US20200360276A1 - Inhalable imatinib metabolite formulations, manufacture, and uses thereof - Google Patents

Abstract

The invention relates to inhalable imatinib metabolite formulations, manufacture, and uses thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This Application claims the benefit of, and priority to, U.S. Provisional Application Nos. 62/849,054, filed May 16, 2019; 62/849,056, filed May 16, 2019; 62/849,058, filed May 16, 2019; 62/849,059, filed May 16, 2019; 62/877,575, filed Jul. 23, 2019; 62/942,408, filed Dec. 2, 2019; 62/984,037, filed Mar. 2, 2020; and 62/958,481, filed Jan. 8, 2020; the content of each of which is hereby incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
• The invention relates to inhalable imatinib metabolite formulations, manufacture, and uses thereof.
BACKGROUND
• Pulmonary arterial hypertension (PAH) is a condition involving elevated blood pressure in the arteries of the lungs with unknown causes and is differentiated from systemic hypertension. PAH is a progressive disease where resistance to blood flow increases in the lungs causing damage to the lungs, the pulmonary vasculature and the heart that can eventually lead to death. While symptoms are treatable with vasodilators and other medications, there is no known disease modifying therapy or cure and advanced cases can eventually require lung transplants.
• Imatinib, especially the mesylate salt thereof, is a tyrosine kinase inhibitor approved for use in treating certain types of cancer. Imatinib's potential to inhibit the tyrosine kinase PDGFR (platelet-derived growth factor receptor) which is highly upregulated in the pulmonary arteries in cases of PAH, led to interest in its use in treating PAH. See, Olschewski, H, 2015, Imatinib for Pulmonary Arterial Hypertension—Wonder Drug or Killer Drug? Respiration, 89:513-514, incorporated herein by reference. To that end, studies have been conducted to determine the potential of imatinib in treating PAH and patients have been found to respond favorably to said treatment. Unfortunately, an unacceptable amount of severe adverse events including subdural hematoma blunted enthusiasm for the drug. Frost, et al., 2015, Long-term safety and efficacy of imatinib in pulmonary arterial hypertension, J Heart Lung Transplant, 34(11):1366-75, incorporated herein by reference.
SUMMARY
• Compositions and methods of the invention address problems with imatinib-based PAH treatments through the use of specialized formulations and delivery mechanisms. Particularly, the invention recognizes that direct delivery to the lung tissues through inhalation can offer greater lung exposure than equivalent doses of imatinib or salts thereof administered through conventional oral routes or by IV. Accordingly, while a relatively high oral dose of imatinib or imatinib mesylate would be required to achieve the same target lung exposure as achieved by inhalation of the inventive formulations. Therefore, the use of inhalable formulations of the invention allows for therapeutic amounts of imatinib, its active metabolite, or salts thereof to reach the lungs for treatment of PAH and other conditions of the pulmonary cardiovascular system without the adverse events experienced with prolonged oral administration of imatinib mesylate.
• The primary active metabolite of imatinib is N-desmethyl imatinib and has been found to exhibit the same potency as the imatinib parent compound. Additionally, N-desmethyl imatinib exhibits an increased half-life relative to the parent imatinib compound. Compounds and methods of the invention take advantage of this characteristic by providing inhalable formulations of N-desmethyl imatinib in the absence of the parent compound. Such formulations provide therapeutic benefits in treating PAH and other conditions with more efficient delivery to and longer residence in the effected tissue due to the increased half-life of the metabolite. This combination can allow for fewer doses with lower concentrations of active pharmaceutical ingredient relative to conventional oral or IV administration of imatinib mesylate.
• In certain embodiments inhalable N-desmethyl imatinib formulations may be micronized through wet or dry milling (e.g., jet milling) to achieve the desired particle size for dry powder formulations for inhalation. N-desmethyl imatinib or appropriate salts thereof may be micronized to particle sizes of about 0.5 μm to about 5 μm mass median aerodynamic diameter (MMAD) for desired deep lung penetration. Inhaled products can be limited in terms of mass of powder that can be administered and certain imatinib salts will contribute significantly to the molecular weight of the inhaled compound. Accordingly, in certain embodiments, the imatinib metabolite may be preferred for efficient delivery of the active moiety to lung tissue. If required, various excipients or carriers can be added the metabolite or salts thereof before or after micronization depending on application. For example, carriers, excipients, conditioners, and force control agents may be included with lactose (which may be conditioned with various solvents to increase separation of imatinib during inhalation), magnesium stearate, leucine, isoleucine, dileucine, trileucine, lecithin, distearylphosphatidylcholine (DSPC) or other lipid-based carriers, or various hydrophilic polymers. The skilled artisan will appreciate that excipients or carriers are optional and that many embodiments of the invention do not require excipients or carriers.
• Because the inhalable formulations described herein can modulate the uptake of imatinib in the target tissue of the lungs or microvasculature, formulations of the invention can be used to treat various conditions of the pulmonary cardiovascular system while avoiding the adverse events associated with higher doses that are administered by other routes of administration that introduce the drug systemically prior to reaching the target tissue. For example, compounds and methods of the invention can be used to treat PAH as well as lung transplant rejection, pulmonary veno-occlusive disease (PVOD) and pulmonary hypertension secondary to other diseases like heart failure with preserved ejection fraction (HFpEF) or schistosomiasis. Dose ranges can include between about 10 mg to about 100 mg per dose for inhalation on a twice to four times per day schedule. About 0.1 mg to about 20 mg of N-desmethyl imatinib may then be present within the lungs after inhalation.
• Methods and formulations of the invention may include spray-dried N-desmethyl imatinib or salts thereof for inhalation. While carriers such as lactose may be used after micronization to aid in delivery via inhalation, those carriers may generally comprise larger diameter particles and complication in the separation of the active imatinib metabolite may result in lower amounts of the inhaled compound reaching the lungs. Furthermore, the amount of active compound reaching the lungs may be less predictable using such carriers and methods, making dosing more complicated. Accordingly, spray-dried methods may be used wherein N-desmethyl imatinib or salts thereof along with various excipients or other additives may be micronized to a desired particle size and suspended or solubilized for spray-drying and inhalation.
• In certain embodiments, the micronized imatinib metabolite is suspended in a feedstock for the purposes of spray-drying to avoid the creation of amorphous or polymorphic N-desmethyl imatinib content that may occur if dissolved in a solution (e.g. in an appropriate organic solvent or within an acidified aqueous solution) upon spray-drying. By creating a stable suspension of micronized N-desmethyl imatinib for spray-drying, once dried, the inhalable formulation can retain the desired crystal structure, particle size, and low levels of amorphous content obtained before the micronization process.
• Stable suspensions for spray-drying may be obtained through manipulation of factors affecting compound solubility such as pH, ionic strength, and dispersing agents or surfactants. Excipients that may be used before micronization in the spray-drying methods described above include, for example, leucine, dileucine, trileucine, bulking agents such as trehalose or mannitol, lecithin, DSPC or other lipid-based carriers, citrate, or acetate.
• The inhalable formulation may be in a dry powder. In some embodiments, the inhalable formulation may be a suspension of crystalline N-desmethyl imatinib. The N-desmethyl imatinib may be present in a therapeutically effective amount to treat a condition of the pulmonary cardiovascular system, such as pulmonary arterial hypertension (PAH). The salt may be at least one selected from the group consisting of glycollate, isethionate, xinafoate, furoate, trifenatate, HCl, sulfate, phosphate, lactate, maleate, malate, fumarate, tartrate, succinate, adipate, citrate, and malonate. The inhalable formulation may further include one or more carrier agents.
• Aspects of the invention include an inhalable formulation comprising N-desmethyl imatinib or a salt thereof, wherein the formulation does not include imatinib. The N-desmethyl imatinib may be present in a therapeutically effective amount to treat a condition of the pulmonary cardiovascular system which may be pulmonary arterial hypertension (PAH). The inhalable formulation can be a dry powder and can include micronized particles comprising a mass median aerodynamic diameter in the range of 0.5-5 μm.
• In salt formulations, the salt may be selected from mesylate, glycollate, isethionate, xinafoate, furoate, trifenatate, HCl, sulfate, phosphate, lactate, maleate, malate, fumarate. In certain embodiments, the inhalable formulation can include one or more carrier agents. The carrier agent can be selected from lactose, magnesium stearate, leucine, isoleucine, dileucine, trileucine, lecithin, and distearylphosphatidylcholine (DSPC).
• In certain aspects, the invention can include methods of treating a condition of the pulmonary cardiovascular system by providing to a subject an inhalable formulation comprising N-desmethyl imatinib or a salt thereof, wherein the formulation does not include imatinib. In various embodiments, the subject may be a human and the condition of the pulmonary cardiovascular system can be pulmonary arterial hypertension (PAH).
DETAILED DESCRIPTION
• The invention relates to inhalable formulations of N-desmethyl imatinib and salts thereof. N-desmethyl imatinib is the primary active metabolite of imatinib formed when imatinib undergoes demethylation by the cytochrome P450 (CYP) isomer CYP3A4. N-desmethyl imatinib has the following structure:
• 
• The methods and compositions described herein provide greater concentrations of N-desmethyl imatinib in target lung tissue than obtained with equivalent doses administered orally or through IV. Furthermore, N-desmethyl imatinib has been found to exhibit the same potency as the imatinib parent compound but exhibits an increased half-life relative to the parent imatinib compound. Accordingly, inhalable formulations of N-desmethyl imatinib as described herein provide therapeutic benefits with reduced risk of adverse events through more efficient delivery to and longer residence in the effected tissue relative to conventional oral or IV administration of imatinib mesylate.
• Thus, the invention provides improved treatment methods for life threatening disease that were heretofore too risky for practical application.
• In certain embodiments, compounds of the invention include formulations of N-desmethyl imatinib or salts thereof. In preferred embodiments, N-desmethyl imatinib is used in a formulation (either in dry powder or suspension) for inhalation to treat a condition of the pulmonary cardiovascular system such as PAH. Certain salt forms are also contemplated. In various embodiments, salts contemplated herein include glycollate, isethionate, malonate, tartrate, and malate. Other salt forms contemplated herein are xinafoate, furoate, trifenatate, HCl, sulfate, phosphate, lactate, maleate, fumarate, succinate, adipate, and citrate
• In various embodiments, micronized N-desmethyl imatinib and salts thereof retain crystallinity, even after micronization and spray drying (as discussed in detail below). Of particular note is, by suspending micronized N-desmethyl imatinib particles in a solution as opposed to solubilizing, the desired crystalline form and low amorphous content obtained during micronization is carried through to the spray-dried inhalable powder because the N-desmethyl imatinib crystals are not dissolved in the solution to a significant degree.
• In various embodiments, N-desmethyl imatinib or salts thereof are provided in dry powder formulations for inhalation. Dry powder can be administered via, for example, dry powder inhalers such as described in Berkenfeld, et al., 2015, Devices for Dry Powder Drug Delivery to the Lung, AAPS PharmaSciTech, 16(3):479-490, incorporated herein by reference. Dry powder compounds may be divided into single doses for single, twice daily, three times daily, or four times daily inhalation to treat disorders such as PAH or other conditions of the pulmonary cardiovascular system. The single doses may be divided into individual capsules or other formats compatible with the dry powder inhaler to be used.
• In other embodiments, N-desmethyl imatinib suspensions having the characteristics described herein (e.g., low polymorphism and amorphous content) can be delivered via inhalation using, for example, a nebulizer. N-desmethyl imatinib suspensions may offer advantages over solutions as discussed below. For nebulized suspensions, micronization and particle diameter may be of particular importance for efficient delivery and N-desmethyl imatinib may be preferably micronized to a mass median diameter of 2 μm or less. The suspension solution for nebulizer inhalation can be aqueous and doses may be divided into individual containers or compartments for sterile storage prior to use.
• Micronized N-desmethyl imatinib particle size can range from about 0.5 μm to about 5 μm depending on application (e.g., dry powder or suspension for inhalation). In preferred embodiments the size range is about 1 μm to about 3 μm in dry powder formulations to achieve deep lung penetration.
• In certain embodiments, N-desmethyl imatinib formulations of the invention may include one or more excipients. Excipients may include, for example, lactose in various forms (e.g., roller dried or spray dried). Larger lactose particles can be used as a carrier for inhalation of micronized N-desmethyl imatinib formulations. The carrier particles, with their larger size, can be used to increase aerodynamic forces on the combined N-desmethyl imatinib/carrier in order to aid in delivery through inhalation. Solvents may be used to condition the lactose surface such that the active component can be effectively separated from the lactose as it leaves the inhaler device and within the oral cavity when being used as a carrier. Magnesium stearate can be used as a force-control agent or conditioning agent in various embodiments. In some embodiments, leucine can be used as a force-control agent including different forms of leucine (e.g. isoleucine) along with dileucine and even trileucine.
• Lecithin phospholipids such as DSPC may be used as an excipient for dry powder inhalation. In certain embodiments, excipients may include various hydrophilic polymers. See, for example, Karolewicz, B., 2016, A review of polymers as multifunctional excipients in drug dosage form technology, Saudi Pharm J., 24(5):525-536, incorporated herein by reference.
• In various embodiments, the N-desmethyl imatinib formulations of the invention may be pharmaceutical compositions for use in treating various conditions of the pulmonary cardiovascular system, such as PAH. For example, N-desmethyl imatinib is a potent inhibitor of the platelet-derived growth factor receptor (PDGFR). Accordingly, the compositions of the invention may be used to treat any disease or disorder that involves inhibition of PDGFR or other kinases sensitive to N-desmethyl imatinib.
• In certain embodiments, the compositions of the invention may be used to treat PAH. For treatment of PAH or other disorders, a therapeutically effective amount of a pharmaceutical composition of N-desmethyl imatinib according to the various embodiments described herein can be delivered, via inhalation (e.g., via dry powder inhaler or nebulizer) to deliver the desired amount of N-desmethyl imatinib compound to the target lung tissue.
• Dosages for treating PAH and other conditions of the pulmonary cardiovascular system may be in the range of between about 10 mg to about 100 mg per dose for inhalation on once, twice or three times per day schedule. About 0.1 mg to about 20 mg of the active N-desmethyl imatinib compound may then be present at the lung after inhalation. In certain embodiments about 10 mg to 30 mg of N-desmethyl imatinib may be given in a capsule for a single dry-powder inhalation dose with about 5 mg to about 10 mg of the compound to be expected to reach the lungs. In inhalable suspension embodiments, N-desmethyl imatinib may be present at about 0.3 to about 1 mg/kg in a dose and may be administered one to four times a day to obtain the desired therapeutic results.
• In certain embodiments, N-desmethyl imatinib formulations of the invention may be used to treat pulmonary hypertension as a result of schistosomiasis. See, for example, Li, et al., 2019, The ABL kinase inhibitor imatinib causes phenotypic changes and lethality in adultSchistosoma japonicum, Parasitol Res., 118(3):881-890; Graham, et al., 2010, Schistosomiasis-associated pulmonary hypertension: pulmonary vascular disease: the global perspective, Chest, 137(6 Suppl):20S-29S, the content of each of which is incorporated herein by reference.
• N-desmethyl imatinib pharmaceutical compositions of the invention may be used to treat lung transplant recipients to prevent organ rejection. See, Keil, et al., 2019, Synergism of imatinib, vatalanib and everolimus in the prevention of chronic lung allograft rejection after lung transplantation (LTx) in rats, Histol Histopathol, 1:18088, incorporated herein by reference.
• In certain embodiments, pharmaceutical compositions described herein can be used to treat pulmonary veno-occlusive disease (PVOD). See Sato, et al., 2019, Beneficial Effects of Imatinib in a Patient with Suspected Pulmonary Veno-Occlusive Disease, Tohoku J Exp Med. 2019 February; 247(2):69-73, incorporated herein by reference.
• For treatment of any conditions of the pulmonary cardiovascular system for which N-desmethyl imatinib may produce a therapeutic effect, compounds and methods of the invention may be used to provide greater concentration at the target lung tissue through inhalation along with consistent, predictable pharmacokinetics afforded by low polymorphism and amorphous content. The efficient localization of therapeutic compound at the target tissue allows for lower systemic exposure and avoidance of the adverse events associated with prolonged oral administration of imatinib mesylate.
• Methods of the invention can include preparation of N-desmethyl imatinib formulations. As noted above, N-desmethyl imatinib or salts thereof may be administered via inhalation in suspension or dry powder form. Dry powder formulations may be obtained via any known method including, in preferred embodiments, jet milling. Jet milling can be used to grind N-desmethyl imatinib and, potentially, various additives (e.g., excipients) using a jet (or jets) of compressed air or gas to force collisions between the particles as they transit at near sonic velocity around the perimeter of a toroidal chamber. The size reduction is the result of the high-velocity collisions between particles of the process material. Outputs of the jet mill may allow particles to exit the apparatus once a desired size has been reached. As noted herein, desired particle size for dry powder inhalation and other formulations may be in the range of about 0.5 μm to about 5 μm.
• In certain embodiments, bulk N-desmethyl imatinib may be micronized to the desired size for inhalation via wet milling wherein the imatinib particles are suspended in a slurry and reduced through shearing or impact with a grinding media.
• Once micronized, in dry powder form, N-desmethyl imatinib formulations of the invention, with their low polymorphic and amorphous content, can be prepared for inhalation. In certain embodiments, the dry powder N-desmethyl imatinib can be combined with larger carrier particles such as lactose as discussed above.
• In some embodiments an N-desmethyl imatinib suspension can be formed. The suspension may result from dry micronization followed by suspension of the resulting dry powder or can be obtained as the outcome of a wet milling procedure. N-desmethyl imatinib suspensions of micronized crystal forms may be used in nebulized inhalation treatment or may be spray dried for dry powder treatments.
• Spray drying techniques are well characterized and described, for example, in Ziaee, et al., 2019, Spray drying of pharmaceuticals and biopharmaceuticals: Critical parameters and experimental process optimization approaches, Eur. J. Pharm. Sci., 127:300-318, and Weers et al., 2019, AAPS Pharm Sci Tech. 2019 Feb. 7; 20(3):103. doi: 10.1208/s12249-018-1280-0, and 2018/0303753, each of which is incorporated herein by reference. Spray drying micronized N-desmethyl imatinib or salts thereof provides for uniform and predictable crystallinity and particle size and can avoid the need for large carrier molecules that may adversely affect the amount of inhaled drug that reaches the target lung tissue.
• In spray-dried embodiments, micronized drug particles may be suspended within a non-aqueous solvent or within an emulsion of a non-aqueous solvent which, in turn is emulsified or dispersed within an aqueous environment (e.g. oil in water) and spray-dried, resulting in crystalline drug particles. The non-aqueous component may or may not be fugitive and thus could be removed completely during spray drying or, it could be retained, depending on the desired properties required. In such embodiments, each atomized droplet (mass median diameter ˜10 μm) contains dispersed drug crystals. During the initial moments of the drying process, the more volatile aqueous phase begins to evaporate. The rapidly receding atomized droplet interface drives enrichment of the slowly diffusing drug and emulsion particles at the interface. This leads to formation of a void space in the center of the drying droplet. As the drying process continues, the less volatile oil phase in the emulsion droplets evaporates, resulting in formation of hollow pores in their place. Overall, the resulting hollow spray-dried composite particles contain drug crystals.
• Maintaining a stable solution of crystalline N-desmethyl imatinib is important in certain embodiments of the formulations and methods of the invention. Accordingly, formulation methods include manipulation of the suspension to prevent dissolution of the N-desmethyl imatinib. Aqueous solution factors such as pH, ionic strength and dispersing agents may be used to obtain a stable suspension for nebulized inhalation or spray drying. For example, the pH of the aqueous solution may be adjusted to prevent dissolution. Solubility of the N-desmethyl imatinib increases as the pH drops and, therefore, the pH of the aqueous solution in various embodiments may be above and, preferably, the solution may be neutral.
• Additionally, the presence of ions in aqueous solution may tend to ‘salt out’ the N-desmethyl imatinib. The solubility of the both N-desmethyl imatinib and its mesylate salt may decrease with salinity. Accordingly, salt in the aqueous solution may be used to reduce solubility of the N-desmethyl imatinib crystals in certain embodiments.
• To promote dispersion and thoroughly deagglomerate the N-desmethyl imatinib particles, a dispersing agent or surfactant (e.g., Tween 20 or Tween 80) may be added but should not cause dissolution of the N-desmethyl imatinib in suspension.
• In certain embodiments, excipients can be added to the suspension before spray drying. In various embodiments, the excipient may be a water-soluble excipient, such as leucine, dileucine, trileucine, trehalose, mannitol, citrate or acetate. In other embodiment, the excipient may be a water insoluble excipient, such as lecithin, distearylphosphatidylcholine (DSPC) or limonene. Such insoluble excipients may be dissolved in a non-aqueous medium that is miscible or immiscible with water, thereby creating an emulsion. Alternatively, a liposomal dispersion could be created into which the suspended N-desmethyl imatinib could be added and homogenized or where it could be spray dried in separate feedstocks.
• When the compounds of the present invention are administered as pharmaceuticals, to humans and mammals, they can be given per se or as a pharmaceutical composition containing, for example, 0.1 to 99.5% (more preferably, 0.5 to 90%) of active ingredient, i.e., at least one a therapeutic compound of the invention and/or derivative thereof, in combination with a pharmaceutically acceptable carrier.
• The effective dosage of each agent can readily be determined by the skilled person, having regard to typical factors each as the age, weight, sex and clinical history of the patient. In general, a suitable daily dose of a compound of the invention will be that amount of the compound which is the lowest dose effective to produce a therapeutic effect. Such an effective dose will generally depend upon the factors described above.
• If desired, the effective daily dose of the active compound may be administered as two, three, four, five, six or more sub-doses administered separately at appropriate intervals throughout the day, optionally, in unit dosage forms.
• The pharmaceutical compositions of the invention include a “therapeutically effective amount” or a “prophylactically effective amount” of one or more of the compounds of the present invention, or functional derivatives thereof. An “effective amount” is the amount as defined herein in the definition section and refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired therapeutic result, e.g., a diminishment or prevention of effects associated with PAH. A therapeutically effective amount of a compound of the present invention or functional derivatives thereof may vary according to factors such as the disease state, age, sex, and weight of the subject, and the ability of the therapeutic compound to elicit a desired response in the subject. A therapeutically effective amount is also one in which any toxic or detrimental effects of the therapeutic agent are outweighed by the therapeutically beneficial effects.
• A “prophylactically effective amount” refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired prophylactic result. Typically, since a prophylactic dose is used in subjects prior to, or at an earlier stage of disease, the prophylactically effective amount may be less than the therapeutically effective amount. A prophylactically or therapeutically effective amount is also one in which any toxic or detrimental effects of the compound are outweighed by the beneficial effects.
• Dosage regimens may be adjusted to provide the optimum desired response (e.g. a therapeutic or prophylactic response). For example, a single inhalable bolus may be administered, several divided doses may be administered over time or the dose may be proportionally reduced or increased as indicated by the exigency of the therapeutic situation. Actual dosage levels of the active ingredients in the pharmaceutical compositions of this invention may be varied so as to obtain an amount of the active ingredient which is effective to achieve the desired therapeutic response for a particular subject, composition, and mode of administration, without being toxic to the patient.
• The term “dosage unit” as used herein refers to physically discrete units suited as unitary dosages for the mammalian subjects to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on (a) the unique characteristics of the compound, and (b) the limitations inherent in the art of compounding such an active compound for the treatment of sensitivity in individuals.
• In some embodiments, therapeutically effective amount can be estimated initially either in cell culture assays or in animal models, usually mice, rabbits, dogs, or pigs. The animal model is also used to achieve a desirable concentration range and route of administration. Such information can then be used to determine useful doses and routes for administration in other subjects. Generally, the therapeutically effective amount is sufficient to reduce PAH symptoms in a subject. In some embodiments, the therapeutically effective amount is sufficient to eliminate PAH symptoms in a subject.
• Dosages for a particular patient can be determined by one of ordinary skill in the art using conventional considerations, (e.g. by means of an appropriate, conventional pharmacological protocol). A physician may, for example, prescribe a relatively low dose at first, subsequently increasing the dose until an appropriate response is obtained. The dose administered to a patient is sufficient to effect a beneficial therapeutic response in the patient over time, or, e.g., to reduce symptoms, or other appropriate activity, depending on the application. The dose is determined by the efficacy of the particular formulation, and the activity, stability, or half-life of the compounds of the invention or functional derivatives thereof, and the condition of the patient, as well as the body weight or surface area of the patient to be treated. The size of the dose is also determined by the existence, nature, and extent of any adverse side-effects that accompany the administration of a particular vector, formulation, or the like in a particular subject. Therapeutic compositions comprising one or more compounds of the invention or functional derivatives thereof are optionally tested in one or more appropriate in vitro and/or in vivo animal models of disease, such as models of PAH, to confirm efficacy, tissue metabolism, and to estimate dosages, according to methods well known in the art. In particular, dosages can be initially determined by activity, stability or other suitable measures of treatment vs. non-treatment (e.g., comparison of treated vs. untreated cells or animal models), in a relevant assay. Formulations are administered at a rate determined by the LD50 of the relevant formulation, and/or observation of any side-effects of compounds of the invention or functional derivatives thereof at various concentrations, e.g., as applied to the mass and overall health of the patient. Administration can be accomplished via single or divided doses.
• In certain embodiments, in which an aqueous suspension is part of the manufacturing process, the aqueous suspension may contain the active material in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents dispersing or wetting agents such as a naturally occurring phosphatide, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such a polyoxyethylene with partial esters derived from fatty acids and hexitol anhydrides, for example polyoxyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl, or n-propyl p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose, mannitol, or trehalose.
• Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives.
• The term “pharmaceutical composition” means a composition comprising a compound as described herein and at least one component comprising pharmaceutically acceptable carriers, diluents, adjuvants, excipients, or vehicles, such as preserving agents, fillers, disintegrating agents, wetting agents, emulsifying agents, suspending agents, sweetening agents, flavoring agents, perfuming agents, antibacterial agents, antifungal agents, lubricating agents and dispensing agents, depending on the nature of the mode of administration and dosage forms. The term “pharmaceutically acceptable carrier” is used to mean any carrier, diluent, adjuvant, excipient, or vehicle, as described herein. Examples of suspending agents include ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, or mixtures of these substances. Prevention of the action of microorganisms can be ensured by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, and the like. It may also be desirable to include isotonic agents, for example sugars, sodium chloride, and the like. Prolonged absorption of the injectable pharmaceutical form can be brought about by the use of agents delaying absorption, for example, aluminum monosterate and gelatin. Examples of suitable carriers, diluents, solvents, or vehicles include water, ethanol, polyols, suitable mixtures thereof, vegetable oils (such as olive oil), and injectable organic esters such as ethyl oleate. Examples of excipients include lactose, milk sugar, sodium citrate, calcium carbonate, and dicalcium phosphate. Examples of disintegrating agents include starch, alginic acids, and certain complex silicates. Examples of lubricants include magnesium stearate, sodium lauryl sulphate, talc, as well as high molecular weight polyethylene glycols.
• The term “pharmaceutically acceptable” means it is, within the scope of sound medical judgment, suitable for use in contact with the cells of humans and lower animals without undue toxicity, irritation, allergic response, and the like, and are commensurate with a reasonable benefit/risk ratio.
INCORPORATION BY REFERENCE
• References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.
EQUIVALENTS
• Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.

Claims (16)

What is claimed is:

1. An inhalable formulation comprising N-desmethyl imatinib or a salt thereof, wherein the formulation does not include imatinib.

2. The inhalable formulation ofclaim 1, wherein the N-desmethyl imatinib is present in a therapeutically effective amount to treat a condition of the pulmonary cardiovascular system.

3. The inhalable formulation ofclaim 2, wherein the condition of the pulmonary cardiovascular system is pulmonary arterial hypertension (PAH).

4. The inhalable formulation ofclaim 1, wherein the inhalable formulation is a dry powder.

5. The inhalable formulation ofclaim 4, wherein the dry powder comprises micronized particles comprising a mass median aerodynamic diameter in the range of 0.5-5 μm.

6. The inhalable formulation ofclaim 1, wherein the salt is at least one selected from the group consisting of mesylate, glycollate, isethionate, xinafoate, furoate, trifenatate, HCl, sulfate, phosphate, lactate, maleate, malate, fumarate, tartrate, succinate, adipate, citrate, and malonate.

7. The inhalable formulation ofclaim 1, wherein the inhalable formulation further comprises one or more carrier agents.

8. The inhalable formulation ofclaim 7, wherein the carrier agent is selected from the group consisting of lactose, magnesium stearate, leucine, isoleucine, dileucine, trileucine, lecithin, and distearylphosphatidylcholine (DSPC).

9. A method of treating a condition of the pulmonary cardiovascular system, the method comprising providing to a subject an inhalable formulation comprising N-desmethyl imatinib or a salt thereof, wherein the formulation does not include imatinib.

10. The method ofclaim 9, wherein the inhalable formulation is a dry powder.

11. The method ofclaim 10, wherein the dry powder comprises micronized particles comprising a mass median aerodynamic diameter in the range of 0.5-5 μm.

12. The method ofclaim 9, wherein the subject is a human.

13. The method ofclaim 9, wherein the condition of the pulmonary cardiovascular system is pulmonary arterial hypertension (PAH).

14. The method ofclaim 9, wherein the salt is at least one selected from the group consisting of glycollate, isethionate, xinafoate, furoate, trifenatate, HCl, sulfate, phosphate, lactate, maleate, malate, fumarate, tartrate, succinate, adipate, citrate, and malonate.

15. The method ofclaim 9, wherein the inhalable formulation further comprises one or more carrier agents.

16. The method ofclaim 15, wherein the carrier agent is selected from the group consisting of lactose, magnesium stearate, leucine, isoleucine, dileucine, trileucine, lecithin, and distearylphosphatidylcholine (DSPC).