Radiotherapy is used in 60% of cancer cases, but it is prone to damaging nearby healthy cells and can be ineffective against metastases.

Nanobiotix has developed a nanomaterial product that enhances the X-ray exposure to tumour cells without increasing the dose inflicted on nearby healthy cells.

They now show that the same product can be used to arm the immune system to attack cancer in metastasis as well.

"We are going in the opposite direction from medicine at present," says Nanobiotix CEO Laurent Levy. "Pharma and biotech in general is going more and more in the direction of personalised medicine – so it is more effective but for fewer patients. We wanted to introduce the idea of a mass medicine product."

The trend towards more personalised medicine stems from the hit-or-miss efficacy of traditional treatments, which often had little effect without escalating the treatment to debilitating levels.

A return to a "one-size-fits-all" approach may seem a backwards step, but Levy believes it has produced an effective therapeutic that leverages physical responses common to all human beings.

Their core product NBTXR3 tackles the limitations of radiotherapy, which is used to treat the majority of cancer patients by exposing the cancerous tissue to a level of X-rays that will destroy the diseased cells.

Although radiotherapy can destroy all cancers, it is indiscriminate and attacks both diseased and healthy cells.

By injecting NBTXR3 into tumours, the X-ray exposure is enhanced for the tumour cells but not the surrounding tissues.

While NBTXR3 is already in the final stages of clinical trials, Nanobiotix has now revealed another killer attribute of the product, which could make it effective against non-localised cancer in metastasis too.

For non-local cancer, immuno-oncology can be used to boost the immune system so that it attacks the tumour.

However it only works well in a few patients who have tumours that the body recognises as immunogenic – so-called hot tumours.

Radiotherapy can also cause tumours to release antigens and other immunogenic molecules that stimulate the immune system into action, prompting oncologists to combine immuno and radiotherapy.

"We thought if we can make a product that makes tumours release more of these immunogenic molecules we could turn cold tumours into hot tumours," says Levy.

As it turned out, they already had the product that would do this with NBTXR3.

The product itself consists of hafnium oxide nanoparticles with a coating that makes them stick to cells.

They are 50 nm in diameter – small enough to inject – and biologically inert so that they are safe in the body.

Most importantly, HfO2 has a high density of electrons, so it absorbs X-rays particularly well, and cells of tumours directly injected with the nanoparticles experience a higher radiation dose than healthy cells nearby.

The released fragments of destroyed tumour cell nucleus and other molecules trigger immunogenic responses, and Nanobiotix has shown that using NBTXR3 significantly promotes the release of these immunogens after radiotherapy.

"This improves the number of patients that can be treated with immuno-oncology," says Levy.

Source: Nanobiotix