Analytical characterization of hybrid nanoparticles for clinical trial – ANALYTAGUIX

AnalytAguix ANR aims at answering different questions cocerning AGuIX nanoparticles:
- Quantification of free gadolinium from drug product in aqueous and biological media.
- Kenetic of liberation of gadolinium compared with conventional gadolinium contrast agents.
- Identification and characterization of degradation fragments.
- Determination of the size (hydrodynamic diameter) in complex media.
- Determination of surface charge of the nanoparticle.

To answer these questions, three principal technics have been used : (i) HPLC coupled to ICP/MS, (ii) capillary electrophoresis coupled to ICP-MS and (iii) HPLC coupled to mass spectrometry.

Quantification technic for free gadolinium has been validated and transferred to industry for standard characterization of clinical batches of AGuIX nanoparticles of NH TherAguix company.
Taylor diffusion analysis and capillary electrophoresis have led to robust and reproducible characterization for size and surface charge of nanoparticles in complex media.

AnalytAguix proposal has two main perspectives :
- Help to the development of AGuIX nanoparticles currently in phase 2 clinical trial for the treatment of brain metastases by radiotherapy and in phase 1 clinical trial for the treatment of advanced uterine cancer by radiotherapy. Other clinical trials on primary tumors will begin soon.
Development of analytical technics that can be used for other hybrid nanoparticles that will be translated to the clinic.

N.A.

Currently a lot of research is made on nanoparticles for biomedical applications. Unfortunately, only a few reach the market (and even the clinical assays). In the case of hybrid nanoparticles, only iron oxides have been used in the clinic as contrast agents for MRI. One of the main difficulties to go to the clinic with nanoparticles is due to their eventual toxicity. By using ultrasmall nanoparticles that display size lower than 5 nm, this risk is limited due to the rapid elimination of the nanoparticles by the kidneys. The Institute of Light and Matter and NH TherAguix Company have developed a gadolinium based nanoparticle (named AGuIX) that has shown very exciting radiosensitizing properties on different animal models. This ultrasmall nanoparticle is composed of a polysiloxane network surrounded by gadolinium chelates (DOTA derivatives chelates) and displays a particle hydrodynamic diameter lower than 5 nm. Due to their size, the AGuIX accumulate passively in tumors and are rapidly eliminated by kidney. Thanks to the presence of gadolinium, the biodistribution of the nanoparticles can be followed by MRI and optimized irradiation can be determined. Due to these properties, a transfer to the clinic of the AGuIX has been performed. The cGMP production of a batch of 1000 vials of AGuIX has been already made and no evidence of toxicity has been observed on two animal species (rodents and non-human primates) after intravenous injection of the nanoparticles in BPL toxicity tests. In May 2016, ANSM has given the authorization for a first clinical trial on these nanoparticles for the treatment of brain metastases (NANO-RAD NCT02820454). In February 2018, all the 15 patients of the clinical trial have been included and treated and no sign of toxicity has been detected. A second clinical trial (NANO-COL NCT03308604) for treatment of locally advanced cervical cancer has been validated by ANSM and will include its first patient in March 2018.
Through the discussion with ANSM, the need of an in-depth characterization of AGuIX was pointed out for the assessment of eventual toxic side effects. For the new batches of nanoparticles in depth analytical characterizations will be required in order to identify the degradation products and to obtain a very precise quantification of all the gadolinium compounds. The new specific and sensitive analytical tools developed during this project will be also helpful to study the kinetics of liberation and the transmetallation with endogenous metallic ions.
In addition, measurements in biological samples to assess the integrity of the nanoparticles in different localizations will be a real analytical challenge. Information on the future of nanoparticle in serum, in urine, in kidneys or in the tumor will also be of real interest to better understand the in vivo properties of the AGuIX. To address these questions, ILM and NH TherAguix will benefit from a collaboration with ISA (Institut des Sciences Analytiques) in Lyon that is specialized in the development of advanced analytical methods and tools and with GLINCS Company that is specialized in the detection of metals in complex medium. This collaboration gives access and expertise on analytical tools like HPLC or capillary electrophoresis coupled to ICP/MS or mass spectrometry. The application of these techniques to the characterization of nanoparticles and their degradation products is a necessity for the industrial batches and for assessing their in vivo behavior.
The objective is to propose a methodology able to give complete characterization of the nanoparticles and meet ANSM specifications but also to follow the fate of the nanoparticles after intravenous administration. This methodology will be valuable for the further industrial batches and hybrid nanomedicine in the future.