WO2012103116A1 - Pulmonary administration of rifalazil and analogs thereof - Google Patents

Abstract

Methods for treating bacterial lung infections, such as tuberculosis infections, using a poorly absorbable form of rifalazil, are described. Compositions for pulmonary administration of a non-microgranulated rifalazil formulation are also described. In one embodiment, the patients that are treated are immuno-compromised, for example, by co-infection with HIV, HBV, or HCV. The delivery of rifalazil in a poorly absorbed form reduces potential adverse events that might result from systemic delivery, and the local delivery to the lungs allows targeted treatment. Where the particles are both relatively large and porous, delivery can be to the deep lung, and systemic delivery can be largely avoided.

Description

PULMONARY ADMINISTRATION OF RIFALAZIL

AND ANALOGS THEREOF

Field of the Invention

The invention is generally directed to the use of rifalazil to treat bacterial infections in the lungs and upper airway (pharynx, larynx, trachea within mediastinum, diaphragm, parietal pleura , and visceral pleura), while maintaining a minimal absorption in the systemic circulation, and minimizing adverse events from the antibiotic administration.

Background of the Invention

Tuberculosis (TB) is a common and often deadly infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs, though it can also affect other parts of the body. It is spread through the air when people who have the disease cough, sneeze, or spit. Most infections in humans result in an asymptomatic, latent infection, and about one in ten latent infections eventually progresses to active disease, which, if left untreated, kills more than 50% of its victims.

The classic symptoms are a chronic cough with blood-tinged sputum, fever, night sweats, and weight loss. The disease is diagnosed using chest X-rays, a tuberculin skin test, blood tests, and microscopic examination and microbiological culture of bodily fluids. Treatment is difficult, typically requiring long courses of multiple antibiotics, and antibiotic resistance is a growing problem in (extensively) multi-drug-resistant tuberculosis.

One third of the world's population is thought to be infected with M. tuberculosis. About 80% of the population in many Asian and African countries test positive in tuberculin tests, while only 5-10% of the US population test positive.

Tuberculosis is becoming a significant problem in the developed world, because of substance abuse, AIDS, and exposure to immunosuppressive drugs.

Over nine million people contracted TB in 2007, including around 1.4 million people with HIV/AIDS. More than one death in four of the 1.75 million TB deaths recorded in 2007 is thought to involve an HIV/ AIDS patient, and TB is the leading infectious killer of people with HIV/AIDS. TB-HIV co-infections are on the rise in sub-Saharan Africa and other areas of the world, particularly Asia and Eastern Europe. In 2005, 2.7 million people were newly infected with HIV/AIDS. As long as HIV/ AIDS continues to spread, TB will remain a constant and deadly threat.

It has been estimated that patients living with HIV have a twenty-fold increase in the risk of developing tuberculosis relative to HIV negative people. The combination of poor diagnosis, rising drug resistance, and the impact on HIV/AIDS patients has heightened alarm among health experts. Drug-resistant strains are believed to have infected an estimated 500,000 people, of whom around 150,000 of which die from the disease, according to the World Health Organization ("WHO"). Furthermore, around 10 percent of the drug resistant strains are almost incurable extra-resistant strains (XDR-TB), and these extra-resistant strains are now found in at least 55 countries.

It is difficult to treat HIV-infected patients, because of the patient's immunologic status, the need for highly active antiretroviral therapy (HAART), and potential drug reactions. A need remains for anti-TB therapy that is compatible with HAART.

Rifamycin antibiotics have been proposed for use in treating a variety of disorders, including MRSA and TB. Rifalazil is a synthetic antibiotic designed to modify the parent compound, rifamycin. Compared to other antibiotics in the rifamycin class, it has extremely high antibacterial activity, particularly against TB. However, while it has a broad spectrum of antibacterial action covering Gram- positive and Gram-negative organisms, both aerobes and anaerobes, it also has low solubility, which hinders its ability to be administered systemically.

There have been several methods proposed to overcome the solubility issues associated with Rifalazil. For example, U.S. Patent 5,547,683 is directed to a method for producing a microgranulated particle form of rifalazil, and U.S. Patent Application Ser. No. 10/453,155 discloses intravenous compositions including rifalazil.

Rifalazil has been proposed for use in treating TB, particularly in HIV-positive patients, because rifalazil, unlike other rifamycins, does not affect the CYP450 enzymes responsible for metabolism of common anti-HIV therapeutics, such as protease inhibitors. However, a potential limitation of using rifalazil is that it is difficult to administer systemically, due to its low aqueous solubility, and at high systemic dosage levels, can lead to side effects.

While systemic formulations can be advantageous for treating certain disorders, it would be advantageous to provide new uses for rifalazil that take advantage of its low solubility, as well as to provide new pharmaceutical compositions for delivering rifalazil in a manner in which one can take advantage of its low solubility. The present invention provides such compositions and uses.

TB infection begins when the mycobacteria reach the pulmonary alveoli, where they invade and replicate within the endosomes of alveolar macrophages. The primary site of infection in the lungs is called the Ghon focus, and is generally located in either the upper part of the lower lobe, or the lower part of the upper lobe.

It would therefore be useful to provide compositions and methods for locally administering rifalazil to the pulmonary system, such as the pulmonary alveoli and/or the Ghon focus, particularly if the administration did not result in significant systemic delivery. The present invention provides such compositions and methods.

Summary of the Invention

Compositions and methods for treating TB or other bacterial lung infections are disclosed. The compositions include rifalazil in a poorly absorbable, non- microgranulized form, in the form of particles that can be administered via inhalation, preferably in a size and/or density that maximizes delivery to the deep lung. The compositions optionally include a carrier for pulmonary administration, such as a propellant.

Rifalazil is delivered in a form that is poorly absorbed in the lung after pulmonary administration, and the vast majority of the rifalazil is not absorbed in the lungs (i.e., will not travel systemically). Accordingly, the antibacterial potency in the pulmonary environment will be enhanced, while absorption and systemic circulation will be reduced, thus reducing potential adverse events and maintaining a minimal amount of rifalazil absorbed which will allow the unabsorbed rifalazil to remain in the lungs to enable longer term antibacterial effect and prevent potential relapses or bacterial reinfections.

In one embodiment, the average diameter of the particles is between about 5 μιη and about 100 μιη. In one aspect of this embodiment, the average diameter of the particles is between about 10 μιη and about 50 μιη. In another aspect of this embodiment, the average diameter of the particles is between about 10 μιη and about 30 μιη. These particle size ranges help ensure that the rifalazil will not be systemically administered to a large extent, due to its insolubility, and will therefore remain largely in the pulmonary system, where it can locally treat the TB or other bacterial lung infection.

Relatively small, dense particles tend to be administered more to the alveolar region of the lungs than relatively large, dense particles. However, relatively small particles tend to be phagocytosed in the lungs. To address these issues, in one embodiment, the particles are relatively large (i.e., have the ranges of particle sizes described above) and porous. The relatively large particle size helps ensure that the particles are large enough to avoid being phagocytosed in the lungs, and also minimizing the systemic administration of the rifalazil that is delivered, while the porosity helps contribute to a relatively low density, making the particles behave, on pulmonary administration, much in the same way as smaller, denser particles.

In some embodiments, the particles include further components. Representative components include pharmaceutical excipients, biodegradable polymers that can provide sustained drug delivery, surfactants to minimize particle aggregation, and one or more additional bioactive agents. Representative additional bioactive agents include additional antibiotic agents, anti-inflammatories, anti-viral agents, anti-fungal agents, and the like.

The particles are suitable for delivery to the pulmonary system. Preferably, particles administered to the respiratory tract travel through the upper airways (oropharynx and larynx), the lower airways which include the trachea followed by bifurcations into the bronchi and bronchioli and through the terminal bronchioli which in turn divide into respiratory bronchioli leading then to the ultimate respiratory zone, the alveoli or the deep lung. In a preferred embodiment of the invention, most of the mass of particles deposits in the deep lung or alveoli.

The particles can be administered via dry particle inhalers, or other suitable drug delivery devices designed for pulmonary administration. In one embodiment, the dosage administered with each administration is between 0.1 and lg of rifalazil. In another embodiment, the dosage is between 0.1 and 100 mg, between 1 and 50 mg, between 1 and 25 mg, or between 1 and 10 mg. The administration can be once a day, once a week, twice a week, or monthly. The rifalazil can be administered alone, or in combination or alternation with other anti-TB drugs, as described herein. Ideally, when administered in alternation with other anti-TB drugs, the rifalazil is administered first. The administration of the particles to the lungs can provide targeted antibiotic therapy for lung infections. However, in one embodiment, the patient is also treated via oral or parenteral administration of one or more additional antibiotics, which can include rifalazil, to augment the pulmonary rifalazil therapy. Representative antibiotics include isoniazid, ethambutol, pyrazinamide and/or streptomycin. When used to treat pulmonary lung infections other than TB, the treatment can include a combination of rifalazil and vancomycin. The vancomycin can be present in the particles for pulmonary administration, or provided via oral or parenteral, such as intravenous, administration. The unit dosages for Rifalazil can range from 0.01 to 50 mg (e.g., between 0.1 and 30 mg, or between 1 and 5 mg), or reside in any other therapeutic range, and the unit dosages for vancomycin can range from 125 to 2000 mg, or from 500 to 2000 mg or from 750 to 1500 mg, or reside in any other suitable therapeutic range.

The compositions can be administered to patients over the period of several days to several months, or even up to a year or more, depending on the severity of the condition, the type of bacteria, and other factors.

In one embodiment, the compositions are administered prophylactically to individuals, such as health care providers, police officers, and soldiers, likely to be exposed to bacteria that cause pulmonary bacterial infections, such as TB, Bacillus anthracis, and the like.

In one embodiment, the compositions predominantly include rifalazil, along with one or more pharmaceutically acceptable excipients and carriers. While the invention is described herein with particular reference to rifalazil, it is to be appreciated that the invention may be carried out with rifalazil derivatives as the active component of the therapeutic composition.

In one aspect of this embodiment, the compositions can include a minor amount, e.g., less than about 15% by weight of ingredients other than rifalazil, to provide minimal solubility to the rifalazil. In one embodiment, a portion of the rifalazil is delivered systemically, whereby it is available to treat any of the bacterial infection not treated by the initially-delivered amount of poorly-absorbed rifalazil.

Such pharmaceutical formulations can be in the form of microgranules, optionally coated with a polymer, such as a biodegradable and/or mucoadhesive polymer, which can provide sustained drug release and/or adhere the particle to the lung tissue. The methods can be used to treat a subject having antibiotic-associated bacterial lung infection, such as a TB infection, or to prevent such a disease or infection in the subject. The methods can also be used to treat Gram positive bacterial infections, including those involving multi-drug resistant strains, such as Staph and Strep respiratory infections of the ears and the upper airways and the lung.

Other features, aspects and embodiments of the invention will be more fully apparent from the ensuing disclosure and appended claims.

Detailed Description

The invention described herein relates to the discovery that pulmonary administration of rifalazil, and certain rifalazil derivatives, alone or in combination with one or more additional antibiotics suitable for treating tuberculosis (TB) infections, can be effective to treat a subject suffering from tuberculosis. The particle size of the rifalazil is ideally selected to provide minimal systemic administration, so that the therapy remains in the lungs, which is the active site of infection.

The invention described herein relates to the discovery that rifalazil, administered to the lungs in a poorly- soluble form, alone or in combination with one or more additional antibiotics, can be effective to treat a subject having bacterial lung infections, such as TB.

The present invention in various specific embodiments utilizes rifalazil particles, at a size in which the particles are poorly absorbed, and, ideally, with a density sufficient to allow the particles to be administered to the deep lungs (i.e., the alveolar portion of the lungs) to treat lung infections such as TB.

Using the non-microgranulated formulation, the rifalazil will be poorly absorbed in the lungs after pulmonary administration, and the vast majority of the rifalazil is not systemically delivered. This enhances the anti-bacterial potency in the pulmonary system, while reducing absorption and systemic circulation, thereby reducing potential adverse events.

The therapy can be particularly useful where patients are immunocompromised, such as cancer patients, HIV-, HBV-, or HCV-positive patients, and the like. These patients typically are already on a number of systemically-administered drugs, which drugs frequently interact with other anti-tuberculosis agents such as rifampicin and rifabutin that modulate CYP450. The present invention will be better understood with reference to the following detailed description, and with respect to the following definitions.

Definitions

As used herein, poorly soluble means a classification of a therapeutic agent in the Biopharmaceutical Classification System (BCS) of Class III or Class IV. In general, therapeutic agents having a solubility below 0.1 mg/mL present significant solubilization difficulties, and even compounds with solubilities below 10 mg/mL may present solubilization issues during their formulation.

The term "an effective amount" refers to the amount of rifalazil, alone or in combination with one or more additional antibiotics, needed to eradicate a lung infection, such as TB, in a subject, or to prevent such an infection, as determined by a diagnostic test that detects TB or other such lung infection. Tests for the presence of TB are well known and need not be described here.

An "effective amount" can also mean the amount of rifalazil, alone or in combination with one or more additional antibiotics, required to treat TB or other pulmonary infections in a subject.

By "subject" is meant any warm-blooded animal including but not limited to a human, cow, horse, pig, sheep, goat, bird, mouse, rat, dog, cat, monkey, baboon, or the like. It is most preferred that the subject be a human.

As used herein, the term "a" or "an" refers to one or more.

The term "nominal dose" as used herein, refers to the total mass of rifalazil which is present in the mass of particles targeted for administration and represents the maximum amount of rifalazil available for administration.

I. Rifalazil

As used herein, "Rifalazil" refers to 3'-hydroxy-5'-(4-isobutyl-l-piperazinyl) benzoxazinorifamycin, also known as KRM-1648 or ABI1648. Methods of making rifalazil and microgranulated formulations thereof are described in U.S. Pat. Nos. 4,983,602 and 5,547,683, respectively. The invention as previously discussed contemplates the use of Rifalazil derivatives that are similar or superior in therapeutic effect to Rifalazil. Rifalazil is a synthetic antibiotic designed to modify the parent compound, rifamycin. Compared to other antibiotics in the rifamycin class, it has extremely high antibacterial activity. However, while it has a broad spectrum of antibacterial action covering Gram-positive and Gram-negative organisms, both aerobes and anaerobes, it also has low solubility.

Particle Size Range

The rifalazil used in the invention described herein can be in the form of crystals in amorphous form, or as porous particles. In any of these forms, it is poorly absorbed, and is not very soluble in a variety of commonly used FDA-approved liquid formulation ingredients. As used here, the term "rifalazil in poorly dissolvable form" means that the average particle size of the rifalazil is greater than about 5 μιη, typically between about 10 μιη and about 50 μιη, more typically between about 10 and 30 μιη. Rifalazil particles in this size range are believed to have limited potential absorption and solubility. Various salt forms of rifalazil also can be used in the broad practice of the present invention.

II. Pharmaceutical Compositions

The rifalazil is administered in a composition for pulmonary delivery, ideally one which can deliver the particles to the alveolar region of the lungs. Representative drug delivery formulations for pulmonary administration are known in the art. Particles including rifalazil are administered to the respiratory tract of a patient in need of treatment or prophylaxis. Administration of particles to the respiratory system can be by means such as known in the art. For example, particles are delivered from an inhalation device. In a preferred embodiment, particles are administered via a dry powder inhaler (DPI). Metered-dose-inhalers (MDI) or instillation techniques also can be employed.

Various suitable devices and methods of inhalation which can be used to administer particles to a patient's respiratory tract are known in the art. For example, suitable inhalers are described in U.S. Pat. No. 4,069,819, issued Aug. 5, 1976 to Valentini, et al, U.S. Pat. No. 4,995,385 issued Feb. 26, 1991 to Valentini, et al., and U.S. Pat. No. 5,997,848 issued Dec. 7, 1999 to Patton, et al. Other examples include, but are not limited to, the SPINHALER® (Fisons, Loughborough, U.K.), ROTAHALER® (Glaxo-Wellcome, Research Triangle Technology Park, N.C.), FLOWCAPS® (Hovione, Loures, Portugal), INHALATOR®. (Boehringer-Ingelheim, Germany), and the AEROLIZER® (Novartis, Switzerland), the DISKHALER® (Glaxo- Wellcome, RTP, NC) and others, such as known to those skilled in the art. Preferably, the particles are administered as a dry powder via a dry powder inhaler.

The dosage of Rifalazil in various specific embodiments can range from about 0.01 to 50 mg, although any specific dosage that is advantageous in a given application can be employed. The dosage of rifalazil in various emobodiments can be any suitable amount, e.g., about 0.1 to 10 mg, or between about 1 and 5 mg. The Rifalazil may be given daily (e.g., once, or twice daily) or less frequently (e.g., once every other day, once or twice weekly, or twice monthly), or in any other dosing regimen that provides therapeutic benefit.

The compound may be contained in any appropriate amount in any suitable carrier substance, and is generally present in an amount of 1-95% by weight of the total weight of the particles that are administered.

The pharmaceutical composition can generally be formulated according to conventional pharmaceutical practice (see, e.g., Remington: The Science and Practice of Pharmacy (20th ed.), ed. A. R. Gennaro, 2000, Lippincott Williams & Wilkins, Philadelphia, and Encyclopedia of Pharmaceutical Technology, eds. J. Swarbrick and J. C. Boylan, 1988-1999, Marcel Dekker, N.Y.).

The pharmaceutical compositions used to deliver the rifalazil can be formulated to release rifalazil at a predetermined time period by using biodegradable polymers, or other polymeric drug delivery systems.

When controlled release formulations are used, they are preferably a) formulations that after a predetermined lag time create a substantially constant concentration of the drug within the lungs over an extended period of time, or b) formulations that localize drug action by, e.g., spatial placement of a controlled release composition adjacent to or in the lungs, for example, using mucoadhesive polymers.

Examples of suitable polymeric materials include, for example, acrylic polymers, methacrylic acid copolymers with an acrylic or methacrylic ester (e.g., methacrylic acid ethylacrylate copolymer (1:1) and methacrylic acid methylmethacrylate copolymer (1:2), polyvinyl acetate phthalate, hydroxypropyl cellulose acetate phthalate and cellulose acetate phthalate), as well as cellulose acetate phthalate, hydroxypropyl methylcellulose phthalate, polyvinyl acetate phthalate. Commercially available products include, for example, KOLLIKOAT®, EDRAGIT® (e.g., EUDRAGIT 40), AQUATERIC®, AQOAT®. The enteric polymers used can also be modified by mixing with other coating products that are not pH sensitive. Examples of such coating products include, for example, the neutral methacrylic acid esters with a small portion of trimethylammonioethyl methacrylate chloride, sold currently under the trade names EUDRAGIT® and EUDRA GIT® RL; a neutral ester dispersion without any functional groups, sold under the trade names EUDRAGIT® NE30D and EUDRAGIT® NE30, EUDRAGIT® 40; polysaccharides, like amylose, chitosan, chondroitin sulfate, dextran, guar gum, inulin and pectin; and other pH independent coating products.

The polymer in various embodiments is from between about 5% and about 75% of the weight of the microgranule. In other embodiments, the polymer is from between about 10% and about 60%, 20% and about 55%, about 30% to about 80%, or 25% and about 50% of the weight of the microgranule. The weight percent of the polymer to the weight of the microgranule can depend, in part, on the polymer used, and the temperature of the polymer.

The microgranules may further comprise one or more of diluents, plasticizers, anti-agglomeratives, anti-sticking, glidants, anti-foam surfactants, or coloring substances. These, along with other polymers and coatings (e.g., protective coatings, over-coatings, and films) are more fully described below.

In order to deliver to the deep lung, it can be important to minimize particle agglomerization, and for this reason, excipients with anti-agglomerative properties can also be used. Examples include talc; plasticizing materials, like acetylated glycerides, diethylphthalate, propylene glycol and polyethylene glycol; surfactants like polysorbate and polyoxyethylenate esthers, anti-foaming agents, as well as anti- sticking agents.

Suitable ingredients can be incorporated into the coating formula such as plasticizers, which include, for example, adipates, azelates, benzoates, citrates, isoebucates, phthalates, sebacates, stearates and glycols. Representative plasticizers include acetylated monoglycerides, butyl phthalyl butyl glycolate, dibutyl tartrate, diethyl phthalate, dimethyl phthalate, ethyl phthalyl ethyl glycolate, glycerin, ethylene glycol, propylene glycol, triacetin citrate, triacetin, tripropinoin, diacetin, dibutyl phthalate, acetyl monoglyceride, polyethylene glycols, castor oil, triethyl citrate, polyhydric alcohols, acetate esters, gylcerol triacetate, acetyl triethyl citrate, dibenzyl phthalate, dihexyl phthalate, butyl octyl phthalate, diisononyl phthalate, butyl octyl phthalate, dioctyl azelate, epoxydized tallate, triisoctyl trimellitate, diethylhexyl phthalate, di-n-octyl phthalate, di-1 -octyl phthalate, di-l-decyl phthalate, di-n- undecyl phthalate, di-n-tridecyl phthalate, tri-2-ethylhexyl trimellitate, di-2-ethylhexyl adipate, di-2-ethylhexyl sebacate, di-2-ethylhexyl azelate, dibutyl sebacate, glyceryl monocaprylate, and glyceryl monocaprate. Other various layers, as recognized by one of skill in the art are also envisioned. The amount of plasticizer used in the polymeric material typically ranges from about 10% to about 50%, for example, about 10, 20, 30, 40, or 50%, based on the weight of the dry polymer. Optional modifying components of a protective layer which can be used over the enteric or other coatings include a water penetration barrier layer (semi-permeable polymer) which can be successively coated after the enteric or other coating to reduce the water penetration rate through the enteric coating layer and thus increase the lag time of the drug release. Coatings commonly known to one skilled in the art can be used for this purpose by coating techniques such as fluid bed coating using solutions of polymers in water or suitable organic solvents or by using aqueous polymer dispersions. For example, useful materials include cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, ethyl cellulose, fatty acids and their esters, waxes, zein, and aqueous polymer dispersions such as EUDRAGIT® RS and RL 30D, EUDRAGIT® NE 30D, EUDRAGIT® 40, AQUACOAT®, SURELEASE®, cellulose acetate latex. Combinations of the polymers and hydrophilic polymers such as hydroxy ethyl cellulose, hydroxypropyl cellulose (KLUCEL®, Hercules Corp.), hydroxypropyl methylcellulose (METHOCEL®, Dow Chemical Corp.), polyvinylpyrrolidone may also be used.

The amount of polymer to be used in the formulations is typically adjusted to achieve the desired drug delivery properties, including the amount of drug to be delivered, the rate and location of drug delivery, the time delay of drug release, and the size of the multiparticulates in the formulation. The combination of all solid components of the polymeric material, including co-polymers, fillers, plasticizers, and optional excipients and processing aids, typically provides about 1% to about 50% weight of the core.

The granules have good properties in respect of ability to flow freely, cohesiveness and lubrication, therefore the ratio between gastroresistant microgranules and excipients is between 1:0.2 and 1:0.05, preferably between 1:0.15 and 1:0.1.

The polymers can be used as solutions, utilizing either an aqueous or an organic solvent-based system. Incorporating a plasticizer enables the flexibility of the coating film to be improved; by addition of plasticizers, the risk of film cracking is reduced, and the adhesion of the film to the substrate is improved. Examples of typical plasticizers include glycerin, propylene glicol, polyethylene glycols, triacetin, acetylated monoglycerides, citrate esthers and phtalate esthers. Colorants can be used to improve the appearance of the product. Water-soluble and/or organic solvent- soluble dyes can be used, e.g., albumin lake, titanium dioxide, and iron oxide. Finally, stabilizers such as EDTA can be added to the coating.

Porous Particles for Pulmonary Administration

In one embodiment, the particles are porous, so that they have an appropriate density to avoid deposition in the back of the throat when administered via an inhaler. The combination of relatively large particle size and relatively low density avoids phagocytosis in the lungs, provides appropriately targeted delivery, avoids systemic delivery of rifalazil, and provides a high concentration of rifalazil at the location of the pulmonary bacterial infection.

Representative methods for preparing such particles, and for delivering such particles, are described, for example, in U.S. Patent No. 7,384,649, entitled, "Particulate compositions for pulmonary delivery," U.S. Patent No. 7,182,961 , entitled "Particulate compositions for pulmonary delivery," U.S. Patent No. 7,146,978, entitled, "Inhalation device and method," U.S. Patent No. 7,048,908, entitled "Particles for inhalation having sustained release properties," U.S. Patent No. 6,956,021, entitled "Stable spray-dried protein formulations," U.S. Patent No. 6,766,799, entitled "Inhalation device," and U.S. Patent No. 6,732,732, entitled "Inhalation device and method."

Additional patents disclosing such particles include U.S. Patent No. 7,279,182, entitled "Formulation for spray-drying large porous particles," U.S. Patent No. 7,252,840, entitled "Use of simple amino acids to form porous particles," U.S. Patent No. 7,032,593, entitled "Inhalation device and method," U.S. Patent No. 7,008,644, entitled "Method and apparatus for producing dry particles," U.S. Patent No. 6,848,197, entitled "Control of process humidity to produce large, porous particles," and U.S. Patent No. 6,749,835, entitled "Formulation for spray-drying large porous particles."

U.S. Patent No. 7,678,364, entitled "Particles for inhalation having sustained release properties," discloses methods for delivering particles to the pulmonary system comprising: administering to the respiratory tract of a patient in need of treatment, prophylaxis or diagnosis an effective amount of a dry powder comprising: a) a multivalent metal cation which is complexed with a therapeutic, prophylactic or diagnostic agent; b) a pharmaceutically acceptable carrier; and c) a multivalent metal cation-containing component wherein the dry powder is spray-dried and has a total amount of multivalent metal cation which is about 10% w/w or more of the total weight of the agent, a tap density of about 0.4 g/cm³ or less, a median geometric diameter of between about 5 micrometers and about 30 micrometers and an aerodynamic diameter of from about 1 to about 5 microns.

Delivery of bioactive agents to the pulmonary system typically results in rapid release of the agent following administration. For example, Further, Heinemann, Traut and Heise teach in Diabetic Medicine 14:63-72 (1997) that the onset of action, assessed by glucose infusion rate, in healthy volunteers after inhalation was rapid with the half-maximal action reached in about 30 minutes. However, the large particle size of the rifalazil reduces the systemic delivery of rifalazil. That said, the formulation can be prepared so that the rifalazil is released into the lungs in a sustained fashion.

Particles suitable for inhalation can be designed to possess a sustained release profile. This sustained released profile provides for prolonged residence of the administered rifalazil in the lung and thereby, increases the amount of time in which therapeutic levels of the rifalazil are present in the local environment, or, when microgranulated particles of rifalazil are also present, to the systemic circulation. In addition, one can provide a high initial release or burst of rifalazil, if desired. Consequently, patient compliance and comfort can be increased by not only reducing frequency of dosing, but by providing a therapy which is more amenable and efficacious to patients.

"Pulmonary delivery", as that term is used herein refers to delivery to the respiratory tract. The "respiratory tract", as defined herein, encompasses the upper airways, including the oropharynx and larynx, followed by the lower airways, which include the trachea followed by bifurcations into the bronchi and bronchioli (e.g., terminal and respiratory). The upper and lower airways are called the conducting airways. The terminal bronchioli then divide into respiratory bronchioli which then lead to the ultimate respiratory zone, namely, the alveoli, or deep lung. The deep lung, or alveoli, are typically the desired target of inhaled therapeutic formulations for systemic drug delivery.

"Pulmonary pH range", as that term is used herein, refers to the pH range which can be encountered in the lung of a patient. Typically, in humans, this range of pH is from about 6.4 to about 7.0, such as from 6.4 to about 6.7. pH values of the airway lining fluid (ALF) have been reported in "Comparative Biology of the Normal Lung", CRC Press, (1991) by R. A. Parent and range from 6.44 to 6.74)

The particles of the invention comprise a pharmaceutically acceptable carrier. Suitable pharmaceutically acceptable carriers can be chosen, for example, based on achieving particles having the proper characteristics for inhalation to the area of the respiratory tract where delivery is desired and therapeutic action is achieved.

In a preferred embodiment of the invention, the pharmaceutically acceptable carrier of the particles is a phospholipid. Examples of suitable phospholipids include, among others, phosphatidic acids, phosphatidylcholines, phosphatidylalkanolamines such as a phosphatidylethanolamines, phosphatidylglycerols, phosphatidylserines, phosphatidylinositols and combinations thereof.

Specific examples of phospholipids include, l,2-diacyl-sn-glycero-3- phosphocholine and a l,2-diacyl-sn-glycero-3-phosphoalkanolamine phospholipids. Suitable examples of l,2-diacyl-sn-glycero-3-phosphocholine phospholipids include, but are not limited to, l,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2- distearoyl-sn-glycero-3-phosphocholine (DSPC), 1 ,2-dilaureoyl-sn-3-glycero- phosphocholine (DLPC), l,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2- dioleoyl-sn-glycero-3-phosphocholine (DOPC).

Suitable examples of l,2-diacyl-sn-glycero-3-phosphoalkanolamine phospholipids include, but are not limited to, l,2-dipalmitoyl-sn-glycero-3- ethanolamine (DPPE), l,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE), l,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE), 1,2-dilauroyl-sn-glycero- 3-phosphoethanolamine (DLPE), and l,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE).

Other classes of phospholipids suitable for use in the invention as a pharmaceutically acceptable carrier include l,2-diacyl-sn-glycero-3- alkylphosphocholines and l,2-diacyl-sn-glycero-3-alkylphosphoalkanolamines. Specific examples of l,2-diacyl-sn-glycero-3-alkylphosphocholine phospholipids include, but are not limited to, l,2-dipalmitoyl-sn-glycero-3- ethylphosphocholine (DPePC), 1 ,2-dimyristoyl-sn-glycero-3-ethylphosphocholine (DMePC), l,2-distearoyl-sn-glycero-3-ethylphosphocholine (DSePC), 1,2-dilauroyl- sn-glycero-3-ethylphosphocholine (DLePC), and l,2-dioleoyl-sn-glycero-3- ethylphosphocholine (DOePC).

Specific examples of l,2-diacyl-sn-glycero-3-alkylphosphoalkanolamines include, but are not limited to l,2-dipalmitoyl-sn-glycero-3-ethylethanolamine (DPePE), l,2-dimyristoyl-sn-glycero-3-ethylphosphoethanolamine (DMePE), 1,2- distearoyl-sn-glycero-3-ethylphosphoethanolamine (DSePE), 1,2-dilauroyl-sn- glycero-3-ethylphosphoethanolamine (DLePE), and l,2-dioleoyl-sn-glycero-3- ethylphosphoethanolamine (DOePE).

Other phospholipids are known to those skilled in the art and are described in U.S. patent application Ser. No. 09/752,109 entitled "Particles for Inhalation Having Sustained Release Properties" filed on Dec. 29, 2000 and U.S. patent application Ser. No. 09/752,106 entitled "Particles for Inhalation Having Sustained release Properties" filed on Dec. 29, 2000 the contents of all of which are incorporated herein in their entirety. In a preferred embodiment, the phospholipids are endogenous to the lung.

The phospholipid, can be present in the particles in an amount ranging from about 0 to about 90 weight . More commonly it can be present in the particles in an amount ranging from about 10 to about 60 weight .

In another embodiment of the invention, the phospholipids or combinations thereof are selected to impart controlled release properties to the highly dispersible particles. The phase transition temperature of a specific phospholipid can be below, around or above the physiological body temperature of a patient. Preferred phase transition temperatures range from 30 to 50°C, (e.g., within +/-10 degrees of the normal body temperature of patient). By selecting phospholipids or combinations of phospholipids according to their phase transition temperature, the particles can be tailored to have controlled release properties. For example, by administering particles which include a phospholipid or combination of phospholipids which have a phase transition temperature higher than the patient's body temperature, the release of active agent can be slowed down. On the other hand, rapid release can be obtained by including in the particles phospholipids having lower transition temperatures. Particles having controlled release properties and methods of modulating release of a biologically active agent are described in U.S. patent application Ser. No. 09/644,736 entitled Modulation of Release From Dry Powder Formulations by Controlling Matrix Transition, filed on Aug. 23, 2000, the entire contents of which are incorporated herein by reference.

In another embodiment, the particles of the invention do not include a pharmaceutically acceptable carrier. For example, the dry powder for use in the invention comprises a multivalent metal cation which is complexed with a therapeutic, prophylactic or diagnostic agent or any combination thereof having a charge which permits complexation with the cation upon association with the agent and optionally, a multivalent metal cation-containing component wherein the total amount of multivalent metal cation present in the dry powder is more than 1% weight/weight of the total weight of the agent (% w/w).

The amount of rifalazil present in the particles can be from about 0.1 weight % to about 95 weight %, though in some cases, can even be as high as 100%. For example, from about 1 to about 50%, such as from about 5 to about 30%. Particles in which the drug is distributed throughout a particle can be preferred.

In a further embodiment, the particles can also include other excipients such as, for example, buffer salts, dextran, polysaccharides, lactose, trehalose, cyclodextrins, proteins, polycationic complexing agents, peptides, polypeptides, fatty acids, fatty acid esters, inorganic compounds, phosphates. It is understood, however, that in certain embodiments, the particles are in the substantial absence of the polycationic complexing agent, protamine.

In one embodiment of the invention, the particles can further comprise polymers. Biocompatible or biodegradable polymers are preferred. Such polymers are described, for example, in U.S. Pat. No. 5,874,064, issued on Feb. 23, 1999 to Edwards et al., the teachings of which are incorporated herein by reference in their entirety.

In yet another embodiment, the particles include a surfactant other than the phospholipids described above. As used herein, the term "surfactant" refers to any agent which preferentially absorbs to an interface between two immiscible phases, such as the interface between water and an organic polymer solution, a water/air interface or organic solvent/air interface. Surfactants generally possess a hydrophilic moiety and a lipophilic moiety, such that, upon absorbing to particles, they tend to present moieties to the external environment that do not attract similarly-coated particles, thus reducing particle agglomeration. Surfactants may also promote absorption of a therapeutic or diagnostic agent and increase bioavailability of the agent.

Suitable surfactants which can be employed in fabricating the particles of the invention include but are not limited to hexadecanol; fatty alcohols such as polyethylene glycol (PEG); polyoxyethylene-9-lauryl ether; a surface active fatty acid, such as palmitic acid or oleic acid; glycocholate; surfactin; a poloxamer; a sorbitan fatty acid ester such as sorbitan trioleate (Span 85); Tween 80 and tyloxapol.

The surfactant can be present in the particles in an amount ranging from about 0 to about 5 weight . Preferably, it can be present in the particles in an amount ranging from about 0.1 to about 1.0 weight .

The particles, also referred to herein as powder, can be in the form of a dry powder suitable for inhalation. In a particular embodiment, the particles can have a tap density of less than about 0.4 g/cm.sup.3. Particles which have a tap density of less than about 0.4 g/cm.sup.3 are referred to herein as "aerodynamically light particles". More preferred are particles having a tap density less than about 0.1 g/cm³.

Aerodynamically light particles have a preferred size, e.g., a volume median geometric diameter (VMGD) of at least about 5 microns (μιη). In one embodiment, the VMGD is from about 5 μιη to about 30 μιη. In another embodiment of the invention, the particles have a VMGD ranging from about 9 μιη to about 30 μιη. In other embodiments, the particles have a median diameter, mass median diameter (MMD), a mass median envelope diameter (MMED) or a mass median geometric diameter (MMGD) of at least 5 μιη, for example from about 5 μιη to about 30 μιη.

Aerodynamically light particles preferably have "mass median aerodynamic diameter" (MMAD), also referred to herein as "aerodynamic diameter", between about 1 μιη and about 5 μιη. In one embodiment of the invention, the MMAD is between about 1 μιη and about 3 μιη. In another embodiment, the MMAD is between about 3 μιη and about 5 μιη.

In another embodiment of the invention, the particles have an envelope mass density, also referred to herein as "mass density" of less than about 0.4 g/cm³. The envelope mass density of an isotropic particle is defined as the mass of the particle divided by the minimum sphere envelope volume within which it can be enclosed.

Tap density can be measured by using instruments known to those skilled in the art such as the Dual Platform Microprocessor Controlled Tap Density Tester (Vankel, N.C.) or a GeoPyc.TM. instrument (Micrometrics Instrument Corp., Norcross, Ga. 30093). Tap density is a standard measure of the envelope mass density. Tap density can be determined using the method of USP Bulk Density and Tapped Density, United States Pharmacopia convention, Rockville, Md., 10^th Supplement, 4950-4951, 1999. Features which can contribute to low tap density include irregular surface texture and porous structure.

The diameter of the particles, for example, their VMGD, can be measured using an electrical zone sensing instrument such as a Multisizer He, (Coulter Electronic, Luton, Beds, England), or a laser diffraction instrument (for example Helos, manufactured by Sympatec, Princeton, N.J.). Other instruments for measuring particle diameter are well known in the art. The diameter of particles in a sample will range depending upon factors such as particle composition and methods of synthesis. The distribution of size of particles in a sample can be selected to permit optimal deposition within targeted sites within the respiratory tract.

Experimentally, aerodynamic diameter can be determined by employing a gravitational settling method, whereby the time for an ensemble of particles to settle a certain distance is used to determine the aerodynamic diameter of the particles. An indirect method for measuring the mass median aerodynamic diameter (MMAD) is the multi-stage liquid impinger (MSLI). Specific instruments which can be employed to determine aerodynamic diameters include those known under the name of Aerosizer.TM. (TSI, Inc., Amherst, Mass.) or under the name of Anderson Cascade Impactor (Anderson Inst., Sunyra, Gas.).

The aerodynamic diameter, d_aer, can be calculated from the equation: d_aer=d_g rho_top where d_g is the geometric diameter, for example the MMGD and rho is the powder density.

Particles which have a tap density less than about 0.4 g/cm³, median diameters of at least about 5 μιη, and an aerodynamic diameter of between about 1 μιη and about 5 μιη, preferably between about 1 μιη and about 3 μιη, are more capable of escaping inertial and gravitational deposition in the oropharyngeal region, and are targeted to the airways or the deep lung. The use of larger, more porous particles is advantageous since they are able to aerosolize more efficiently than smaller, denser aerosol particles such as those currently used for inhalation therapies.

In comparison to smaller particles the larger aerodynamically light particles, preferably having a VMGD of at least about 5 μιη, also can potentially more successfully avoid phagocytic engulfment by alveolar macrophages and clearance from the lungs, due to size exclusion of the particles from the phagocytes' cytosolic space. Phagocytosis of particles by alveolar macrophages diminishes precipitously as particle diameter increases beyond about 3 μιη. Kawaguchi, H., et al, Biomaterials 7:61-66 (1986); Krenis, L. J. and Strauss, B., Proc. Soc. Exp. Med., 107:748-750 (1961); and Rudt, S. and Muller, R. H., J Contr. Rel., 22:263-272 (1992). For particles of statistically isotropic shape, such as spheres with rough surfaces, the particle envelope volume is approximately equivalent to the volume of cytosolic space required within a macrophage for complete particle phagocytosis.

The particles may be fabricated with the appropriate material, surface roughness, diameter and tap density for localized delivery to selected regions of the respiratory tract such as the deep lung or upper or central airways. For example, higher density or larger particles may be used for upper airway delivery, or a mixture of varying sized particles in a sample, provided with the same or different therapeutic agent may be administered to target different regions of the lung in one administration. Particles having an aerodynamic diameter ranging from about 3 to about 5 μιη are preferred for delivery to the central and upper airways. Particles having an aerodynamic diameter ranging from about 1 to about 3 μιη are preferred for delivery to the deep lung.

Inertial impaction and gravitational settling of aerosols are predominant deposition mechanisms in the airways and acini of the lungs during normal breathing conditions. Edwards, D. A., J Aerosol Sci., 26:293-317 (1995). The importance of both deposition mechanisms increases in proportion to the mass of aerosols and not to particle (or envelope) volume. Since the site of aerosol deposition in the lungs is determined by the mass of the aerosol (at least for particles of mean aerodynamic diameter greater than approximately 1 μιη), diminishing the tap density by increasing particle surface irregularities and particle porosity permits the delivery of larger particle envelope volumes into the lungs, all other physical parameters being equal.

The low tap density particles have a small aerodynamic diameter in comparison to the actual envelope sphere diameter. The aerodynamic diameter, d_aer, is related to the envelope sphere diameter, d (Gonda, I., "Physico-chemical principles in aerosol delivery," in Topics in Pharmaceutical Sciences 1991 (eds. D. J. A. Crommelin and K. K. Midha), pp. 95-117, Stuttgart: Medpharm Scientific Publishers, 1992)), by the formula: d.sub.aer=d .rho. where the envelope mass p is in units of g/cm³. Maximal deposition of monodispersed aerosol particles in the alveolar region of the human lung (.about.60%) occurs for an aerodynamic diameter of approximately d.sub.aer=3 um. Heyder, J. et al., J Aerosol Sci., 17: 811-825 (1986). Due to their small envelope mass density, the actual diameter d of aerodynamically light particles comprising a monodisperse inhaled powder that will exhibit maximum deep-lung deposition is: d=3/rho_fim (where rho<l g/cm³); where d is always greater than 3 μιη. For example, aerodynamically light particles that display an envelope mass density, p=0.1 g/cm.sup.3, will exhibit a maximum deposition for particles having envelope diameters as large as 9.5 μιη. The increased particle size diminishes interparticle adhesion forces. Visser, J., Powder Technology, 58:1-10. Thus, large particle size increases efficiency of aerosolization to the deep lung for particles of low envelope mass density, in addition to contributing to lower phagocytic losses.

The aerodynamic diameter can be calculated to provide for maximum deposition within the lungs, previously achieved by the use of very small particles of less than about five microns in diameter, preferably between about one and about three microns, which are then subject to phagocytosis. Selection of particles which have a larger diameter, but which are sufficiently light (hence the characterization "aerodynamically light"), results in an equivalent delivery to the lungs, but the larger size particles are not phagocytosed. Improved delivery can be obtained by using particles with a rough or uneven surface relative to those with a smooth surface.

Suitable particles can be fabricated or separated, for example by filtration or centrifugation, to provide a particle sample with a preselected size distribution. For example, greater than about 30%, 50%, 70%, or 80% of the particles in a sample can have a diameter within a selected range of at least about 5 μιη. The selected range within which a certain percentage of the particles must fall may be for example, between about 5 and about 30 μιη, or optimally between about 5 and about 15 μιη. In one preferred embodiment, at least a portion of the particles have a diameter between about 6 and about 11 μιη. Optionally, the particle sample also can be fabricated wherein at least about 90%, or optionally about 95% or about 99%, have a diameter within the selected range. The presence of the higher proportion of the aerodynamically light, larger diameter particles in the particle sample enhances the delivery of therapeutic or diagnostic agents incorporated therein to the deep lung. Large diameter particles generally mean particles having a median geometric diameter of at least about 5 μιη.

The particles can be prepared by spray drying. For example, a spray drying mixture, also referred to herein as "feed solution" or "feed mixture", which includes rifalazil, a pharmaceutically acceptable carrier, and optionally a multivalent metal cation component are fed to a spray dryer.

The total amount of solvent or solvents being employed in the mixture being spray dried generally is greater than 99 weight percent. The amount of solids (drug, charged lipid and other ingredients) present in the mixture being spray dried generally is less than about 1.0 weight percent. Preferably, the amount of solids in the mixture being spray dried ranges from about 0.05% to about 0.5% by weight.

Using a mixture which includes an organic and an aqueous solvent in the spray drying process allows for the combination of hydrophilic and hydrophobic components, while not requiring the formation of liposomes or other structures or complexes to facilitate solubilization of the combination of such components within the particles.

Suitable spray-drying techniques are described, for example, by K. Masters in "Spray Drying Handbook", John Wiley & Sons, New York, 1984. Generally, during spray-drying, heat from a hot gas such as heated air or nitrogen is used to evaporate the solvent from droplets formed by atomizing a continuous liquid feed. Other spray- drying techniques are well known to those skilled in the art. In a preferred embodiment, a rotary atomizer is employed. An example of a suitable spray dryer using rotary atomization includes the Mobile Minor spray dryer, manufactured by Niro, Inc., Denmark. The hot gas can be, for example, air, nitrogen or argon.

Preferably, the particles of the invention are obtained by spray drying using an inlet temperature between about 100 and about 400 °C. and an outlet temperature between about 50 and about 130°C.

The spray dried particles can be fabricated with a rough surface texture to reduce particle agglomeration and improve flowability of the powder. The spray-dried particle can be fabricated with features which enhance aerosolization via dry powder inhaler devices, and lead to lower deposition in the mouth, throat and inhaler device. The particles of the invention can be employed in compositions suitable for drug delivery via the pulmonary system. The particles can be co-delivered with larger carrier particles, not including a therapeutic agent, the latter possessing mass median diameters for example in the range between about 50 μιη and about 100 μιη. The particles can be administered alone or in any appropriate pharmaceutically acceptable vehicle, such as a liquid, for example saline, or a powder, for administration to the respiratory system.

Preferably, particles administered to the respiratory tract travel through the upper airways (oropharynx and larynx), the lower airways which include the trachea followed by bifurcations into the bronchi and bronchioli and through the terminal bronchioli which in turn divide into respiratory bronchioli leading then to the ultimate respiratory zone, the alveoli or the deep lung. In a preferred embodiment of the invention, most of the mass of particles deposits in the deep lung. In another embodiment of the invention, delivery is primarily to the central airways. Delivery to the upper airways can also be obtained.

In one embodiment of the invention, delivery to the pulmonary system of particles is in a single, breath-actuated step, as described in U.S. Patent Application, High Efficient Delivery of a Large Therapeutic Mass Aerosol, application Ser. No. 09/591,307, filed Jun. 9, 2000, which is incorporated herein by reference in its entirety. In another embodiment of the invention, at least 50% of the mass of the particles stored in the inhaler receptacle is delivered to a subject's respiratory system in a single, breath-activated step. In a further embodiment, at least 5 milligrams and preferably at least 10 milligrams of a medicament is delivered by administering, in a single breath, to a subject's respiratory tract particles enclosed in the receptacle. Amounts as high as 15, 20, 25, 30, 35, 40 and 50 milligrams can be delivered.

As used herein, the term "effective amount" means the amount needed to achieve the desired therapeutic or diagnostic effect or efficacy. The actual effective amounts of drug can vary according to the specific drug or combination thereof being utilized, the particular composition formulated, the mode of administration, and the age, weight, condition of the patient, and severity of the symptoms or condition being treated. 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). For example, effective amounts of rifalazil range from about 100 micrograms ^g) to about 10 milligrams (mg).

Aerosol dosage, formulations and delivery systems also may be selected for a particular therapeutic application, as described, for example, in Gonda, I. "Aerosols for delivery of therapeutic and diagnostic agents to the respiratory tract," in Critical Reviews in Therapeutic Drug Carrier Systems, 6:273-313, 1990; and in Moren, "Aerosol dosage forms and formulations," in: Aerosols in Medicine. Principles, Diagnosis and Therapy, Moren, et al., Eds, Esevier, Amsterdam, 1985.

The mass median aerodynamic diameter can be determined using an Aerosizer/Aerodisperser (Amherst Process Instrument, Amherst, Mass). Approximately 2 mg of powder formulation was introduced into the Aerodisperser and the aerodynamic size can be determined by time of flight measurements.

The volume median geometric diameter can be measured using a RODOS dry powder disperser (Sympatec, Princeton, N.J.) in conjunction with a HELOS laser diffractometer (Sympatec). Powder was introduced into the RODOS inlet and aerosolized by shear forces generated by a compressed air stream regulated at 2 bar. The aerosol cloud can be subsequently drawn into the measuring zone of the HELOS, where it scatters light from a laser beam and produced a Fraunhofer diffraction pattern used to infer the particle size distribution and determine the median value.

The volume median geometric diameter can also determined using a Coulter Multisizer II. Approximately 5-10 mg powder formulation can be added to 50 mL isoton II solution until the coincidence of particles was between 5 and 8%.

Formulations and Dosages for Combination Therapies

Rifalazil can be administered to a subject suffering from, or at risk of being infected by, a bacterial lung infection, optionally in conjunction with one or more additional antibiotics. Rifalazil can be administered before, during, or after administration of the additional antibiotics, or any combination thereof. If desired, the administration of Rifalazil can be continued while the additional antibiotic is being administered. The further antibiotics can be co-administered in the pulmonary particles, and/or via oral or parenteral administration. For treatment of TB, exemplary antibiotics include one or more of isoniazid, streptomycin, pyrazinamide, and ethambutol. For treatment of other lung infections, other antibiotics that can be administered include beta-lactams such as penicillins (e.g., penicillin G, penicillin V, methicillin, oxacillin, cloxacillin, dicloxacillin, nafcillin, ampicillin, amoxicillin, carbenicillin, ticarcillin, mezlocillin, piperacillin, azlocillin, and temocillin), cephalosporins (e.g., cepalothin, cephapirin, cephradine, cephaloridine, cefazolin, cefamandole, cefuroxime, cephalexin, cefprozil, cefaclor, loracarbef, cefoxitin, cefmatozole, cefotaxime, ceftizoxime, ceftriaxone, cefoperazone, ceftazidime, cefixime, cefpodoxime, ceftibuten, cefdinir, cefpirome, cefepime, BAL5788, and BAL9141), carbapenams (e.g., imipenem, ertapenem, and meropenem), and monobactams (e.g., astreonam); beta-lactamase inhibitors (e.g., clavulanate, sulbactam, and tazobactam); aminoglycosides (e.g., streptomycin, neomycin, kanamycin, paromycin, gentamicin, tobramycin, amikacin, netilmicin, spectinomycin, sisomicin, dibekalin, and isepamicin); tetracyclines (e.g., tetracycline, chlortetracycline, demeclocycline, minocycline, oxytetracycline, methacycline, and doxycycline); lipopetides (e.g., daptomycin); macrolides (e.g., erythromycin, azithromycin, and clarithromycin); ketolides (e.g., telithromycin, ABT-773); lincosamides (e.g., lincomycin and clindamycin); glycopeptides (e.g., vancomycin, oritavancin, dalbavancin, and teicoplanin); streptogramins (e.g., quinupristin and dalfopristin); sulphonamides (e.g., sulphanilamide, para-aminobenzoic acid, sulfadiazine, sulfisoxazole, sulfamethoxazole, and sulfathalidine); oxazolidinones (e.g., linezolid); quinolones (e.g., nalidixic acid, oxolinic acid, norfloxacin, perfloxacin, enoxacin, ofloxacin, ciprofloxacin, temafloxacin, lomefloxacin, fleroxacin, grepafloxacin, sparfloxacin, trovafloxacin, clinafloxacin, gatifloxacin, moxifloxacin, gemifloxacin, and sitafloxacin); rifamycins (e.g., rifampicin, rifabutin, rifapentine, and rifaximin); metronidazole; garenoxacin; ramoplanin; faropenem; polymyxin; tigecycline, AZD2563; CBR-2092 and trimethoprim.

These antibiotics can be used in the dose ranges and formulations currently known and used for these agents. Different concentrations may be employed depending on the clinical condition of the subject, the goal of therapy (treatment or prophylaxis), the anticipated duration, and the severity of the C. difficile or other infection. Additional considerations in dose selection include the type of infection, age of the subject (e.g., pediatric, adult, or geriatric), general health, and comorbidity. Determining what concentrations to employ are within the skills of the pharmacist, medicinal chemist, or medical practitioner. Typical dosages and frequencies are provided, e.g., in the Merck Manual of Diagnosis & Therapy (17th Ed. M H Beers et al., Merck & Co.) and Physicians' Desk Reference 2003 (57.sup.th Ed. Medical Economics Staff et al., Medical Economics Co., 2002).

In one example, rifalazil is administered in combination with vancomycin. Either the rifalazil or the vancomycin or both may be given daily (e.g., once, twice, three times, or four times daily) or less frequently (e.g., once every other day, once every two days, once every three days, once or twice weekly, or monthly). Typical daily dosages for vancomycin range from 20 mg to 2 gm, preferably 125 mg to 2 gm, or 500 mg to 2 gm, but it may be administered in any higher tolerated amounts as necessary. Daily dosages of vancomycin can be distributed over one to four doses. Exemplary daily oral dosages include from 500 mg to 2 gm distributed over one to four doses for adult subjects and 40 mg/kg distributed over one to four doses for pediatric subjects. Intravenous administration can be given as a one-time bolus per 24-hour period, or for any subset of time over the 24-hour period (e.g., half an hour, one hour, two hours, four hours, or up to 24 hours).

For combination therapy, the rifalazil and the additional antibiotic can be administered simultaneously or sequentially. For sequential administration, the rifalazil can be administered before, during, or after administration of the additional antibiotic, or any combination thereof. In one example, vancomycin is administered for five days and Rifalazil is administered as a single dose on the sixth day. In another example, vancomycin and rifalazil are administered simultaneously on day one followed by administration of vancomycin for an additional six days. These examples are provided to illustrate two potential combinations for sequential therapy. They are not intended to limit the invention in any way.

For combination therapy, the dosage and the frequency of administration of each component of the combination can be controlled independently. For example, one of the compounds (i.e., rifalazil or the additional antibiotic) may be administered three times per day, while the second compound may be administered once per day. The compounds may also be formulated together such that one administration delivers both compounds.

The invention contemplates the use in combination of a therapeutic agent selected from among rifalazil and rifalazil derivatives, with any of the following: antiinflammatory agents, anti-fungal agents, and anti-viral agents.

The invention further contemplates the use of pulmonary administration of rifalazil and/or rifalazil derivatives for treatment of TB, while minimizing the nosocomial infections that can result when antibiotics are systemically administered. Where other antibiotics are simultaneously administered, such as via the oral route, nosocomial infections such as C. difficile can be minimized by administering probiotic bacteria.

Pharmaceutical Packages

The invention also features a pharmaceutical pack comprising (i) rifalazil in an amount effective to treat a subject having TB or another lung infection, in a drug delivery device for pulmonary administration. Desirably, thedrug delivery device is capable of administering rifalazil in unit amounts, such as between 0.01 and 50 mg (e.g., between 0.1 and 10 mg, or between 1 and 5 mg), and is present in amounts sufficient to treat for at least 1, 3, 5, 7, 10, 14, 21, or 31 days. The

pharmaceutical pack of the invention can further comprise one or more antibiotics. Preferred examples of the additional antibiotic, if the infection being treated is not TB, include metronidazole, gentamicin, daptomycin, azithromycin, quinupristin, dalfopristin, linezolid, teicoplanin, ciprofloxacin., and vancomycin. Typical dosages for vancomycin range from 20 to 2000 mg, preferably from 125 to 2000 mg.

Exemplary additional antibiotics that can be administered in the methods of the invention or included in the pharmaceutical pack of the invention are beta-lactams such as penicillins (e.g., penicillin G, penicillin V, methicillin, oxacillin, cloxacillin, dicloxacillin, nafcillin, ampicillin, amoxicillin, carbenicillin, ticarcillin, mezlocillin, piperacillin, azlocillin, and temocillin), cephalosporins (e.g., cepalothin, cephapirin, cephradine, cephaloridine, cefazolin, cefamandole, cefuroxime, cephalexin, cefprozil, cefaclor, loracarbef, cefoxitin, cefmatozole, cefotaxime, ceftizoxime, ceftriaxone, cefoperazone, ceftazidime, cefixime, cefpodoxime, ceftibuten, cefdinir, cefpirome, cefepime, BAL5788, and BAL9141), carbapenams (e.g., imipenem, ertapenem, and meropenem), and monobactams (e.g., astreonam); beta-lactamase inhibitors (e.g., clavulanate, sulbactam, and tazobactam); beta-lactamases, specifically designed to inactivate residual amounts of antibiotics in the patient's gastrointestinal tract, after parenteral administration of beta-lactam antibiotics for serious infections; aminoglycosides (e.g., streptomycin, neomycin, kanamycin, paromycin, gentamicin, tobramycin, amikacin, netilmicin, spectinomycin, sisomicin, dibekalin, and isepamicin); tetracyclines (e.g., tetracycline, chlortetracycline, demeclocycline, minocycline, oxytetracycline, methacycline, and doxycycline); lipopetides (e.g., daptomycin); macrolides (e.g., erythromycin, azithromycin, and clarithromycin); ketolides (e.g., telithromycin, ABT-773); lincosamides (e.g., lincomycin and clindamycin); glycopeptides (e.g., vancomycin, oritavancin, dalbavancin, and teicoplanin); streptogramins (e.g., quinupristin and dalfopristin); sulphonamides (e.g., sulphanilamide, para-aminobenzoic acid, sulfadiazine, sulfisoxazole, sulfamethoxazole, and sulfathalidine); oxazolidinones (e.g., linezolid); quinolones (e.g., nalidixic acid, oxolinic acid, norfloxacin, perfloxacin, enoxacin, ofloxacin, ciprofloxacin, temafloxacin, lomefloxacin, fleroxacin, grepafloxacin, sparfloxacin, trovafloxacin, clinafloxacin, gatifloxacin, moxifloxacin, gemifloxacin, and sitafloxacin); rifamycins (e.g., rifampicin, rifabutin, rifapentine, and rifaximin); metronidazole; garenoxacin; ramoplanin; faropenem; polymyxin; tigecycline, AZD2563; REP3123, OPT-80 and trimethoprim, C. difficile toxin- specific inhibitors (e.g., tolevamer) .

III. Methods of Treatment

Being virtually non-absorbed when administered in the form of relatively large particles, rifalazil's bioavailability within the lungs tract is rather high, with concentrations that largely exceed the minimal inhibitory concentration values observed in vitro against a wide range of pathogenic organisms. The pulmonary tract represents, therefore, the primary therapeutic target and lung infections the main indication. The compositions can also be used to treat TB and other lung infections, such as pneumonia and pleurisy with causative agents including Mycobacterium tuberculosis, Chlamydia pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Haemophilus influenzae. The methods can also be used to treat drug resistant and multi-drug resistant Mycobacterium tuberculosis, drug resistant and multi-drug resistant Chlamydia pneumoniae, drug resistant and multidrug resistant Streptococcus pyogenes, drug resistant and multi-drug resistant Streptococcus agalactiae, drug resistant and multi-drug resistant Staphylococcus aureus, drug resistant and multi-drug resistant Klebsiella pneumoniae, drug resistant and multi-drug resistant Escherichia coli, drug resistant and multi-drug resistant Pseudomonas aeruginosa and drug resistant and multi-drug resistant Haemophilus influenzae. Certain of these lung infections, such as TB, have been treated with rifampicin and rifabutin in conjunction with isoniazid, ethambutol, pyrazinamide and/or streptomycin. When used to treat TB, these agents are commonly administered daily for several months without a break in treatment, to minimize the risk of drug-resistant tuberculosis is greatly increased. Drug resistance is one of the main reasons that rifalazil may be administered in tandem with the three aforementioned drugs, particularly isoniazid.

Because rifalazil has poor solubility, when administered according to the teachings of the invention, it will have little activity outside the pulmonary area, and thus will minimize both antimicrobial resistance and systemic adverse events.

Treatment of TB

Mycobacterium tuburculosis is an anaerobic Gram-positive, spore-forming bacillus, refractory to a number of antimicrobial agents, and endemic in the third world and among immunocompromised patients.

In one embodiment, the methods described herein are directed to the use of a poorly absorbed form of rifalazil, administered locally to lungs, but not significantly available systemically, to treat the lung infection. The methods involve treating TB or other such lung infection, can be treated by maintaining an active concentration of rifalazil in the lungs for a relatively long period of time. That is, by minimizing the systemic circulation of rifalazil, and, ideally, by delivering the rifalazil to the lungs in a drug delivery composition that is specific for pulmonary administration, the rifalazil remains in the lungs for a suitable period of time to treat the lung infections.

In one embodiment, a small portion of the dosage of rifalazil is absorbed systemically, for example, by including microparticulate forms of Rifalazil in combination with the larger particle forms, so the microparticulate forms can travel systemically. Based on the long half-life of rifalazil, by systemically administering a portion of the rifalazil, where it circulates through the body and can travel to the lungs, one can prevent relapses of the disorder, should any of the bacteria survive the initial presentation of Rifalazil in the lungs.

Co-Administration with Other Antibiotics

If desired, rifalazil can be administered with one or more additional antibiotics. Preferred examples of additional antibiotics include one or more of isoniazid, streptomycin, pyrazinamide, and ethambutol. The isoniazid, streptomycin, pyrazinamide, or ethambutol can be administered via pulmonary administration, or, alternatively, can be administered orally or parenterally.

In one embodiment, the isoniazid, streptomycin, pyrazinamide, or ethambutol is administered daily for 8 weeks. In another embodiment, the isoniazid, streptomycin, pyrazinamide, or ethambutol are administered daily for at least the first 2 weeks, followed by twice-a-week dosing for 6 weeks, to complete a 2-month induction phase, then 2-3 times a week for approximately 7 months.

In addition, or in place of to the conventional treatments, such as isozianid, there are new treatments being developed. One or more of these compounds can be used, in one embodiment, to replace one or more of isoniazid, streptomycin, pyrazinamide, and ethambutol.

These compounds include, for example, the diarylquinoline TMC207 (J&J/Tibotec, previously R207910), analogs of TMC-207, as described, for example, in U.S. Application Publication No. 2006/0142279, entitled "Quinoline derivatives as antibacterial agents," fluoroquinolones, Gatifloxacin (G), Moxifloxacin (M), Nitroimidazopyran PA-824, and new compounds by Otsuka Pharmaceuticals (Otsuka Pharmaceutical's OPC-67683) and Lupin Laboratory (a four-in-one therapy including rifampicin, isoniazide, ethambutol, and pyrazinamide, as well as Sudoterb, a pyrrole derivative). The nitroimidazole derivative PA-824, a Chiron compound, can also be used.

The fluoroquinolone (FQ) compounds are a class of synthetic antibiotic derived from nalidixic acid, with a broad spectrum of activity. This family includes ciprofloxacin and a variety of related compounds, two of which are in the current TB pipeline. FQs are well absorbed orally, and have good tissue penetration and relatively long duration of activity. Quinolones are "broad-spectrum antibacterial agents that block DNA replication and kill bacterial cells" (Drlica K, Lu T, Malik M, Zhao X. Fluoroquinolones as antituberculosis agents. Chapter 53 in Rom WN, Garay SM, Tuberculosis, 2nd edition, Lippincott Williams & Wilkins (2004), 791-806). Some newer fluoroquinolones are effective against non-dividing bacteria as well; they do not have cross-resistance to other classes of TB drugs. Several fluoroquinolones have been studied for their antimycobacterial activities (Pletz MW, De Roux A, Roth A, Neumann KH, Mauch H, Lode H. Early bactericidal activity of moxifloxacin in treatment of pulmonary tuberculosis: a prospective, randomized study. Antimicrob Agents Chemother. 2004 Mar;48(3):780-2.; Gradelski E, Kolek B, Bonner D, Fung- Tome J. Bactericidal mechanism of gatifloxacin compared with other quinolones. J Antimicrob Chemother. 2002 Jan;49(l): 185-8).

Further, Pfizer and MicuRx are collaborating on a compound called MRX-1, which is intended to be used in a Phase I clinical trial in the near future.

TMC-207, l-(6-bromo-2-methoxy-quinolin-3-yl)-4-dimethylamino-2- naphthalen-l-yl-1 -phenyl -butan-2-ol, with the following structure:

Analogs of TMC-207 are described, for example, in U.S. Application Publication No. 2006/0142279.

Rifampin can still be included in first line therapy for treating tuberculosis, as can rifapentine. Moxifloxacin can be used to replace isoniazid in first line treatment.

Rifalazil therapy can be combined with protease inhibitor therapy, when the patient is co-infected with HIV and tuberculosis or other lung infection, particularly where the patients to be treated are children.

Combinations of rifalazil and isoniazid, olptoinally also includking rifabutin, rifampicin, or rifapentine, can be used, ideally at a dosage of once per week. The dosage can be for as little as three months, versus daily isoniazid for nine months, for treating latent tuberculosis infection.

Particularly for treating latent tuberculosis, rifalazil can be used to replace rifapentine in the conventional treatment.

Rifalazil can be combined with TMC 207 (Tibotec/Johnson and Johnson), and both drugs have relatively long half lives. TMC 207 is also useful for treating multidrug resistant tuberculosis (MDR-TB), so combination therapy with TMC 207 can be preferred for this indication.

Additional antimicrobial compounds that can be added include CPZEN-45 (Microbial Chemistry Research Foundation, Tokyo, Japan, Lilly TB Drug Discovery Initiative, NIAID, IDRI, Lilly, YourEncore), Quinolone DC-159a (Japan Anti- Tuberculosis Association, JATA, Daiichi-Sankyo Pharmaceutical Co.), SQ609 (Sequella),

SQ641 (Sequella), Benzothiazinone (New Medicines For Tuberculosis (NM4TB)), Q201-(Quro Science, Inc.), PNU-100480 (Pfizer), SQ109 (Sequella, NIHS), AZD5847 (Astrazeneca), PA-824 (TB Alliance), NCOOl (TB Alliance), and low-dose linezolid, particularly for the Treatment of Multi-Drug Resistant Tuberculosis (TBTC, Pfizer).

In another embodiment, rather than, or in addition to, including rifalazil in absorbable form (i.e., microparticulate form), one can co-administer oral vancomycin. The co- administration of rifalazil can minimize the development of vanco-resistant bacterial infections.

In certain embodiments of the invention, the method includes administering rifalazil and one or more additional antibiotics simultaneously or sequentially. Rifalazil and one or more additional antibiotics can be administered within fourteen days of each other, or within five days, three days, or within twenty-four hours of each other. If desired, the one or more additional antibiotics can be administered via pulmonary administration, though they can also be administered orally or parenterally.

The dosage of rifalazil in various embodiments can range from 0.01 mg to 100 mg. The dosage of rifalazil is e.g., normally about 1 to 100 mg (desirably about 0.1 to 10 mg, more desirably about 1 to 5 mg). The Rifalazil can be given daily (e.g., once, twice, three times, or four times daily) or less frequently (e.g., once every other day, once or twice weekly, or monthly). Rifalazil is administered for a length of time sufficient to treat the subject. Treatment may be for 1 to 31 days, desirably 1 to 21 days, 1 to 14 days or even 1, 3, 5, or 7 days. If desired, treatment can continue for up to a year or even for the lifetime of the subject. In one example, rifalazil is administered at an initial dose of between 5 and 100 mg, followed by subsequent doses of between 1 and 50 mg for 3 to 7 days. A single dose of rifalazil (e.g., in a dosage of between 1 and 100 mg) can also be employed.

The method can be employed as an initial treatment of a subject having or being at risk for developing a lung infection, for example, health care providers, police officers, and soldiers, particularly those serving in geographic regions where there is a high incidence of TB infection. The method can also be employed when the subject is colonized with TB that is resistant to one or more antibiotics commonly used to treat this disorder.

Co-Administration with Anti-Fungals

Lung infections may include, in addition to a bacterial component, a fungal component. This is particularly true with respect to immunocompromised patients. Representative fungal infections include Pneumocystis jiroveci pneumonia, aspergillosis pulmonary infections, and cryptococcosis.

Pneumocystis jiroveci pneumonia (also referred to as PCP) is the most common opportunistic infection among HIV patients, and is caused by a fungus called Pneumocystis jiroveci. This disease is considered an AIDS-defining illness, because when HIV-infected patients develop PCP, their condition has progressed to AIDS. This disease almost always affects the lungs causing a type of pneumonia, with symptoms such as difficulty breathing, fever, and a dry cough. Other common symptoms include chest discomfort, weight loss, chills, spitting up blood (rare), rapid breathing, fast heart rate, cyanosis (bluish discoloration of the skin), nasal flaring, and intercostal retractions (visible use of muscles between the ribs that indicates labored breathing).

PCP can be treated effectively with antifungal medications. TMP/SMX (Bactrim® or Septra®) is the most effective treatment for PCP. The drug is a combination of two antibiotics, trimethoprim (TMP) and sulfamethoxazole (SMX), which work synergistically to kill the fungus. Patients typically receive treatment for the rest of their lives to prevent the infection from recurring.

The Aspergillus fungus causes aspergillosis pulmonary infections. Although there are more than 100 Aspergillus species, most human illnesses are caused by Aspergillus fumigatus or Aspergillus niger or, less frequently, Aspergillus flavus or Aspergillus clavatus. Aspergillosis is not considered an AIDS-defining illness. This means that patients who develop aspergillosis do not necessarily have AIDS.

There are four main types of aspergillosis: allergic bronchopulmonary aspergillosis (ABPA), chronic necrotizing Aspergillus pneumonia (CNAP), aspergilloma, and invasive aspergillosis. ABPA is a hypersensitive reaction to A. fumigatus, which causes inflammation of the airways and air sacs of the lungs. CNAP is a rare condition that usually occurs in patients who have weakened immune systems. An aspergilloma is a fungus ball (mycetoma) that develops in a preexisting lung cavity (abnormal space between the membranes that line the lungs). Invasive aspergillosis is a rapidly progressive, often fatal infection that occurs in patients who have extremely weakened immune systems.

When a human host inhales the fungus spores, the organism enters the lungs. Macrophages (white blood cells that kill microorganisms that enter the body) and neutrophils (white blood cells that destroy foreign substances that enter the body) will engulf the invading fungus to prevent infection.

However, many species of Aspergillus produce toxic metabolites that may prevent macrophages and neutrophils from engulfing them. Individuals who are taking corticosteroids or have immunodeficiencies (like HIV/AIDS) have impaired macrophage and neutrophil function, making it even more difficult to fight off the fungus. Consequently, HIV patients are unable to fight off the invading fungus and therefore suffer from pulmonary infections.

Common symptoms include fever, cough, dyspnea (shortness of breath), tachypnea (rapid breathing), chest pain, hypoxemia (low levels of oxygen in the blood), and sometimes hemoptysis (blood in sputum).

Aspergillosis is diagnosed once the fungus has been identified in the patient's tissue. Procedures and tests, such as a sputum sample analysis, bronchoalveolar lavage, lung biopsy, chest X-ray, and computerized tomography (CT) scan, are performed to identify the fungus and to assess the tissue damage.

Treatment varies depending on the specific type of aspergillosis. An antifungal called voriconazole (Vfend®) is commonly used to treat pulmonary aspergillosis. Other antifungals, such as itraconazole (Sporanox®), caspofungin (Cancidas), or amphotericin B formulations (Fungilin®, Fungizone®, Abelcet®, AmBisome®, Fungisome®, Amphocil®, and Amphotec®), have also been used.

Cryptococcus neoformans, a type of yeast found worldwide, can cause pulmonary and central nervous system (CNS) infections that can potentially spread to other areas of the body. This infection is called cryptococcosis. HIV/AIDS patients are especially vulnerable to developing the infection. If the infection spreads from the lungs to the CNS (brain and spinal cord) of an HIV patient, the condition is considered an AIDS-defining illness. This means the patient's condition has progressed to AIDS. Most infections develop after the yeast has been inhaled into the lungs. The fungus strongly resists phagocytosis, so the immune system cells have to work hard to engulf the organism.

Cryptococcosis usually starts with a pulmonary (lung) infection, which then spreads to the CNS. If left untreated, the infection may continue to spread to other organs in the body, including the skin, prostate and medullary cavity of the bones. Common symptoms of pulmonary involvement include fever, general feeling of discomfort, dry cough, pain in the membrane surrounding the lungs, and rarely, hemoptysis (blood in sputum).

Initially, amphotericin B (Amphocin® or Fungizone®), a type of antifungal medication, is administered at 0.7-1 milligrams/kilogram/day for two weeks, with or without two weeks 100 milligrams/kilogram/day of flucytosine. Once initial treatment is completed, a maintenance therapy of 200-400 milligrams/day of fluconazole for life is recommended as a preventative measure against future Cryptococcus infections.

In immunocompromised patients suffering from both fungal and bacterial infections, co-administration of azole antifungals, such as fluconazole, itraconazole, sulfamethoxazole, and voriconazole to treat the fungal infection and rifalazil to treat the bacterial infection can be useful for maintaining the therapeutic efficacy of the azole antifungal. Unlike co- administration of rifabutin or rifampicin, there will not be a massive reduction of systemic exposure to azole antifungals due to induced metabolism.

The anti-fungals can be administered via pulmonary administration, oral administration, or parenteral administration, as appropriate, and the therapy is not expected to interfere with the administration of rifalazil, particularly since the rifalazil is being administered to the pulmonary system, and is expected to provide very low systemic levels of rifalazil due to its poor solubility.

VII. Methods of Treating Disorders Other than Tuberculosis

The compositions described herein can be used to treat bacterial infections other than tuberculosis, and disorders mediated by such infections. In one embodiment, the patients are immunocompromised patients.

Where a patient is suffering from a bacterial infection caused by one of the above-listed bacteria, which have an active form as well as an inactive, latent form, and is also being treated for another disorder with an agent that is metabolized by CYP450, the patient can be treated for the bacterial infection by administering rifalazil or a rifalazil analog that does not modulate CYP450. Ideally, the rifalazil or a rifalazil analog is administered for a longer period of time than would be required to treat the active bacteria, so that it can accumulate in the patient's cells, and the drug's persistence in the blood stream and within the cells will enable it to be present to treat the latent form of the bacteria, when it transitions into the active form. In this manner, one can prevent a relapse of a bacterial infection.

The compositions can be used to treat drug resistant Gram-positive cocci, such as methicillin-resistant S. aureus and vancomycin-resistant enterococci, and are useful in the treatment of community- acquired pneumonia, upper and lower respiratory tract infections, skin and soft tissue infections, hospital-acquired lung infections, bone and joint infections, and other bacterial infections.

The time sufficient to treat a bacterial infection in the lungs ranges from one week to one year, but it can also be extended over the lifetime of the individual patient, if necessary. In more preferable embodiments, the duration of treatment is at least 30 days, at least 45 days, at least 100 days, or at least 180 days. Ultimately, it is most desirable to extend the treatment for such a time that the bacterial infection is no longer detected.

The compositions described herein can be used as therapy for treating tuberculosis and other bacterial disorders treatable with rifalazil and rifalazil derivatives described herein, in any and all of these patients. When used to treat immunocompromised patients, the treatment with rifalazil can be in combination or alternation with existing therapies used to manage disorders that result in the patient being immunocompromised, such as, for example, cancers, liver disorders, HIV, HBV, and HCV.

Treatment of Asthma Patients

In one embodiment, the compositions can also be used to treat asthma patients suffering from tuberculosis. In this embodiment, the rifalazil is combined with an anti- asthmatic, such as ventoline, or steroidal anti-inflammatory agents commonly used to treat asthma. Methods for treating asthma patients suffering from tuberculosis, which involve administering this composition to a patient in need of treatment thereof, are also within the scope of the invention. Treatment of Immunocompromised Patients

The compositions described herein can be used to treat immunocompromised patients, including cancer patients, HIV-positive patients, HBV patients, and HCV patients, suffering from a tuberculosis or other bacterial lung infection, or at risk for being infected with tuberculosis or other bacterial lung infection.

When the immunocompromised patients have an HIV, HBV, and/or HCV infection, and are co-infected with tuberculosis, by using the compositions described herein, the patients can continue their existing HIV, HBV, and/or HCV treatments without fear of complications resulting from induction of CYP450, as is the case with other rifamycins, such as rifampicin and rifabutin.

Treatment of HIV-Positive Patients

Ideally, the management of TB among HIV-infected patients taking antiretroviral drugs includes directly observed therapy, and the availability of experienced and coordinated TB/HIV care givers (CDC, Recommendations and Reports, October 30, 1998 / 47(RR20);1-51, Prevention and Treatment of Tuberculosis Among Patients Infected with Human Immunodeficiency Virus: Principles of Therapy and Revised Recommendations). As described herein, the management of TB also includes the use of a TB treatment regimen that includes rifalazil instead of rifampin. The same holds true for patients with cancer, HBV, HCV, and various liver disorders.

Because the use of rifalazil as an alternative to the use of rifampin or rifabutin for antituberculosis treatment is now available, the previously recommended practice of stopping protease inhibitor therapy to allow the use of rifampin or rifabutin for TB treatment is no longer needed for patients with HIV -related TB. This is particularly true due to the low degree of systemic administration of rifalazil, as it is administered in a poorly dissolved form.

The use of the anti-tuberculosis regimens described herein may further include an assessment of the patient's response to treatment to decide the appropriate duration of therapy (i.e., 6 months or 9 months). Physicians and patients also should be aware that paradoxical reactions might occur during the course of TB treatment when antiretroviral therapy restores immune function. Short-course (i.e., 2 months) multidrug regimens (e.g., rifalazil or a rifalazil derivative, combined with pyrazinamide or other anti-TB agents) can be used to prevent TB in persons with HIV infection.

The co-treatment of mycobacterium tuberculosis infection and HIV infection can take into consideration the frequency of co-existing TB and HIV infection and rates of drug-resistant TB among patients infected with HIV; the co-pathogenicity of TB and HIV disease; the potential for a poorer outcome of TB therapy and paradoxical reactions to TB treatment among HIV-infected patients; and therapies to prevent TB among HIV-infected persons. Effective treatments for TB patients co- infected with HIV can not only help reduce new cases of TB in general, but also help decrease further transmission of drug-resistant strains and new cases of drug-resistant TB.

The Use of Rifalazil in Combination with Anti-Retroviral Agents

Widely used antiretroviral drugs available in the United States include protease inhibitors (saquinavir, indinavir, ritonavir, and nelfinavir) and nonnucleoside reverse transcriptase inhibitors (NNRTIs) (nevirapine, delavirdine, and efavirenz). Protease inhibitors and NNRTIs have substantive interactions with certain rifamycins (rifampin, rifabutin, and rifapentine) used to treat mycobacterial infections. These drug interactions principally result from changes in the metabolism of the antiretroviral agents and the rifamycins secondary to induction or inhibition of the hepatic cytochrome CYP450 enzyme system. Rifamycin-related CYP450 induction decreases the blood levels of drugs metabolized by CYP450. For example, if protease inhibitors are administered with rifampin (a potent CYP450 inducer), blood concentrations of the protease inhibitors (all of which are metabolized by CYP450) decrease markedly, and most likely the antiretroviral activity of these agents declines as well. Conversely, if ritonavir (a potent CYP450 inhibitor) is administered with rifabutin, blood concentrations of rifabutin increase markedly, and most likely rifabutin toxicity increases as well. These undesirable side effects are avoided by using rifalazil or the other rifamycin analogs described herein, instead of rifampin, rifabutin, or rifapentine.

In contrast to the protease inhibitors and the NNRTIs, the other class of antiretroviral agents available, nucleoside reverse transcriptase inhibitors (NRTIs) (zidovudine, didanosine, zalcitabine, stavudine, and lamivudine) are not metabolized by CYP450. Rifampin (and to a lesser degree, rifabutin) increases the glucuronidation of zidovudine and thus slightly decreases the serum concentration of zidovudine. The effect of this interaction probably is not clinically important, and the concurrent use of NRTIs and rifamycins is not contraindicated.

Because current treatment regimens frequently include two NRTIs combined with a potent protease inhibitor (or, as an alternative, combined with an NNRTI), and the protease inhibitors and NNRTIs are adversely affected by conventional anti-TB agents, the patients receiving dual treatment with these regimens are at risk for developing resistant mutations of HIV. Accordingly, the use of rifampin to treat active TB in a patient who is taking a protease inhibitor or an NNRTI is always contraindicated. Rifabutin is a less potent inducer of the CPY450 cytochrome enzymes than rifampin, and, in modified doses, might not be associated with a clinically significant reduction of protease inhibitors or nevirapine. Rifapentine is not recommended as a substitute for rifampin because its safety and effectiveness have not been established for treating patients with HIV-related TB.

TB treatment regimens that contain no rifamycins, for example, TB treatment regimens consisting of streptomycin and isoniazid, have been proposed as an alternative for patients who take protease inhibitors or NNRTIs. However, these TB regimens have not been studied among patients with HIV infection.

For this reason, the treatment regimens using rifalazil or rifalazil derivatives described herein overcome the limitations of the prior TB treatment for HIV-infected individuals.

In one embodiment, the initial phase of a 9-month TB regimen consists of rifalazil or a rifalazil derivative, along with one or more of isoniazid, streptomycin, pyrazinamide, and ethambutol administered a) daily for 8 weeks or b) daily for at least the first 2 weeks, followed by twice-a-week dosing for 6 weeks, to complete the 2-month induction phase. The second phase of treatment involves administration of rifalazil or a rifalazil derivative, along with one or more of isoniazid, streptomycin, and pyrazinamide, 2-3 times a week for 7 months.

Another option is a 6-month regimen that includes rifalazil or a rifalazil derivative, along with one or more of isoniazid, rifampin, pyrazinamide, and ethambutol (or streptomycin). These drugs are administered a) daily for 8 weeks or b) daily for at least the first 2 weeks, followed by 2-3-times-per-week dosing for 6 weeks, to complete the 2-month induction phase. The second phase of treatment includes a) isoniazid and rifalazil or a rifalazil derivative administered daily or 2-3 times a week for 4 months. Rifalazil or a rifalazil analog, and one or more of isoniazid, pyrazinamide, and ethambutol (or streptomycin) also can be administered three times a week for 6 months

Pyridoxine (vitamin B6) (25-50 mg daily or 50-100 mg twice weekly) can be administered to all HIV-infected patients who are undergoing TB treatment with isoniazid, to reduce the occurrence of isoniazid-induced side effects in the central and peripheral nervous system.

The CDC's most recent recommendations for the use of treatment regimens is 6 months, to complete a) at least 180 doses (one dose per day for 6 months) or b) 14 induction doses (one dose per day for 2 weeks) followed by 12 induction doses (two doses per week for 6 weeks) plus 36 continuation doses (two doses per week for 18 weeks). While the use of rifalazil and/or rifalazil derivatives may obviate the need for such lengthy treatment, the CDC guidelines can be useful in determining an appropriate baseline treatment modality, and patient monitoring can be used to determine whether the treatment duration can be shortened.

The minimum duration of short-course rifampin-containing TB treatment regimens can be, for example, 6 months, to complete a) at least 180 doses (one dose per day for 6 months) or b) 14 induction doses (one dose per day for 2 weeks) followed by 12-18 induction doses (two to three doses per week for 6 weeks) plus 36- 54 continuation doses (two to three doses per week for 18 weeks). The same duration can be used for rifalazil therapy.

Three-times-per-week rifalazil regimens can include at least 78 doses administered over 26 weeks.

The final decision on the duration of therapy should consider the patient's response to treatment. For patients with delayed response to treatment, the duration of rifalazil-based regimens should be prolonged from 6 months to 9 months (or to 4 months after culture conversion is documented).

Interruptions in therapy because of drug toxicity or other reasons should be taken into consideration when calculating the end-of-therapy date for individual patients. Completion of therapy is typically based on the total number of medication doses administered, rather than on duration of therapy alone.

Reinstitution of therapy for patients with interrupted TB therapy might require a continuation of the regimen originally prescribed (as long as needed to complete the recommended duration of the particular regimen) or a complete renewal of the regimen. In either situation, when therapy is resumed after an interruption of greater than or equal to 2 months, sputum samples (or other clinical samples as appropriate) should be taken for smear, culture, and drug- susceptibility testing.

When caring for persons with HIV infection, clinicians should make aggressive efforts to identify those who also are infected with M. tuberculosis. Because the reliability of the tuberculin skin test (TST) can diminish as the CD4+ T- cell count declines, it can be important to screen for TB with TST as soon as possible after HIV infection is diagnosed. Because the risk of infection and disease with M. tuberculosis is particularly high among HIV-infected contacts of persons with infectious pulmonary or laryngeal TB, these persons should be evaluated for TB as soon as possible after learning of exposure to a patient with infectious TB.

Monthly Monitoring of Patients During TB Preventive Treatment

Patients in high-risk areas, in high-risk occupations, such as medical care professionals, police officers, and soldiers, or at high risk for exposure to TB, such as family members, friends, and immunocompromised individuals, may undergo preventative treatment. Patients undergoing preventive treatment for TB can optionally receive a periodic, for example, a monthly clinical evaluation of their adherence to treatment and medication side effects.

In one embodiment, the preventive therapy regimens include the use of a combination of at least two antituberculosis drugs that the infecting strain is believed to be susceptible to (e.g., rifalazil or a rifalazil derivative, in combination with ethambutol pyrazinamide, levofloxacin or ethambutol). The clinician can review the drug-susceptibility pattern of the M. tuberculosis strain isolated from the infecting source-patient before choosing a preventive therapy regimen.

Follow-up of HIV-infected Persons Who Have Completed Preventive Therapy Follow-up care, including chest x-rays and medical evaluations, may not be necessary for patients who complete a course of TB preventive treatment, unless they develop symptoms of active TB disease or are subsequently re-exposed to a person with infectious TB disease. All publications and patents mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described method and system of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention.

Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention that are obvious to those skilled in microbiology or related fields are intended to be within the scope of the invention.

Claims

Claims

1. A method for treating a subject having a bacterial lung or upper airway or ear infection or preventing a bacterial lung infection in a patient, comprising administering to said patient an effective amount of rifalazil in a poorly absorbed form, wherein the average particle size of the rifalazil is greater than about 10 μιη, wherein the administration is pulmonary administration.

2. The method of claim 1, wherein said rifalazil is administered in an amount between 0.01 and 100 mg/day.

3. The method of claim 2, wherein said rifalazil is administered in an amount between 0.1 and 10 mg/day.

4. The method of claim 3, wherein said rifalazil is administered in an amount between 1 and 5 mg/day.

5. The method of any of Claims 1-4, wherein said rifalazil is administered for one to fourteen days.

6. The method of claim any of Claims 1-4, wherein said rifalazil is administered for three to seven days.

7. The method of any of Claims 1-4, wherein said rifalazil is administered once per week, twice per week, once per month, or twice per month.

8. The method of claim 1, wherein said Rifalazil is administered at an initial dose of between 5 and 100 mg, followed by subsequent doses of between 0.1 and 50 mg for three to seven days.

9. The method of any of Claims 1-4, wherein the bacterial lung infection is a tuberculosis, staphylococcus, or streptococcus infection.

10. The method of Claim 9, wherein the tuberculosis is drug-resistant tuberculosis, drug resistant staphyloccocus and streptococcus.

11. The method of any of Claims 1-4, wherein the patient is immunocompromised with an infection selected from the group consisting of HIV, HBV, or HCV infections.

12. The method of any of Claims 1-4, further comprising the coadministration of one or more additional antibiotics.

13. The method of any of Claims 1-4, wherein rifalazil is administered with an additional antibiotic, either in combination or alternation.

14. The method of Claim 13, wherein the one or more additional antibiotics are selected from the group consisting of isoniazid, streptomycin, pyrazinamide, and ethambutol.

15. The method of Claim 14, wherein the isoniazid, streptomycin, pyrazinamide, or ethambutol is administered orally or parenterally.

16. The method of Claim 14, wherein the isoniazid, streptomycin, pyrazinamide, or ethambutol is administered daily for 8 weeks.

17. The method of Claim 14, wherein the isoniazid, streptomycin, pyrazinamide, or ethambutol is administered daily for at least the first 2 weeks, followed by twice-a-week dosing for 6 weeks, to complete a 2-month induction phase, then 2-3 times a week for approximately 7 months.

18. A composition for pulmonary administration, comprising an effective amount of particles of rifalazil in a poorly absorbed form, wherein the average particle size of the rifalazil is greater than about 10 μιη, and a drug delivery device capable of administering the particles of rifalazil to the pulmonary system.

19. The composition of Claim 18, wherein said Rifalazil is administered in an amount between 0.01 and 100 mg/day.

20. The composition of Claim 18, wherein said Rifalazil is administered in an amount between 0.1 and 10 mg/day.

21. The composition of Claim 18, wherein said Rifalazil is administered in an amount between 1 and 5 mg/day.

22. The composition of Claim 18, wherein the composition comprises a sufficient amount of rifalazil for administration over a fourteen day period, in metered doses.

23. The composition of Claim 18, wherein the drug delivery device is a metered dosage inhaler.

24. The composition of Claim 18, further comprising one or more antibiotics selected from the group consisting of isoniazid, streptomycin, pyrazinamide, and ethambutol.

25. The composition of Claim 24, wherein the isoniazid, streptomycin, pyrazinamide, or ethambutol is provided in a drug delivery vehicle for oral or parenteral administration.

26. The composition of Claim 18, further comprising ventoline.

27. A method of treating asthma patients suffering from tuberculosis, comprosing administering the composition of Claim 18 to a patient in need of treatment thereof.

28. The composition of Claim 18, further comprising Izoniazide

29. Use of particles of rifalazil in a poorly absorbed form, wherein the average particle size of the rifalazil is greater than about 10 μιη, in the preparation of a medicament for treating a subject having a bacterial lung infection, or preventing a bacterial lung infection in a patient, wherein rifalazil particles are present in a suitable drug delivery device for delivering the particles via pulmonary administration.

30. The use of claim 29, wherein the drug delivery device for delivering the particles of rifalazil via pulmonary administration is a metered inhaler, which administers between 0.01 and 100 mg of rifalazil per dose.

31. The use of claim 30, wherein each dose of Rifalazil is between 0.1 and 10 mg/day.

32. The use of claim 30, wherein each dose of Rifalazil is between 1 and 5 mg/day.

33. The use of claim 30, wherein the inhaler comprises at least fourteen metered doses.

34. The use of Claim 18, wherein the medicament further comprises one or more additional antibiotics selected from the group consisting of isoniazid, streptomycin, pyrazinamide, and ethambutol.

35. The use of Claim 34, wherein the medicament is selected to provide isoniazid, streptomycin, pyrazinamide, or ethambutol via oral or parenteral administration.