TerraPower Isotopes and Belgian joint venture PanTera have announced a collaboration to increase the global availability of actinium-225 (Ac-225), while Arizona-based Serva Energy has developed a new research reactor-based production method to ramp up the supply of the rare radioisotope.

PanTera uses a Rhodotron to produce Ac-225 (Image: SCK CEN)

Targeted alpha 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.

The collaborative agreement between TerraPower Isotopes and PanTera, a joint venture of medical technology company and particle accelerator specialist IBA and the Belgian nuclear research centre SCK CEN, aims to increase the global availability of Ac-225 by using both their production routes: TerraPower Isotopes extracts Ac-225 from the natural decay of thorium-229 derived from legacy US nuclear material, while PanTera uses a so-called "gamma route" to produce the isotope from radium-226 (Ra-226) using a Rhodotron electron accelerator.

"Demand for actinium-225 is expected to increase as more radiopharmaceutical treatments using actinium-225 are developed to treat a variety of different types of cancers," TerraPower Isotopes President Scott Claunch said. "This collaboration will help us supply this valuable material to the pharmaceutical industry and meet the growing global demand."

CEO Sven Van den Berghe said PanTera will continue to develop its own technology for large-scale production of Ac-225, but the collaboration will increase the market availability of the isotope, making it available for use in research and clinical trials, as well as to physicians for compassionate use, from 2024. "This volume would be equivalent to 50% of today’s supply and underpin the wider development of these targeted alpha therapy radiopharmaceuticals as an effective treatment modality for cancer," he said.

New method

Serva has been working with nuclear facilities and chemistry laboratories at the University of California-Irvine (UCI) and Arizona State University (ASU), with support from the US Department of Energy's (DOE) National Isotope Development Center, to develop its proprietary technology to produce Ac-225 from Ra-226 supplied by the DOE Isotope Program.

Initial batches produced this technology which have now been validated by the non-profit Mayo Clinic. Ian Horn, senior associate consultant of radiochemistry and radiopharmaceuticals at the Mayo Clinic Rochester, said Serva's production method is "highly promising" with "significant potential" to make commercial quantities of the isotope suitable for radiopharmaceutical use. "Targeted alpha therapies are the next generation of therapeutic radiopharmaceutical products. To facilitate the development and use of these novel treatments, it is critical that the supply chain of alpha emitting isotopes, such as actinium-225, be improved to support multiple commercial applications," he said.

The company said its new production method will allow it to collaborate with "dozens" of existing research reactors around the world.

"What's really exciting about this innovation is the potential to save lives," Serva Energy CEO Ian Horvath said. "Actinium-225 is the miracle isotope that can open the doors to the cancer treatments we've been wishing for. The more actinium we can produce, the more lives we can save."

Researched and written by World Nuclear News