TerraPower Isotopes announced it is producing the actinium-225 at commercial scale. The medical radioisotope is being produced from material recovered from a legacy uranium-233 inventory at a US national laboratory.

In November 2019, nuclear innovation company TerraPower, Isotek Systems and the US Department of Energy (DOE) signed a public-private partnership agreement to use material recovered from the legacy uranium-233 (U-233) inventory at the DOE’s Oak Ridge National Laboratory (ORNL) to increase the supply of the medical radioisotope actinium-225 (Ac-225).

AtkinsRéalis subsidiary Isotek - a federal cleanup contractor in Oak Ridge - is responsible for the removal of the inventory of U-233 currently stored at ORNL. Under the agreement, Isotek extracts thorium-229 (Th-229) from the U-233, which TerraPower then uses for the production of Ac-225.

Oak Ridge’s U-233 inventory is a legacy of Cold War-era operations and its disposition is the DOE Office of Environmental Management’s highest priority at the Tennessee site. It is stored in Building 3019, which has been described as the oldest operating nuclear facility in the world.

TerraPower Isotopes (TPI) - a subsidiary of TerraPower - has now announced it is producing Ac-225 at commercial scale, “providing sustained access to highly pure Ac-225 to the global pharmaceutical community through weekly production runs”.

Ac-225 is a short-lived alpha-emitting isotope that can be used in a form of treatment known as targeted alpha therapy. This therapy, in which a molecule such as a monoclonal antibody is combined with an alpha emitter such as Ac-225, has the potential to treat a variety of cancers, targeting solid tumours, metastases, and systemic cancers such as leukemia. However, the scarcity of Ac-225 - sometimes described as one of the world’s rarest radioisotopes - is limiting its development and therapeutic use.

“This scale-up of production capacity of TerraPower Isotopes’ actinium-225 opens a new chapter in the development of cancer treatment options, and I’m proud to be part of the journey,” said Scott Claunch, president of TerraPower Isotopes. “We are proud to be the first company to provide actinium-225 at this scale, transforming how the pharmaceutical industry approaches cancer treatment with targeted alpha therapies.”

TPI said it uses a natural decay method to produce Ac-225 that is free of isotopic impurities. “This method increases the efficiency and automation of the process, which enables TPI to produce a significant, consistent supply of the isotope to the market.”

It added: “TPI’s collaboration with Isotek reduces the cost associated with the ultimate disposal of uranium-233, while enabling a secure supply chain for the actinium-225 isotope.”