PHARMACEUTICAL COMPOSITIONS COMPRISING BORTEZOMIB

Bortezomib, chemically 3-methyl-l(R)-[N-(pyrazin-2-ylcarbonyl)-L-phenylalanyl- amino]-butylboronic acid of formula (1),

is a pharmaceutically active compound used in treatment of various tumors.

Bortezomib is a selective proteasome inhibitor. Inhibition of proteasome by bortezomib affects cancer cells in a number of ways, resulting in cell cycle arrest and apoptosis.

Structurally, bortezomib is a boronated dipeptidic compound comprising L-leucine and L-phenylalanine moieties. Therefore, it comprises two chiral carbons and the molecule has rigid spatial orientation thus being a single diastereomer. It may form acid addition salts.

In solid state, bortezomib is present in trimeric boroxine (cyclic anhydride) form. Various crystalline polymorphs of the trimeric bortezomib have been described in the literature.

The solubility of bortezomib, as the monomeric boronic acid, in water is 3.3 to 3.8 mg/mL in a pH range of 2 to 6.5.

The bortezomib pharmaceutical composition is currently on the market, under trade name Velcade®. It is a single dose vial comprising a sterile lyophilized mixture of 3.5 mg bortezomib with 35 mg of mannitol. In this formulation mannitol reacts with bortezomib during the lyophilization process forming certain amount of mannitol boronic ester of formula (2),

Such ester hydrolyses releasing bortezomib after the reconstitution of the lyophilizate with the injection fluid but such hydrolysis is not complete and proceeds to an equilibrium. Thus, the formulation of the drug product containing bortezomib is chemically complex.

Bortezomib has been first disclosed in WO 96/13266. The mannitol esters of bortezomib have been disclosed in WO 2002/059130, the trimeric form of bortezomib has been disclosed in WO 2002/059131.

Mannitol excipient serves as a bulking agent for lyophilization and also it stabilizes the inherently unstable bortezomib.

As a possible replacement of excipients derived from sugars, e.g. mannitol, WO 2009/154737 describes an alternative formulation comprising the use of certain hydroxy- acids as ester-forming excipients with stabilizing effects. The preferred excipient of this kind was citric acid. However, citric acid has relatively poor lyophilization properties.

Accordingly, a co-excipient has to be present in the composition, serving as a bulking agent. A suitable excipient of this kind is glycine. This formulation also requires a buffer because the inherent pH of the composition comprising only bortezomib and the hydroxy-acid is too acidic for intravenous administration.

While lyophilized compositions comprising bortezomib are known in the art, an improved composition is still desirable. BRIEF DESCRIPTION OF THE PRESENT INVENTION

The present invention relates to a new pharmaceutical composition for parenteral administration of bortezomib.

In a first aspect, the invention relates to a lyophilized pharmaceutical composition comprising bortezomib in an admixture with sodium gluconate. Preferably, the ratio between the bortezomib and sodium gluconate ranges from 1 : 2 to 1 : 20 (w/w), more preferably from 1 : 5 to 1 : 15 (w/w), most preferably about 1: 10 ( w/w). In an advantageous embodiment, the composition comprises sodium gluconate as the only bulking agent. In another advantageous embodiment, the composition is formulated into a single dose composition, which preferably comprises from 1 - 5 mg of bortezomib, advantageously about 1 mg or about 3.5 mg of bortezomib.

In a second aspect, the invention relates to a process of making the composition as defined above, comprising dissolving bortezomib and sodium gluconate in a water- comprising solvent, with optional adjustment of pH, and freeze drying the solution. In an advantageous embodiment, the water -comprising solvent is a mixture of water with tert- butanol. In yet an advantageous embodiment, the concentration of bortezomib in the solution is about 1 mg/ml.

In a third aspect, the invention relates to a liquid pharmaceutical composition comprising a solution of a composition comprising bortezomib and sodium gluconate in a diluent suitable for parenteral administration. In a preferred embodiment, the diluent is a 0.9% NaCl solution or an isotonic glucose solution. In a particular aspect, the concentration of bortezomib in the solution is between about 0.5 mg/ml to 3 mg/ml and the ratio between the bortezomib and sodium gluconate is from 1 : 2 to 1 : 20 (w/w), more preferably from 1 : 5 to 1 : 15 (w/w), most preferably about 1 : 10 ( w/w). In a fourth aspect, the invention relates to the use of sodium gluconate for making pharmaceutical compositions comprising bortezomib.

In a fifth aspect, the invention relates to pharmaceutical compositions as described above for use as a medicament.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a pharmaceutical composition for parenteral administration of bortezomib, particularly to a solid lyophilized composition for

reconstitution with diluents suitable for parenteral administration, e.g. with isotonic saline or carbohydrate solutions, and to the so reconstituted liquid composition. The composition of the present invention has good physical properties, its pH value is within physiological pH range, and is easily reconstitutable with infusion fluids. Accordingly, it represents a suitable alternative to the mannitol-comprising bortezomib composition of the prior art marketed under the trade name Velcade, particularly in cases when mannitol is not desirable for parenteral administration.

Bortezomib of formula (1) above is a known compound, which is commercially available or may be produced by procedures known in the art. The expression "bortezomib", as used for purpose of the present invention, comprises also the trimeric form of bortezomib, including any hydrated or solvated form thereof.

The content of bortezomib in the compositions of the present invention is expressed throughout the disclosure and claims as the content of the monomer of formula (1), regardless the form, in which bortezomib is actually present in the composition ( i.e. regardless the active substance is present, fully or partially, in the trimeric anhydrate form and/or as an ester). The present invention is based on finding that stable solid injectable bortezomib compositions can be made by combining bortezomib with sodium gluconate. Sodium gluconate (Sodium (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanoate) of formula (3),

OH OH (3),

is a known and pharmaceutically acceptable compound, very soluble in water and pH neutral. Despite of its advantageous properties, it is seldom used in pharmaceutical applications.

Sodium gluconate is commercially available or may be produced by methods well known in the art. It may be easily obtained in pharmaceutical grade of purity, including pyrogen-free grade. Such purity grade is preferred for purpose of use in compositions of the present invention.

Thus, in a first aspect, the invention relates to a solid pharmaceutical composition comprising bortezomib in an admixture with sodium gluconate. The composition may be advantageously formulated into dosage forms for parenteral administration. It is

advantageous that the composition is in an amorphous form. The pharmaceutical composition is preferably formulated as a lyophilized powder comprising a mixture of bortezomib and sodium gluconate.

Sodium gluconate primarily serves as a bulking agent. In a preferred embodiment, the ratio between the bortezomib and sodium gluconate is from 1 : 2 to 1 : 20 (w/w), more preferably from 1 : 5 to 1 : 15 (w/w), most preferably about 1 : 10 (w/w).

It was found that sodium gluconate has very good lyophilization properties, so that it needs not to be accompanied with any auxiliary bulking agent. It can form homogeneous and sufficiently porous lyophilization cake, which results in desirably short reconstitution time during final administration. The lyophilised admixture of bortezomib and sodium gluconate is also relatively stable during storage. Thus, in an advantageous aspect, the composition of the present invention comprises sodium gluconate as the only bulking agent. Specifically, the composition of the present invention does not comprise any other stabilizing agent, specifically mannitol.

Contrary to certain suggestions in the prior art, the composition of the present invention does not comprise any acid excipient. Inherently, the sodium gluconate, which is a weak base, buffers the otherwise acidic bortezomib solution to a value of between 6.5 to 7.0, dependent on the concentration and the relative amount of the gluconate. At this pH, the composition is also the most stable, as proven in stability studies. Thus, the presence of an extra buffering agent or a pH adjustor is essentially not necessary. However, in case of need or desire, the pH of the composition may be further adjusted by a suitable pH adjustor, e.g. by a pharmaceutically acceptable base, in particular by sodium hydroxide. Advantageously, the final pH of the composition is between 6.0 and 8.0.

If desirable, the composition of the present invention may comprise also one or more auxiliary excipient(s). The pharmaceutically acceptable auxiliary excipients for purpose of the present invention are preferably water soluble and may include, e.g., one or more of antibacterial preservatives, including one or more of thiomersal, benzalkonium chloride, benzethonium chloride or tonicity contributors including one or more of sodium chloride, potassium chloride, dextrose, and lactose.

The solid product may comprise residual water and/or organic solvent. Typically, the product comprises less than 10% of these volatile components.

In a specific embodiment, the composition of the present invention is formulated as a single dose composition. The single dose of the pharmaceutical composition according to the present invention typically comprises from 1 to 5 mg of bortezomib, advantageously about 1 mg or 3.5 mg of bortezomib, calculated as the monomeric form. Thus, in a specific aspect, the invention also includes a vial or similar container comprising a single dose amount of the composition of the invention. Any suitable sterile vial or container fit for the sterile storage of a pharmaceutical such as bortezomib for extended periods of time may be used. Suitable containers can be glass vials, polypropylene or polyethylene vials, CZ-resin vials or other special purpose containers.

A further aspect of the invention includes a kit and / or pharmaceutical container for holding the bortezomib-containing compositions described herein. The kit contains at least one pharmaceutically acceptable vial or container containing one or more doses of the bortezomib-containing formulations/compositions as well as other pharmaceutically necessary materials for storing and/or administering the drug, including instructions for storage and use, injection syringe, or container with an infusion diluent etc.

The solid pharmaceutical composition of bortezomib according to the present invention can be made by a process comprising a step of mixing bortezomib and sodium gluconate in a solvent comprising water, followed by a step of removal of the solvent. Said solvent may be water per se or it may comprise a mixture of water with a pharmaceutically acceptable cosolvent, particularly with a cosolvent, which is susceptible to lyophilization. Such cosolvents are known in the art, an example of a suitable one is iert-butanol. In an

embodiment, a mixture of water and iert-butanol in a volume ratio from 10 : 1 to 10 : 5, preferably from 10 : 2 to 10 : 4, is used. Water must be of pharmaceutically acceptable quality. Typically, water for injections, as defined in acknowledged Pharmacopoeias, is used.

The final concentration of bortezomib in the solution is not particularly limited and is rather directed by technological aspects, which comprise the need of final removal of the solvent. Thus, in practice, a suitable but not limiting concentration of bortezomib in the solution is about 1 mg/ml. The process typically comprises weighing the respective ingredients (bortezomib and sodium gluconate) and dissolving them in the solvent system, preferably under stirring.

Advantageously, the solvent system is first deoxygenated by a suitable technique, e.g. by saturating it by an inert gas, by deaerating with ultrasound etc.

The dissolution process is preferably conducted in the atmosphere of an inert gas such as nitrogen or argon.

The dissolution is typically carried out at a temperature not exceeding 45°C, preferably at room temperature.

In practice, it is advantageous to prepare a solution of sodium gluconate in the solvent and to add bortezomib into such solution.

Further, auxiliary excipient(s) may be optionally added to said solution. The non exhaustive list of such excipients was given above. The excipients must be sufficiently soluble in the solvent system.

In the final stage, pH of the solution is optionally adjusted to the desired value, which is typically from 6.0 to 8.0. The pH adjustor may be any suitable pharmaceutically acceptable acid, base, salt or a combination thereof.

In certain embodiments, the obtained solution is filtered and sterilized and filled into vials comprising the desired amount of bortezomib per vial.

In the next step, the solvent is removed from the composition. Typically, it is removed by lyophilization (freeze-drying) under suitable conditions. Freeze drying can be conducted at temperatures from about -10 to about -50°C, under vacuum in the range of about 0.5 to about 50 Pa.

In an advantageous embodiment, the subject of the lyophilization process is the content of vials prepared as shown above. As a result, the lyophilization process yields a solid pharmaceutical composition comprising a unit dose of bortezomib, which typically comprises from 1 - 5 mg of bortezomib, advantageously 1 or 3.5 mg of bortezomib.

In the last step of the overall process, the vials are closed by a suitable stopper, labelled and packed into suitable container.

It is anticipated that the contact of bortezomib with sodium gluconate in the above process results, at least in certain degree, in the formation of an ester of bortezomib with gluconic acid or a sodium salt thereof. As known in the art and briefly stated above, esters of bortezomib easily undergo to a hydrolysis after reconstitution with water and before the administration to a patient. Thus, the degree of formation of the ester of bortezomib with gluconic acid as a result of subjecting a solution of bortezomib and sodium gluconate to freeze drying is not decisive and the invention is not specifically limited thereto.

Accordingly, the phrase "bortezomib in an admixture with sodium gluconate" as used throughout the disclosure and claims, also comprises an ester of bortezomib with gluconic acid or a sodium salt thereof, of any actual structure.

As any ester of bortezomib and gluconic acid or a sodium salt thereof is an

advantageous and useful compound, it represents a specific subject the present invention.

The lyophilized composition of the present invention is primarily used for a parenteral application to a patient in need thereof. Parenteral application preferably comprises intravenous injection or infusion, subcutaneous injection, intramuscular injection etc..

For the injection administration, the lyophilized composition disclosed above is reconstituted by dilution with a diluent suitable for parenteral administration, resulting in a liquid pharmaceutical composition comprising a solution of bortezomib and sodium gluconate. Thus the present invention also comprises a liquid pharmaceutical composition comprising a solution of a composition comprising bortezomib and sodium gluconate in a diluent suitable for parenteral administration, preferably such composition which is prepared by dissolving the lyophilized composition disclosed above in such diluent.

In an embodiment, the liquid composition of the present invention has the concentration of bortezomib of between about 0.5 mg/ml to 3 mg/ml, preferably about 1 mg/ml (e.g., for use in intravenous application) or 2.5 mg/ml (e.g., for use in subcutaneous application). The diluent is typically 0.9% sodium chloride solution, or, in an alternative, it may be isotonic glucose solution.

The liquid composition of the present invention is typically administered to a patient in need thereof either as a bolus intravenous injection or a bolus subcutaneous injection.

Recommended dose is max. 1.3 mg/m (body surface area). The solution should be administered within several hours after preparation, e.g. within 8 hours or less, and should be stored in original vial at a temperature not exceeding 25°C.

For the infusion administration, the above reconstituted solution may be further diluted by an infusion liquid, e.g. with 0.9% saline, a dextrose solution, Ringer's lactate solution etc..

The compositions of the present invention may be used in medicine, particularly for treating a bortezomib sensitive disease in mammals. Thus, in yet another aspect of the invention, there are provided methods of treating a bortezomib sensitive disease in mammals. Bortezomib sensitive diseases include, but are not limited to, cancers, e.g. multiple myeloma or mantle cell lymphoma. The use or methods include administering an effective amount of the bortezomib-containing composition as described herein to a mammal in need thereof.

The following non-limiting examples illustrate the invention. EXAMPLES

Example 1: Composition with bortezomib - sodium gluconate ratio 1 : 10 ( WAV)

Composition of the final form

Composition of the bulk solution

Procedure of preparation

46.8 g of iert-butanol was mixed with 60 ml of water. Solution was heated to 40°C. 1.5 g of sodium gluconate was added and dissolved during 5 minutes. 143.0 mg of Bortezomib was added and dissolved during 20 minutes. Formed solution was cooled to room

temperature. The pH of solution was 6.86 and was adjusted with 0.1M NaOH to 7.5. Solution was transferred into volumetric flask and filled with water up to 150 ml. Prepared solution was filtered (Durapore ^® membrane 0.22 microns), filled in tubular glass vials 10R (3.5 ml per vial) and lyophilized. After lyophilization, the final product was reconstituted with 0.9 % NaCl and colour, clarity and pH of solution were tested. Then GC (Head space) and HLPC analysis of the lyo- cake were performed.

Similarly, compositions with the Bortezomib - sodium gluconate ratio 1 : 20 and 1 : 50 were prepared.

Example 2: Composition with bortezomib - sodium gluconate ratio 1 : 20 ( WAV)

Composition of the final form

Composition of the bulk solution

Procedure of preparation

23.4 g of iert-butanol was mixed with 90 ml of water. Solution was heated to 40°C. 3.0 g of sodium gluconate was added and dissolved during 5 minutes. 143.0 mg of Bortezomib was added and dissolved during 20 minutes. Formed solution was cooled to room

temperature. The pH of solution was 6.41 and was adjusted with 0.1M NaOH to 7.5.

Solution was transferred into volumetric flask and filled with water up to 150 ml. Prepared solutions were filtered (Durapore ^® membrane 0.22 microns), filled in tubular glass vials 10R (3.5 ml per vial) and lyophilized.

After lyophilization final product was reconstituted with 0.9 % NaCl and color, clarity and pH of solution were tested. Then GC (Head space) and HLPC analysis of lyo-cake were performed.