Joe McBrearty
President & CEO, Canadian Nuclear Laboratories
Actinium-225, one of the most sought-after isotopes in the world, is being studied and produced in Canada’s national nuclear laboratories.
If you haven’t heard of Actinium-225, it’s for good reason. Even with an army of nuclear scientists, you’d be hard-pressed to find more than a trace of the isotope anywhere on Earth. Actinium-225 is so rare that the annual global production is less than a grain of sand, which is why it has been dubbed ‘the rarest drug on Earth.’
Today, the unique properties of Actinium-225 have also made it one of the most sought-after isotopes in the world by the medical community. The material made headlines in 2016 when a German patient suffering from terminal cancer was treated with a novel therapy enabled by the rare isotope. Eight months later, the tumours had largely disappeared, the patient was still alive, and international researchers were clamouring for more Actinium-225.
Further studies have shown just as much promise, but the limited supply of Actinium-225 has hampered international efforts to advance research related to the isotope. That’s where Canadian Nuclear Laboratories (CNL) comes in.
A proud history in medical isotopes
CNL operates the Chalk River Laboratories, which is owned by Atomic Energy of Canada Limited (AECL). Chalk River once produced more than half the world’s supply of Molybdenum-99, a key isotope used for cancer diagnostic procedures, and it’s estimated that isotopes produced in Chalk River have been used in over one billion medical procedures. CNL still fulfills a vital role as a national research laboratory. With the growing interest in Actinium-225, we recognized that we were one of a handful of companies in the world that could not only produce research quantities of the rare material but study it as well.
CNL not only has all of the health science laboratories, equipment, and expertise to conduct research programs based on Actinium-225, but we also have the nuclear materials needed to produce more of this rare isotope. Over the past three years, CNL has developed a small-scale generator that produces enough Actinium-225 for our research and meaningful quantities that we provide to our strategic partners advancing research in treatment safety and efficacy.
The ‘goldilocks’ isotope
How does the new treatment work, exactly? Actinium-225 is attached to a targeting molecule that’s designed to seek out and bind with cancer cells. Then, as the isotope decays, it emits high-energy alpha particles that effectively kill cancer cells, leaving nearby healthy cells virtually unharmed. With a half-life of 10 days, Actinium-225 lasts long enough to do its job in fighting cancer but doesn’t harmfully linger in the body. This is why it’s seen as a “goldilocks” isotope in nuclear medicine.
This treatment is collectively known as targeted alpha therapy (TAT), and CNL is positioning itself to be an international hub for this type of research in the future. In addition to radioisotope production, CNL also maintains capabilities to conduct biological research at its Biological Research Facility, a unique facility that can perform TAT-related research and development for universities and innovative companies.
A promising future
But even bigger plans are in the works. CNL sees an opportunity to build on its legacy in isotope production and processing and is exploring the construction of new facilities on the Chalk River campus that would establish a stable, commercial-scale supply chain for Actinium-225. In pursuit of that goal, CNL has signed a Memorandum of Understanding with ITM Isotope Technologies Munich, a leading radiopharmaceutical biotech company based out of Germany.
It’s all very exciting for a Canadian science institution that once transformed the way the world fights cancer. With Actinium-225, we plan to do it again.
