Methods of treating tumors

Abstract

The present disclosure relates to methods of treating tumors. In particular, the present disclosure relates to a method of treating a tumor in a subject in need thereof by ionizing radiation, the method comprising: (i) injecting a first therapeutically effective amount of nanoparticles containing a high Z element as a radiosensitizer into the subject in need thereof for a period of 2-10 days prior to a first irradiation of the tumor, (ii) within 1-12 hours prior to the first irradiation of the tumor, injecting a second therapeutically effective amount of identical or different nanoparticles containing high Z element, and (iii) irradiating the tumor of the subject with a therapeutically effective amount of radiation; wherein the nanoparticles containing high element Z are nanoparticles containing an element having an atomic Z number higher than 40, and the nanoparticles have an average hydrodynamic diameter lower than 10 nm.

Description

[0001] This application is a divisional application of the invention patent application with application date of July 28, 2020, application number 202080055043.3, and invention name “Method for treating tumors”. Technical Field

[0002] The present disclosure relates to methods for treating tumors. In particular, the present disclosure relates to methods for treating tumors in subjects in need thereof by ionizing radiation, the methods comprising:

[0003] (i) injecting a first therapeutically effective amount of nanoparticles containing a high-Z element as a radiosensitizer into a subject in need thereof within 2-10 days prior to the first irradiation of the tumor,

[0004] (ii) injecting a second therapeutically effective amount of the same or different nanoparticles containing a high-Z element within 1 hour to 12 hours before the first irradiation of the tumor, and,

[0005] (iii) irradiating the subject's tumor with a therapeutically effective dose of radiation;

[0006] The nanoparticles containing high-Z elements are nanoparticles containing elements with an atomic Z number higher than 40, and the nanoparticles have an average hydrodynamic diameter lower than 10 nm. Background Art

[0007] Radiation therapy (also known as radiotherapy) is one of the most commonly used anti-tumor strategies. More than half of cancer patients are treated with ionizing radiation (IR) alone or in combination with surgery or chemotherapy. 1 Recent advances in medical physics (with the development of low / high energy radiation, the implementation of monofractionated, hypofractionated or hyperfractionated regimens and the diversification of the dose rates used) and the development of innovative medical technologies (such as 3D conformational radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT), stereotactic radiosurgery (SRS) and functional imaging) have helped to better deliver effective doses of radiation to tumors while sparing surrounding healthy tissues, which is the most common side effect of radiotherapy. 2 Several applications of nanomedicine, such as radioisotope labeling or metal nanoparticles, have been developed to improve this therapeutic index by using nanomaterials as imaging or contrast agents to better deliver radiation doses to tumor sites and / or as radiosensitizers to enhance dose deposition in tumors and reduce radiation-related side effects. 3,4,5,6,7 Considering that the radiation dose absorbed by any tissue is proportional to the square of the material's relative atomic number (Z 2 ) is related to (where Z is the atomic number) 8Nanoparticles containing high-Z atoms, such as gold or gadolinium, have been extensively studied for their potential to improve radiotherapy. Upon exposure to ionizing radiation, heavy metal-based nanoparticles generate photons and Auger electrons that increase the total dose rate deposited into the tumor, induce the generation of reactive oxygen species (ROS), and cause cellular damage to many tumors, including, for example, melanoma, glioblastoma, breast cancer, and lung cancer. 9,10,11 Although some preclinical animal models have shown that heavy metal-based nanoparticles combined with ionizing radiation can reduce tumor growth, there is still a need to improve the use of radiosensitizing nanoparticles combined with ionizing radiation in anticancer therapy.

[0008] In particular, an important rule for the success of therapeutic strategies involving radiosensitizing nanoparticles is to protect surrounding healthy tissue while optimizing the concentration and distribution of radiosensitizing nanoparticles in the tumor to be treated.

[0009] In the present disclosure, the inventors have now surprisingly found that more than 10% of the Gd-based nanoparticles initially targeted to the tumor are still visible in the tumor 8 days after the first injection. This unexpected long-term persistence of the nanoparticles in human tumors enables the inventors to design a new nanoparticle administration regimen for use as a radiosensitizer in conjunction with radiotherapy in human patients. The method of the present disclosure includes at least two injections of nanoparticles prior to irradiation, wherein one or more injections are typically performed less than 24 hours prior to irradiation, but also includes a first injection within a period of 2-10 days prior to the first irradiation of the tumor. Summary of the invention

[0010] Accordingly, the present disclosure relates to a method of treating a tumor in a subject in need thereof by ionizing radiation, the method comprising:

[0011] (i) injecting a first therapeutically effective amount of nanoparticles containing a high-Z element as a radiosensitizer into the subject in need thereof 2-10 days, preferably 2-7 days, before the first irradiation of the tumor,

[0012] (ii) injecting a second therapeutically effective amount of the same or different nanoparticles containing a high-Z element within 1 hour to 12 hours before the first irradiation of the tumor, and,

[0013] (iii) irradiating the subject's tumor with a therapeutically effective dose of radiation;

[0014] The nanoparticles containing high-Z elements are nanoparticles containing elements with atomic Z numbers higher than 40, preferably higher than 50, and the nanoparticles have an average hydrodynamic diameter lower than 10 nm, such as 1-8 nm, preferably lower than 6 nm, more preferably 2-6 nm.

[0015] In specific embodiments of this method, said nanoparticles are injected intravenously.

[0016] In a specific embodiment, the nanoparticles comprise a rare earth metal or a mixture of rare earth metals as the high-Z element. In a more specific embodiment, the nanoparticles comprise gadolinium, bismuth or a mixture thereof as the high-Z element.

[0017] Typically, the nanoparticles comprise chelates of high-Z elements, such as chelates of rare earth elements.

[0018] In a specific embodiment, the nanoparticles used in the above method comprise:

[0019] (i) polyorganosiloxane,

[0020] (ii) a chelate covalently bonded to the polyorganosiloxane,

[0021] (iii) A high Z element complexed by the chelate.

[0022] In a specific embodiment, the nanoparticles used in the above method comprise:

[0023] (i) polyorganosiloxane, the weight ratio of silicon of which is at least 8%, preferably 8% to 50%, based on the total weight of the nanoparticles,

[0024] (ii) a chelate covalently bonded to the polyorganosiloxane in a ratio of 5 to 100, preferably 5 to 20, per nanoparticle, and

[0025] (iii) a high Z element complexed with the chelate.

[0026] In a specific embodiment, the nanoparticles used in the above method may contain a chelate for complexing a high-Z element, which is obtained by grafting one or more of the following chelating agents on the nanoparticles: DOTA, DTPA, EDTA, EGTA, BAPTA, NOTA, DOTAGA and DTPABA, or a mixture thereof.

[0027] In a particularly preferred embodiment, the nanoparticles are gadolinium chelated polysiloxane nanoparticles of the formula:

[0028]

[0029] Wherein PS is a matrix of polysiloxane, and

[0030] n is 5-50, preferably 5-20, and wherein the hydrodynamic diameter is 2-6 nm.

[0031] In specific embodiments, the nanoparticles are AGuIX nanoparticles.

[0032] In a specific embodiment, the nanoparticles are lyophilized powders contained in pre-filled vials to be reconstituted in an aqueous solution for intravenous injection.

[0033] In a specific embodiment, the nanoparticles used in the above method are contained in the injectable solution at a concentration of 50-150 mg / mL, preferably 80-120 mg / mL, such as 100 mg / mL.

[0034] Typically, the therapeutically effective amount administered in each injection step is 50 mg / kg-150 mg / kg, typically 80-120 mg / kg, for example 100 mg / kg.

[0035] In a specific embodiment, the tumor to be treated is a solid tumor, preferably selected from the group consisting of glioblastoma, brain metastasis, meningioma, or primary tumors of cervical cancer, rectal cancer, lung cancer, head and neck cancer, prostate cancer, colorectal cancer, liver cancer, and pancreatic cancer. Typically, the tumor is a brain metastasis, typically a brain metastasis from a melanoma, lung cancer, breast cancer, kidney cancer, or colon primary cancer.

[0036] In a specific embodiment, the subject is exposed to whole brain radiotherapy in step (iii). For example, the whole brain radiotherapy comprises exposing the subject to a total dose of 25-35 Gy, such as 30 Gy of ionizing radiation. Typically, the subject is exposed to a dose of about 3 Gy of ionizing radiation each time, and the total dose is preferably administered in a maximum of 10 times.

[0037] In a specific embodiment, the method comprises the step of injecting a third therapeutically effective amount of the same or different high-Z element-containing nanoparticles within 5-10 days after the second injection step, such as within 7 days after the second injection step.

[0038] In a specific embodiment, the method further comprises the step of imaging the tumor by magnetic resonance imaging (MRI) after the first injection step of the nanoparticles, wherein the nanoparticles serve as a T1 contrast agent for the MRI. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 .MRI enhancement vs. administered dose. Each point on the graph corresponds to the MRI enhancement value measured in metastases with a longest diameter greater than 1 cm. Statistically significant differences in MRI enhancement were found between each dose, the combined 15-30 mg / kg dose, the combined 50-75 mg / kg, and 100 mg / kg.

[0040] Figure 2.MRI enhancement vs AGuIX concentration. Each point on the graph corresponds to the MRI enhancement and the AGuIX concentration value measured in a metastasis with the longest diameter greater than 1 cm in patient #13. The black curve corresponds to the linear regression applied to the series of points. The dashed curve corresponds to the 95% confidence band.

[0041] Figure 3 MRI enhancement one week after nanoparticle administration. A partial signal enhancement map (color coded) of patient #13 is superimposed on the original 3D T1-weighted image obtained 2 hours (left image) and one week (right image) after intravenous injection into the patient. Arrows point to AGuIX-enhanced metastases.

[0042] Figure 4 .Summary of Phase II clinical study and objectives. DETAILED DESCRIPTION

[0043] The present disclosure arises in part from the surprising discovery, as shown by the inventors, that certain nanoparticles persist for long periods of time in human tumors for use as radiosensitizers in cancer radiation therapy.

[0044] The beneficial effects of the disclosed treatment methods are particularly related to two characteristics of the nanoparticles:

[0045] (i) They contain high-Z elements, typically high-Z cationic complexes with radiosensitizing properties;

[0046] (ii) Their average hydrodynamic diameter is smaller.

[0047] As used herein, the term "radiosensitization" will be readily understood by those of ordinary skill in the art and generally refers to the process of increasing the sensitivity of cancer cells to radiation therapy (eg, photon radiation, electron radiation, proton radiation, heavy ion radiation, etc.).

[0048] As used herein, the high-Z element is an element having an atomic Z number higher than 40, such as higher than 50.

[0049] In a specific embodiment, the high-Z element is selected from heavy metals, more preferably Au, Ag, Pt, Pd, Sn, Ta, Zr, Tb, Tm, Ce, Dy, Er, Eu, La, Nd, Pr, Lu, Yb, Bi, Hf, Ho, Pm, Sm, In and Gd, and mixtures thereof.

[0050] The high Z element is preferably a cationic element, either contained in the nanoparticle as an oxide and / or chalcogenide or halide, or as a complex with a chelating agent, such as an organic chelating agent.

[0051] The particle size distribution of the nanoparticles is measured, for example, using a commercial particle size analyzer, such as the Malvern Zêtasizer Nano-S particle sizer based on PCS (Photon Correlation Spectroscopy).

[0052] For the purposes of the present invention, the term "mean hydrodynamic diameter" or "average diameter" is intended to mean the harmonic mean of the diameters of the particles. The method for measuring this parameter is also described in standard ISO 13321:1996.

[0053] Nanoparticles having an average hydrodynamic diameter of, for example, 1-10 nm, even more preferably 1-8 nm, or for example 2-6 nm, or typically about 3 nm are suitable for use in the methods disclosed herein. In particular, they have been shown to provide excellent passive targeting in tumors, including brain tumors, after intravenous injection, and have rapid renal elimination (and therefore low toxicity).

[0054] In another embodiment, which may be combined with the previous embodiments, the nanoparticles may also be advantageously used as imaging or contrast agents, for example in image-guided radiotherapy.

[0055] As used herein, the term "contrast agent" is intended to mean any product or composition used in medical imaging, the purpose of which is to artificially increase contrast so that specific anatomical structures (e.g., certain tissues or organs) or pathological anatomical structures (e.g., tumors) relative to adjacent or non-pathological structures can be visualized. The term "imaging agent" is intended to mean any product or composition used in medical imaging, the purpose of which is to produce a signal that allows visualization of specific anatomical structures (e.g., certain tissues or organs) or pathological anatomical structures (e.g., tumors) relative to adjacent or non-pathological structures. The principle of how a contrast agent or imaging agent works depends on the imaging technology used.

[0056] In some embodiments, imaging is performed using magnetic resonance imaging (MRI), computed tomography imaging, positron emission tomography imaging, or any combination thereof.

[0057] Advantageously, it will be possible to combine the use of nanoparticles in the therapeutic methods of the present disclosure, with in vivo detection of tumors by MRI, thereby enabling, for example, monitoring of therapeutic treatments as described in the present disclosure.

[0058] Preferably, only lanthanides, including at least 50 wt. % of gadolinium (Gd), dysprosium (Dy), lutetium (Lu), bismuth (Bi) or holmium (Ho), or mixtures thereof, (relative to the total weight of high-Z elements in the nanoparticles), such as at least 50 wt. % of gadolinium, will be selected as the high-Z elements in the nanoparticles.

[0059] In particularly preferred embodiments, the nanoparticles used in the methods of the present disclosure are gadolinium-based nanoparticles.

[0060] In a specific embodiment, the high-Z element is a cationic element complexed with an organic chelating agent, for example selected from chelating agents having carboxylic acid, amine, thiol or phosphonate groups.

[0061] In a preferred embodiment, in addition to the high Z element and the optional chelating agent, the nanoparticles also comprise a biocompatible coating. Suitable agents for such biocompatibility include, but are not limited to, biocompatible polymers such as polyethylene glycol, polyethylene oxide, polyacrylamide, biopolymers, polysaccharides or polysiloxanes.

[0062] In a specific embodiment, the nanoparticles are selected such that their relaxivity r1 per particle is 50-5000 mM - 1 .s -1 (at 37°C and 1.4F) and / or a Gd weight ratio of at least 5%, such as 5%-30%.

[0063] In a specific embodiment, the nanoparticles having a very small hydrodynamic diameter, such as 1-10 nm, preferably 2-6 nm, are nanoparticles comprising chelates of high-Z elements, such as chelates of rare earth elements. In certain embodiments, the nanoparticles comprise chelates of gadolinium or bismuth.

[0064] In a specific embodiment that may be combined with any of the preceding embodiments, the high-Z element-containing nanoparticles comprise:

[0065] Polyorganosiloxane,

[0066] a chelate covalently bonded to the polyorganosiloxane,

[0067] - High Z elements complexed by the chelate.

[0068] As used herein, the term "chelator" refers to a group capable of complexing one or more metal ions.

[0069] Exemplary chelating agents include, but are not limited to, 1,4,7-triazacyclononanetriacetic acid (NOTA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), 1,4,7-triazacyclononane-1-pentanedioic acid-4,7-diacetic acid (NODAGA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), cyclohexyl-1,2-diaminetetraacetic acid (CDTA), ethylene glycol-0,0'-bis(2-aminoethyl)-N,N,N',N'-tetraacetic acid (EGTA), , N,N-bis(hydroxybenzyl)-ethylenediamine-N,N'-diacetic acid (HBED), triethylenetetraaminehexaacetic acid (TTHA), hydroxyethylenediaminetriacetic acid (HEDTA), 1,4,8,11-tetraazacyclotetradecane-N,N',N",N"'-tetraacetic acid (TETA) and 1,4,7,10-tetraaza-1,4,7,10-tetra-(2-carbamoylmethyl)-cyclododecane (TCMC) and 1,4,7,10-tetraazacyclododecane, 1-(pentanedioic acid)-4,7,10-triacetic acid (DOTAGA).

[0070] In some embodiments, the chelating agent is selected from the group consisting of:

[0071]

[0072] Wherein the wavy bond represents the bond connecting the chelator to the linking group forming the biocompatible coating of the nanoparticle.

[0073] In a specific embodiment which can be preferably combined with the preceding embodiments, the rare earth element chelate is a chelate of gadolinium and / or bismuth, preferably DOTA or DOTAGA chelates Gd 3+ and / or Bi.

[0074] In specific and preferred embodiments, the ratio of high Z elements per nanoparticle, for example a rare earth element such as gadolinium (optionally chelated with DOTAGA) is 3-100, preferably 5-20, typically about 10 per nanoparticle.

[0075] For imaging by scintigraphy, the nanoparticles may additionally comprise a radioactive isotope which can be used for scintigraphy and is for example preferably selected from the group consisting of radioactive isotopes of In, Tc, Ga, Cu, Zr, Y or Lu, for example: 111 In, 99m Tc, 67 Ga, 68 Ga, 64 Cu, 89 Zr, 90 Y or 177 Lu.

[0076] For fluorescence in the near-infrared range, the nanoparticles may additionally comprise lanthanides selected from Nd, Yb or Er.

[0077] For fluorescence in the visible range, the nanoparticles may additionally comprise a lanthanide selected from Eu or Tb.

[0078] For fluorescence in the near infrared range, the nanoparticles may additionally comprise an organic fluorophore selected from Cyanine 5.5, Cyanine 7, Alexa 680, Alexa 700, Alexa 750, Alexa 790, Bodipy.

[0079] In a specific embodiment, the hybrid nanoparticles are of the core-shell type.Core-shell nanoparticles based on a core consisting of a rare earth oxide and an optionally functionalized polyorganosiloxane matrix are known (see in particular WO 2005 / 088314, WO 2009 / 053644).

[0080] The nanoparticles may further be functionalized with molecules that allow the nanoparticles to be targeted to specific tissues. The agents may be coupled to the nanoparticles by covalent coupling, or entrapped by non-covalent bonding, such as by encapsulation or hydrophilic / hydrophobic interactions or the use of chelating agents.

[0081] In one embodiment, hybrid nanoparticles comprising:

[0082] -Polyorganosiloxane (POS) matrix, including rare earth cations M n+ , n is an integer of 2 to 4, optionally partially in the form of metal oxides and / or oxyhydroxides, optionally with doping cations D m+ In combination, m is an integer of 2-6, and D is preferably a rare earth metal, an actinide element and / or a transition element other than M;

[0083] - Chelates bound to POS via covalent bonds -Si-C-,

[0084] -M n+ cations, and where appropriate D m+ The cations are complexed by chelates.

[0085] In the case of a core-shell structure, the POS matrix forms a surface layer surrounding the metal cation-based core. Its thickness may be 0.5-10 nm and may occupy 25%-75% of the total volume.

[0086] The POS matrix serves to protect the core from the external medium (particularly against hydrolysis) and it can optimize the properties of the contrast agent (eg luminescence). It also allows the functionalization of the nanoparticles by grafting of chelators and target molecules.

[0087] Ultrafine nanoparticles

[0088] In a specific embodiment, the nanoparticles are gadolinium chelated polysiloxane nanoparticles of the formula:

[0089]

[0090] wherein PS is a matrix of polysiloxane, and wherein n is 5-50, typically 5-20, and wherein the hydrodynamic diameter is 2-6 nm.

[0091] More specifically, the gadolinium chelated polysiloxane nanoparticles described in the above formula are AGuIX ultrafine nanoparticles described in the next section.

[0092] Such ultrafine nanoparticles that can be used according to the methods of the present disclosure can be obtained or obtainable by a top-down synthetic route comprising the following steps:

[0093] a. obtaining a metal (M) oxide core, wherein M is a high Z element as described above, preferably gadolinium,

[0094] b. adding a polysiloxane shell around the M oxide core, for example by a sol-gel process,

[0095] c. grafting a chelating agent onto the POS shell, so that the chelating agent is bonded to the POS shell via a -Si-C- covalent bond, thereby obtaining core-shell precursor nanoparticles, and

[0096] d. purifying and transferring the core-shell precursor nanoparticles in aqueous solution,

[0097] The amount of grafting agent is sufficient to dissolve the metal (M) oxide core in step d and complex the cationic form of (M), thereby reducing the average hydrodynamic diameter of the resulting hybrid nanoparticles to less than 10nm, such as 1-8nm, preferably less than 6nm, more preferably 2-6nm.

[0098] The nanoparticles obtained according to the above described manner do not comprise a core of a metal oxide encapsulated by at least one coating. More details on the synthesis of these nanoparticles are provided in the next section.

[0099] This top-down synthesis approach leads to observed sizes typically in the range of 1-8 nm, more specifically 2-6 nm. The term then used is ultrafine nanoparticles.

[0100] Alternatively, another "one-pot" synthesis method is described below to prepare the coreless nanoparticles having an average diameter of less than 10 nm, such as 1-8 nm, typically 2-6 nm.

[0101] Further details about these ultrafine or coreless nanoparticles, methods for their synthesis and their uses are described in patent applications WO2011 / 135101, WO2018 / 224684 or WO2019 / 008040, which are incorporated by reference.

[0102] Methods of obtaining preferred embodiments of nanoparticles used according to the present disclosure

[0103] In general, a person skilled in the art will be able to readily produce nanoparticles for use in accordance with the present invention. More specifically, the following elements will be noted:

[0104] For core-shell nanoparticles based on a core of lanthanide oxides or oxyhydroxides, production methods using alcohols as solvents are used, for example as described in P. Perriat et al., J. Coll. Int. Sci, 2004, 273, 191; O. Tillement et al., J. Am. Chem. Soc., 2007, 129, 5076 and P. Perriat et al., J. Phys. Chem. C, 2009, 113, 4038.

[0105] For POS matrices, several techniques derived from those created by Stoeber (Stoeber, W; J. Colloid Interf Sci 1968, 26, 62) can be used. Methods for coating as described in Louis et al. (Louis et al., 2005, Chemistry of Materials, 17, 1673-1682) or in International Application WO 2005 / 088314 can also be used.

[0106] In practice, the synthesis of ultrafine nanoparticles is described, for example, in Mignot et al Chem. Eur. J. 2013, 19, 6122-6136: Typically, core / shell type precursor nanoparticles are formed from a lanthanide oxide core (via a modified polyol route) and a polysiloxane shell (via sol / gel); the objects have a hydrodynamic diameter of, for example, about 5-10 nm.

[0107] Thus, lanthanide oxide cores of very small size (adjustable to less than 10 nm) can be produced in alcohol by one of the methods described in the following publications: P. Perriat et al., J. Coll. Int. Sci, 2004, 273, 191; O. Tillement et al., J. Am. Chem. Soc., 2007, 129, 5076 and P. Perriat et al., J. Phys. Chem. C, 2009, 113, 4038.

[0108] For example, the cores can be coated with a layer of polysiloxane according to the protocols described in the following publications: C. Louis et al., Chem. Mat., 2005, 17, 1673 and O. Tillement et al., J. Am. Chem. Soc., 2007, 129, 5076.

[0109] For the intended metal cation, a specific chelating agent (e.g., Gd 3+ DOTAGA) is grafted to the surface of the polysiloxane; it is also possible to insert a portion of it into the layer, but controlling the formation of the polysiloxane is complicated and simple external grafting provides sufficient grafting ratios at these very small sizes.

[0110] The nanoparticles are separated from the synthesis residues by dialysis or tangential filtration on a membrane containing pores of appropriate size.

[0111] The core is destroyed by dissolution (e.g. by changing the pH or introducing complexing molecules into the solution). This destruction of the core then allows the scattering of the polysiloxane layer (according to a slow erosion or collapse mechanism), which ultimately makes it possible to obtain polysiloxane objects with complex morphology, the characteristic dimensions of which are on the order of the thickness of the polysiloxane layer, i.e., much smaller than the objects produced so far.

[0112] Thus, the removal of the core makes it possible to reduce the particle size from about 5-10 nanometers in diameter to less than 8 nanometers. Moreover, this operation makes it possible to increase the number of nanoparticles per nm compared to theoretical polysiloxane nanoparticles of the same size but containing M (e.g. gadolinium) only on the surface. 3 The M number of nanometer size can be estimated by the M / Si atomic ratio measured by EDX. Typically, the M number of each ultrafine nanoparticle is 5-50.

[0113] In a specific embodiment, the nanoparticles according to the invention comprise a chelating agent with an acid function, such as DOTA or DOTAGA. For example, in the presence of an appropriate amount of the target molecule, the acid function of the nanoparticles is activated using EDC / NHS (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydrogen succinimide). For example, the nanoparticles grafted in this way are then purified by tangential filtration.

[0114] Alternatively, the nanoparticles according to the present disclosure may be obtained or obtainable by a synthetic method ("one-pot method") comprising mixing at least one hydroxysilane or alkoxysilane that is negatively charged at physiological pH and at least one chelating agent selected from polyaminopolycarboxylic acids with:

[0115] - at least one hydroxysilane or alkoxysilane which is neutral at physiological pH, and / or

[0116] - at least one hydroxysilane or alkoxysilane which is positively charged at physiological pH and contains amino functional groups,

[0117] in:

[0118] - the molar ratio A of neutral silane to negatively charged silane is defined as follows: 0≤A≤6, preferably 0.5≤A≤2;

[0119] - the molar ratio B of the positively charged silane to the negatively charged silane is defined as follows: 0≤B≤5, preferably 0.25≤B≤3;

[0120] The molar ratio C of neutral and positively charged silanes to negatively charged silanes is defined as follows: 0≤C≤8, preferably 1≤C≤4.

[0121] According to a more specific embodiment of this one-pot synthesis method, the method comprises mixing at least one alkoxysilane that is negatively charged at physiological pH, the alkoxysilane being selected from APTES-DOTAGA, TANED, CEST and mixtures thereof, with:

[0122] - an alkoxysilane which is neutral at least at physiological pH, said alkoxysilane being selected from TMOS, TEOS and mixtures thereof, and / or

[0123] - APTES is positively charged at physiological pH,

[0124] in:

[0125] - the molar ratio A of neutral silane to negatively charged silane is defined as follows: 0≤A≤6, preferably 0.5≤A≤2;

[0126] - the molar ratio B of the positively charged silane to the negatively charged silane is defined as follows: 0≤B≤5, preferably 0.25≤B≤3;

[0127] The molar ratio C of neutral and positively charged silanes to negatively charged silanes is defined as follows: 0≤C≤8, preferably 1≤C≤4.

[0128] According to one specific embodiment, the one-pot synthesis method comprises mixing APTES-DOTAGA, which is negatively charged at physiological pH, with:

[0129] - at least one alkoxysilane which is neutral at physiological pH, selected from TMOS, TEOS and mixtures thereof, and / or

[0130] - APTES is positively charged at physiological pH,

[0131] in:

[0132] - the molar ratio A of neutral silane to negatively charged silane is defined as follows: 0≤A≤6, preferably 0.5≤A≤2;

[0133] - the molar ratio B of the positively charged silane to the negatively charged silane is defined as follows: 0≤B≤5, preferably 0.25≤B≤3;

[0134] The molar ratio C of neutral and positively charged silanes to negatively charged silanes is defined as follows: 0≤C≤8, preferably 1≤C≤4.

[0135] AGuIX Nanoparticles

[0136] In a more specific embodiment, the gadolinium chelated polysiloxane-based nanoparticles are core-free ultrafine AGuIX nanoparticles of the formula:

[0137]

[0138] Wherein PS is polysiloxane, n is about 10 on average, and the hydrodynamic diameter is 4±2 nm, and the mass is about 10±1 kDa.

[0139] The AGuIX nanoparticles can also be described by the average chemical formula:

[0140] (GdSi 4-7 C 24-30 N 5-8 O 15-25 H 40-60 ,5-10H2O) x

[0141] Pharmaceutical formulations of nanoparticles for use according to the disclosed methods

[0142] When used as a medicament, the compositions comprising the high Z nanoparticles provided herein for use thereof can be administered in the form of pharmaceutical preparations of nanoparticle suspensions. These preparations can be prepared as described herein or elsewhere and can be administered by a variety of routes, depending on whether local or systemic treatment is desired and on the area to be treated.

[0143] In particular, the pharmaceutical formulations used as described herein contain a suspension containing high-Z nanoparticles as provided herein as an active ingredient and one or more pharmaceutically acceptable carriers (excipients). In preparing the pharmaceutical formulations provided herein, the nanoparticle composition can be, for example, mixed with an excipient or diluted with an excipient. When an excipient is used as a diluent, it can be a solid, semisolid or liquid material that serves as a vehicle, carrier or medium for the nanoparticle composition.

[0144] Thus, the pharmaceutical preparation may be in the form of a powder, tablet, elixir, suspension, emulsion, solution, syrup, aerosol (as a solid or liquid medium), sterile injectable solution, sterile packaged powder, and the like.

[0145] In a specific embodiment, the pharmaceutical formulation used as described herein is a lyophilized powder contained in a pre-filled vial to be reconstituted, for example, in an aqueous solution for intravenous injection. In a specific embodiment, the lyophilized powder comprises as an active ingredient an effective amount of the high-Z containing nanoparticles as described herein, typically nanoparticles based on gadolinium chelated polysiloxane, and more specifically, AGuIX nanoparticles. In certain specific embodiments, the lyophilized powder contains about 200 mg-15 g per bottle, for example 280-320 mg AGuIX per bottle, typically 300 mg AGuIX per bottle or about 800 mg-1200 mg, for example 1 g AGuIX per bottle.

[0146] The powder may also contain one or more additional excipients, in particular CaCl2, for example 0.5-0.80 mg CaCl2, typically 0.66 mg CaCl2.

[0147] The lyophilized powder can be reconstituted in an aqueous solution, typically water for injection. Thus, in a specific embodiment, the pharmaceutical solution used according to the present disclosure is an injectable solution comprising as an active ingredient an effective amount of the high-Z containing nanoparticles as described herein, typically nanoparticles based on gadolinium chelated polysiloxane and in particular AGuIX nanoparticles.

[0148] For example, the injectable solution used in the methods disclosed herein is a solution of gadolinium-chelated polysiloxane-based nanoparticles, typically AGuIX nanoparticles, at a concentration of 50-150 mg / mL, such as 80-120 mg / mL, typically 100 mg / mL, optionally containing one or more additional pharmaceutically acceptable excipients, such as 0.1-0.3 mg / mL of CaCl2, typically 0.22 mg / mL of CaCl2.

[0149] How to use this disclosure

[0150] The present invention relates to a method for treating a tumor in a subject in need thereof, the method comprising:

[0151] (i) injecting a first therapeutically effective amount of nanoparticles containing a high-Z element as a radiosensitizer into the subject in need thereof 2-10 days, preferably 2-7 days, before the first irradiation of the tumor,

[0152] (ii) injecting a second therapeutically effective amount of the same or different nanoparticles containing a high-Z element within 1 hour to 12 hours before the first irradiation of the tumor, and,

[0153] (iii) irradiating the subject's tumor with a therapeutically effective dose of radiation;

[0154] The nanoparticles containing high-Z elements are nanoparticles containing elements with atomic Z numbers higher than 40, preferably higher than 50, and the nanoparticles have an average hydrodynamic diameter lower than 10 nm, preferably lower than 6 nm, such as 2-6 nm.

[0155] The present disclosure also relates to nanoparticles containing a high-Z element for use in a method of treating a tumor in a subject in need thereof, the method comprising:

[0156] (i) injecting a first therapeutically effective amount of nanoparticles containing a high-Z element as a radiosensitizer into the subject in need thereof 2-10 days, preferably 2-7 days, before the first irradiation of the tumor,

[0157] (ii) injecting a second therapeutically effective amount of the same or different nanoparticles containing a high-Z element within 1 hour to 12 hours before the first irradiation of the tumor, and,

[0158] (iii) irradiating the subject's tumor with a therapeutically effective dose of radiation;

[0159] The nanoparticles containing high-Z elements are nanoparticles containing elements with atomic Z numbers higher than 40, preferably higher than 50, and the nanoparticles have an average hydrodynamic diameter lower than 10 nm, preferably lower than 6 nm, such as 2-6 nm.

[0160] The present disclosure also relates to nanoparticles containing high-Z elements for use in preparing a medicament for treating a tumor in a subject in need thereof, the method comprising:

[0161] (i) injecting a first therapeutically effective amount of nanoparticles containing a high-Z element as a radiosensitizer into the subject in need thereof 2-10 days, preferably 2-7 days, before the first irradiation of the tumor,

[0162] (ii) injecting a second therapeutically effective amount of the same or different nanoparticles containing a high-Z element within 1 hour to 12 hours before the first irradiation of the tumor, and,

[0163] (iii) irradiating the subject's tumor with a therapeutically effective dose of radiation;

[0164] The nanoparticles containing high-Z elements are nanoparticles containing elements with atomic Z numbers higher than 40, preferably higher than 50, and the nanoparticles have an average hydrodynamic diameter lower than 10 nm, preferably lower than 6 nm, such as 2-6 nm.

[0165] As used herein, the terms "treating" or "treatment" refer to one or more of the following: (1) inhibiting a disease; e.g., inhibiting a disease, condition, or disorder in an individual who is experiencing or exhibiting the pathology or symptomology of the disease, condition, or disorder (i.e., preventing further development of the pathology and / or symptomology); (2) ameliorating a disease; e.g., ameliorating a disease, condition, or disorder in an individual who is experiencing or exhibiting the pathology or symptomology of the disease, condition, or disorder (i.e., reversing the pathology and / or symptomology), such as reducing the severity of the disease or reducing or alleviating one or more symptoms of the disease. In particular, with respect to the treatment of a tumor, the term "treating" may refer to inhibiting the growth of a tumor, or reducing the size of a tumor.

[0166] The terms "patient" and "subject" used interchangeably herein refer to any member of the animal kingdom, including mammals and invertebrates. For example, mice, rats, other rodents, rabbits, dogs, cats, pigs, cattle, sheep, horses, primates, fish, and humans. Preferably, the subject is a mammal or a human, including, for example, a subject with a tumor.

[0167] In a specific embodiment, the tumor is a solid tumor, preferably selected from the group consisting of glioblastoma, brain metastasis, meningioma, or primary tumors of cervical cancer, rectal cancer, lung cancer, head and neck cancer, prostate cancer, colorectal cancer, liver cancer, and pancreatic cancer. In particular, the tumor is a brain metastasis, typically a brain metastasis from a melanoma, lung cancer, breast cancer, or a primary renal cancer.

[0168] In a specific embodiment, the subject is selected from a human patient with multiple brain metastases. In other specific embodiments, the subject is selected from a human patient with multiple brain metastases that are not suitable for local treatment by surgery or stereotactic radiation.

[0169] The method for treating cancer disclosed herein comprises at least two steps of administering an effective amount of the nanoparticles to a tumor of a subject.

[0170] The nanoparticles can be administered to a subject using different possible routes, such as topical (intratumoral (IT), intraarterial (IA)), subcutaneous, intravenous (IV), intradermal, airway (inhalation), intraperitoneal, intramuscular, intrathecal, intraocular, or oral routes.

[0171] In specific embodiments, the nanoparticles are administered intravenously.In fact, the nanoparticles disclosed herein are advantageously targeted to human tumors through passive targeting, such as through enhanced permeability and retention effects.

[0172] When appropriate, nanoparticles may be further injected or administered. Typically, when fractionated radiotherapy is used, nanoparticles may be further injected once a week during radiotherapy. For example, in a specific embodiment, the method disclosed herein further comprises a step of injecting a third therapeutically effective amount of the same or different nanoparticles containing a high-Z element within 5-10 days after the second injection step, for example within 7 days after the second injection step.

[0173] In a specific embodiment, the nanoparticles are gadolinium chelated polysiloxane based nanoparticles and the therapeutically effective amount administered intravenously in each injection step is 50 mg / kg-150 mg / kg, typically 80-120 mg / kg, for example 100 mg / kg.

[0174] Advantageously, the same nanoparticles can be used as theranostics to detect tumors by MRI before being used as radiosensitizers. Therefore, the method also includes a step of imaging the tumor by magnetic resonance imaging (MRI) after the first injection step of the nanoparticles, wherein the nanoparticles are used as T1 contrast agents for the MRI. The results in this example provide evidence of excellent signal enhancement in human patients for detecting tumors (e.g., brain metastases) by MRI after injection of the high-Z containing nanoparticles.

[0175] Steps to irradiate the tumor

[0176] The method of using the nanoparticles comprises the step of irradiating a tumor of a subject in need thereof for radiotherapy of the corresponding cancer, wherein the nanoparticles advantageously enhance the dose efficacy of the radiotherapy.

[0177] As used herein, radiation therapy or radiotherapy is the medical use of radiation - that is, ionizing radiation - to control malignant cells as part of cancer treatment. It is used as a palliative or curative treatment. Radiation therapy is considered an important standard of care for the treatment of various cancers.

[0178] As used herein, the term "radiotherapy" is used to treat diseases of a neoplastic nature with radiation corresponding to ionizing radiation. Ionizing radiation deposits energy that injures or destroys cells in the area being treated (target tissue) by damaging their genetic material, rendering them unable to continue to grow.

[0179] In a specific embodiment, the method of the present disclosure comprises exposing the tumor to be treated to an effective dose of ionizing radiation, wherein the ionizing radiation is photons, such as X-rays. Depending on the amount of energy they have, the rays can be used to destroy cancer cells on the surface or deep inside the body. The higher the energy of the X-ray beam, the deeper the X-rays can penetrate into the target tissue. Linear accelerators and electron accelerators produce X-rays with increasing energy. Using a machine to focus radiation (such as X-rays) on the cancer site is called external beam radiotherapy.

[0180] In an alternative embodiment of the method of treatment according to the invention, gamma rays are used.Gamma rays are produced spontaneously as certain elements, such as radium, uranium and cobalt 60, release radiation when they decompose or decay.

[0181] The ionizing radiation is typically 2keV-25000keV, in particular 2keV-6000keV (ie 6MeV) or 2keV-1500keV (such as a Cobalt 60 source).

[0182] Those skilled in the art of radiotherapy know how to determine the appropriate dosage and application schedule according to the nature of the disease and the patient's constitution. In particular, the technician knows how to assess dose-limiting toxicity (DLT) and how to determine the maximum tolerated dose (MTD) accordingly.

[0183] The amount of radiation used in photon radiotherapy is measured in gray (Gy) and varies depending on the type and stage of the cancer being treated. Typical total doses for solid tumors range from 20-120 Gy for curative cases. Radiation oncologists consider many other factors when selecting a dose, including whether the patient is receiving chemotherapy, the patient's comorbidities, whether the radiation therapy is administered before or after surgery, and how successful the surgery was.

[0184] Typically, the total dose is fractionated (distributed over time). The amounts and schedules (planning and delivery of ionizing radiation, fractionated doses, fractionated delivery regimen, total dose alone or in combination with other anticancer agents, etc.) are defined for any disease / anatomical site / disease stage patient setting / age and constitute the standard of care in any specific case.

[0185] A typical conventional fractionation schedule for adults may be 2.5-3.5 Gy per day, five days per week, for example, for 2-8 consecutive weeks. In a specific embodiment, the radiotherapy comprises exposing the subject to a total dose of 25-35 Gy of ionizing radiation, for example 30 Gy.

[0186] In other specific embodiments, the subject is exposed to a dose of about 2-8 Gy of ionizing radiation each time, and the total dose is preferably administered in a maximum of 10 times.

[0187] In a specific embodiment where the subject suffers from brain cancer (e.g., multiple brain metastases), the radiotherapy applied in step (iii) of the methods disclosed herein is whole brain radiotherapy (WBRT). The most common dose / fractionation regimen used in WBRT is 30 Gy delivered in 10 fractions over the course of 2 weeks, as used in Example 2.

[0188] Combination Therapies Using the Methods of the Disclosure

[0189] Nanoparticles used as disclosed herein can be administered as the sole active ingredient or in combination or co-administered, for example, as an adjuvant or with other drugs (e.g., cytotoxic agents, antiproliferative agents or other anti-tumor agents), for example, to treat or prevent cancer diseases as described above.

[0190] Suitable cytotoxic, antiproliferative or antineoplastic agents may include, but are not limited to, cisplatin, doxorubicin, paclitaxel (taxol), etoposide, irinotecan, topotecan, paclitaxel, docetaxel, epothilone, tamoxifen, 5-fluorouracil, methotrexate, temozolomide, cyclophosphamide, tipifarnib, gefitinib, erlotinib, imatinib, gemcitabine, uracil mustard, nitrogen mustard, ifosfamide, melphalan, chlorambucil, pipobroman, trothamide , busulfan, carmustine, lomustine, streptozotocin, dacarbazine, floxuridine, cytarabine, 6-mercaptopurine, 6-thioguanine, fludarabine phosphate, oxaliplatin, folinic acid, pentostatin, vinblastine, vincristine, vindesine, bleomycin, actinomycin D, daunorubicin, epirubicin, idarubicin, mithramycin, deoxycoformycin, mitomycin-C, L-asparaginase, teniposide.

[0191] In some embodiments, additional therapeutic agents are administered while administering the compositions provided herein. In some embodiments, additional therapeutic agents are administered after administering the compositions provided herein. In some embodiments, additional therapeutic agents are administered before administering the compositions provided herein. In some embodiments, the compositions provided herein are administered during a surgical procedure. In some embodiments, the compositions provided herein are administered in conjunction with additional therapeutic agents during a surgical procedure.

[0192] The additional therapeutic agents provided herein can be effective in a wide dosage range and are generally administered in an effective amount. However, it should be understood that the amount of the therapeutic agent actually administered is generally determined by the physician based on relevant circumstances, including the condition to be treated; the route of administration selected; the compound actually administered; the age, weight, body weight and response of the individual subject; the severity of the subject's symptoms, etc.

[0193] Other aspects and advantages of the disclosed method will become apparent from the following examples, which are given for purposes of illustration only.

[0194] Example

[0195] Example 1: First-in-Human Trial of Gd-Based Theranostic Nanoparticles: Uptake and Biodistribution in Four Patients with Brain Metastases

[0196] 1.1 Materials and methods

[0197] Study Design

[0198] This study was part of a prospective, dose-escalating Phase Ib clinical trial designed to evaluate the tolerability of intravenously administered radiosensitizing AGuIX nanoparticles in combination with whole-brain radiotherapy for the treatment of brain metastases. The Nano-Rad trial (Radiosensitization of Multiple Brain Metastases Using AGuIX Gadolinium-Based Nanoparticles) is registered as NCT02820454. Here, we report the results of an MRI protocol applied to 15 enrolled patients. The objectives assigned to this MRI-assisted study were i) to evaluate the distribution of AGuIX nanoparticles in brain metastases and surrounding healthy tissues and ii) to measure T1-weighted contrast enhancement and nanoparticle concentrations in brain metastases and surrounding healthy tissues after intravenous administration of AGuIX nanoparticles (Verry C, et al. BMJ Open. 9: e023591 (2019)).

[0199] Patient selection

[0200] Patients with multiple brain metastases who were not amenable to local treatment with surgery or stereotactic radiotherapy were recruited. Inclusion criteria included: i) minimum age 18 years, ii) secondary brain metastases from histologically confirmed solid tumors, iii) no prior brain irradiation, iv) no renal insufficiency (glomerular filtration rate >60 mL / min / 1.73 m 2 ), v) normal liver function (bilirubin <30 μmol / L; alkaline phosphatase <400 UI / L; aspartate aminotransferase (AST) <75 UI / L; alanine aminotransferase (ALT) <175 UI / L).

[0201] Experimental Design

[0202] The main steps of the trial protocol are as follows. On D0, patients received the first imaging session (see MRI protocol in the next paragraph), consisting of an intravenous bolus of Dotarem (gadolinium meglumine) at a dose of 0.2 mL / kg (0.1 mmol / kg) body weight. One to 21 days after the first imaging session (depending on patient availability and radiation therapy plan), patients were administered an AGuIX nanoparticle solution intravenously at a dose of 15, 30, 50, 75, or 100 mg / kg body weight. The day of AGuIX nanoparticle administration is referred to as D1.

[0203] Synthesis of AGuIX nanoparticles

[0204] AGuIX nanoparticles have been obtained via a six-step synthesis. The first step is the formation of the gadolinium oxide core by adding soda on gadolinium trichloride in diethylene glycol. The second step is the growth of the polysiloxane shell by adding TEOS and APTES. After ripening, DOTAGA anhydride is added to react with free amino functional groups on the surface of the inorganic matrix. After transfer to water, the dissolution of the gadolinium oxide core is observed, and gadolinium is chelated by DOTAGA on the matrix surface. Then, the fragmentation of the polysiloxane matrix in the ultrasmall AGuIX nanoparticles is observed. The last step is the freeze-drying of the nanoparticles.

[0205] The theranostic agent consists of a polysiloxane network surrounded by a gadolinium cyclic ligand, to which a derivative of DOTA (1,4,7,10-tetraazacyclododecanoic acid-1,4,7,10-tetraacetic acid) is covalently grafted. Its hydrodynamic diameter is 4±2 nm, its mass is about 10 kDa, and it has the average chemical formula (GdSi 4-7 C 24-30 N 5-8 O 15-25 H 40-60 ,5-10H2O) x Description. On average, each nanoparticle has 10 DOTA ligands on its surface that chelate the core gadolinium ion. The longitudinal relaxation r1 at 3 Tesla is equal to 3+ Ion 8.9mM -1 .s -1 , resulting in a total r1 of 89 mM per AGuIX nanoparticle -1 .s -1 The same MRI session was performed 2 hours after the nanoparticle administration, without the injection of gadolinium meglumine. The patients then received whole-brain radiotherapy (30 Gy, delivered in 10 fractions of 3 Gy). Similar MRI sessions were performed for each patient 7 days (D8) and 4 weeks (D28) after the administration of AGuIX nanoparticles.

[0206] MRI protocol

[0207] MRI acquisitions were performed on a 3 Tesla Philips scanner. A 32-channel Philips head coil was used. Patients underwent the same imaging protocol, which included the following MRI sequences: i) 3D T1-weighted gradient echo sequence, ii) 3D FLASH sequence with multiple flip angles, iii) susceptibility-weighted imaging (SWI) sequence, iv) fluid-attenuated inversion recovery (FLAIR) sequence, and v) diffusion-weighted imaging (DWI) sequence. Some of these imaging sequences are recommended for evaluating the response of brain metastases after radiotherapy following the RECIST (Response Evaluation Criteria in Solid Tumors) and RANO (Response Evaluation in Neuro-Oncology) criteria (24,25). The 3D T1-weighted imaging sequence provides high-resolution contrast-enhanced images of healthy tissue and brain metastases after MRI contrast agent administration. The 3D FLASH sequence is repeated several times with different flip angles to calculate T1 relaxation time and contrast agent concentration. The SWI sequence is used to detect the presence of hemorrhage. The FLAIR sequence is used to monitor the presence of inflammation or edema. Finally, the DWI sequence can be used to detect abnormal water diffusion in tissue or brain metastases. Total acquisition time was 30 min-40 min, depending on the imaging parameters adjusted for the patient. The key features and main acquisition parameters of these imaging sequences are detailed in the Supplementary Materials section.

[0208] Image processing and quantization pipeline

[0209] MRI analysis was performed using a method developed by GIN Laboratories (Grenoble, France) and performed in The software running under MP 3 (https: / / github.com / nifm-gin / MP3) was used as an in-house computer program. Image analysis included counting and measurement of metastases, quantification of contrast enhancement, relaxation times, and concentration of nanoparticles. According to RECIST and RANO criteria, only metastases with a longest diameter exceeding 1 cm were considered measurable and retained in subsequent analyses. MRI enhancement expressed as a percentage was defined as the ratio of the MRI signal amplitude after contrast administration to the MRI signal amplitude before contrast administration; MRI signal amplitude was measured in a 3D T1-weighted image dataset. T1 relaxation times were derived from 3DFLASH images acquired at four different flip angles. The concentration of nanoparticles in brain metastases was derived from changes in T1 relaxation times before and after contrast administration and from the known relaxivity of the nanoparticles.

[0210] The BrainVISA / Anatomist software developed at NeuroSpin (CEA, Saclay, France) was used. http: / / brainvisa.info) for 3D image rendering. To better visualize the location of different metastases, the Morphologist pipeline of BrainVISA was used to generate a mesh of the brain and head for each patient.

[0211] Statistical analysis

[0212] All analyses were performed using GraphPad Prism (GraphPad Software Inc.). Unless otherwise stated, significance was fixed at a probability level of 5%. Unless otherwise stated, all data are presented as mean ± SD.

[0213] 1.2 Results

[0214] Administered AGuIX Gd-based nanoparticles induced MRI contrast enhancement in all four types of brain metastases

[0215] Patient recruitment resulted in the inclusion of four types of brain metastases, namely NSCLC (non-small cell lung cancer) N = 6, breast cancer N = 2, melanoma N = 6 and colon cancer N = 1. All patients were successfully injected with the theranostic nanoparticles AGuIX (as described in Materials and Methods) at each increasing step of the administered dose (N = 3 for 15, 30, 50, 75 and 100 mg / kg body weight).

[0216] On D1, two hours after AGuIX injection, MRI signal enhancement was observed in all types of brain metastases, all patients, and all administered doses. Within the target region drawn around each metastasis, MRI signal enhancement was found to increase with the administered dose of AGuIX nanoparticles ( Figure 1 The mean signal enhancement of all measurable metastases (longest diameter greater than 1 cm) was equal to 26.3 ± 15.2%, 24.8 ± 16.3%, 56.7 ± 23.8%, 64.4 ± 26.7%, and 120.5 ± 68% for 15, 30, 50, 75, and 100 mg / kg body weight AGuIX doses, respectively. MRI enhancement was found to be linearly correlated with the injected dose (slope 1.08, R 2 =0.90) (data not shown).

[0217] Gd-based nanoparticles demonstrate MRI enhancement of brain metastases comparable to clinically used contrast agents

[0218] For each patient, a clinically approved Gd-based contrast agent ( MRI enhancement was measured 15 minutes after injection (Guerbet, Villepinte, France). Averaged over all measurable metastases with a longest diameter greater than 1 cm, MRI enhancement was equal to 182.9 ± 116.2%. This MRI enhancement observed 15 minutes after injection was of the same order of magnitude as the enhancement observed 2 h after administration of the highest dose of AGuIX nanoparticles.

[0219] The detection sensitivity of AGuIX nanoparticles (defined as their ability to enhance MRI signal in measurable brain metastases) was evaluated for all administered doses and compared with clinically used contrast agents. Expressed as a percentage of Dotarem sensitivity, the sensitivity of AGuIX nanoparticles was equal to 12.1, 19.5, 34.2, 31.8, and 61.6% for injection doses of 15, 30, 50, 75, and 100 mg / kg body weight, respectively.

[0220] The concentration of AGuIX nanoparticles can be quantified in brain metastases

[0221] Multi-flip angle 3D FLASH acquisition was successfully used to calculate pixel maps of T1 values ​​(data not shown) and was able to quantify the longitudinal relaxation time of the target area. These T1 maps clearly showed the reduction of T1 relaxation time in brain metastases caused by the uptake of AGuIX nanoparticles. As expected, the reduction in T1 values ​​co-localized with contrast-enhanced brain metastases.

[0222] The concentration of AGuIX nanoparticles in contrast-enhanced metastases was calculated based on the change in T1 values ​​after administration. For patients administered 100 mg / kg body weight, AGuIX concentration measurements were performed in metastases with a longest diameter greater than 1 cm. In patients #13, #14, and #15, the average AGuIX concentration in brain metastases was measured to be 57.5±14.3, 20.3±6.8, and 29.5±12.5 mg / L, respectively.

[0223] The correlation between MRI enhancement and nanoparticle concentration was evaluated in patients at the highest (100 mg / kg) administered dose. Figure 2 This correlation is exemplified in Figure 2 using MRI data from patient #13 with NSCLC metastasis. A strong positive correlation was observed between the two MRI parameters, with a nearly linear relationship over the range of measured values.

[0224] For each patient, MRI enhancement and T1 values ​​were assessed in target brain regions without visible metastases (three representative target regions per patient, of similar size for all patients). No significant MRI enhancement and T1 changes were observed in these healthy brain regions.

[0225] MRI enhancement was observed one week after administration of the nanoparticles

[0226] For patients who received the highest dose (100 mg / kg body weight), MRI enhancement was observed to persist in measurable metastases (largest diameter greater than 1 cm) on D8, up to 1 week after administration of AGuIX nanoparticles. Figure 3 As shown. The mean MRI enhancement measurements for patients #13, #14, and #15 were equal to 32.4±10.8%, 14±5.8%, and 26.3±9.7%, respectively. As a point of comparison, the mean MRI enhancement on day D1 was equal to 175.8±45.2%, 58.3±18.4%, and 154.1±61.9% for patients #13, #14, and #15, respectively. Due to the low T1 change, the concentration of AGuIX nanoparticles could not be calculated. Based on the observed correlation between MRI enhancement and nanoparticle concentration, the upper limit of AGuIX concentration at day 8 in brain metastases can be estimated to be 10M. No significant MRI enhancement was observed in any patient on day D28, 4 weeks after administration of AGuIX nanoparticles.

[0227] discuss

[0228] The occurrence of brain metastases is a common event in the history of cancer and has a negative impact on the patient's life expectancy. For patients with multiple brain metastases, whole brain radiotherapy (WBRT) remains the standard treatment. However, the median overall survival is less than six months, and new methods need to be developed to improve the treatment effect of these patients. Therefore, the use of radiosensitizers has aroused great interest. The in vivo therapeutic diagnostic properties (radiosensitization and multimodal imaging diagnosis) of AGuIX nanoparticles have been previously confirmed in preclinical studies of eight tumor models in rodents (F. Lux, et al. Br J Radiol. 18: 20180365 (2018)), and in particular in brain tumors (G. Le Duc, et al. ACS Nano. 5, 9566-9574 (2011), C. Verry C, et al. Nanomedicine 11, 2405-2417 (2016)). The clinical evaluation of the diagnostic value of AGuIX nanoparticles for brain metastases is one of the secondary objectives of the Nano-Rad clinical trial. The target dose of AGuIX nanoparticles for radiotherapy application in patients is 100 mg / kg, so the conclusions and opinions of this study mainly focus on this dose.

[0229] The maximum dose of AGuIX nanoparticles administered to patients (100 mg / kg body weight or 100 μmol / kg body weight Gd 3+ ) corresponds to the injection of a clinically used MRI contrast agent (such as ) in the chelated gadolinium ion Gd 3+ The amount ( WeightGd 3+ ). Therefore, it is appropriate to compare the MRI enhancement observed in metastases with the maximal AGuIX dose with the Gd-based contrast agent doses used in clinical routine.

[0230] In this study, there was a 2-hour delay between nanoparticle administration and MRI acquisition to monitor the patient's response to the injection. The average nanoparticle plasma half-life is about 1 hour, and this delay resulted in an 86% decrease in nanoparticle concentration in plasma. In contrast, There was only a 15-minute delay between injection and MRI acquisition. Despite this significant clearance of the nanoparticles and reduced concentrations in the patients' blood, MRI enhancement at the highest nanoparticle dose was close to that observed with clinical contrast agents.

[0231] The remarkable diagnostic performance of AGuIX nanoparticles in enhancing MRI signals in brain metastases can be attributed to two independent factors. The first factor is related to the intrinsic magnetic properties of the nanoparticles. Compared with clinical Gd-based contrast agents, their larger diameter and molecular weight result in a higher longitudinal relaxation coefficient r1, which improves the ability to modify MRI signal intensity. Specifically, under a magnetic field of 3 Tesla, AGuIX nanoparticles and The r1 value is equal to each Gd 3+ Ion 8.9 and 3.5mM -1 .s -1 (BR Smith, SS Gambhir. Chem Rev. 117, 901-986 (2017)).

[0232] The second factor may be related to the ability of AGuIX nanoparticles to passively accumulate in brain metastases. This passive targeting phenomenon utilizes the so-called enhanced permeability and retention (EPR) effect, which assumes that the accumulation of nano-objects in tumors is due to defective and leaky tumor blood vessels and lack of effective lymphatic drainage (A. Bianchi, et al. MAGMA. 27, 303-316 (2014)). In previous studies on cancer animal models, the passive targeting effect of AGuIX nanoparticles on tumors has been observed. In a mouse model of multiple brain melanoma metastasis, it was reported that AGuIX nanoparticles were internalized in tumor cells, and the presence of nanoparticles in brain metastases was still observed 24 hours after intravenous injection of animals (Kotb, A. et al. Theranostics 6 (3): 418-427 (2016)). At the highest dose of 100 mg / kg, all metastases with a diameter greater than 1 cm were contrast-enhanced for up to 7 days after the administration of nanoparticles.

[0233] This accumulation and delayed clearance of nanoparticles from metastases is highlighted by the continued enhancement of MRI signal in metastases one week after administration. To the best of the inventors' knowledge, there are no reports in the literature of such late MRI enhancement of metastases after administration of clinically used Gd-based contrast agents.

[0234] The design of this first-in-human clinical trial included dose escalation, so patients received five increasing dose levels of AGuIX nanoparticles. From the linear correlation observed between the metastatic signal enhancement and the concentration of nanoparticles administered, it can be concluded that the dose of nanoparticles (within the dose range studied) is not a limiting factor for passive targeting of metastases. Importantly, despite the limited number of patients participating in this first clinical study, these preliminary results show that nanoparticle uptake and signal enhancement are present in the four metastatic lesions studied (NSCLC, melanoma, breast, and colon), regardless of the injected dose.

[0235] Considering the radiosensitizing properties of AGuIX nanoparticles, it is key to evaluate and possibly quantify the local concentration of nanoparticles accumulated in metastases. To this end, the MRI protocol includes a T1 mapping imaging sequence, from which the nanoparticle concentration is derived. The concentration values ​​obtained in this clinical study can be compared with those obtained in preclinical studies in tumor animal models. The calculated concentrations of AGuIX nanoparticles in NSCLC and breast cancer metastases of the three patients injected with the highest dose varied between 8 and 63 mg / L, corresponding to the concentrations of Gd in brain metastases. 3+ The concentration of ions ranged from 8 to 63 M. In the three patients mentioned above, the %ID / g ranged between 8% and 63%. The %ID / g was found to be of the same order of magnitude in the two preclinical MRI studies mentioned above, at 28% and 45%ID / g, respectively. Interestingly, these concentrations were obtained with a delayed injection (several hours), which is compatible with the setting of a radiotherapy session.

[0236] In this study, we also evaluated the relationship between nanoparticle concentration and MRI signal enhancement SE obtained using a robust T1-weighted 3DMRI sequence. Within the range of nanoparticle concentrations measurable in metastases, a linear relationship between MRI enhancement and nanoparticle concentration was observed using the acquisition protocol used in this study. Therefore, with the specific protocol used in this study, MRI enhancement can be used as a robust and simple metric to assess AGuIX nanoparticle concentration.

[0237] While metastasis targeting is beneficial for both diagnostic and radiosensitization purposes, it is desirable to maintain low concentrations of nanoparticles in healthy surrounding tissue. In this regard, no MRI enhancement was observed in metastasis-free brain tissue two hours after administration of the highest dose of AGuIX nanoparticles. This lack of enhancement is consistent with the rapid clearance of the nanoparticles measured in the patient's plasma and is a positive sign that the nanoparticles are not harmful to the healthy brain.

[0238] In conclusion, the preliminary results of the clinical trial reported here show that intravenous administration of gadolinium-based nanoparticles is effective in enhancing different types of brain metastases in patients. These first clinical findings - pharmacokinetics, passive targeting, metastatic lesion concentrations - are consistent with previous observations obtained in preclinical studies in animal models of brain tumors and bode well for the successful translation of this therapeutic agent from preclinical to clinical levels.

[0239] In addition, preliminary results from the Nano-Rad Phase 1 clinical trial showed that intravenous administration of AGuIX nanoparticles was well tolerated up to the 100 mg / kg dose selected for this study.

[0240] Finally, the persistence of nanoparticles in the tumor at day 8 supports a regimen that includes the first injection within a time period of 2 to 7 days before the first irradiation to optimize the concentration and distribution within the tumor while minimizing the presence of nanoparticles in the surrounding healthy tissue.

[0241] All these results and observations provide strong and credible support for the Phase 2 clinical trial (NANORAD2, NCT03818386) disclosed in Example 2 below.

[0242] Example 2: Radiotherapy of multiple brain metastases using AGuIX gadolinium chelated polysiloxane-based nanoparticles: a prospective randomized phase II clinical trial

[0243] 2.1 Research Hypotheses and Expected Results

[0244] Preliminary results from the Phase Ib trial Nanorad confirm the interest in combining AGuIX nanoparticles with radiation therapy for the treatment of cancer patients, especially those with brain metastases.

[0245] The purpose of this randomized Phase II study is to evaluate the efficacy of AGuIX in combination with WBRT to demonstrate an increased intracranial response rate compared to WBRT alone. In addition, it is expected that intracranial progression-free survival will be increased and the quality of life of patients will be improved. In addition, since gadolinium is a T1-positive contrast agent in MRI, an MRI study will be performed to evaluate the distribution of the product in brain metastases and surrounding healthy tissues.

[0246] The target population chosen was patients with brain metastases who were eligible for whole-brain RT, regardless of their primary cancer.

[0247] The target population was selected based on:

[0248] - Correlation of intravenously administered radiosensitizers with multifocality of brain metastases;

[0249] - Differences in tissue enhancement between tumor lesions and healthy brain in preclinical in vivo studies and in patients enrolled in the Phase I Nanorad trial (EudraCT 2015-004259-30; NCT02820454);

[0250] - There is a lack of alternative treatment options for patients who have a life expectancy of approximately 4.5 months treated with standard radiation therapy.

[0251] Other tumor sites may also benefit from the increase in dose efficacy associated with the radiosensitizing effects of nanoparticles.

[0252] 2.2 Study Design / Methods

[0253] This is a prospective, randomized, open blinded end-point, phase II clinical trial designed to evaluate the efficacy of AGuIX combined with whole-brain radiotherapy versus whole-brain radiotherapy alone in the treatment of brain metastases (Blood Press. 1992 Aug; 1(2): 113-9. Prospective randomized open blinded end-point (PROBE) study. A novel design for intervention trials. Prospective Randomized Open Blinded End-Point. Hansson L) (Hansson et al., 1992).

[0254] Patients will be assigned to one of two treatment groups after a centrally performed minimization procedure to balance potential prognostic factors between treatment groups. The minimization algorithm will take into account the following factors: center, age (as a continuous variable), histology of primary cancer (lung cancer vs breast cancer vs melanoma vs other), DS-GPA score (≤1 vs >1), history of intracranial locoregional therapy (yes vs no), immunotherapy (yes vs no), use of corticosteroids at inclusion (yes vs no), and intended hippocampal protection (yes vs no).

[0255] The study will be adaptive: an interim analysis is planned after the recruitment of 20 patients in each treatment group (WBRT and AGuIX+WBRT) in order to abandon a priori defined subgroups in case of no differences between the groups. The two defined groups chosen provisionally are (i) patients with brain metastases from melanoma and (ii) patients with brain metastases from all other primary cancers (lung cancer, breast cancer, kidney cancer, ...).

[0256] In each of the two subgroups, the contingency table will describe the response rate, and any group with no response or poor response (i.e., best objective intracranial response rate equal to or worse than the reference group) may be deleted.

[0257] 2.3 Eligibility criteria / subject characteristics

[0258] Inclusion criteria

[0259] - Patients with brain metastases from histologically confirmed solid tumors who are eligible for WBRT

[0260] -At least 18 years old

[0261] -Signed informed consent

[0262] -ECOG (Eastern Cooperative Oncology Group) performance status 0-2

[0263] - Extracranial diseases:

[0264] Complete or partial response or stability on systemic therapy

[0265] No extracranial disease

[0266] Or first-line treatment

[0267] -Life expectancy greater than 6 weeks

[0268] - Effective contraceptive methods for all patients of childbearing potential

[0269] - Belong to the social security system or its beneficiaries

[0270] Non-inclusion criteria

[0271] - Leptomeningeal metastasis

[0272] - Evidence of metastasis from recent major bleeding

[0273] - Progressive and threatening extracranial disease under systemic therapy

[0274] - Previous cranial irradiation (except stereotactic irradiation)

[0275] - Known contraindications, sensitivity or allergy to gadolinium

[0276] - Known contraindications to MRI

[0277] - Renal insufficiency (glomerular filtration rate ≤ 50 mL / min / 1.73 m 2 )

[0278] - Inclusion in another clinical trial protocol

[0279] - Pregnancy or breastfeeding

[0280] - Subjects in the exclusion period of another study

[0281] - Subjects under administrative or judicial control

[0282] 2.4 Permitted Treatments / Procedures

[0283] Maintaining or discontinuing systemic cancer therapy before brain irradiation was left to the discretion of each investigator and must adhere to current recommendations.

[0284] The following treatments are contraindicated during radiotherapy: As well as tyrosine kinase inhibitors. According to current recommendations, they must be stopped before irradiation.

[0285] Aside from these restrictions, the patient's usual care is permitted and will be listed on each patient's CRF.

[0286] As a precaution, radiotherapy should not be administered less than 2 hours after administration of AGuIX. The plasma half-life of the particles in humans is 1.08 hours (0.75-2 hours). Even in animal models, the content of nanoparticles in healthy brain tissue remains low, and premature radiotherapy may increase the impact of radiotherapy on healthy brain tissue (Verry, C., et al. (2016). MRI-guided clinical 6-MV radiosensitization of gliomas using a unique gadolinium-based nanoparticle injection. Nanomedicine (Lond).

[0287] 2.5 Treatments used in the study

[0288] Drug / treatment name and trade name: AGuIX

[0289] Chemical name (DCI): Gadolinium chelated polysiloxane based nanoparticles

[0290] Drug form: Sterile lyophilized off-white powder containing 300 mg AGuIX as the active ingredient (300 mg AGuIX / vial). Each vial contains 0.66 mg CaCl2 as an inactive ingredient. The drug product is packaged in a disposable 10 mL clear glass vial with a bromobutyl rubber stopper.

[0291] Preparation procedure: Reconstitute the solution with 3 mL of water for injection to obtain a 100 mg / mL AGuIX solution. The pH of the solution is 7.2 ± 0.2.

[0292] One hour after reconstitution with water for injection, place the reconstituted solution into a syringe and inject using a syringe pump.

[0293] Administer within a minimum of 1 hour and a maximum of 24 hours after reconstitution.

[0294] The AGuIX solution is to be administered half a day after reconstitution, however, the nanoparticles must be stored at [+2°C; +8°C] and administered within a maximum of 24 hours after reconstitution.

[0295] Administer intravenously by slow infusion (2 mL / min) using a syringe pump

[0296] Dose per administration: 100 mg / kg, 1 mL / kg

[0297] 2.6 Treatment and related procedures

[0298] Radiation therapy: Whole brain radiation therapy:

[0299] -Dose scanner and individual contention mask

[0300] - Permitted irradiation techniques:

[0301] ○Conformation, equidistant, lateral beam of two 6MV photons

[0302] ○ or IMRT (tomographic radiotherapy or VMAT)

[0303] -dose

[0304] ○Prescription dose: 30Gy

[0305] ○Dose per time: 3Gy

[0306] ○Number of times: 10

[0307] ○Number of times per day: 1

[0308] ○Total treatment duration should not exceed 3 weeks

[0309] Target volume:

[0310] Clinical target volume (CTV) = brain + brainstem + cerebellum

[0311] Planning target volume (PTV) = CTV + 3 mm

[0312] Organs at risk:

[0313] Eye, lens, retina, hippocampus, inner ear, and cochlea

[0314] Dosage Limitations:

[0315] PTV: V95%>95, Dmax<107%

[0316] Hippocampal preservation:

[0317] Sparing the hippocampus is recommended if possible but is not mandatory. In the case of hippocampal sparing intensity modulated irradiation, fusion between the dose scanner and the reference MRI is necessary. Bilateral hippocampal contours were manually generated on the fused MRI-CT image set and dilated by 5 mm to generate hippocampal avoidance areas. The planning target volume (PTV) was defined as the clinical target volume excluding the hippocampal avoidance area. IMRT was delivered in 10 fractions at a dose of 30 Gy to cover the PTV while avoiding the hippocampus. The dose to 100% of the hippocampus could not exceed 9 Gy, and the maximum hippocampal dose could not exceed 16 Gy.

[0318] 2.7 Visits during treatment

[0319] Experimental treatment group: AGuIX+WBRT

[0320] D0 (2 to 7 days before WBRT):

[0321] - Patients hospitalized in outpatient department

[0322] - Clinical examination to determine ECOG OMS performance status, pain, weight, and constants (heart rate, blood pressure, temperature)

[0323] - Neurological examination

[0324] - Placement for Peripheral intravenous catheter for injection

[0325] -Biological examination: complete blood count, serum electrolytes, renal function, liver function (see Tables §7.3 and §8.3 for details)

[0326] - First administration of AGuIX between 2 and 7 days before the start of WBRT (H0)

[0327] - Brain MRI within one hour of injection*

[0328] - Safety Assessment

[0329] First week of radiotherapy:

[0330] Step 1:

[0331] - Patients hospitalized in outpatient department

[0332] - Clinical examination to determine ECOG OMS performance status, pain, weight, and constants (heart rate, blood pressure, temperature)

[0333] - Neurological examination

[0334] - Placement for Peripheral intravenous catheter for injection

[0335] - Biological examination: complete blood count, serum electrolytes, renal function, liver function (see Tables §7.3 and §8.3 for details). Before giving the injection, the doctor must confirm that the patient has no changes in kidney function.

[0336] -Second administration of AGuIX (H0)

[0337] - Radiotherapy session n°1, 3 to 5 hours after the second injection of AGuIX

[0338] -(As a precaution, radiotherapy should not be given within 2 hours of AGuIX administration)

[0339] - Safety Assessment

[0340] Phase 2 / Phase 3 / Phase 4 / Phase 5:

[0341] Outpatient radiotherapy sessions n°2, n°3, n°4 and n°5

[0342] Radiotherapy treatment week 2:

[0343] Phase 6 (before phase 6 radiotherapy):

[0344] - Patients hospitalized in outpatient department

[0345] - Clinical examination to determine ECOG OMS performance status, pain, weight, and constants (heart rate, blood pressure, temperature)

[0346] - Neurological examination

[0347] - Placement for Peripheral intravenous catheter for injection

[0348] -Biological examinations: complete blood count, serum electrolytes, renal function, liver function (see Tables §7.3 and §8.3 for details). Before administering AGuIX injection, the physician must confirm that the patient's renal function has not changed.

[0349] - Third administration of AGuIX (H0)

[0350] - Radiotherapy session n°6, performed 3 to 5 hours after AGuIX injection.

[0351] -(As a precaution, radiotherapy should not be given within 2 hours of AGuIX administration)

[0352] - Safety Assessment

[0353] Phase 7 / Phase 8 / Phase 9 / Phase 10:

[0354] - Outpatient radiotherapy sessions n°7, n°8, n°9 and n°10

[0355] Control treatment group: WBRT

[0356] First week of radiation therapy

[0357] Step 1:

[0358] - Clinical examination to determine ECOG OMS performance status, pain, weight, and constants (heart rate, blood pressure, temperature)

[0359] - Neurological examination

[0360] -Biological examination: complete blood count, serum electrolytes, renal function, liver function (see Tables §7.3 and §8.3 for details).

[0361] -Radiotherapy session n°1

[0362] - Safety Assessment

[0363] Phase 2 / Phase 3 / Phase 4 / Phase 5:

[0364] Outpatient radiotherapy sessions n°2, n°3, n°4 and n°5

[0365] Radiotherapy treatment week 2:

[0366] Phase 6 (before phase 6 radiotherapy):

[0367] - Clinical examination to determine ECOG OMS performance status, pain, weight, and constants (heart rate, blood pressure, temperature);

[0368] - Neurological examination;

[0369] - Biological examination: complete blood count, serum electrolytes, renal function, liver function (see Tables §7.3 and §8.3 for details);

[0370] - Radiotherapy session n°6;

[0371] - Safety assessment.

[0372] Phase 7 / Phase 8 / Phase 9 / Phase 10:

[0373] - Outpatient radiotherapy sessions n°7, n°8, n°9 and n°10

[0374] Follow-up

[0375] The follow-up schedule will be the same regardless of the treatment group (ie, experimental treatment group AGuIX + WBRT and control treatment group WBRT).

[0376] Follow-up will be performed at week 6 and then at 3, 6, 9, and 12 months (+ / - 1 week) after the start of radiation therapy.

[0377] End of study visit

[0378] The study was terminated 12 months after the start of radiotherapy in both treatment groups (ie, AGuIX+WBRT in the experimental treatment group and WBRT in the control treatment group).

[0379] Figure 4 The study plan and objectives are also summarized.

[0380] result

[0381] A clinical trial was initiated using the treatment regimen described in this Example 2. To date, 10 patients have been enrolled who received several administrations of AGuIX nanoparticles without any major adverse reactions reported.

[0382] References

[0383] 1.Schaue D,McBride WH.Opportunities and challenges of radiotherapy for treating cancer.Nat Rev Clin Oncol 2015,12(9):527-540.

[0384] 2. Beasley M, Driver D, Dobbs HJ. Complications of radiotherapy: improving the therapeutic index. Cancer Imaging 2005,5:78-84.

[0385] 3.Hainfeld JF,O'Connor MJ,Dilmanian FA,Slatkin DN,Adams DJ,SmilowitzHM.Micro-CT enables microlocalisation and quantification of Her2-targetedgold nanoparticles within tumor regions.Br J Radiol2011,84(1002):526-533.

[0386] 4.Dorsey JF,Sun L,Joh DY,Witztum A,Kao GD,Alonso-Basanta M,et al.Goldnanoparticles in radiation research:potential applications for imaging andradiosensitization.Transl Cancer Res 2013,2(4):280-291.

[0387] 5.Taupin F,Flaender M,Delorme R,Brochard T,Mayol JF,Arnaud J,etal.Gadolinium nanoparticles and contrast agent as radiation sensitizers.PhysMed Biol 2015,60(11):4449-4464.

[0388] 6.McQuaid HN,Muir MF,Taggart LE,McMahon SJ,Coulter JA,Hyland WB,etal.Imaging and radiation effects of gold nanoparticles intumour cells.Sci Rep2016,6:19442.

[0389] 7.Zhu J,Zhao L,Cheng Y,Xiong Z,Tang Y,Shen M,et al.Radionuclide(131)I-labeled multifunctional dendrimers for targetedSPECT imaging andradiotherapy of tumors.Nanoscale 2015,7(43):18169-18178.

[0390] 8.Mi Y,Shao Z,Vang J,Kaidar-Person O,Wang AZ.Applicationofnanotechnology to cancer radiotherapy.Cancer Nanotechnol 2016,7(1):11.

[0391] 9.Le Duc G,Miladi I,Alric C,Mowat P,Brauer-Krisch E,BouchetA,etal.Toward an image-guided microbeam radiation therapy usinggadolinium-basednanoparticles.ACS Nano 2011,5(12):9566-9574.

[0392] 10.Dufort S,Bianchi A,Henry M,Lux F,Le Duc G,Josserand V,etal.Nebulized gadolinium-based nanoparticles:a theranostic approachfor lungtumor imaging and radiosensitization.Small 2015,11(2):215-221.

[0393] 11.Hainfeld JF,Slatkin DN,Smilowitz HM.The use of goldnanoparticlesto enhance radiotherapy in mice.Phys Med Biol 2004,49(18):N309-315.

Claims

1. A nanoparticle containing a high-Z element for use in a method of treating a tumor in a subject in need thereof by ionizing radiation, the method comprising: (i) injecting a first therapeutically effective amount of nanoparticles containing a high-Z element as a radiosensitizer into the subject in need thereof 2-10 days, preferably 2-7 days, before the first irradiation of the tumor, (ii) injecting a second therapeutically effective amount of the same or different nanoparticles containing a high-Z element within 1 hour to 12 hours before the first irradiation of the tumor, and, (iii) irradiating the subject's tumor with a therapeutically effective dose of radiation; The nanoparticles containing high-Z elements are nanoparticles containing elements with atomic Z numbers higher than 40, preferably higher than 50, and the nanoparticles have an average hydrodynamic diameter lower than 10 nm, such as 1-8 nm, preferably lower than 6 nm, more preferably 2-6 nm.

2. The nanoparticle for use thereof according to claim 1, wherein the nanoparticle is injected intravenously.

3. Nanoparticles for use thereof according to any one of claims 1 or 2, wherein the nanoparticles contain a rare earth metal or a mixture of rare earth metals as the high-Z element.

4. The nanoparticle for use thereof according to any one of claims 1 or 2, wherein the nanoparticle comprises gadolinium, bismuth or a mixture thereof as the high-Z element.

5. The nanoparticle for use thereof according to any one of claims 1 to 3, wherein the nanoparticle comprises a chelate of a high-Z element, such as a chelate of a rare earth element.

6. The nanoparticle for use thereof according to any one of claims 1 to 5, wherein the nanoparticle comprises: Polyorganosiloxane, a chelate covalently bonded to the polyorganosiloxane, - High Z elements complexed by the chelate.

7. The nanoparticle for use thereof according to any one of claims 1 to 6, wherein the nanoparticle comprises: Polyorganosiloxane, the weight ratio of silicon of which is at least 8%, preferably 8% to 50%, based on the total weight of the nanoparticles, chelates covalently bonded to the polyorganosiloxane in a ratio of 5 to 100, preferably 5 to 20 per nanoparticle, and - A high Z element complexed with the chelate.

8. The nanoparticles for use according to any one of claims 1 to 7, wherein the nanoparticles contain chelates for complexing high-Z elements, which are obtained by grafting one or more of the following chelating agents on the nanoparticles: DOTA, DTPA, EDTA, EGTA, BAPTA, NOTA, DOTAGA and DTPABA, or mixtures thereof.

9. The nanoparticle for use thereof according to any one of claims 1 to 8, wherein the nanoparticle is a gadolinium chelated polysiloxane nanoparticle of the following formula: Wherein PS is a matrix of polysiloxane, and n is 5-50, preferably 5-20, and wherein the hydrodynamic diameter is 2-6 nm.

10. The nanoparticle for use thereof according to any one of claims 1 to 9, wherein the nanoparticle is a lyophilized powder contained in a pre-filled vial to be reconstituted in an aqueous solution for intravenous injection.

11. The nanoparticle for use thereof according to any one of claims 1 to 10, wherein the nanoparticle is contained in an injectable solution at a concentration of 50-150 mg / mL, preferably 80-120 mg / mL, for example 100 mg / mL.

12. The nanoparticle for use thereof according to any one of claims 1 to 11, wherein the therapeutically effective amount administered in each injection step is 50 mg / kg-150 mg / kg, typically 80-120 mg / kg, such as 100 mg / kg.

13. The nanoparticle for use thereof according to any one of claims 1-12, wherein the tumor is a solid tumor, preferably selected from the group consisting of glioblastoma, brain metastasis, meningioma, or primary tumors of cervical cancer, rectal cancer, lung cancer, head and neck cancer, prostate cancer, colorectal cancer, liver cancer and pancreatic cancer.

14. The nanoparticle for use according to any one of claims 1 to 13, wherein the tumor is a brain metastasis, typically a brain metastasis from melanoma, lung cancer, breast cancer, or kidney primary cancer.

15. The nanoparticle for use thereof according to claim 14, wherein the subject is exposed to whole brain radiotherapy in step (iii).

16. The nanoparticle for use thereof according to claim 15, wherein the whole brain radiotherapy comprises exposing the subject to a total dose of ionizing radiation of 25-35 Gy, such as 30 Gy.

17. The nanoparticle for use thereof according to claim 15 or 16, wherein the subject is exposed to an ionizing radiation dose of about 3 Gy each time, and the total dose is preferably administered in a maximum of 10 times.

18. Nanoparticles for use thereof according to any one of claims 1-17, wherein the method comprises the step of injecting a third therapeutically effective amount of the same or different nanoparticles containing a high-Z element within 5-10 days after the second injection step, for example within 7 days after the second injection step.

19. The nanoparticles for use thereof according to any one of claims 1 to 18, wherein the method further comprises a step of imaging the tumor by magnetic resonance imaging (MRI) after the first injection step of the nanoparticles, wherein the nanoparticles serve as a T1 contrast agent for the MRI.

Images