Link:  Pharm/Biotech Resources

Title:  Storage stable powder compositions of interleukin-4 receptor

United States Patent:  6,896,906

Issued:  May 24, 2005

Inventors:  Hastedt; Jayne E. (San Carlos, CA); Cabot; Kirsten M. (San Francisco, CA); Gong; David K. (Foster City, CA); Hester; Dennis M. (Richmond, CA)

Assignee:  Nektar Therapeutics (San Carlos, CA)

Appl. No.:  032238

Filed:  December 21, 2001

The present invention provides storage stable dry powder compositions of IL-4R. The powder compositions demonstrate superior chemical and physical stability over their solution counterparts, particularly upon storage under varying conditions of temperature and humidity. Moreover, the powders, as prepared, possess good aerosol properties, which are maintained upon storage.

FIELD OF THE INVENTION

The present invention generally relates to spray dried, inhaleable powder compositions of interleukin-4 receptor (IL-4R) and to methods for making and pulmonarily administering such compositions. The powders of the invention are particularly stable with respect to monomer content and aggregate level upon both preparation and storage, and additionally possess superior aerosol properties, even in the absence of stabilizing carriers or excipients. The powders of the invention, when administered to the deep lung, are useful for treating allergic diseases, such as asthma, atopy, and atopic dermatitis.

BACKGROUND OF THE INVENTION

Interleukin 4 (IL-4, also known as B cell stimulating factor, or BSF-1) is a cytokine produced by T helper cells, mast cells, and basophils. IL-4 has been shown to possess a broad spectrum of biological activities, including growth co-stimulation of T cells, mast cells, granulocytes, megakaryocytes, and erythrocytes. In addition, IL-4 stimulates the proliferation of several IL-2 and IL-3 dependent cell lines, induces the expression of class II major histocompatibility complex molecules on resting B cells, influences the production of IgE and enhances the secretion of IgE and IgG₁ isotypes by lipopolysaccharide-stimulated B cells. IL-4 has been identified to play a critical role in the development of allergic diseases, and is most commonly associated with asthma and allergies; or diseases characterized by difficulty breathing.

IL-4 binds to IL-4 receptor (IL-4R), an endogenous membrane-bound protein on the surface of certain cells. Upon such binding, IL-4R transduces a biological signal to various immune effector cells, thereby triggering a cascade of events that lead to clinical symptoms (Renz H et al., 1991, J Immunol, 146(9):3049-55). Nucleotide and protein sequence determination for IL-4R has been carried out. Mature human IL-4R has three domain structures: an extracellular domain (about 207 amino acids), a membrane passage region (about 24 amino acids), and an intracytoplasmic domain (about 569 amino acids) (European Patent No. EP 585-681 (1994)). Soluble IL-4R (sIL-4R) has also been isolated, cloned and extensively investigated (European Patent No. EP 367-566(1997); Mosley et al., 1989, Cell, 59-335, 1989; U.S. Pat. No. 5,767,065 and Garrone P et al., 1991, Eur J Immunol, 21(6):1365-9). IL-4 preferentially binds to sIL-4R in solution rather than to the endogenous cell-surface IL-4R, thereby preventing cellular activation and blocking the biological response, e.g., the cascade of effects associated with IL-4 and its binding to the endogenous receptor (Renz H et al., 1991, supra. and Renz, H, 1999, Inflamm Res., 48(8): 425-31).

IL4-R has been described as an immunosuppressant and an anti-inflammatory agent, and administration of IL-4R may be beneficial in the treatment of conditions such as allergy, rhinitis, atopic dermatitis, rheumatoid arthritis, graft rejection, chronic graft-versus-host disease (GvH) and systemic lupus erthematosus (SLE) (See, e.g., U.S. Pat. No. 5,856,296; Renz H et al., 1992, J Invest Dermatol, 99(4):403-8; Hackstein H et al., 1999, Tissue Antigens, 54(5):471-7; Rivas D et al., 1995, J. Autoimmun, 8(4):587-600and Schorlemmer H U et al., 1995, Inflamm Res, 44 Suppl 2:S194-6).

Like many biopeptides, IL-4R tends toward instability. It tends to degrade and/or aggregate under extreme conditions (e.g., highly acidic or basic pH, high temperatures) and is susceptible to oxidizing agents and endogenous proteases. The inherent chemical and physical instability of IL-4R makes pharmaceutical formulation particularly problematic. To maintain the stability and bioactivity of the protein, current IL-4R formulations are primarily solution-based, and stored prior to administration as lyophilizates (e.g., U.S. Pat. Nos. 5,856,296; 5,767,065, and 6,063,371). A soluble, solution-based IL-4R peptide composition for administration by inhalation, Nuvance™, is currently in clinical trials for the treatment of asthma (Borish L C et al., 1999, Am J Resp Crit Care Med, 160(6): 1816-23).

Solution-based formulations of IL-4R suffer from drawbacks other than those associated with solution phase instability. First, solution-based formulations take up more room and require more care than solid formulations thus and are more costly. Moreover, in general, they must be refrigerated (typically maintained in an environment of 2 to 80° C.) which further restricts the storage and transport options. In addition, many solution-based formulations exhibit a protein concentration loss over time, which is presumably due to the formation of dimers and other protein aggregates in solution. Such formulations frequently must be supplemented with stabilizing additives such as buffers and/or antioxidants to minimize solution instability. Thus, it would be desirable to provide a solid or powder-based composition of IL-4R, particularly one that could not only be stably prepared and stored, but additionally administered in solid form, such as an inhaleable dry powder. Many preclinical and clinical studies with inhaled proteins, peptides, DNA and small molecules have demonstrated efficacy both within the lungs and systemically.

Powder formulations represent an alternative to solution formulations, and proteins, when desired in powder form, are most often prepared as lyophilizates (e.g., U.S. Pat. No. 5,856,296). Unfortunately, lyophilized powders are typically formed as cakes, which require additional grinding and milling and optionally sieving processing steps to provide flowing powders. In the past few years, spray drying has been employed as an alternative approach for preparing a number of therapeutic protein-based powders, particularly for aerosolized administration (e.g., International Patent Publication Nos. WO 96/32149; WO 95/31479; WO 97141833, assigned to Inhale Therapeutic Systems, Inc.). Unfortunately, certain proteins, and cytokines in particular, are prone to degradation during spray drying and loss of their secondary structure (Maa, Y. F., et al., J. Pharm. Sciences, 87(2), 152-159(1998)). For a representative cytokine, human growth hormone, Mumenthaler reported that spray drying at 90° C. resulted in 4% formation of insoluble aggregates and 21% formation of soluble aggregates—a loss of 25% intact protein (Pharmaceutical Res., 11, 12-20 (1994)). The instability of the illustrative cytokine, hGH, was further demonstrated by Maa, Y. F., et al., ibid, who reported 42% aggregate formation (soluble and insoluble) upon atomization of a solution of hGH.

Additionally, sIL-4R possesses a number of potential instability sites leading to both solution and solid state-based instability. Specifically, sIL-4R contains 7 cysteines (Cys11, 21, 31, 51, 61, 63 and 184), ensuring at least one free sulfhydryl which may be available for intermolecular disulfide linkages. Such intermolecular disulfide linkages lead to the ready formation of dimers, trimers and other self-aggregates. Thus, this molecule is particularly prone to instability. In addition to sites susceptible to aggregation, the IL-4R peptide also has sites susceptible to degradation. For example, sites likely vulnerable to oxidative attack include four methionine residues (Met3, 16, 25, and 67). Additionally, an acid labile Asp-Pro linkage disruptable at low pH is found at amino acid residues 145-146. Two likely deamidation sites include Asn-Gly (26-27), and Asn-Gly (56-57), although the molecule possesses numerous other potential deamidation residues (Asn and Gln).

Thus, the challenge facing the inventors was not only to provide an improved dry powder formulation of IL-4R for overcoming some of the disadvantages associated with solution-based formulations of IL-4R as described above, but also to balance the factors affecting the instability and aerosol properties of IL-4R to arrive at a stable dry powder formulation suitable for pulmonary administration. That is to say, prior to the present invention, the development of a chemically and physically stable, bioactive dry powder of IL-4R that also possesses the physical properties necessary for aerosolization (e.g., high dispersibilities which remain stable over time, appropriate aerodynamic size) was unknown.

SUMMARY OF THE INVENTION

The present invention is based upon the unexpected discovery of chemically and physically stable spray dried powder compositions of IL-4R, even though such molecules (i.e., cytokines) are known to be particularly unstable when exposed to the shear stress, liquid-wall interactions, high temperature conditions and the like of spray drying. Surprisingly, the spray-dried powder of the invention exhibits both a monomer content and aggregate level that is essentially unchanged relative to that of its pre-spray dried solution. Moreover, the invention provides IL-4R dry powder compositions that are storage stable with respect to both monomer content and aggregate level, even under extreme conditions of humidity. That is to say, the spray dried powders described herein exhibit both superior chemical and physical stability, as well as having good dispersibilties, (i.e., aerosol properties) making them suitable for administration to the lung.

In one aspect, the invention provides a spray dried IL-4R powder composition that is capable of being stored for extended periods of time, 14 days or more, in extreme humitidy and temperature conditions without experiencing substantial alterations in aerosol performance, chemical and/or physical character, bioactivity, and the like. More particularly, the IL-4R content of the powder compositions of the present invention is essentially unchanged as compared to the pre-spray dried suspensions or solutions, i.e., experiencing minimal aggregate formation and/or protein monomer loss over time.

The IL-4R powder composition, demonstrating insignificant degradation upon preparation and storage, may be prepared in the absence of stabilizing additives or excipients, or may further include a pharmaceutically acceptable excipient. Preferred excipients include zinc salts, citrate, leucine, and combinations thereof.

The IL-4R powder composition preferably has a monomer content that is substantially unchanged as compared to that of the pre-dried solution or suspension. The change in monomer content is presented herein as a percent decrease (as compared to pre-dried solution or suspension). The decrease in monomer content is preferably less than about 10%, more preferably less than 7%, most preferably less than 5%.

The IL-4R powder composition preferably exhibits minimal aggregate formation as compared to that of the pre-dried solution or suspension. The level of aggregate formation is presented herein as a percent increase (as compared to pre-dried solution or suspension). The increase in aggregate content is preferably less than 10%, more preferably less than 7%, most preferably less than 5%.

Additionally, the IL-4R powder compositions of the invention comprise particles effective to penetrate into the alveoli of the lungs, that is, having in a particular embodiment, a mass median diameter (MMD) of less than about 10 μm, preferably less than about 7.5 μm, and most preferably less than 5 μm in diameter. In a particularly preferred embodiment, the powder is composed of particles having an MMD from about 1.0 to 3.5 μm.

Further embodiments of the IL-4R powder compositions in accordance with the invention include spray dried IL-4R particles having a mass median aerodynamic diameter (MMAD) of less than about 10 microns, preferably less than about 5.0 microns, and more preferably less than about 3.5 microns. In an especially preferred embodiment, the MMAD ranges from 1.5 to 3.5 microns.

Also encompassed by the invention is an aerosolized IL-4R powder formulation, and an IL-4R powder in a unit dosage form.

In another aspect, the invention is directed to a method for administering an IL-4R powder composition as described herein to the lungs of a patient in need thereof. In the method, a composition as described above is administered by inhalation in aerosolized form.

The invention also encompasses, in yet another aspect, a method for preparing a dispersible, dry IL-4R powder composition having the features described above.

In one embodiment, the respirable IL-4R powder composition is prepared by combining the active IL-4R agent(s) in a suitable solvent to form a mixture or solution and spray-drying the mixture or solution to obtain discrete, substantially amorphous particles, preferably in the form of a dry powder. The IL-4R remains essentially intact upon spray drying, resulting in powder particles in which the extent of protein degradation (as characterized by decrease in monomer content and aggregate formation) is insignificant.

An optional pharmaceutical excipient may be further added to the solvent to form a homogeneous solution or heterogeneous mixture, such that spray-drying of the solution or mixture produces particles comprising, in combination with IL-4R, excipient, buffer, and any other components which are present in the solution or mixture. Alternatively, the pharmaceutical excipient may be separately dissolved and spray dried to yield separate yet co-administrable powder particles.

DETAILED DESCRIPTION OF THE INVENTION

Components Of The Respirable IL-4R Powder Composition

The present invention provides highly dispersible respirable powder compositions containing IL-4R for pulmonary delivery thereof. The powder compositions described herein overcome many of the problems often encountered heretofore in administering peptide agents by systemic routes, particularly the problems associated with solution-based formulations of IL-4R. Examples of such problems include prolonged response time (e.g., time between administration and onset of physiological response), low systemic absorption and relatively low concentrations in tissues and secretions, the inability to maintain acceptable serum levels, and the instability of peptides, and cytokines in particular, in solution.

The compositions of th present invention are particularly effective for the treatment of allergic diseases and conditions, such as asthma and atopic dermatitis. Moreover, the spray dried IL-4R powder containing compositions described herein are surpisingly stable (i.e., exhibit minimal chemical and physical degradation upon preparation and storage, even wider extreme conditions of temperature and humidity). That is to say, the powders provided herein are surpisingly robust, even in the abscence of stabilizing or dispersibility enhancing excipients, The IL-4R powders of the invention (i) are readily dispersed by aerosol delivery devices (i.e., demonstrate good aerosol performance), (ii) exhibit surprisingly good physical and chemical stability during powder manufacture and processing, and upon storage, and (iii) are reproducibly prepared (Examples 1-5).

The respirable IL-4R powder compositions according to the present invention contain IL-4R, and, optionally but not necessarily, a pharmaceutically acceptable excipient. The components of the respirable IL-4R powder compositions of the invention will now be described.

IL-4R for use in the invention is generally characterized as follows. Endogenous mature interleukin-4 receptor is expressed as a 140 kDA membrane glycoprotein that binds IL-4 with high affinity (Idzerda R L et al., 1990 J. EXP. Med., 171 (3), 861-873; Jacobs, C A et al. 1991, Blood, 77(11):2396-2403, both of which are incorporated by reference herein). The extracellular domain of human IL-4R, cloned and produced in CHO cells in serum containing media, is a highly glycosylated (N-linked) and sialylated protein having a nonglycosylated molecular weight of 23.9 kDa and containing 209 amino acid residues. The extracellular domain IL-4R is located between residues 24 and 234 of the mature interleukin-4 receptor. Mass spectrometry data shows the protein molecular weight to be about 37 kDa, suggesting at least 35% glycosylation. By SDS-PAGE analysis, the protein elutes as a 54 kDa band. The pI of IL-4R is 3.36 to 5.18 as determined by isoelectric focusing. The unfolding transition temperature as determined by DSC is 57.80° C. and the unfolding process is highly reversible.

IL-4R for use in the compositions described herein may be purchased from a commercial source, or may be recombinantly produced, for example, using a process described in U.S. Pat. No. 5,767,065 and by Armitage et al. in Adv Exp Med Biol 1991;292:121-30, both of which are incorporated by reference herein in their entirety. The IL-4R may be neutral (i.e., uncharged) or may be in the form of a pharmaceutically acceptable salt, for example, an acid addition salt such as acetate, maleate, tartrate, methanesulfonate, benzenesulfonate, toluenesulfonate, etc., or an inorganic acid salt such as hydrochloride, hydrobromide, sulfate, phosphate, etc. Cationic salts may also be employed, such as salts of sodium, potassium, calcium, magnesium, or ammonium salts.

The amount of IL-4R contained within the respirable powder compositions will be that amount necessary to pulmonarily deliver a therapeutically effective amount (i.e., amount required to exert the therapeutic effect) of IL-4R per unit dose over the course of a daily dosing regimen. In practice, this will vary depending upon the particular IL-4R (e.g., natural vs. synthetic, full-length vs. fragment and its corresponding bioactivity), the patient population, and dosing requirements. Due to the highly dispersible nature of the respirable powders of the invention, losses to the inhalation device are minimized, meaning that more of the powder dose is actually delivered to the patient. This, in turn, correlates to a lower required dosage to achieve the desired therapeutic goal.

In general, the total amount of IL-4R contained in the respirable powder compositions will range from 1 to 100% of the total weight of the respirable powder composition, preferably from 5 to 98%, more preferably from 10 to 95%, even more preferably from about 45% to 95% by weight to about 50% to about 90%. A preferred dry powder composition will contain from about 40% to 80% IL-4R (% by weight of composition), and even more preferably will contain from about 0.2% to 99% IL-4R by weight.

The effective amount of IL-4R required will vary from one patient to the next and from one therapeutic regimen to the next. The amount and frequency of administration will depend, of course, on such factors as the nature and severity of the indication being treated, the desired response, the patient population, condition of the patient, and so forth.

The generally accepted dosage appropriate for inducing a biological effect for parenterally administered sIL-4R ranges from about 1 ng/kg/day to about 10 mg/kg/day, more preferably from about 5 ug/kg/day to about 2 mg/kg/day. Such parenteral formulations of IL-4R are discussed in U.S. Pat. Nos. 5,856,296 and 6,063,371, discussed above. However, since pulmonary delivery is frequently more efficient than parenteral delivery, dosages required may vary, and in fact, may be slightly less than those utilized in parenteral formulations. Dosing of IL-4R, particularly for the treatment of allergic diseases such as asthma, is typically weekly. Weekly dosage of an IL-4R powder by inhalation can range from about 0.1 to 10 mg, more preferably between 0.5-5 mg, even more preferably between 1-2 mg. Precise dosages will depend upon various factors such as the concentration of IL-4R in the spray dried powder. Desired dosages are typically achieved in 1 to 10 breaths or 2 to 6 breaths, more preferably 1-4 breaths, depending upon the precise unit dosage form employed.

The efficiency of systemic Il-4R delivery via the method described herein, i.e., the percentage of administered dose that reaches the bloodstream (e.g., in lung pulmonary bioavailability) from a solid inhaled dosage form will typically be at least about 1%, more preferably at least about 2%, typically at least about 3-5%. In a more preferred embodiment, the efficiency of systemic delivery into the bloodstream from the lung is at least about 15% to 30%.

C. Excipients and Additives

The respirable powder compositions of the present invention may be formulated "neat" i.e. without pharmaceutical excipients or additives. This finding was particularly surprising in view of the tendency of cytokines such as IL-4R towards both degradation and aggregation. In one specific embodiment of the invention, the respirable composition is a "neat" dry powder formulation. In another embodiment, the dry powder formulation is absent particular excipients and additives, such as penetration enhancers.

Alternatively, the compositions of the invention may contain IL-4R combined with one ore more pharmaceutically acceptable excipients or additives that are suitable for respiratory and pulmonary administration. Such excipients, if present, are generally present in the powder composition in amounts ranging from about 0.01% to about 99% percent by weight, preferably from about 0.1% to about 95%, more preferably from about 0.5% to about 80%, even more preferably from about 1% to about 50-60%. Examples of excipient-containing respirable 11-4R compositions are described in Example 1. Interestingly, in the exemplary compositions described in the Examples, the presence or absence of one or more excipients did not substantially impact the chemical or physical stability of the spray dried powders of the invention, either during preparation or storage.

However, preferred excipients will, in part, serve to improve one or more of the following: the aerosol properties of the composition, its chemical stability, its physical stability, and/or storage stability. Preferred excipients may also function to provide more efficient and reproducible delivery of IL-4R by dry powder inhaler, and additionally improve the handling characteristics of the IL-4R powder composition (e.g., flowability and consistency) to facilitate manufacturing and powder filling.

In particular, the excipient materials can often function to improve the physical and chemical stability of the respirable IL-4R powder composition or active agents contained therein. For example, the excipient may minimize the residual moisture content and hinder moisture uptake and/or enhance particle size, degree of aggregation, surface properties (i.e., rugosity), ease of inhalation, and targeting of the resultant particles to the lung. The excipient(s) may also simply serve simply as bulking agents for reducing the active agent concentration in the dry powder composition.

Pharmaceutical excipients and additives useful in the present composition include, but are not limited to, proteins (i.e., large molecules composed of one or more chains of amino acids in a specific order), oligopeptides (i.e., short chains of amino acids connected by peptide bonds), peptides (i.e., a class of molecules that hydrolyze into amino acids), amino acids, lipids (i.e., fatty, waxy or oily compounds typically insoluble in water but soluble in organic solvents, containing carbon, hydrogen and, to a lesser extent, oxygen), polymers (i.e., large molecules formed by the combination of many similar smaller molecules), and carbohydrates (e.g., sugars, including monosaccharides, di-, tri-, tetra-, and oligosaccharides; derivatized sugars such as alditols, aldonic acids, esterfied sugars and the like; and plysaccharides or sugar polymers), which may be present singly or in combination. Suitable excipients include those provided in International Publication No. WO 96/32096 assigned to Inhale Therapeutic Systems, Inc., the entire contents of which are incorporated by reference herein.

Preferred excipients include sugar alcohols, lipids, DPPC, DSPC, calcium/magnesium, and hydrophobic excipients, such as hydrophobic amino acids and hydrophobic sugars. Particularly preferred excipients include zinc salts, leucine, citrate, and sugars such as raffinose. For particulate formulations, preferred excipients are those having glass transition temperatures (Tg), above about 35° C., preferably above about 45° C., more preferably above about 55° C.

Exemplary polypeptide and protein excipients include serum albumin such as human serum albumin (HSA), recombinant human albumin (rHA), gelatin, casein, hemoglobin and the like. Particularly preferred are dispersiblity enhancing polypeptide, e.g., HSA, as described in International Publication No. WO 96/32096, assigned to Inhale Therapeutic Systems, Inc., the contents of which are incorporated by reference herein.

Representative amino acid/polypeptide components, which may also function in a buffering capacity, include alanine, glycine, arginine, betaine, histidine, glutamic acid, aspartic acid, cysteine, lysine, leucine, isoleucine, valine, methionine, phenylalanine, aspartame, tyrosine, tryptophan, and the like. Preferred are amino acids and peptides that function as dispersing agents. Amino acids falling into this category include hydrophobic amino acids such as leucine (leu), valine (val), isoleucine (isoleu), tryptophan (try) alinine (ala), methionine (met), phenylalanine (phe), tyrosine (try), histidine (his), and probe (pro). One particularly preferred amino acid is the amino acid leucine. Leucine, when use in the formulations described herein includes D-leucine, L-leucine, and racemic leucine. Dispersibility enhancing peptides for use in the invention include dimers, trimers, tetramers, and pentamers composed of hydrophobic amino acid components such as those described above. Examples include di-leucine, di-valine, di-isoleucine, di-tryptophan, di-alanine, and the like, tripleucine, tripvaline, tripisoleucine, triptryptophan etc.; mixed di- and tri-peptides, such as leu-val, isoleu-leu, try-ala, leu-try, etc., and leu-val-leu, val-isoleu-try, ala-leu-val, and the like and homo-tetramers or pentamers such as tetra-alanine and penta-alanine. Particularly preferred oligopeptide excipients are dimers and trimers composed of two or more leucine residues, as described in Inhale Therapeutic Systems Inc. International Patent Application PCT/US/00/09785 entitled, "Dry Powder Compositions Having Improved Dispersiblity. Of these, dileucine and trileucine are particularly prefered.

Another preferred feature of an excipient for use in the invention is surface activity. Surface active excipients, which may also function as dispering agents, such as hydrophobic amino acids (e.g., leu, val isoleu, phe, etc.), di- and tri-peptides, polyamino acids (e.g., polyglutamic acid) and proteins (e.g., HSA, rHA, hemoglobin gelatin) are particularly preferred, since due to their surface active nature, these excipients tend to concentrate on the surface of the particles of the respirable IL-4R composition, making the resultant particles highly dispersible in nature. Other exemplary surface active agents that may be included in the respirable IL-4R compositions described herein include but are not limited to polysorbates, lecithin, oleic acid, benzalkonium chloride, and sorbitan esters.

Carbohydrate excipients suitable for use in the invention include, for example, monosaccharides such as fructose, maltose, galactose, glucose, d-mannose, sorbose, and the like; disaccharides, such as raffinose, melezitose, maltodestrins, dextrans, straches and the like; and alditols, such as mannitol, xylitol, maltitol, lactitol, xylitol sorbital (glucito). myoinasitol and the like.

The respirable IL-4R compositions may also include a buffer or a pH adjusting agent; typically, the buffer is a salt prepared from an organic acid or base. Representative buffers include organic acid salts such as salts of citric acid, ascorbic acid, gluconic acid, carbonic acid, taratric acid, succinic acid, acetic acid, or phthalic acid, Tris, tromethamine hydrochloride, or phosphate buffer.

Additionally, the respirable IL-4R composition of the invention may inducts polymeric excipients/additives such as polyvinylpyrrolidones, derrivatized celluloses such as hydroxypropylmethylcellulose, Ficcols (a polymeric Sugar), hydroxyethylsartch, dextrates (e.g., cyclodextrins, much as 2-hydroxypropyl-β-cyclodextrin and sulfobutylether-β-cyclodextrin), polyethylene glycols, pectin flavoring agents, salts (e.g., sodium chloride), antimicrobial agents, sweeteners, antioxidants, antistatic agents, surfactants (e.g., polysorbates such as "TWEEN 20" and "TWEEN 80"), lecithin, oleic acid, benzalkonium chloride, sorbitan esters, lipids (e.g. phospholipids, fatty acids), steroids (e.g. cholesterol) and chelating agents (e.g., EDTA). For compositions containing a polymeric component, the polymer is typically present to a limited extent in the composition. i.e., at levels less than about 10% by weight. Preferred compositions of the invention are those in which the IL-4R is preferably non-liposomally or polymer encapsulated or non-coated (i.e., absent a discrete coating layer). Preferred IL-4R compositions such as those exemplified herein are immediate-acting formulations, i.e., designed for immediate rather than for sustained release applications.

Other pharmaceutical excipients and/or additives suitable for use in the respirable IL-4R compositions according to the invention are listed in "Remington: the Science & Practice of Pharmacy", 19^th ed., Williams & Williams, (1995, in the "Physician's Desk Reference, 52^nd ed., Medical Economics, Montvale, N.J. (1998), and in 37 The Handbook of Pharmaceutical Excipients", 3^rd Edition, A. H. Kibbe, ed., American Pharmaceutical Association, Pharmaceutical Press, 2000, the disclosures of which are herein incorporated by reference,

In accordance with the invention, the respirable IL-4R powder composition may be a dry powder, the dry powder being crystalline, an amorphous glass, or a mixture of both forms. For formulations containing a surface active agent, the surface active material (in either crystalline or amorphous form), will typical be present on the surface of the particles in a higher concentration than in the bulk powder.

D. Preparing The Respirable Il-4R Compositions

Respirable Il-4R powder compositions, such as dry powder formulations are preferably prepared by spray-drying. Spray-drying of the formulations is carried out, for example, as described generally in the "Spray-drying Handbook", 5^th ed., K. masters, John Wiley & Sons, Inc., NY,N.Y. (1991), in Platz, R., et al., International Patent Publication Nos. WO 97/41833 (1997) and WO 96/32149 (1996), the contents of which are incorporated herein by reference.

To prepare an IL-4R solution for spray-drying, IL-4R (and any other exipients) is generally dissolved in water, optionally containing a physiologically acceptable buffer. The pH range of solution is generally between about 3 and 10, which nearer neutral pHs being preferred, since such pHs may aid in maintaining the physiological compatibility of the powder after dissolution of powder within the lung. The aqueous formulation may optionally contain additional water-miscible solvents, such as acetone, alcohols and the like. Representative alcohols are lower alcohols such as methanol, ethanol, propanol, isopropanol, and the like. The solutions will generally contain IL-4R dissolved at a concentration from 0.01% (weight/volume) to about 20% (weight/volume), preferably from 0.1% to 10% (weight/volume), more preferably 1% to 3% (weight/volume). Alternatively, components of the IL-4R formulation may be spray-dried using an organic solvent or co-solvent system, employing one or more solvents such as acetone, alcohols (e.g., methanol and ethanol), ethers, aldehydes, hydrocarbons, ketones and polar aprotic solvents.

The IL-4R containing solutions are then spray dried in a conventional spray drier, such as those available from commercial suppliers such as Niro A/S (Denmark), Buchi (Switzerland) and the like, resulting in a dispersible, respirable IL-4R composition, preferably in the form of a respirable dry powder. Optimal conditions for spray-drying the active agent solutions will vary depending upon the formulation components, and are generally determined experimentally. The gas used to spray-dry the material is typically air, although inert gases such as nitrogen or argon are also suitable. Moreover, the temperature of both the inlet and outlet of the gas used to dry the sprayed material is such that it does not cause decomposition of the IL-4R in the sprayed material. Such temperatures are typically determined experimentally, although generally, the inlet temperature will range from about 50° C. to about 200° C. while the outlet temperature will range from about 30° C. to about 150° C.

The preparation of respirable, dry IL-4R powder compositions under a variety of spray-drying process parameters are described in Examples 1 and 2. Surprisingly, the shear forces produced by atomization of the solution during spray-drying do not result in hydrolysis or aggregation of IL-4R. As described herein, highly dispersible dry powders having good physical and chemical stability and good aerodynamic properties can be prepared reproducibly and under a variety of process conditions.

Alternatively, although less preferably, the respirable IL-4R powder compositions may be prepared by lyophilization, vacuum drying, spray freeze drying, super critical fluid processing, air drying, or other forms of evaporative drying.

In some instances, it may be desirable to provide the respirable IL-4R dry powder formulation in a form that possesses improved handling/processing characteristics, e.g., reduced static, better flowability, low caking and the like, by preparing compositions composed of fine particle aggregates, that is, aggrogates or agglomerates of the above-described respirable IL-4R. Dry powder particles, where the aggregates are readily broken back down to the fine powder components for pulmonary delivery, as described, e.g., in Johnson, K., et al., U.S. Pat. No. 5,654,007, 1997, incorporated herein by reference. Alternatively, the respirable IL-4R powders may be prepared by agglomerating the powder components, sieving the materials to obtain the agglomerates, spheronizing to provide a more spherical agglomerate, and sizing to obtain a uniformly-sized product, as described, e.g., in Ahlneck, C., et al. International PCT Publication No. WO 95/09616 (1995), incorporated herein by reference.

The respirable IL-4R dry powders are preferably maintained under dry (i.e., relatively low humidity) conditions during manufacture, processing, and storage. Irrespective of the drying process employed, the process will preferably result in respirable highly dispersible compositions composed of substantially amorphous IL-4R particles.

E. Characteristics Of The Respirable IL-4R Powder Compositions

Certain physical characteristics of the spray dried IL-4R powder compositions are preferred to maximize the efficiency of aerosolized delivery of such compositions to the lung.

The respirable IL-4R powder compositions are composed of particles effective to penetrate into the lungs. Passage of the particles into the lung physiology is an improtant aspect of the present invention. To this end, the particles of the invention have a mass median diameter (MMD) of less than about 10 μm, preferably less than 7.5 μm, and more preferably less than 5 μm, and usually are in the range of 0.1 μm to 5 μm in diameter. Preferred compositions are composed of particles having and MMD from about 0.5 to 3.5 μm . Examples of respirable IL-4R powder compositions of varying concentrations of active agent(s) and/or excipient are described in Example 1. The respirable IL-4R powder compositions may also contain non-respirable carrier particles such as lactose, where the non-respirable particles are typically greater than about 40 microns in size. In a preferred embodiment, the dry powder is non-liposomal or non-lipid containing.

The respirable IL-4R powder compositions of the invention are further characterized by an aerosol particle size distribution less than about 10 μm mass median aerodynamic diameter (MMAD), preferably less than 5.0 μm, and more preferably less than 3.5 μm. The mass median aerodynamic diameters of the powders will characteristically range from about 0.5-10 μm, preferably from about 0.5-5.0 μm MMAD, more preferably from about 1.0-4.0 μm MMAD, and even more preferably from about 1.5 to 3.5 μm.

The respirable IL-4R powder compositions, particularly the respirable dry powder compositions, generally have a moisture content below about 10% by weight, usually below about 5% by weight, and preferably below about 3% by weight. Such low moisture-containing solids tend to exhibit a greater stability upon packaging and storage.

The dry powders preferably have a bulk density ranging from about 0.1-10 g/cc, preferably from about 0.25-4 g/cc, more preferably from about 0.5-2 g/cc, and most preferably from about 0.7-1.4 g/cc.

The emitted dose (ED) of these powders is greater than 30% and usually greater than 40%. More preferably, the ED of the powders of the invention is greater than 50%, and is often greater than 55%.

An additional measure for characterizing the overall aerosol performance of a dry powder is the fine particle dose (FPD) or fine particle fraction (FPF), which describes the mass percentage of powder having an aerodynamic diameter less than 3.3 microns. Dry powders having an FPF value greater than 40%, more preferably greater than 50%, even more preferably greater than 60% are particularly well suited for pulmonary delivery. Powders containing at least fifty percent of aerosol particles sized between 0.5 and 3.5 μm are extremely effective when delivered in aerosolized form, in reaching the regions of the lung, including the alveoli.

The spray dried respirable IL-4R powder compositions of the present invention are further characterized as having an essentially unchanged monomer content as compared to that of its pre-spray dried solution or suspension. In other words, the spray drying process does not induce the formation of dimers or other aggregates, thereby affecting the percent monomer in the composition. That is to say, the change in monomer content between spray dried powder and pre-spray dried solution or suspension is "essentially unchanged", e.g., the percentage of monomer content of spray dried powder as compared to that of the pie-spray dried solution or suspension is preferably no more than about 15%, more preferably no more than about 10%, more preferably no more than about 7%, even more preferably about 5% or less, as exemplified by the representative IL-4R powders described in the Examples.

The spray dried respirable IL-4R powder compositions of the present invention are "storage stable", i.e., characterized by minimal insoluble aggregate formation and/or a minimal decrease in monomer content, when stored for extended periods at extreme temperatures ("temperature stable") and humidities ("moisture stable"). For example, the spray dried respirable IL-4R powder compositions of the present invention experience minimal aggregate formation and minimal decrease in monomer content after storage for a period of time (e.g., two weeks or more) at a temperature ranging from about 2° C. to about 50° C., preferably about 25° C., and/or a relative humidity ranging from 0% to about 75%, preferably about 33% RH. Specifically, the stored spray dried respirable IL-4R powder compositions of the present invention preferably form less than about 15% insoluble aggregates (as compared to the pre-spray dried solutions or suspensions), more preferably less than about 10% insoluble aggregates, more preferably less than about 7% insoluble aggregates, even more preferably about 5% or less insoluble aggregates. Alternatively, the stored spray dried respirable IL-4R powder compositions of the present invention preferably experience a decrease in monomer content that is no more than about 20%, preferably no more than about 10%, more preferably no more than about 7%, even more preferably about 5% or less.

It is important to note the distinctions between respirable powder-based formulations and nebulized formulations. Despite the fact that nebulized formulations may be considered by some to be "inhaleable", in that they are breathed through the mouth and into the lungs, they are not "respirable" as defined herein. For example, nebulized formulations typically cannot reach the tissues of the deep lung and be absorbed through the epithelial cells therein into blood circulation. Moreover nebulized formulations are solution-based, i.e., are administered in solution rather than in solid form.

Representative respirable IL-4R powder compositions for pulmonary delivery are provided in Examples 1-5.

F. Pulmonary Administration Of The Respirable IL-4R Powder Compositions

The respirable IL-4R powder compositions, particularly the dry powder compositions described herein, are preferably delivered using any suitable dry powder inhaler (DPI), i.e., an inhaler device that utilizes the patient's inhaled breath as a vehicle to transport the previously dispersed (by passive or active means) dry powder to the lungs. Preferred are Inhale Therapeutic Systems' dry powder inhalation devices as described in Patton, J. S., et al., U.S. Pat. No. 5,458,135 (1995); Smith, A., et al., U.S. Pat. No. 5,740,794, (1998); Smith A., et al., U.S. Pat. No. 5,785,049(1998), and in International Patent application PCT 00/18084.

When administered using a device of this type, the respirable IL-4R powder composition is contained in a receptacle having a puncturable lid or other access surface, preferably a blister package or cartridge, where the receptacle may contain a single dosage unit or multiple dosage units. Large numbers of cavities are conveniently filled with metered doses of dry powder medicament as described in Parks, D. J. et al., International Patent Publication WO 97/41031 (1997).

Also suitable for delivering the respirable IL-4R powder formulations described herein are dry powder inhalers of the type described, for example, in Cocozza, S., U.S. Pat. No. 3,906,950 (1974), and Cocozza, S., U.S. Pat. No. 4,013,075, (1977), wherein a premeasured dose of dry powder for delivery to a subject is contained within a hard gelatin capsule.

Other dry powder dispersion devices for pulmonary administration of dry powders include those described, for example, in Newell, R. E. et al., European Patent No. EP 129985, (1988); in Hodson, P. D. et al., European Patent No. EP 472598, (1996); in Cocozza, S., et al., European Patent No. EP 467172, (1994), and in Lloyd, L. J. et al., U.S. Pat. No. 5,522,385, (1996). Also suitable for delivering the IL-4R powder compositions of the invention are inhalation devices such as the Astra-Draco "TURBUHALER". This type of device is described in detail in Virtanen, R., U.S. Pat. No. 4,668,218); in Wetterlin, K. et al., U.S. Pat. No. 4,667,668. (1987); and in Wetterlin K., et al., U.S. Pat. No. 4,805.811, (1989). Also suitable are devices which employ the use of a piston to provide air for either entraining powdered medicament, lifting medicament from a carrier screen by passing air through the screen, or mixing air with powder medicament in a mixing chamber with subsequent introduction of the powder to the patient through the mouthpiece of the device, such as described in Mulhauser, P., et al., U.S. Pat. No. 5,388,572, (1997).

The inhaleable IL-4R powder compositions may also be delivered using a pressurized, metered dose inhaler (MDI) containing solution or suspension of drug in a pharmaceutically inert liquid propellant, e.g., a chlorofluorocarbon or fluorocarbon, as described in Laube, et al., U.S. Pat. No. 5,320,094, (1994), and in Rubsamen, R. M. et al., U.S. Pat. No. 5,672,581 (1994). Prior to use, the respirable IL-4R powder compositions are generally stored in a receptacle under ambient conditions, and preferably are stored at temperatures at or below about 25° C., and relative humidities (RH) ranging from about 30 to 60%. More preferred relative humidity conditions, e.g., less than about 30% may be achieved by the incorporation of desiccating agent in the secondary packaging of the dosage form. The respirable dry powders of the invention are characterized not only by good aerosol performance, but by good stability, as well.

When aerosolized for direct delivery to the lung, the IL-4R powder compositions described herein will exhibit good in-lung bioavailabilities.

G. Utility The respirable IL-4R powder compositions of the invention, when administered pulmonarily, are particularly effective in the treatment of allergic diseases and disorders, such as asthma, atopy, atopic dermititis, and other conditions associated with high serum levels of IgE and IgG₁.

The respirable IL-4R powder compositions can also be used for treating or preventing allergic, viral, parasitic, and bacterial diseases and mildew infectious diseases, particularly when administered in combination with y-interferon. (See European Patent No. EP 585,681 (1994)).

The inventive powder compositions, when inhaled, penetrate into the airways of the lungs, enter the circulatory system and achieve effective systemic delivery. Moreover, the doses of IL-4R powder administered pulmonarily are typically much less than those administered orally due to the loss associated with digestion and degradation for oral dosage forms.

The respirable IL-4R powder compositions of the present invention find utility as alternates or adjuncts to current asthma therapies.

The respirable IL-4R powder compositions find particular utility in the physiological regulation of serum levels of IL-4 and immunoglobulins associated therewith (e.g., IgE, and IgG₁).

The respirable IL-4R powder compositions find further utility as enhancers of the biological activity of the cytokine IL-4, thereby allowing for the reduction in cytokine dosage required and the minimization of negative side effects associated therewith (See U.S. Pat. No. 6,063,371, incorporated by reference herein).

Claim 1 of 38 Claims

1. A powder composition comprising spray-dried particles consisting essentially of soluble interleukin-4 receptor (sIL-4R) as an active agent and one or more excipients selected from the group consisting of carbohydrates, lipids, divalent metal cation, buffers, amino acids, oligopeptides, peptides, and proteins, wherein the powder composition comprises particles having a mass median aerodynamic diameter (MMAD) of less than about 10 microns.

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