Critical Isotope for Thyroid Cancer Now Produced in the US

Fran Lowry

November 20, 2018

A radioisotope used for diagnosing and treating thyroid cancer and hyperthyroidism, iodine-131 (I-131), is now being produced in the United States for the first time in almost 30 years.

It is made at the University of Missouri Research Reactor (MURR) in Columbia. The center recently shipped its first batch.

I-131 is the second most-used isotope in nuclear medicine in the United States, David Robertson, PhD, professor of chemistry and director of the reactor, told Medscape Medical News.

I-131 was the first medical isotope to be approved by the US Food and Drug Administration (FDA). It was approved in the 1950s but has not been made in the United States since the 1980s.

"That wasn't a problem because it was made in North America at a reactor in Canada, but that reactor closed last year. There are sources from overseas, but you can imagine, with something that has a very short shelf life — in this case, I-131 has a half-life of 8 days — you can't make a whole lot and put it on the shelf," Robertson said.

"So when it comes to making sure patients get their treatments when they are scheduled, we think it is very important to either have a North American, or now, a domestic supply," he said.

The MURR is the largest reactor at any university in the United States. It operates 52 weeks a year, "which is really important when your reactor is being used to make short-lived radioisotopes for medical treatment," Robertson said.

In addition to I-131, the MURR provides TheraSphere (Biocompatibles UK), a product consisting of yttrium-90 microspheres that is used in the treament of inoperable liver cancer; Quadramet (Lantheus Medical), a radiopharmaceutical consisting of samarium lexidronam that is used palliatively for pain associated with metastatic bone cancer; and Lutathera (AAA Pharmaceutical), a radiopharmaceutical consisting of lutetium dotate that was recently approved by the FDA to treat pancreatic cancer.

"The reactor has been supplying medical isotopes for most of our history. We view that as part of our mission, to use this very unique tool to save lives," Robertson said.

Thyroid Cancer on the Rise

According to the American Cancer Society, the incidence of thyroid cancer has increased more rapidly than that of any other cancer in the United States, with diagnoses tripling during the past 3 decades. It is estimated that 54,000 new cases of thyroid cancer will occur in the United States in 2018 and that 2060 deaths will occur because of the disease.

The MURR, which recently shipped its first batch of I-131, is expecting to produce adequate amounts of the isotope to meet this increasing demand, Robertson said.

"This summer there was an international shortage of I-131, just as we were turning on the reactor. We were asked to ramp up our production faster, but I wasn't willing to do so. You have to make sure you know what you're doing. You don't want to make a mistake when you are making radioactive materials. Now we're slowly ramping up as we gain experience, and we hope to be a significant supplier for the United States," he said.

Dr Robertson has disclosed no relevant financial relationships.


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