Tech Briefs

New technique increases radiotherapy to cancer cells without harming healthy ones.

The nanoscale is creating a massive paradigm shift. Referring to structures of between 1 and 100 nm, the nanoscale is marked as the point where the properties of a material change to have new and specific physical properties. To get a sense of the size, a nanometer is one-millionth of a millimeter. Nanoparticles can be designed with precise competencies such as the ability to cut, glue, or deliver energy. Increasingly, they are also being used to develop game-changing medicines.

NBTXR3 is a first-in-class radio-enhancer designed to be administered by a single and unique intratumoral injection, before the first radiotherapy session.

By approaching the human body from a physics rather than a chemical or biological perspective, a new realm of cancer treatment possibilities has emerged. For years, radiotherapy has been widely used in oncology. About 60 percent of cancer patients undergo radiotherapy at some point during their treatment. Along with surgery, it is the standard of care for local cancer treatment and improves the prognosis for many patients. When it is most efficient, it can even help to cure a patient.

However, radiotherapy still has significant limitations in terms of both efficacy and toxicity. Healthy tissues surrounding the tumors are regularly damaged during courses of radiotherapy. Given this major conundrum, cancer patients often receive a dose of radiotherapy that isn't high enough to kill their tumors.

Scientists in Nanobiotix's lab explore new applications of nanoparticles in healthcare.

Nanobiotix has been pioneering the development of a technology to address radiotherapy's very real limitations. The technology, NanoXray, uses nanoparticles, which aim to enhance the effectiveness of the radiotherapy. The nanoparticles do this by increasing the amount of the dose of radiotherapy that is absorbed into the cancer cells. At the same time, the goal of the technology is to avoid any further damage to healthy tissues nearby.

NanoXray particles have an inorganic core of crystallized hafnium oxide (HfO2). On average, they are approximately 50 nm — or about 3,000 times smaller than the diameter of a human hair. The nanoscopic size means they are small enough to enter cancer cells effectively. The size, shape, and surface of the nanoparticles have been designed to secure a strong binding to the cancer cell and to persist within the tumor mass throughout the entire radiation therapy treatment.

How It Works

The most important feature of HfO2 is its high electron density. This enables the nanoparticle to absorb the x-ray energy particularly well, and it ensures that the tumor cells experience a higher radiation dose and greater damage as a result. HfO2 is an inert material with a good safety profile that has been tested in both preclinical and clinical studies.

NanoXray nanoparticles. With an average size of 50 nm (about 3,000 times smaller than the diameter of a human hair), these particles are able to enter cancer cells to enhance the radiotherapy dose without increasing damage in the surrounding healthy tissues.

NanoXray's lead compound, NBTXR3, is a first-in-class radioenhancer that could potentially target most solid tumors. With the company's partner PharmaEngine for the Asia-Pacific region, the compound is being evaluated in soft tissue sarcoma (STS), head and neck cancers, prostate cancer, and liver cancers (primary and metastases). Additionally, trials led by PharmaEngine are underway in the Asia Pacific region. These trials include head and neck cancers in patients receiving chemotherapy as well as rectal cancer.

NanoXray requires a single intratumoral injection one day prior to a patient's first radiotherapy session. Following this local injection, nanoparticles accumulate in cancer cells thanks to their specific size and particular coating. Once inside the tumor, the nanoparticles absorb the ionizing radiation delivered by radiotherapy with a goal of destroying the cancer cells in an efficient manner. This process amplifies the x-ray dose delivered to the tumor, while the dose delivered to healthy tissues remains unchanged. It should be noted that NanoXray only produces an effect when the particles are exposed to radiotherapy.

NanoXray's mode of action is physical and universal, which means it can potentially target any type of solid tumor. This could be game-changing when it comes to cancer treatments and the use of radiotherapy. Usually, biology-based individualized treatments are the norm in oncology. A physics-based approach, however, does not target a biological pathway and thus is not affected by the biological variability of patients. Instead, it is focused on conquering cancer cells as a whole. As such, NanoXray could one day potentially treat millions of patients who receive radiotherapy.

This article was written by Laurent Levy, CEO and Cofounder of Nanobiotix, Paris, France. For more information, Click Here. A video explaining the technology is available at here.