or choose a less reliable method.

"Today's approval will help ensure more reliable, clean, and secure access to this important imaging agent," she said.

Dr Woodcock explained during the briefing that to address these challenges, Congress enacted the American Medical Isotopes Production Act of 2012, which contained provisions to eliminate the use of highly enriched uranium for medical isotope production. It also encouraged the development of US domestic supplies of Mo-99 and associated isotopes.

"Many federal agencies, including the FDA, NRC, as well as the Department of Energy's National Nuclear Security Administration and National Laboratories, have been working together with industry to develop a technology that minimizes dependence on highly enriched uranium and brings the supply chain within the US," said Dr Woodcock. "As a result of this collaboration, the US medical community will now have a domestic source of Tc-99m through the use of the RadioGenix System, which marks the first nonuranium process for the production of Mo-99 to prepare the Tc-99m."

Today's approval also allows the RadioGenix System to produce sodium pertechnetate Tc-99m injection, which can be administered intravenously, instilled into the bladder or eye, or administered with other imaging agents. The approval did not require new clinical studies to be conducted because it relied on safety and efficacy data already available from an FDA-approved Tc-99m generator.

Dr Marzella also pointed out that NorthStar will not be the only manufacturer of this product. "The initial intent was to fund four different manufacturers, and NorthStar is just the first," he said. "We hope that that there will be a long list of other producers.

"The FDA is working with, if you will, other contenders, and in addition, RadioGenix System is being envisaged as being a platform for other isotope production," he added.

Peter Hanlon, assistant deputy administrator, Office of Material Management and Minimization, National Nuclear Security Administration, US Department of Energy, agreed, adding that "we hope to have at least two companies producing Mo-99."

Among the most common adverse effects of Tc-99m are allergic reactions, including anaphylaxis, which have been reported infrequently after injection of sodium pertechnetate Tc-99m. Healthcare providers should monitor all patients for hypersensitivity reactions.

The FDA cautioned that sodium pertechnetate Tc-99m injection contributes to a patient's long-term cumulative radiation exposure, and practitioners should ensure safe handling to protect patients and healthcare workers from unintentional radiation exposure in accordance with instructions in the product labeling.

More news on today's announcement is available on the FDA website.

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