ES2382041T3 - Alpha and beta emission hydroxyapatite particles - Google Patents

Abstract

The present invention provides Hydroxyapatite (HA) incorporating an alpha-emitting radionuclide or an in vivo generator for an alpha-emitting radionuclide. The invention further provides methods for the formation of such HA, pharmaceutical compositions comprising the HA and methods of medical treatment of cancerous or non-cancerous disease including administering the HA or compositions thereof.

Description

Alpha and beta emission hydroxyapatite particles

The present invention relates to compositions suitable for administering a radionuclide in vivo. In particular, the invention relates to particulate compositions comprising alpha emission radionuclides or generators for alpha emission radionuclides. The compositions of the invention are suitable for use in the treatment of neoplastic diseases.

The introduction of novel therapies is important in pharmaceutical research in all fields and, especially, in cancer research. One field of this research refers to the use of radionuclides for therapeutic purposes. For many years, beta-particle emitters have been investigated for use in the treatment of cancers and colloids labeled with beta-particle emitters have been proposed to treat intracavitary diseases, including metastatic ovarian cancer.

15 In recent years, efforts have been made to use alpha emitters in antineoplastic agents. Alpha emitters have various characteristics that distinguish them from beta emitters, which include higher energy and shorter tissue ranges. The radiation range of typical alpha emitters in physiological environments is generally less than 100 micrometers, the equivalent of only some cell diameters. This makes these sources suitable for the treatment of tumors, including micrometastases because very little radiated energy will pass beyond the target cells and, therefore, damage to the surrounding healthy tissue can be minimized. On the contrary, a beta particle has a range of 1 mm or more in water.

The radiation energy of alpha particles is also higher compared to beta particles, the

25 gamma rays and X-rays, typically being 5-8 MeV, or 5 to 10 times that of a beta particle and 20 or more times the energy of a gamma ray. Therefore, this deposition of a large amount of energy over a very short distance gives alpha radiation an exceptionally high linear energy transfer (LET) when compared to gamma or beta radiation. This explains the exceptional cytotoxicity of alpha emission radionuclides and also imposes stringent demands on the level of control and the study of radionuclide distribution necessary to avoid unacceptable adverse effects.

It has been suggested that alpha emitters be used together with particulates and colloids for internal radionuclide therapy (see Bloomer et al., Int. J. Radiat. Oncol. Biol. Phys. 10 (3) 341-348 (1984); Rotmensch et al., Int.

J. Radiat. Oncol. Biol. Phys. 34, 609-616 (1996); US 970062, US 5030441 and US 5085848; and Vergote and 35 col., Gynecol Oncol. 47 (3): 366-372 (1992) and Gynecol Oncol 47 (3): 358-65 (1992)).

A problem with these previously used particulate and colloidal vehicles is that the vehicle materials used are neither biocompatible nor biodegradable. As a result, vehicles can accumulate, especially when repeatedly administered to a body cavity. This accumulation of non-biocompatible material can therefore cause inflammation, etc.

Another problem, especially for example with astatine-211 colloids and lead colloids 212, is the escape of free radionuclide, since it has been shown that astate-211 and bismuth-212 (generated from lead 212) they accumulate in normal tissues such as the thyroid and stomach for the astate and in the kidneys with bismuth.

45 A third problem with many of the radionuclides used is that they are difficult to prepare and are available only in small quantities or have a half-life that is too short, which makes them unsuitable for use in therapeutic preparations.

The very high energy of an alpha particle, combined with its significant mass, causes a significant velocity to be imparted to the particle emitted after nuclear decay. As a result, an equal but opposite speed is imparted to the rest of the "child" nucleus in the form of "nuclear recoil." This recoil is powerful enough to break most chemical bonds and force newly formed child nuclides out of chelation. This is highly significant when the child nucleus is itself alpha-radioactive because this child will no longer be confined.

55 for the chelated particle or complex in which the precursor nucleus was administered. As a result, a significant problem with the prior methods of distribution of alpha radiochemical compounds has been to control the biodistribution of the alpha-emitting child nucleides. This may limit the choice of alpha emitters to those without children of alpha emission or cause the dose to be limited thereby reducing the exposure of healthy tissue.

When control over the biodistribution of the child nuclides can be maintained, then the formation of radiopharmaceutical compounds with alpha emitters having an additional alpha emission chain of children is a considerable advantage. By this method, the dose received by healthy tissue during administration can be minimized and, ideally, several alpha decays can occur in the diseased area. However, if control over the fate of the child nuclides cannot be established, then these will become a problem if

65 are alpha emitters. This is because they can accumulate later in healthy tissues and cause unwanted adverse effects.

In WO 01/60417 a method was proposed to maintain control of the alpha-emitting child nuclides. This method uses liposomes that contain a chelating agent to contain the alpha emitters and prevent nuclear recoil from propelling the child nuclei into the solution. However, liposomes are not ideal for

5 all administration methods and may show undesirable rates and clearance routes in some cases.

Therefore, there is a considerable need for improved radiotherapeutic compositions that show the stable labeling of alpha emission radionuclides and that have little or no escape from radioactive children to other tissues. There is an additional need for radiotherapeutic compositions having biocompatible and biodegradable components. Additionally, there is a need for radiotherapeutic compositions in which radionuclides are sufficiently easy to prepare and are available in amounts large enough for use in pharmaceutical preparations.

Surprisingly, the present inventors have established that the hydroxyapatite (HA) particles can be radiolabelled with alpha emission radionuclides and will stably retain the radionuclides for a considerable period. In addition, the present inventors have established that the radioactively labeled HA with alpha emitters will retain, at an unexpectedly high level, the child nuclides after disintegration of the precursor nuclide. This was a very unexpected finding since the recoil produced by alpha decay normally breaks the chemical bonds and affects the release of the child product.

In a first aspect, the present invention therefore provides a hydroxyapatite (HA) that incorporates an alpha emission radionuclide or a radionuclide that is an in vivo generator for an alpha emission radionuclide.

The hydroxyapatites of the present invention are preferably stable in the sense that the radionuclide is stably trapped within the HA and is not significantly poured into solution or into other tissues under physiological conditions. HA are also preferably stable in the sense that the child nuclides are also trapped in the vehicle HA and, substantially, is not poured into the solution or into other tissues under physiological conditions.

In addition, desirable alpha emitters whose disintegration provides a chain of additional alpha emissions may preferably be used because the hydroxyapatites of the present invention provide control over the fate of these children. The only known prior use of hydroxyapatite particles as a vehicle has been for beta-emitting radionuclides in radiosynovectomy (i.e., in the treatment of pain due to arthritis) by

35 Unni et al. (Nucl Med Biol 29, 199-209 (2002)) and Brodack et al. (WO 97/01304). Previously used beta emitters all disintegrated into stable nuclides unimportant for dose distribution (i.e., essentially no recoil was observed after disintegration and the child product was not radioactive and, therefore, its distribution was of no importance) .

WO 0128587 A2 describes magnetically responsive compositions comprising iron and ceramic particles carrying substances for diagnosis and / or medical treatment in vivo.

Vergote I. et al., 1992, (47), Gynecologic Oncology, 366-372 describe 211At bound to synthetic organic polymers for the treatment of tumors.

The hydroxyapatites of the present invention and the compositions prepared therewith are very suitable for use in the treatment of neoplastic diseases. Especially this is because the therapeutically active alpha emitters, administered directly with the hydroxyapatites of the invention or generated in vivo, provide high cytotoxicity and cause less damage to the deep and surrounding regions of normal tissues compared to the beta emitters. This applies especially when the HAs of the invention are used in local, regional or directed administration methods as well as in directed intracavitary, systemic or intratumoral methods and results in a shorter range of alpha radiation.

In a second aspect, the present invention further provides compositions for use in a method of

Treatment of a human or animal subject, especially a mammal (especially one that needs it) by administering an effective amount of a hydroxyapatite (HA) that incorporates an alpha-emitting radionuclide or a radionuclide that is an in vivo generator for a alpha emission radionuclide, or by administering a composition prepared from this HA.

In a further aspect, the present invention provides a pharmaceutical composition comprising a hydroxyapatite of the present invention and at least one physiologically acceptable carrier.

Still in a further aspect, the present invention provides a hydroxyapatite (HA) that incorporates an alpha emission radionuclide or a radionuclide that is an in vivo generator for an alpha 65 emission radionuclide for use in therapy. Still in a further aspect the invention provides the use of hydroxyapatite (HA) that incorporates an alpha-emitting radionuclide or a radionuclide that is an in vivo generator for a radionuclide of

Alpha emission in the manufacture of a medicine (especially an injectable, perfusible or locally applicable medicine) for the treatment of a neoplastic or non-neoplastic disease (such as any of the diseases indicated in this document below).

Still still in a further aspect, the invention relates to pharmaceutical compositions and devices comprising a hydroxyapatite (HA) incorporating an alpha emission radionuclide or an in vivo generator of an alpha emission radionuclide such as syringes loaded with pharmaceutical preparations.

The invention further relates to a process for preparing a hydroxyapatite (HA) that incorporates an alpha emission radionuclide or an in vivo generator of an alpha emission radionuclide, comprising the steps of:

(a) contacting a solution of an alpha emission radionuclide or an in vivo generator of an alpha emission radionuclide with hydroxyapatite particulates, and

15 (b) optionally crystallizing a hydroxyapatite coating on the labeled particulates prepared in step (a) to thereby encapsulate said radionuclide or said generator in vivo in the particulate.

Preferably, said process comprises:

(to)

 absorbing a solution of the alpha emission radionuclide or the in vivo generator of the alpha emission radionuclide to the hydroxyapatite particulates, preferably at a pH in the range of about 3-12; Y

(b)

 optionally crystallize a hydroxyapatite coating on the labeled particulates prepared in step (a) to thereby encapsulate said radionuclide in the particulate.

The term hydroxyapatite is used in the art to indicate various related phosphate compounds, especially calcium hydroxyapatite having the formula [Ca10 (PO4) 6 (OH) 2]. Calcium hydroxyapatite is a constituent of the matrix of healthy bones in all vertebrates. It is currently used as a material in artificial limbs, especially in bone inserts "without cement." An additional use of hydroxyapatite is as selective cation exchangers in columns. Hydroxyapatite is a biocompatible and biodegradable material and is therefore especially useful for in vivo application. In this connection, an additional advantage is that it can be heat treated or autoclaved. The present invention, therefore, further provides products and compositions that are stable for autoclaving under conventional conditions.

As used herein in the description and in the claims, the term "hydroxyapatite (HA)" is used to indicate any hydroxyapatite and any derivative or analogue thereof that is biocompatible or biodegradable. Preferably, these should not show adverse effects for the intended use.

For example, the term hydroxyapatite or HA, as used herein encompasses calcium hydroxyapatite as well as any compound where the calcium ion Ca2 + is replaced by any other cation (preferably biotolerable) such as Sr2 +, Ba2 +, Bi3 + or Ac3 +, or a combination of one or more of these cations. In one embodiment, hydroxyapatite comprising sodium hydroxyapatite is preferred. The HA can also be sedimented together or crystallized with other minerals that have low solubility, especially Ca salts of low solubility.

The HA used in the present invention and referred to as hydroxyapatite or HA herein may also be modified on its surface to carry other substituents or groups, such as fluorine, phosphonates such as bisphosphonates and tetraphosphonates, proteins, amino acids, peptides and magnetic substances.

Through surface modification, different properties can be provided to HA particles, such as increased resistance to degradation. Another use of the surface modification is to include molecules that bind to the receptor that can act as the target ligand to target biological target structures, especially tumor-associated receptors.

Hydroxyapatite or HA as used herein also encompasses compounds such as any compound of

Combined or sedimented hydroxyapatite together with other materials such as metals, oxides, proteins, amino acids, carbohydrates, phosphonates such as bisphosphonates, organic compounds, for example, polylactide, polyethylenedones, glass-ceramic, titanium oxide, alumina, zirconite, silica, polyethylene, epoxy, polyethylene glycol, polyhydroxybutyrate, gelatin, collagen, chithane, phosphazene, iron, iron oxides and / or magnetic iron. These combinations are useful for providing additional desired properties to final HA particulates such as, for example, magnetism (magnetic iron) or the ability to form a gel (gelatin, collagen, chitosan). Additionally, some of the groups mentioned above will make HA more lipophilic, as one skilled in the art knows, and this is considered an advantageous property for any derivative or analogue of HA used in the present invention.

The hydroxyapatites that are useful for use in the present invention can have any solid form and will generally be referred to as "particulates" in the present invention and in the claims to distinguish them from radioactive particles such as alpha particles (helium nuclei). or beta particles (electrons). HA particles may be, for example, crystals, microspheres or colloids. The shape, pore size and density of the particulates can be chosen to accommodate the intended use.

5 The size of the HA particles can generally be within the range of about 10 nm to about 100 µm, but colloids and other small particulates including particulates of only 1 nm can be used.

In one embodiment it is preferable that the particulates have a size that allows them to remain in suspension without sedimentation. Sedimentation taken in this context includes flotation, where “sediment” is formed at the top, rather than at the bottom of the suspension. In particular, it is preferable that the particulates are of a size such that they will not sediment when stored for a period of at least 1 hour, preferably at least 6 hours and, more preferably, at least 1 month when suspended in a liquid such as pharmaceutically tolerable (especially aqueous) solution. Therefore, suitable particle sizes are

15 will easily determine for any particular type of HA by routine sedimentation experiments.

An especially preferred general size range for HA particulates according to this invention will be 1 μm to 20 μm, especially 1 μm to 5 μm.

It is preferable to use particulates that have a basically uniform size distribution. Different size ranges will be preferred and chosen depending on the desired use.

Small particulates can be better distributed in areas where steric hindrance exists. They may also have advantages when the composition of the invention is administered intravenously (i.e.,

25 for systemic cancer treatment) or for local administration (i.e., to an organ invaded by cancer such as the liver). Therefore, a preferred small size range, especially for intravenous administration, is about 1 nm to about 2 µm and a more preferred range is about 8 nm to 40 nm.

In one embodiment, very small particulates are administered to preferably target tumor cells. In particular, tumor capillaries may be more prone to leaks than healthy tissue capillaries (for example, due to their communications). The very small "nanoparticulate" HA particles of the present invention (such as 1 to 50 nm, preferably 2 to 10 nm, more preferably 3 to 5 nm) can, therefore, selectively escape from the capillaries within tumors and effectively direct radionuclides

35 incorporated into the tumor site. These particulates can also bind to target moieties (such as antibodies or molecules that bind to the receptor; see below) thereby increasing their target effect.

On the other hand, larger particles can be better retained within the administered site, for example, in a body cavity. A second advantage of these larger particulates is that they are not so easy to swallow or degrade by macrophages and, therefore, are expected to retain radionuclides better in vivo.

Therefore, another preferred size range, especially for administration to a body cavity, is about 100 nm to 100 µm and a more preferred range is about 500 nm to 20 µm.

45 As used herein, the "size" of a particulate refers to the average size (mode) of the longest dimension of the particulates. The particulates may have any shape or mixture of shapes, such as spheres, discs, needles, rods, etc., but in general, the longest dimension will not be more than 20 times, preferably not more than five times the shortest dimension. When the particulates are formulated for injection or infusion (especially intravenous or intra-arterial), this will generally be the case where no detectable proportion of particulates has any dimension greater than 8 μm, preferably 5 μm. Local or regional infection, for example, in a cavity, intratumoral, subcutaneous or intramuscular, may not require this restriction.

Porosity is a second property of HA particulates that can be chosen to correspond to the intended use or to the radionuclide with which the particulate will be labeled. In particular, the porosity will be

55 very related to the density of the particulate and it will be favorable in some applications to choose HA particles that have a porosity that offers a density similar to that of water to achieve a very slow or no sedimentation.

A group of nuclei that can be used in the present invention are the alpha emission nuclei of the following group: 211At, 212Bi, 223Ra, 224Ra, 225Ac, 227Th and any combination thereof.

Another group of radionuclides are beta emitters that have at least one alpha-emitting child in their decay chain. These include 211Pb, which acts as a source of 211Bi of alpha emission; 213Bi, which disintegrate into 213Po of alpha emission and 225Ra, whose beta decay provides 225Ac and subsequently disintegrate by

65 four alpha emissions and two beta emissions to finally produce 209Bi stable. A particularly preferred example is: 212Pb, which decays through its son 212Bi of alpha emission.

In a preferred embodiment of the invention, the 212Pb / 212Bi suitable for use in the HA of the present invention can be prepared by a method comprising:

5 i) prepare 224Ra (for example, from a source of 228Torio by anion exchange chromatography),

ii) purifying the 224Ra by contact with a specific f-block binder (for example, an actinide / lanthanide specific resin, specifically in the form of a column),

iii) allow the internal formation of 212Pb (for example, allowing 224Ra to rest for 6-24 hours), and

iv) purify the resulting 212Pb by contact with a specific lead binder (for example, a specific Pb resin, especially in the form of a column).

In the above method, any of the purification steps i), ii) and / or iv) can be repeated at least once with the same or different samples of specific binder. Specific binders of block elements f include methane derivatives of bisphosphonic acid such as P, P'-di-ocitl methaphosphonic acid (for example, DIPEX (RTM)). Suitable Pb-specific binders include corona ethers, especially 18-crown-6 derivatives such as di-t-butyl-cyclohexane-18-crown-6 (for example, the Pb-B25-S cartridge containing the resin specific to Pb Eichrom). When radionuclides are used, it is preferable to use specific binders on a non-labile substrate such as silica but for purification where contact with the resin is short, organic resin supports can be used. This method can be combined with any method to form HA that incorporates the radionuclides referred to herein. The 212Pb and the HA incorporating 212Pb formed and formable by these methods form additional aspects of the invention.

The preparation method of 212Pb indicated above has the advantage of offering a simple and easy to perform procedure and also to provide 212Pb of greater purity of the radionuclide than previously obtained.

The compositions of the present invention are stable until the loss of the radionuclide loaded by HA particles. A composition can be considered stable if, after incubation in a solution at 37 ° C for at least 20 minutes, at least 80% of the activity of the charged radionuclide is detected in the HA particles rather than in the solution. This proportion should preferably be at least 85%, more preferably at least 90% and, most preferably, 95% or more.

The compositions are also stable for the loss of the child nucleides generated from the decay (eg, alpha decay) of the charged radionuclides or one of these degradation products. A composition can be considered stable in this respect if, after incubation for a suitable period, the activity attributable to the child radionuclide generated during this period is distributed so that at least 70% remains associated with HA particulates. This proportion is preferably at least 75%, more preferably at least 80% and, most preferably, at least 90%.

The labeling of the hydroxyapatite with a radionuclide can be carried out, for example, through the following process steps:

(A) absorbing a solution of the alpha emission radionuclide or the in vivo generator of the alpha emission radionuclide to the hydroxyapatite particulates, preferably at pH in the range of about 3-12, more preferably at pH 5 to 10, and

(b) optionally crystallizing a hydroxyapatite coating on the labeled particulates prepared in step (a) to encapsulate said radionuclide in the HA particulate.

The method also preferably comprises the step of:

(c) heating the HA particles of step (a) or step (b) to a temperature of 70 to 150 ° C, preferably 55 to 80 to 130 ° C, more preferably 100 to 120 ° C.

HA particulates labeled according to (a) or (b) may be added to a biocompatible or physiologically acceptable liquid vehicle (preferably an aqueous vehicle) to prepare an injectable or perfusible suspension or dispersion, together with any necessary or desirable excipient and / or additive . Additives include adjuvants suitable for preparing and stabilizing a physiologically acceptable preparation for use in the treatment of cancer and in radiosynovectomy. Typically, these additional components, when present, will be added before the optional step (c).

Pharmaceutically tolerable carriers and excipients are well known to one skilled in the art and can

65 include, for example, salts, sugars and other agents for adjusting tonicity, buffers, acid, bases and other agents for adjusting pH, viscosity modifiers, dyes, etc.

Alternatively, HA particulates labeled according to (a), followed by optional steps (b) and / or (c), may be included in a gel-shaped pharmaceutical composition, together with any necessary excipient and / or additive

or desirable Suitable additives will be well known to persons skilled in the art and may include

5 indicated above and well-known gelling agents, such as natural and / or synthetic polymer gels. Gel compositions preferably have sustained release properties.

All other suitable pharmaceutical formulations that can be prepared starting from HA particles labeled with an alpha emission radionuclide or an in vivo generator for an alpha emission radionuclide, including liquids for injection or infusion, gels, creams, pastes, drops, patches, wipes, nebulizers, impregnated membranes and sheets, etc., form additional embodiments of the invention.

The most preferred pharmaceutical preparations of the compositions according to the invention are generally physiologically acceptable liquid, injectable or perfusible suspensions or dispersions. To prepare these

In pharmaceutical compositions, the compositions of the invention are added to the physiologically acceptable liquid carriers. Especially preferred isotonic saline or phosphate buffers, but any other liquid vehicle or mixture of vehicles that are physiologically acceptable and compatible with the compound of the invention can be used. Many of these liquid vehicles or vehicle systems are known to those skilled in the art of pharmaceutical preparations prepared for injection and / or infusion in vivo.

The compositions of the present invention offer an additional advantage in that these and / or pharmaceutical preparations made therewith can be heat treated, for example, for the purpose of sterilization. The compositions of the invention will typically be stable to heat treatment above 70 ° C, preferably at approximately 80 ° C and, more preferably, at least 100 ° C. This is especially

Significant for larger particulates that cannot be easily sterilized by filtration.

To avoid the aggregation of HA particles when they are in suspension, suitable modifiers or adjuvants that are well known in the art, as dispersing agents, can be added to the liquid pharmaceutical preparation according to the invention. Examples of such modifiers may be carbohydrates or

30 proteins

The effective administration to be administered to a subject in need of treatment will depend on various factors such as half-life and the decay chain of the radionuclide included in the composition according to the invention; the route of administration; the clinical status of the subject and his age or weight, as well as the disease to be treated. This effective dose can be achieved by administering a pharmaceutical composition according to the invention as a single administration once; or by at least one administration per day (typically one, two

or three times a day) during a treatment period of at least a single day or at least one day a week for one or more weeks or months. The treatment can be repeated at least once if the expert considers it necessary or appropriate.

If a radionuclide having a short half-life is used, it is generally administered at a higher activity dose for a single administration compared to a radionuclide that has a longer half-life.

Typical administrations will generally be within the range of 10 kiloBq to 10 gigaBq per single administration, with a more preferred range that is between 1 megaBq and 1 gigaBq per single administration.

The compositions according to the present invention are useful in pharmaceutical compositions, especially preparations or devices in a liquid or gelled state and for the treatment of cancer or non-neoplastic diseases.

As indicated above, the present invention provides, in various aspects, a composition for use in a method for the treatment of cancer and the use of a composition for the manufacture of a medicament for use in this method of treatment. Diseases especially applicable to these aspects of the invention include metastatic and non-metastatic neoplastic diseases, such as small and non-small cell cancer.

55 microcytic lung, malignant melanoma, ovarian cancer, breast cancer, bone cancer, colon cancer, bladder cancer, cervical cancer, sarcomas, lymphomas, leukemia or prostate tumors.

Thus, one embodiment of these aspects refers to compositions for use in a method for the treatment of a tumor locally. This treatment can preferably be applied by intratumoral injection or infusion to a subject (generally a human subject) in need of such treatment, or a therapeutically effective amount of a composition according to the invention. Such a method provides a local irradiation of the tumor tissue. Alpha emission radionuclides are very effective in this embodiment because their range is short and damage to healthy surrounding tissue is minimized. Examples of diseases that can especially benefit from this embodiment of the invention are those that cause solid tumors, such as non-small cell cancer.

65 lung, malignant melanoma, ovarian cancer, colon cancer, sarcomas and prostate tumors.

A further embodiment of the invention relates to compositions for use in methods for the treatment of locally disseminated cancers, such as, for example, liver tumors or peritoneal or intracranially confined diseases. This treatment can be applied especially preferably by means of locoregional injections or infusions to a subject in need of such treatment, or an amount

5 therapeutically effective of a composition according to the invention.

Still another embodiment of the invention is a composition for use in a method for the treatment of locally disseminated cancers such as liver tumors, by administering a therapeutically effective amount of a liquid preparation comprising a radioactively labeled HA according to the invention to a subject that It requires such treatment, especially to the blood supply of said subject, of the affected area or organ, for example, to the blood supply of the liver in the case of a liver tumor. This can promote the transport of the composition within the tumor.

A further embodiment of the invention relates to a composition for use in a method for the treatment of

Systemically disseminated cancer by intravenous injection or infusion, or other systemic administration, to a subject in need of such treatment, or a therapeutically effective amount of a pharmaceutical preparation comprising a radioactively labeled HA according to the invention.

A further embodiment of the invention relates to a composition for use in a method for the treatment of intracavitary tumors, where a therapeutically effective amount of a radionuclide in the form of a composition of the present invention is administered to a subject in need of such treatment by Injection or infusion into the cavity affected by the tumor and is maintained there to obtain irradiation of the cavity surfaces. These cavities include the cranial cavity, the peritoneal cavity and the cavities created by pericardial effusion and mesothelioma, and the administration is suitable for cancers such as intracranial cancers,

25 intraperitoneal cancers or cancers located in the cavities created by pericardial effusion and mesothelioma.

A further embodiment of the invention relates to a composition for use in a method of polytherapy, comprising administration to a subject in need of said treatment of a therapeutically effective amount of radioactively labeled active HA according to the present invention and one or more treatments. additional ones chosen from the group consisting of: surgery, chemotherapy and radiotherapy (especially external beam radiotherapy).

Polytherapy is an especially preferred embodiment of the present invention and can be executed simultaneously, sequentially or alternatively, or any combination thereof. Therefore, a polytherapy can comprise one type of treatment followed by one or more different types of treatment, where each type of

Treatment can be repeated one or more times. An example of simultaneous polytherapy is chemotherapy combined with the administration of a composition according to the present invention at the same point at the same time (by the same method of administration or by a different method). This polytherapy can be combined with sequential therapy starting a simultaneous treatment, for example, after the tumor has been surgically removed. Polytherapy can be repeated one or more times if necessary based on the condition of the subject.

An example of alternative polytherapy could be chemotherapy in one or more alternative periods on different days or weeks with the administration of the pharmaceutical composition of the invention or, for example, surgery after one or more periods of treatment with the radioactively labeled HA according to the invention.

A highly preferred embodiment of the invention relates to a composition for use in a method for treatment by applying a composition or device according to the invention in a therapeutically effective amount during surgery, after a procedure has been performed for remove the cancerous material in a subject. The composition of the present invention can be applied to the tumor bed or surrounding tissue. This application can be run to achieve a sterilizing effect on the location of the surrounding tumor bed and, if relevant, the cavity. This can be especially useful in the event that a tumor rupture occurs (for example, during the surgical procedure). This treatment can also or alternatively achieve an antitumor effect in any remaining tumor cell at this location and / or its proximity. This embodiment could be achieved using a suspension of the active compound (for example, formulated as a nebulizer or wipe). Alternatively, when referring to this method of treatment, you can

It is preferred that the composition of the invention be in the form of a paste, patch, impregnated sheets (especially an absorbable part or sheet), cream or gel and, especially, a formulation (eg, gel) that provides a sustained release of the radioactive agent therapeutic.

In yet another embodiment of the present invention it relates to a composition for use in a method for synovectomy, that is, to treat a subject suffering from joint and / or bone pain, such as pain due to arthritis. .

As used herein, the term "subject" generally indicates a human subject but may also indicate a non-human mammalian subject, especially a canine or feline mammalian subject.

In the following section the invention is explained with examples to show how hydroxyapatite particulates can be labeled with an alpha emission radionuclide and a beta emission radionuclide, respectively. The examples are not considered limiting for the invention. The invention is also illustrated by the attached figure in which:

5 Figure 1 shows the retention of 212Bi in various tissues after 1 and 24 hours after administration of 212Pb. The level of equilibrium is also shown and it is shown that 212Bi levels are close to equilibrium.

General materials and methods

The hydroxyapatite particles used were hydroxyapatite, type 1 buffered aqueous suspension (Sigma, St. Louis, MO, USA) or Macro-Prep ceramic hydroxyapatite type 1, 20 μm (Bio Rad Laboratories, Hercules, CA, USA). .UU.).

Counters and detectors: gamma spectroscopy was performed with a GEM25-P germanium detector from EG&G

15 Ortec. The general radioactivity count was performed with a multi-well NaI detector (Packard Crystal II, Packard Instrument Co., Downers Grove, IL, USA).

Particulate labeling and purification: The reaction mixture was mixed thoroughly in a vortex shaker (MS1 Minishaker, IKA, Germany) for 1 min and then incubated on a shaker for 30 minutes before centrifuging three times (5 minutes, 9,000 rpm, MiniSpin centrifuge, Eppendorf, Germany) and wash the sediment twice with 1 ml of 0.1 M citrate solution.

Example 1

25 Preparation of particulates marked with radius 223.

The radius 223 was prepared from a source of 227Ac / 227Th immobilized on a DIPEX-2 column eluting the 223Ra with 1 M HCl. 0.1 M Na citrate was added to the eluate of HCl until the pH was above of 5. 250 μl of 40 mg / ml hydroxyapatite dispersion and 50 μl of the 223Ra / citrate solution in a 2 ml Eppendorf tube were added, and labeling and purification were performed as described in the materials section and methods The activity linked to the sediment was in an excess of 96% in the three triplicate experiments carried out in parallel.

Example 2

In vitro resting stability of HA particles labeled with 223Ra.

To the 223Ra-HA particulates described in example 1, 500 µl of 0.1 M sodium citrate or bovine serum albumin was added. The dispersion was incubated overnight at 37 ° C and the solutions were centrifuged according to example 1. The sediment bound activity was in excess of 96% measured after 20 minutes. A new measure taken two hours later did not show significant differences in counting rates, indicating that the distribution of the child nuclides was consistent with that of 223Ra.

In a further experiment, using ceramic HA particulates, 223RA (1 mBq) incorporated into 10 mg of

Ceramic HA was incubated in fetal calf serum for two weeks at room temperature, after which 93.2% was bound to the sediment.

Example 3

Preparation of HA particulates labeled with 212Pb and 212Bi.

Lead 212 substantially free of 228Th and 234Ra was prepared.

With 228Th evaporated to dryness as the starting material, 0.5 ml of 8M HNO3 was added and the solution was added.

55 transferred to a column containing a previously balanced anion exchanger (AG1-X8). The radius 224 and its children were extracted in 3ml of 8M HNO3. Subsequently, the 224Ra extract was evaporated to dryness, dissolved in 0.5 ml of 1M HCl and purified on a DIPEX column (AC resin, Eichrom Inc. Darien, IL, USA), eluting the 224Ra in 700 microliths of 1M HCl to obtain a product without thorium 228.

The next day (after the internal formation of 212Pb) the eluted 224Ra was evaporated to dryness and then dissolved in 0.5 ml of 1M HNO3 and transferred to a column containing a specific Pb resin (PB- B25-S, Eichrom). Radio-224 was eluted with 2 ml of 1 M HNO3 and 2 ml of distilled H2O. Lead 212 was extracted from the Pb resin using 650 microliters of a 0.1 M solution of ammonium oxalate.

The final 212Pb solution was directly combinable with the hydroxyapatite and reacted as described for 223Ra in Example 1.

Example 4

Stability test of HA particulates marked with 212Pb and 212Bi.

5 Lead-labeled HA 212 was incubated in fetal calf serum overnight and then centrifuged as described above. The radioactivity of the sediment and the supernatant was measured. It was found that it was in excess of 93% of both 212Pub and 212Bi associated with sediment. The fraction of unit activity to the sediment appeared to be slightly higher with the ceramic particles.

Example 5

Biodistribution of the HA marked with 212Pb.

A 212Pb-labeled HA (20 μm, ceramic) was prepared as described above, washed and centrifuged three times and dissolved in 0.01 M sodium citrate / citric acid in isotonic saline solution at pH 7.4. 7 female balb C mice weighing 21-25 g were administered intraperitoneally 0.5 ml of suspension containing 0.4 MBq of 212Pb bound to 1.0 mg of HA. Animals were sacrificed at 1 h (n = 3) and at 24 h (n = 4) and dissected. Results: the biodistribution data (Table 1) shows that the activity was almost mostly

20 quantitatively in the cavity i.p. and in the organs and tissues within this cavity, which indicated a very small escape outside the cavity. The distribution pattern associated with free 212Bi, that is, a high accumulation in the kidney, was not detected at a significant level.

Table 1. Distribution in tissues at 1 hour and 24 hours after intraperitoneal injection of the particulates of ceramic hydroxyapatite labeled with 212Pb.

Tissue

1 hour 24 hours

Blood

(0.46 ± 0.40) / 0.39  0.34  (0.32 ± 0.19) / 0.30  0.24

Liver

(3.04 ± 2.83) / 3.09  2.93  (2.10 ± 1.56) / 2.06  1.45

Spleen

 (3.03 ± 1.11) / 3.25  1.21  (5.47 ± 5.21) / 5.58  5.27

Kidney

(4.05 ± 3.08) / 3.32  2.84  (4.21 ± 3.29) / 4.12  3.39

Small intestine

(0.78 ± 0.86) / 0.72 0.80  (0.62 ± 0.25) / 0.60  0.26

Large intestine

(0.45 ± 0.41) / 0.43  0.38  (0.52 ± 0.39) / 0.52  0.40

Stomach

(3.20 ± 2.09) / 3.29  2.18  (5.11 ± 2.79) / 5.10  2.79

Diaphragm

(6.23 ± 2.39) / 6.25  2.33  (4.84 ± 1.95) / 4.49  2.47

Heart

(0.10 ± 0.11) / 0.12  0.13  (0.06 ± 0.06) / 0.04  0.03

Lung

 (0.36 ± 0.29) / 0.33  0.27  (0.18 ± 0.12) / 0.13  0.09

Muscle

(1.18 ± 1.89) / 1.32  2.14  (0.35 ± 0.58) / 0.37  0.67

Bone

(0.44 ± 0.46) / 0.44  0.47  (0.44 ± 0.20) / 4.49  2.47

Numbers in brackets: tissues measured approximately 1 hour after sacrificing the animals. Bold numbers: tissues measured one day after sacrificing the animals, that is, time is allowed for the child nuclides to be in equilibrium with the 212Pb precursor nucleid. If the number in parentheses is less than the corresponding bold number, this indicates a removal of the 212Bi child nucleus with respect to 212Pb in the

30 tissue at the time of death (the opposite could mean an enrichment of 212Bi with respect to 212Pb at the time of death).

Claims (10)

1 Use of hydroxyapatite (HA) and an alpha emission radionuclide chosen from the group of 211At, 212Bi, 223Ra, 224Ra, 225Ac, 227Th or a beta emission radionuclide chosen from the group of 212Pb, 211Pb, 213Bi or 225Ra in manufacturing 5 of a medication for use in the treatment of a cancerous disease. 2. Use according to claim 1, wherein said medicament is an injectable, perfusible or locally applicable medicine.

Use according to claim 2, wherein said treatment comprises intratumoral therapy.

4. Use according to claim 2, wherein said treatment comprises administration within the blood supply of a cancerous organ.

15 5. Hydroxyapatite incorporating an alpha emission radionuclide chosen from the group of 211At, 212Bi, 223Ra, 224Ra, 225Ac, 227Th or a beta emission radionuclide chosen from the group of 212Pb, 211Pb, 213Bi or 225Ra for use in therapy antineoplastic

6. Hydroxyapatite for use according to claim 5, wherein the cation is selected from the group consisting of calcium, strontium, barium, bismuth, yttrium, lanthanum, lead or mixture thereof. 7. Hydroxyapatite for use according to claim 5 or 6, wherein the HA is particulate and has a size in the range of 1 nm to 100 µm. 8. Hydroxyapatite for use according to claim 7, wherein the HA has a size in the range of 1 μm to 20 μm. 9. Hydroxyapatite for use according to any one of claims 5 to 8, wherein the HA is combined or sedimented together with a substance selected from polylactide, polyethylenedones, glass-ceramic, oxide 30 of titanium, alumina, zirconia, silica, polyethylene, polyethylene glycol, polyhydroxybutyrate, gelatin, collagen, chitosan, phosphazene or mixtures thereof. 10. A pharmaceutical composition comprising a hydroxyapatite as defined in any one of the claims 5 to 9 and a pharmaceutically acceptable carrier for use in antineoplastic therapy. 35 11. Hydroxyapatite or a composition for use according to any of claims 5 to 10 for the treatment of an intracavitary primary or metastatic tumor. 12. Hydroxyapatite or a composition for use according to any of claims 5 to 10 for use in intratumoral therapy. 13. Hydroxyapatite or a composition for use according to any of claims 5 to 10 for use in the antineoplastic treatment and / or sterilization of the tumor bed and, optionally, the cavity in the case of an intracavitary tumor, wherein said administration is performed after surgical removal of at least part of a 45 tumor