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Sarcoma: nanoparticles to optimise treatment

The surgeon Sylvie Bonvalot, a specialist in soft tissue sarcomas, reveals the results of a clinical trial that used hafnium nanoparticles activated by radiotherapy before surgery for the first time. The results have just been published in Clinical Cancer Research.

Sarcoma: nanoparticles to optimise treatment

Soft tissue sarcomas develop in the support tissues that link the various structures of the body or make up the walls of organs. This cancer can therefore occur in many different parts of the body. “The standard treatment for these tumours at the early stage is surgery”, explains Dr. Sylvie Bonvalot, a world-renowned specialist in the very specific surgery of sarcomas. “This surgery can be very complex: the tumours to be removed are generally very large, since they have been there for a long time without producing symptoms. When the tumours develop in the abdomen, it is sometimes necessary to remove the neighbouring organs to prevent relapses.” To limit the extent of the surgery, radiotherapy may be used before surgery to reduce the size of the tumour and sterilise the surrounding area. However this treatment is limited due to the proximity of other organs, which means that the radiation dose cannot be increased and thus its effectiveness is also limited.

Increasing effectiveness of radiotherapy through nanoparticles

Once they are injected into the tumour, nanoparticles can multiply the effect of the radiation without reaching the neighbouring tissues. This is true of the hafnium nanoparticles (NBTXR3) developed by Nanobiotix.

“In patients suffering from a locally advanced sarcoma of the limbs and walls, we have just completed a phase I/II trial, promoted by Nanobiotix, the aim of which was to assess the impact and tolerance of the injection of hafnium nanoparticles (NBTXR3) into the tumour prior to radiotherapy,” the surgeon, also the trial coordinator, tells us. The day prior to the first radiotherapy session, these particles were injected into the patient’s tumour. A scanner was then used to check that they were in the right position.

25 patients were included in this trial which helped determine the optimum dose of NBTXR3 to be injected with as few side effects as possible. “At the end of the treatment, the results of the combination of nanoparticles and radiotherapy were assessed via MRI in order to then establish the surgical protocol,” continued Dr. Sylvie Bonvalot. “Although this test does not allow us to judge the effectiveness of this therapeutic combination, at the end of the treatment an average of three-quarters of the tumorous area was dead, which is quite encouraging.”

Furthermore, an international phase-III clinical trial coordinated by Institut Curie has already begun to assess the effectiveness of these nanoparticles using a randomised study. Thirty-six countries are taking part. In addition, given their results, these nanoparticles are being assessed on other tumorous locations, such as the prostate, the anal canal, ENT tumours and the liver.

Find out more

First human study testing a new concept of radio enhancement using nanoparticles (NBTXR3) activated by radiation therapy in patients with locally advanced soft tissue sarcomas (STS)

Sylvie Bonvalot, Cécile Le Pechoux, Thierry De Baere, Guy Kantor, Xavier Buy, Eberhard Stoeckle, Philippe Terrier, Paul Sargos, Jean Michel Coindre, Nathalie Lassau, Rafik Ait Sarkouh, Mikaela Dimitriu, Elsa Borghi, Laurent Levy, Eric Deutsch, Jean Charles Soria

Clinical Cancer Research, DOI: 10.1158/1078-0432.CCR-16-1297 Published 6 October 2016

 

Text: Céline Giustranti

Copyright: Alexandre Lescure / Institut Curie

Mathilde Regnault
29/11/2016