The metal hafnium is an obscure chemical element, with just a few minor applications in the electronics and nuclear industries. Now a French company, Nanobiotix, is introducing hafnium to medicine for the first time, in the form of a product that enhances the impact of radiotherapy in cancer patients.
Laurent Lévy, chief executive, says the company chose hafnium as the best material to absorb radiotherapy X-rays because of its use as a radiation absorber in nuclear reactors. It is injected into the tumour via nanoparticles of hafnium oxide about 50 nanometres (0.05 microns) in diameter, a size that absorbs X-rays well without toxic side effects.
This NanoXray technology has begun clinical testing in patients with advanced soft tissue sarcoma, with promising results reported at the American Society of Clinical Oncology meeting earlier this month. More extensive trials will follow soon.
Soft tissue sarcomas are hard to remove surgically. The aim is to hit the tumour with enough radiation to shrink it to a size where it can be cut out safely without leaving cancer cells behind. The hafnium oxide particles help because they absorb radiation within the tumour – increasing the dose ninefold compared to well-focused X-rays on their own, without exposing healthy tissues to extra radiation.
“This product is really safe, with no dose-limiting toxicity,” says Lévy. “It has been designed to stay within the tumour and just to absorb X-rays with no other biological effects, so this approach could be applied to any cancer.”
The technology is a good example of nanomedicine, the application of nanotechnology to healthcare. This is a fast-growing field of research that covers a wide range of projects. Lévy is vice-chair of the European Technology Platform for Nanomedicine, a public-private partnership. “Europe is ahead of the US in nanomedicine and we believe this is one area of healthcare where we can take a world lead,” he says.