WO2016201283A1

WO2016201283A1 - Antifungal agents

Info

Publication number: WO2016201283A1
Application number: PCT/US2016/036966
Authority: WO
Inventors: Kenneth Duke James; James Michael BALKOVEC; Allen Borchardt
Original assignee: Cidara Therapeutics, Inc.
Priority date: 2015-06-12
Filing date: 2016-06-10
Publication date: 2016-12-15

Abstract

The invention features echinocandin class compounds. The compounds can be useful for the treatment of fungal infections.

Description

ANTIFUNGAL AGENTS Background

The need for novel antifungal treatments is significant, and is especially critical in the medical field. Immunocompromised patients provide perhaps the greatest challenge to modern health care. During the last three decades there has been a dramatic increase in the frequency of fungal infections in these patients (Herbrecht, Eur. J. Haematol., 56:12, 1996; Cox et al., Curr. Opin. Infect. Dis., 6:422, 1993; Fox, ASM News, 59:515, 1993). Deep-seated mycoses are increasingly observed in patients undergoing organ transplants and in patients receiving aggressive cancer chemotherapy (Alexander et al., Drugs, 54:657, 1997). The most common pathogens associated with invasive fungal infections are the opportunistic yeast, Candida albicans, and the filamentous fungus, Aspergillus fumigatus (Bow, Br. J. Haematol., 101 :1 , 1998; Wamock, J. Antimicrob. Chemother., 41 :95, 1998). There are an estimated 200,000 patients per year who acquire nosocomial fungal infections (Beck-Sague et al., J. Infect. Dis., 167:1247, 1993). Also adding to the increase in the numbers of fungal infections is the emergence of Acquired Immunodeficiency Syndrome (AIDS) where virtually all patients become affected with some form of mycoses during the course of the disease (Alexander et al., Drugs, 54:657, 1997; Hood et al., J. Antimicrob. Chemother., 37:71 , 1996). The most common organisms encountered in these patients are Cryptococcus neoformans, Pneumocystis carinii, and C. albicans (HIV/AIDS Surveillance Report, 1996, 7(2), Year-End Edition; Polis, M. A. et al., AIDS: Biology, Diagnosis, Treatment and Prevention, fourth edition, 1997). New opportunistic fungal pathogens such as Penicillium marneffei, C. krusei, C. glabrata, Histoplasma capsulatum, and Coccidioides immitis are being reported with regularity in

immunocompromised patients throughout the world.

The development of antifungal treatment regimens has been a continuing challenge. Currently available drugs for the treatment of fungal infections include amphotericin B, a macrolide polyene that interacts with fungal membrane sterols, flucytosine, a fluoropyrimidine that interferes with fungal protein and DNA biosynthesis, and a variety of azoles (e.g., ketoconazole, itraconazole, and fluconazole) that inhibit fungal membrane-sterol biosynthesis (Alexander et al., Drugs, 54:657, 1997).

For decades, the basis of most antifungal therapy has been the polyenes, specifically

amphotericin B-based medications, the cytosine analogue 5-fluorocytosine, and triazole compounds. Polyene-based therapy is plagued by the problem of toxicity. Azoles and 5-fluorocytosine have the limitation of resistance emergence in yeast infections, especially problematic in the therapy of Candida glabrata (Nguyen et al., Am. J. Med., 100:617 (1996); Gumbo et al., Medicine (Baltimore), 78:220 (1999); Alexander et al., Transplantation, 80:868 (2005)). Indeed, even after apparent therapeutic success with these agents, recurrence of infection has been noted months to years later (Nasser et al., Am. J. Med., 103:25 (1997); Clancy et al., Eur. J. Clin Microbiol. Infect. Dis., 19:585 (2000); Gumbo et al., Scand. J. Infect. Dis., 34:817 (2002)). Thus, development of new classes of antifungal agents is imperative. One class of new antifungal agents that have reached clinical use is that of echinocandins, of which anidulafungin is the latest member. The echinocandins have activity against Candida and Aspergillus species, but not C. neoformans. When the echinocandin caspofungin was approved for sale in 2001 , it represented the first new class of antifungal agents to be approved in over a decade. Since that time, two other echinocandin antifungals, micafungin and anidulafungin have been approved in various markets. Each agent in this class of compound acts by inhibition of β-1 ,3-D-glucan synthase, which is a key enzyme in the synthesis of glucan in the cell wall of many fungi. All three of these drugs are made semisynthetically, starting with natural products obtained through fermentation.

The echinocandins are a broad group of antifungal agents that typically are comprised of a cyclic hexapeptide and lipophilic tail, the latter of which is attached to the hexapeptide core through an amide linkage. Although many echinocandins are natural products, the clinically relevant members of this class have all been semisynthetic derivatives. Although the naturally occurring echinocandins possess some degree of anti-fungal activity, they have not been suitable as therapeutics, primarily because of poor aqueous solubility, insufficient potency, and/or hemolytic action. The approved echinocandins are the products of intense efforts to generate derivatives that maintain or improve upon the glucan synthase inhibition, but do not cause the hemolytic effects. As therapeutic agents, they are attractive compounds in terms of their large therapeutic windows, safety profiles, and relative lack of interactions with other drugs. Unfortunately, the poor aqueous solubility and poor intestinal absorption of these compounds have relegated them to delivery by intravenous infusion. Although patients receiving these drugs are often hospitalized with serious infections, the ability to transition patients from intravenous delivery in a hospital setting to oral delivery in a home setting would be very desirable, especially considering the course of the regimen commonly exceeds 14 days. In addition, an oral echinocandin may expand the use of this drug class to include patients that present with mild fungal infections.

Summary of the Invention

Described are derivatives of echinocandin antifungals of formulas (la)-(Vb).

Certain compounds are described by any one of formulas (la)-(lc), or a pharmaceutically acceptable sal

In formulas (la)-(lc), Ri is H, CH₃, CH2CONH2, CH2CN, or CH2CH2NH2; R2 is H or CH₃; R₃ is H, CH3, or OH; each of R4, R5, and R6 is, independently, selected from CH3, CH2CH3, CH2CH2CH3, and CH(CH₃)₂; A is CH2(CH₂)n, C2H4OC2H4, CsHeOCsHe, or C₄H₈OC4H8, C2H4OC2H4OC2H4,

CsHeOCsHeOCsHe, or C4H8OC4H8OC4H8; each of W, X, and Y is, independently, selected from H and OH; Z is H, OH, OSO3H, or OPO3H; each of B, C, and D is, independently, selected from optionally substituted alkyl, alkenyl, alkynyl, aryl, carbocyclyl, heteroaryl, heterocyclyl, or are absent, provided that at least one of B, C, and D is present, wherein B and C, when present, are joined by a direct bond, -0-, or -CH2=CH2- and C and D, when present, are joined by a direct bond, -0-, or -CH2=CH2-; and n is an integer from 1 to 4 (such as 1 or 2), provided that when Ri is CH3; R2 is CH3; R3 is CH3; A is CH2CH2 or C2H4OC2H4 and R₆ is CH₃; each of W, X, and Y is OH; and B, C, and D, together, have the formula

, then Z is OH, OSO3H, or OPO3H; and wherein a) when Ri is CH₃; R₂ is CH₃; R3 is CH₃; A is CH2CH2 or CH2CH2CH2; each of R₄ and R₅ is CH₃; Re is CH₃ or CH2CH2CH3; each of W and X is OH; Y is H or OH; and B, C, and D, together, have the formula -(CH₂)i6CH₃, then Z is OH, OSO3H, or OPO3H or b) the compound of any one of formulas (la)-(lc) is not Compounds C1 , D1 , or E1 , or a salt thereof. In particular embodiments, the compound of any one of formulas (la)-(lc) is not compound of formula A1 , A2, B1 , B2, C1 (also known as tetrahydroechinocandin B 3-trimethylaminoethyl ether), D1 (also known as tetrahydroechinocandin B-N-propyl-3-dimethylaminopropyl ether), E1 (also known as tetrahydro SL 7810/F-ll 2-trimethylaminoethyl ether), or a salt thereof. In other embodiments, the compound of any one of formulas (la)-(lc) is not an Aculeacin A derivative and/or not an S31794 derivative and/or not a tetrahydro-SL 7810 derivative. In certain embodiments, the compound is not a compound described in German Patent Publication No. DE2742435.

In some embodiments, the compound of any one of formulas (la)-(lc) is further described by formula (Ma) or (Mb), or a pharmaceutically acceptable salt thereof:

In formulas (lla) and (Mb), A, FU, Rs, R-6, B, C, and D are as defined in any one of formulas (la)- (lc). In some embodiments of the compounds of formulas (lla) and (Mb), or a pharmaceutically acceptable and D, together, have the formula:

(i) n optionally substituted C1-C10 alkyl;

(ϋ) an optionally substituted C1-C10 alkyl ;

(iii) wherein R7 is an optionally substituted Ci-Cs alkyl;

(iv)

R7 is an optionally substituted C1-C6 alkyl ; or

B, C, and D, together, have a formula selected from :

In some embodiments, the compound of any one of formulas (la)-(lc) is further described by (Ilia) or (lllb), or a pharmaceutically acceptable salt thereof:

In formulas (Ilia) and (lllb), A, Y, FU, Rs, R6, B, C, and D are as defined for any one of formulas (la)-(lc). In some embodiments of the compounds of formulas (Ilia) or (lllb), B, C, and D, together, have a formula selected from:

In some embodiments, the compound of formula (Ilia) or (lllb) is further described by formula (lllc) or (Mid), or a pharmaceutically acceptable salt thereof:

In formulas (lllc) and (llld), A, FU, Rs, R6, and Y are as defined for any one of formulas (la)-(lc), and R7 is an optionally substituted Ci-Cs alkyl.

In some embodiments, the compound of any one of formulas (la)-(lc) is further described by formula (IVa) or (IVb), or a pharmaceutically acceptable salt thereof:

In formulas (IVa) and (IVb), A, Y, FU, Rs, Ft6, B, C, and D are as defined for any one of formulas (la)-(lc). In some embodiments of the compounds of formula (III), B, C, and D, together, have a formula

In formulas (IVc) and (IVd), A, FU, Rs, R6, Y, and Z are as defined for any one of formulas (la)- (lc), and R7 is an optionally substituted Ci-Cs alkyl.

In some embodiments, the compound of any one of formulas (la)-(lc) is further described by formula (Va) or (Vb), or a pharmaceutically acceptable salt thereof:

In formulas (Va) and (Vb), A, FU, Rs, R6, and Y are as defined for any one of formulas (la)-(lc), and R7 is an optionally substituted C1 -C6 alkyl.

In one embodiment of the compounds of any one of formulas (la)-(Vb), each of R4, Rs, and R6 is CH₃.

The compound of any one of formulas (la)-(lc) can be selected from compound 1 , compound 22, compound 23, or a pharmaceutically acceptable salt thereof.

The compounds can exhibit increased amphiphilicity, increased aqueous solubility (e.g., in 0.1 M acetate buffer at pH 5.6), an increased therapeutic index, an increased elimination half-life, and/or an increased volume of distribution. The compounds may also exhibit broad spectrum activity against 2, 3, 4, or more species of Candida or Aspergillus, including, for example, Candida albicans, C. parapsilosis, C. glabrata, C. guilliermondii, C. krusei, C. lusitaniae, C. tropicalis, Aspergillus fumigatus, A. flavus, A. terreus. A. niger, A. candidus, A. clavatus, or A. ochraceus.

Also described are pharmaceutical compositions including a compound of any one of formulas (la)-(Vb), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient. In some embodiments, the pharmaceutical composition includes an acetate salt or a chloride salt of a compound of the invention.

The pharmaceutical compositions can be formulated for intravenous, topical, or oral administration in unit dosage form, or any other dosage form, e.g., as described herein.

Also described are methods of treating a fungal infection in a subject by administering to the subject a pharmaceutical composition described herein in an amount sufficient to treat the infection. In some embodiments, the pharmaceutical composition is administered intravenously, subcutaneously, intramuscularly, orally, or topically. The pharmaceutical composition can be administered to treat a blood stream infection, tissue infection (e.g., lung, kidney, or liver infection) in the subject, or any other type of infection described herein. The fungal infection being treated can be an infection selected from tinea capitis, tinea corporis, tinea pedis, onychomycosis, perionychomycosis, pityriasis versicolor, oral thrush, vaginal candidosis, respiratory tract candidosis, biliary candidosis, eosophageal candidosis, urinary tract candidosis, systemic candidosis, mucocutaneous candidosis, aspergillosis, mucormycosis,

paracoccidioidomycosis, North American blastomycosis, histoplasmosis, coccidioidomycosis, sporotrichosis, fungal sinusitis, or chronic sinusitis. In some embodiments, the infection being treated is an infection by Candida albicans, C. parapsilosis, C. glabrata, C. guilliermondii, C. krusei, C. lusitaniae, C. tropicalis, Aspergillus fumigatus, A. flavus, A. terreus. A. niger, A. candidus, A. clavatus, or A.

ochraceus.

Also described are methods of stabilizing or inhibiting a fungal infection in a subject by administering to the subject a pharmaceutical composition described above in an amount sufficient to prevent the infection. In some embodiments, the pharmaceutical composition is administered intravenously at least once over a period of 1 -30 days (e.g., 1 , 2, 3, 4, or 5 times over a period of 1 -30 days). For example, the methods can be used for prophylaxis treatment in subjects being prepared for an invasive medical procedure (e.g., preparing for surgery, such as receiving a transplant, stem cell therapy, a graft, a prosthesis, receiving long-term or frequent intravenous catheterization, or receiving treatment in an intensive care unit), in immunocompromised subjects (e.g., subjects with cancer, with HIV/AIDS, or taking immunosuppressive agents), or in subjects undergoing long term antibiotic therapy.

In one embodiment of any of the methods described herein, the pharmaceutical composition includes compound 1 , compound 22, compound 23, or any other compound described herein, or a pharmaceutically acceptable salt thereof.

Also described are methods of stabilizing, or inhibiting the growth of fungi, or killing fungi by contacting the fungi or a site susceptible to fungal growth with a compound described herein, or a pharmaceutically acceptable salt thereof.

As used herein, the terms "an amount sufficient" and "sufficient amount" refer to the amount of a drug required to treat or prevent an infection. The sufficient amount used to practice the invention for therapeutic or prophylactic treatment of conditions caused by or contributed to by an infection varies depending upon the manner of administration, the type of infection, the age, body weight, and general health of the subject. Ultimately, the attending physician or veterinarian will decide the appropriate amount and dosage regimen. Such amount is referred to as a "sufficient" amount.

As used herein, the terms "stabilizing" and "inhibiting" refer to reducing the growth of fungi, or killing fungi at a site susceptible (i.e., within a subject or on a surface) to fungal growth by contacting the fungi with a compound described herein, or a pharmaceutically acceptable salt thereof.

By "fungal infection" is meant the invasion of a host by pathogenic fungi. For example, the infection may include the excessive growth of fungi that are normally present in or on the body of a subject or growth of fungi that are not normally present in or on a subject. More generally, a fungal infection can be any situation in which the presence of a fungal population(s) is damaging to a host body. Thus, a subject is "suffering" from a fungal infection when an excessive amount of a fungal population is present in or on the subject's body, or when the presence of a fungal population(s) is damaging the cells or other tissue of the subject.

By "increased amphiphilicity" is meant an increase in the solubility of a compound of any one of formulas (la)-(Vb) in both water (0.1 M acetate buffer at pH 5.6) and glycerol in comparison to the parent echinocandin compound (i.e., compounds of formulas (la)-(Vb) can have an increased amphiphilicity in comparison to a parent echinocandin compound that is anidulafungin; caspofungin; and/or micafungin).

By "increased elimination half-life" is meant an increase in the elimination half-life (e.g., as observed in a PK study as described in Example 24) for a compound of any one of formulas (la)-(Vb) in comparison to the parent echinocandin compound (i.e., compounds of formulas (la)-(Vb) can have an increased elimination half-life in comparison to a parent echinocandin compound that is anidulafungin; caspofungin; and/or micafungin) administered under the same conditions (e.g., with the same carriers and other inactive excipients and by the same route). The compounds described herein can exhibit at least 25%, 50%, 100%, 200%, or 300% longer elimination half-life than the corresponding parent echinocandin class compound.

By "increased volume of distribution" is meant an increase in the volume of distribution (e.g., as observed in a PK study as described in Example 24) for a compound of any one of formulas (la)-(Vb) in comparison to the parent echinocandin compound (i.e., compounds of formulas (la)-(Vb) can have an increased volume of distribution in comparison to a parent echinocandin compound that is anidulafungin; caspofungin; and/or micafungin) administered under the same conditions (e.g., with the same carriers and other inactive excipients and by the same route). The compounds described herein can exhibit at least 25%, 50%, 100%, 200%, or 300% greater volume of distribution than the corresponding parent echinocandin class compound.

By "increased therapeutic index" is meant an increase in the ratio of median lethal dose (LD50) to median effective dose (ED50) (e.g., as observed using a mouse model of infection) for a compound of any one of formulas (la)-(Vb) in comparison to the parent echinocandin compound (i.e., compounds of formulas (la)-(Vb) can have an increased therapeutic index in comparison to a parent echinocandin compound that is anidulafungin; caspofungin; and/or micafungin) administered under the same conditions (e.g., with the same carriers and other inactive excipients and by the same route). The compounds described herein can exhibit at least 25%, 50%, 100%, 200%, or 300% greater therapeutic index than the corresponding parent echinocandin class compound. For example, the compounds described herein can exhibit extended circulating half-lives in vivo, allowing similar efficacy to be achieved at lower doses in comparison to the parent echinocandin compound.

As used herein, the term "treating" refers to administering a pharmaceutical composition for therapeutic purposes. To "treat disease" or use for "therapeutic treatment" refers to administering treatment to a subject already suffering from a disease to improve or stabilize the subject's condition. To "prevent disease" refers to prophylactic treatment of a subject who is not yet ill, but who is susceptible to, or otherwise at risk of, a particular disease.

The term "unit dosage form" refers to physically discrete units suitable as unitary dosages, such as a pill, tablet, caplet, hard capsule, soft capsule, single use pre-filled syringe, or single use vial, each unit containing a predetermined quantity of a drug. By "hard capsule" is meant a capsule that includes a membrane that forms a two-part, capsule-shaped, container capable of carrying a solid or liquid payload of drug and excipients. By "soft capsule" is meant a capsule molded into a single container carrying a liquid or semisolid payload of drug and excipients.

The specification makes reference to compounds of formulas A1 , A2, B1 , B2, C1 , D1 , and E1 , the structures of which are depicted below.

11

As used herein, the term "Aculeacin A derivative" refers to compounds having the formula F1

As used herein, the term "tetrahydro-SL 7810 derivative" refers to compounds having the formula H1 or H2:

and salts thereof, wherein A, FU, Rs, and Ι¾ are as defined in formulas (la)-(lc).

As used herein, the term "alkyl," "alkenyl," and "alkynyl" refers to straight-chain, branched-chain and cyclic monovalent groups, as well as combinations of these, containing only C and H when unsubstituted. Examples include methyl, ethyl, isobutyl, cyclohexyl, cyclopentylethyl, and 2-propenyl, 3-butynyl, among others. Typically, the alkyl, alkenyl, and alkynyl groups contain 1 -12 carbons (e.g., C1-C12 alkyl, C1-C12 alkenyl, or C1-C12 alkynyl). In some embodiments, the groups are C1-C10, Ci-Cs, Ci- C6, C1-5, C2-C10, C2-C8, C2-C6, or C2-5 alkyl, alkenyl, or alkynyl groups. Further, any hydrogen atom on one of these groups can be replaced with a substituent as described herein.

The term "carbocyclyl" refers to an optionally substituted monovalent saturated or unsaturated non-aromatic cyclic alkyl group having between three to nine carbons (e.g., a C3-C9 cycloalkyi), unless otherwise specified, and is exemplified by cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, bicyclo[2.2.1 .]heptyl, and the like. Carbocyclyl groups optionally include one or more carbon-carbon double bonds (e.g., cyclopentenyl and cyclohexenyl, among others).

The term "aryi" refers to any optionally substituted monocyclic or fused ring bicyciic system which has the characteristics of aromaticity in terms of electron distribution throughout the ring system wherein the ring system is formed solely from carbon atoms, such as a phenyl or naphthyi group.

The term "heferoaryl" refers to aromatic monocyclic or fused bicyciic ring systems containing one or more heteroatoms selected from O, S and N and are optionally substituted. Heteroaryls include optionally substituted pyridyl, pyrimidyl, indoiyi, benzimidazolyl, benzotriazoiyi, isoquinoiyi, quinolyl, benzothiazoiyi, benzofurany!, thienyl, fury!, pyrrolyl, thiazolyl, oxazolyi, isoxazoiyi, benzoxazoiyl, benzoisoxazolyl, and imidazolyl, among others.

The term "heterocyclyl" refers to any non-aromatic optionally substituted 3-, 4-, 5-, 6-, or 7- membered ring, either as a monocyclic moiety or fused multicyclic moiety, containing one, two, three, or four heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur. The term "heterocyclyl" includes bicyciic, tricyclic, and tetracyclic groups in which any of the above heterocyclic rings Is fused to one, two, or three carbocyclic rings, e.g., an aryi ring, a cyclohexane ring, a cyciohexene ring, a cyclopentane ring, a cyclopentene ring, or another monocyclic heterocyclic ring, such as indolyl, quinoiyl, Isoquinolyi, tetrahydroquinolyi, benzofuryi, benzothienyl and the like.

The aikyl, alkenyl, alkynyi, aryl, carbocyclyi, heteroaryi, or heterocyciyi group may be substituted. When substituted the group Includes one or more substituents, each selected independently from halo (e.g., chioro, bromo, iodo, or fluoro), =0 and =NOR', CM, N0₂, CF₃, OCF₃, CQOR', CONR'₂, OR', SR', SOR', SO2R', NR'₂, NR'(CO)R',NR'C(0)OR', NR'C(0)NR'₂, NR'S0₂NR'2, or NR'SQ₂R', where each R' is independently H or an optionally substituted group selected from a!kyl, alkenyl, alkynyi, carbocyclyi, heteroaryi, and aryl (all as defined above); or the substituent may be an optionally substituted group selected from alky!, alkenyl, alkynyi, carbocyclyi, aryl, heterocyciyi, and heteroaryi. Preferred substituents for B,C, or D of any one of formulas (ia)-(Vb) include chioro, fluoro, CH3, and OR', where R' is defined as above.

Other features and advantages will be apparent from the following detailed description and the claims. Detailed Description

Described are echinocandin class compounds of formulas (la)-(Vb) that have been modified such that they can exhibit (i) activity against one or more fungal species or genera; (ii) increased aqueous solubility and/or amphiphilicity; (iii) an increased therapeutic index; (iv) suitability for topical

administration; (v) suitability for intravenous administration; (vi) an increased volume of distribution; and/or (vii) an increased elimination half-life.

Synthesis

Compounds of formulas (la)-(Vb) can be synthesized, for example, as described in the examples by coupling functionalized or unfunctionalized echinocandin class compounds with the appropriate acyl, aikyl, hydroxyl, and/or amino groups under standard reaction conditions.

Typically, the semi-synthetic echinocandin class compounds described herein can be made by modifying the naturally occurring echinocandin scaffold. For example, pneumocandin Bo is prepared by fermentation reactions; where fermentation and mixed broths produce a mixture of products which are then separated to produce pneumocandin Bo, which is used in the synthesis of caspofungin (see U.S. Pat. No. 6,610,822, which describes extraction of the echinocandin class compounds, such as, pneumocandin Bo, WF 1 1899, and echinocandin B by performing several extraction processes; and see U.S. Pat. No. 6,610,822, which describes methods for purifying the crude extracts).

For semi-synthetic approaches, the stereochemistry of the compound will be dictated by the starting material. Thus, the stereochemistry of the unnatural echinocandin derivatives will typically have the same stereochemistry as the naturally occurring echinocandin scaffold (representative

stereochemistry is depicted in the examples) from which they are derived. Accordingly, any of the compounds shown below anidulafungin, caspofungin, or micafungin can be used as a starting material in the synthesis of compounds which share the same stereochemical configuration at each of the amino acid residues found in the naturally occurring compound.

Accordingly, echinocandin class compounds can be derived from the cyclic peptide antifungals which are produced by culturing various microorganisms. The compounds described herein can be synthesized, for example, using the methods described in the examples and methods known in the art for synthesizing echinocandin compounds, including Leonard et al., J. Org. Chem. 72:2335 (2007); Boeck, et al., J. Antibiot. 41 :1085 (1988); Boeck et al., J. Antibiot. 42:382 (1989); Debono et al., J. Antibiot. 42:389 (1989); and Jamison et al., J. Antibiot.50:562 (1997), each of which is incorporated herein by reference.

Therapy and Formulation

Described are compositions and methods for treating, stabilizing or inhibiting a disease or condition associated with a fungal infection (e.g., a yeast infection). The compounds may be

administered by any appropriate route for treatment or prevention of a disease or condition associated with a fungal infection. These may be administered to humans, domestic pets, livestock, or other animals with a pharmaceutically acceptable diluent, carrier, or excipient. When administered orally, these may be in unit dosage form, or in as a liquid oral dosage form. Administration may be topical, parenteral, intravenous, intra-arterial, subcutaneous, intramuscular, intracranial, intraorbital, ophthalmic,

intraventricular, intracapsular, intraspinal, intracisternal, intraperitoneal, intranasal, aerosol, by suppositories, or oral administration.

Therapeutic formulations may be in the form of liquid solutions or suspensions; for oral administration formulations in the form of tablets or capsules, syrups, or oral liquid dosage forms;

intranasal formulations, in the form of powders, nasal drops; formulated as ear drops; formulated as aerosols, or formulated for topical administration, such as a cream or ointment.

Methods well known in the art for making formulations are found, for example, in Remington: The Science and Practice of Pharmacy, 21 st Edition; Lippincott Williams & Wilkins: Philadelphia, PA, 2005; Handbook of Pharmaceutical Excipients, 5th Edition; Rowe et al., Eds., The Pharmaceutical Press and the American Pharmaceutical Association: 2005; Handbook of Pharmaceutical Additives, 3rd Edition; Ash and Ash Eds., Gower Publishing Company: 2007; and Pharmaceutical Preformulation and Formulation, Gibson Ed., CRC Press LLC: Boca Raton, FL, 2004). Formulations for parenteral administration may, for example, contain excipients, sterile water, or saline, polyalkylene glycols such as polyethylene glycol, oils of vegetable origin, or hydrogenated napthalenes. Formulations for inhalation may contain excipients, for example, lactose, or may be aqueous solutions containing, for example, polyoxyethylene-9-lauryl ether, glycholate and deoxycholate, or may be oily solutions for administration in the form of nasal drops, or as a gel. The concentration of the compound in the formulation will vary depending upon a number of factors, including the dosage of the drug to be administered, and the route of administration.

The compound or combination may be optionally administered as a pharmaceutically acceptable salt, such as acid addition salts; metal salts formed by the replacement of an acidic proton with a metal, such as an alkali or alkaline earth salts (e.g., sodium, lithium, potassium, magnesium, or calcium salts); or metal complexes that are commonly used in the pharmaceutical industry. Examples of acid addition salts include organic acids such as acetic, lactic, pamoic, maleic, citric, malic, ascorbic, succinic, benzoic, palmitic, suberic, salicylic, tartaric, methanesulfonic, toluenesulfonic, or trifluoroacetic acids; polymeric acids such as tannic acid, and carboxymethyl cellulose; and inorganic acid such as hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid. Metal complexes include zinc, and iron, among others. Formulations for oral use include tablets containing the active ingredient(s) in a mixture with nontoxic pharmaceutically acceptable excipients. These excipients may be, for example, inert diluents or fillers (e.g., sucrose and sorbitol), lubricating agents, glidants, and antiadhesives (e.g., magnesium stearate, zinc stearate, stearic acid, silicas, hydrogenated vegetable oils, or talc). Formulations for oral use may also be provided in unit dosage form as chewable tablets, tablets, caplets, or capsules (i.e., as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium).

The compounds can be formulated with excipients that improve the oral bioavailability of the compound. For example, the compounds can be formulated for oral administration with medium chain (C8 to C12) fatty acids (or a pharmaceutically acceptable salt thereof), such as capric acid, caprylic acid, lauric acid, or a pharmaceutically acceptable salt thereof, or a mixture thereof. The formulation can optionally include a medium chain (C8 to C12) alkyl alcohol, among other excipients. Alternatively, the compounds can be formulated for oral administration with one or more medium chain alkyl saccharides (e.g.. alkyl (C8 to C14) beta-D-maltosides, alkyl (C8 to C14) beta-D-Gulcosides, octyl beta-D-maltoside, octyl beta-D-maltopyranoside, decyl beta-D-maltoside, tetradecyl beta-D-maltoside, octyl beta-D- glucoside, octyl beta-D-glucopyranoside, decyl beta-D-glucoside, dodecyl beta-D-glucoside, tetradecyl beta-D-glucoside) and/or medium chain sugar esters (e.g., sucrose monocaprate, sucrose

monocaprylate, sucrose monolaurate and sucrose monotetradecanoate).

The formulations can be administered to human subjects in therapeutically effective amounts. Typical dose ranges are from about 0.01 g/kg to about 800 mg/kg, or about 0.1 mg/kg to about 50 mg/kg, of body weight per day. The preferred dosage of drug to be administered is likely to depend on such variables as the type and extent of the disorder, the overall health status of the particular subject, the specific compound being administered, the excipients used to formulate the compound, and its route of administration.

The compounds of formulas (la)-(Vb) can be used to treat, for example, tinea capitis, tinea corporis, tinea pedis, onychomycosis, perionychomycosis, pityriasis versicolor, oral thrush, vaginal candidosis, respiratory tract candidosis, biliary candidosis, eosophageal candidosis, urinary tract candidosis, systemic candidosis, mucocutaneous candidosis, aspergillosis, mucormycosis,

paracoccidioidomycosis, North American blastomycosis, histoplasmosis, coccidioidomycosis, sporotrichosis, fungal sinusitis, and chronic sinusitis.

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the methods and compounds claimed herein are performed, made, and evaluated, and are intended to be purely exemplary of the invention and are not intended to limit the scope of what the inventors regard as their invention.

Example 1 . Synthesis of Fmoc-Echinocandin B nucleus (lntermediate-1 ).

Echinocandin B nucleus may be obtained from echinocandin B using echinocandin deacylase derived from Actinoplanes utahensis or similarly by a known procedure (J. Antibiotics 42: 382-388, 1989). Echinocandin B nucleus (150 mg, 0.188 mmol) and Fmoc-OSu (76 mg, 0.226 mmol) were stirred in anhydrous DMF (1 .0 ml_) for 2 h. The product (lnt-1 , depicted below) was isolated by RP-HPLC (10- 100% acetonitrile in water with 0.1 % TFA as the modifier). The appropriate fractions were combined and concentrated in vacuo to yield 142 mg of product. LCMS, 1002.3 [M-OH]⁺ calculated 1002.3.

Example 2. Synthesis of Fmoc-Echinocandin B nucleus choline ether (lntermediate-2).

A mixture of Fmoc-echinocandin B nucleus (lnt-1 ; 142 mg, 0.139 mmol), phenyl boronic acid (21 mg, 0.174 mmol) and dry THF (6 mL) was stirred for 30 minutes. Solvent was removed under reduced pressure by rotary evaporation at 36 °C. The residue was again dissolved in dry THF (6 mL), the solvent removed in vacuo, then dissolved again in dry acetonitrile (6 mL) and the volatiles removed under reduced pressure to remove residual water. To the resulting solid was added anhydrous choline chloride

(91 mg, 8.77 mmol). The mixture was cooled to 0 °C, and then dissolved in 20% TFA/acetonitrile (7.5 mL). After 1 h at 0 °C, LCMS showed consumption of all starting material. The solution was concentrated in vacuo at 36 °C, then purified by RP-HPLC (5-100% acetonitrile in water with 0.1 % TFA as the modifier). The product containing fractions were combined and the volatiles removed in vacuo to yield 82 mg of product (lnt-2, depicted below). LCMS, 1 105.4 [M]⁺ calculated 1 105.5.

Example 3. Synthesis of Fmoc-Echinocandin B nucleus 3-(trimethylammonium)propyl ether

(lntermediate-3).

A mixture of Fmoc-echinocandin B nucleus (lnt-1 ; 2.84 g, 2.78 mmol), phenyl boronic acid (420 mg, 3.48 mmol) and dry THF (120 mL) is stirred for 30 to 60 minutes. Solvent is removed under reduced pressure by rotary evaporation. The residue is subjected to high vacuum to remove residual water. To the resulting material is added anhydrous 3-(trimethylammonium)propan-1 -ol chloride (2.00 g, 175.4 mmol). The mixture is cooled and dissolved in 20% TFA/acetonitrile (150 mL). The reaction is complete when LCMS shows consumption of most of the starting material. The solution is concentrated in vacuo and purified by RP-HPLC (5-100% acetonitrile in water with 0.1 % TFA as the modifier). The product containing fractions are combined and the volatiles are removed in vacuo to yield the product (lnt-3, depicted below) with a molecular weight of 1233.26.

Example 4. Synthesis of the formate salt of compound 1 (1 -[(4R, 5R)-4-hydroxy-/V²-[[4-(5-(4-pentyloxy- phenyl)-isoxazol-3-yl)-phenylcarbonyl]-5-[2- (trimethylammonio) ethoxy] -L-ornithine] echinocandin B, formate salt).

Fmoc-Echinocandin B nucleus choline ether (lnt-2; 82 mg, 0.0746 mmol) was dissolved in DMF (1 .0 mL) and treated with piperidine (0.030 mL). After 1 hour, LCMS showed substantial removal of the Fmoc protecting group. The reaction was concentrated by rotary evaporation at 36 °C. The resulting solid was again dissolved in DMF (1 .0 mL) and the solvent removed in vacuo to remove residual piperidine. The crude product was used in the next step without further purification. Crude echinocandin B nucleus choline ether (0.0746 mmol), 4-(5-(4-pentyloxy-phenyl)-isoxazol-3-yl)-benzoic acid (52 mg, 0.149 mmol), HOBT (20 mg, 0.149 mmol), and EDC (23 mg, 0.149 mmol), were dissolved in DMF (1 .0 mL) and stirred at room temperature. After 1 h, LCMS showed consumption of the echinocandin B nucleus choline ether. The solution was purified by RP-HPLC (5-100% acetonitrile in water with 0.1 % formic acid as the modifier). The product containing fractions were combined and concentrated in vacuo to yield 15 mg of product (depicted below). HRMS, 1216.5728 [M+H]⁺ calculated 1216.5778.

(compound 1 , formate salt)

Example 5. Synthesis of compounds 2-15.

In a manner analogous to that described in Example 4, using lnt-2 as the starting material and the carboxylic acid designated in the table below, the following compounds of formula (A) may be prepared.

20 Example 6. Synthesis of the formate salt of compound 16 (1 -[(4R, 5R)-4-hydroxy-/V²-[[4-(5-(4-pentyloxy- phenyl)-isoxazol-3-yl)-phenylcarbonyl]-5-[3-(trimethylammonio) propoxy]-L-ornithine] echinocandin B, formate salt).

Fmoc-Echinocandin B nucleus 3-(trimethylammonium)propyl ether (lnt-3; 249 mg, 0.224 mmol) is dissolved in DMF (3.0 mL) and treated with piperidine (0.090 mL). After about 1 hour, the reaction is concentrated by rotary evaporation and the resulting material is dissolved in DMF (3.0 mL) and the solvent is removed in vacuo to remove residual piperidine. The crude product is used in the next step without further purification. Crude echinocandin B nucleus 3-(trimethylammonium)propyl ether (0.224 mmol), 4-(5-(4-pentyloxy-phenyl)-isoxazol-3-yl)-benzoic acid (156 mg, 0.447 mmol), HOBT (60 mg, 0.447 mmol), and EDC (69 mg, 0.447 mmol), is dissolved in DMF (3.0 mL) and stirred at room temperature. After about 1 h or once the starting material is consumed as determined by LCMS, the solution is purified by RP-HPLC (5-100% acetonitrile in water with 0.1 % formic acid as the modifier). The product containing fractions are combined and concentrated in vacuo to yield the product (depicted below) with a molecular weight of 1276.4

(compound 16, formate salt) Example 7. Synthesis of compounds 17-19.

In a manner similar to that described in Example 6, using lnt-3 as the starting material and the carboxylic acid designated in the table below, the following compounds may be prepared.

Example 8. Synthesis of the trifluoroacetate salt of compound 20 (mulundocandin choline ether, trifluoroacetate salt).

Mulundocandin (1 .0 mmol), phenyl boronic acid (1 .25 mmol) and dry THF (35 mL) are stirred for about 30 minutes and the solvent is removed by rotary evaporation. The residue is again dissolved in dry THF (35 mL, the solvent is removed under reduced pressure, is dissolved in dry acetonitrile (35 mL) and the solvent is removed under reduced pressure to remove water. To the resulting material is added anhydrous choline chloride (52.0 mmol). The mixture is cooled to 0 °C, and dissolved in 20%

TFA/acetonitrile (30 mL). The stirring solution is allowed to gradually warm to room temperature overnight. The solution is concentrated in vacuo, and purified by RP HPLC (5-100% acetonitrile in water with 0.1 % TFA as the modifier). The product containing fractions are combined and concentrated in vacuo to yield the product (depicted below) with a molecular weight of 1207.35.

(compound 20, trifluoroacetate salt)

Example 9. Synthesis of the trifluoroacetate salt of compound 21 (deoxymulundocandin choline ether, trifluoroacetate salt).

To deoxymulundocandin (0.2 mmol) is added anhydrous choline chloride (10.0 mmol). The mixture is cooled to 0 °C, and dissolved in 20% TFA/acetonitrile (6 mL). The stirring solution is allowed to gradually warm to room temperature overnight. The solution is concentrated in vacuo, and purified by RP HPLC (5-100% acetonitrile in water with 0.1 % TFA as the modifier). The product containing fractions are combined and concentrated in vacuo to yield the product (depicted below) with a molecular weight of 1 191 .35.

(compound 21 , trifluoroacetate salt)

Example 10. Additional compounds.

Other compounds include those bearing the lipophilic tail of anidulafungin and the core of either caspofungin or micafungin, such as those depicted below. The compounds can be synthesized using methods similar to those described herein.

(compound 22; Caspofungin core) (compound 23; Micafungin core)

Example 1 1 . Antifungal activity of compound 1 relative to amphotericin B.

Minimal Effective Concentration (MEC) and Minimal Inhibitory Concentration (MIC) values

^g/mL) against various Aspergillus species and Candida species were obtained.

MIC and MEC assays were performed according to CLSI broth microdilution guidelines (M27-A3, M27-S4, and M38-A2) with the exception of using a 100 μΙ_ assay volume and preparing stock compounds at 50X final concentration. Briefly, starting solutions of all antifungal agents were prepared in 100% DMSO. Stock concentrations were made at 50X the highest final assay concentration and serially diluted 2-fold, 12 times in a 96-well PCR plate (VWR 83007-374). Candida and Aspergillus suspensions from Sabouraud dextrose agar plate cultures were prepared in 0.85% saline at 0.5 McFarland standard (-0.1 OD530 nm). Candida suspensions were diluted 1 :500 in RPMI (MP Biomedicals, cat no. 1060124; buffered with MOPS and adjusted with NaOH to pH 7.0) to a concentration of -0.5-2.5 x 10³ CFU/mL and Aspergillus suspensions were diluted 1 :50 in RPMI to -0.4-5 x 10⁴ CFU/mL final concentration. 98 μΙ_ of each cell suspension in RPMI were added to test wells in a 96-well assay plate (Costar cat. no. 3370). A Beckman Multimek 96 liquid handling robot was used to dispense 2 μΙ_ of each 50X stock compound into the plate containing 98 μΙ_ of each strain in RPMI (2% final solvent concentration). Plates were shaken then incubated at 35 °C for 24-48 h prior to reading. MIC values were read visually at 50% growth inhibition for echinocandins (24 h) and at 100% growth inhibition for amphotericin B (48 h). MEC values (24 h) were read with the aid of a microscope at the lowest echinocandin concentration where rounded/compact hyphal morphology was observed.

The results are tabulated below.

Table 1

Compound 1 Amphotericin B

species strain MIC/MEC (50%, Mg/ml) 100%

A. fumigatus ATCC 13073 0.015 0.125

A. fumigatus MYA-4609 0.0078 0.25

A. flavus ATCC MYA-3631 0.0078 0.5

A. niger ATCC 16404 0.0078 0.125

C. neoformans ATCC 24067 >4 0.5

Other Embodiments

All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each independent publication or patent application was specifically and individually indicated to be incorporated by reference.

While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure that come within known or customary practice within the art to which the invention pertains and may be applied to the essential features hereinbefore set forth, and follows in the scope of the claims.

Other embodiments are within the claims.

What is claimed is:

Claims

1. A compound described by any of formulas (la)-(lc):

wherein,

Ri is H, CH₃, CH2CONH2, CH2CN, or CH2CH2NH2;

R₂ is H or CH₃;

R₃ is H, CH₃, or OH;

each of R4, R5, and R6 is, independently, selected from CH₃, CH2CH₃, CH2CH2CH₃, and CH(CH₃)₂;

A is CH2(CH₂)n, C2H4OC2H4, C₃H₆OC₃H₆, or C₄H₈OC4H8, C2H4OC2H4OC2H4, CsHeOCsHeOCsHe, or C4H8OC4H8OC4H8;

each of W, X, and Y is, independently, selected from H and OH;

Z is H, OH, OSO3H, or OPO3H;

each of B, C, and D is, independently, selected from optionally substituted alkyl, alkenyl, alkynyl, aryl, carbocyclyl, heteroaryl, heterocyclyl, or are absent, provided that at least one of B, C, and D is present, wherein B and C, when present, are joined by a direct bond, -Ο-, or -CH2=CH2- and C and D, when present, are joined by a direct bond, -0-, or -CH₂=CH₂-; and

n is an integer from 1 to 4,

or a pharmaceutically acceptable salt thereof,

wherein when Ri is CH₃; R2 is CH₃; R3 is CH₃; A is CH2CH2 or C2H4OC2H4; each of R4, R5, and R6 is CH3; each of W, X, and Y is OH; and B, C, and D, together, have the formula

^O^^O^^G^⁰⁰^", then Z is OH, OSO3H, or OPO3H; and

wherein a) when Ri is CH₃; R2 is CH₃; R3 is CH₃; A is CH2CH2 or CH2CH2CH2; each of R₄ and R₅ is CH₃; Re is CH₃ or CH₂CH₂CH₃; each of W and X is OH; Y is H or OH; and B, C, and D, together, have the formula -(CH₂)i6CH₃, then Z is OH, OS0₃H, or OP0₃H or b) the compound is not Compounds C1 , D1 , or E1 , or a salt thereof.

2. The compound of claim 1 , further described by formula (lla) or (Mb):

wherein,

A, R4, R5, R6, B, C, and D are as defined above,

or a pharmaceutically acceptable salt thereof.

3. The compound of claim 2, wherein B, C, and D, together, have the formula:

wherein R7 is an optionally substituted C1-C10 alkyl, or a pharmaceutically acceptable salt thereof.

4. The compound of claim 2, wherein B, C, and D, together, have the formula:

wherein R7 is an optionally substituted C1-C10 alkyl, or a pharmaceutically acceptable salt thereof. wherein B, C, and D, together, have the formula:

wherein R7 is an optionally substituted Ci-Cs alkyl, or a pharmaceutically acceptable salt thereof.

6. The compound of claim 2, wherein B, C, and D, together, have the formula:

wherein R7 is an optionally substituted C1-C6 alkyl, or a pharmaceutically acceptable salt thereof.

7. The compound of claim 2, wherein B, C, and D, together, have a formula selected from:

or a pharmaceutically acceptable salt thereof.

A, Y, FU, R5, R6, B, C, and D are as defined above,

or a pharmaceutically acceptable salt thereof.

9. The compound of claim 8, wherein B, C, and D, together, have a formula selected

or a pharmaceutically acceptable salt thereof.

10. The compound of claim 8, further described by formula (lllc) or (llld):

wherein,

A, FU, R5, R6, and Y are as defined above; and

R7 is an optionally substituted Ci-Cs alkyl,

or a pharmaceutically acceptable salt thereof.

11 . The compound of claim 1 , further described by formula (IVa) or (IVb):

wherein,

A, Y, Z, FU, R5, R6, B, C, and D are as defined above,

or a pharmaceutically acceptable salt thereof.

12. The compound of claim 1 1 , wherein B, C, and D, together, have a formula sel

or a pharmaceutically acceptable salt thereof.

13. The compound of claim 1 1 , further described by formula (IVc) or (IVd):

wherein,

A, FU, R5, R6, Y, and Z are as defined above; and

R7 is an optionally substituted Ci-Cs alkyl,

or a pharmaceutically acceptable salt thereof.

14. The compound of claim 1 , further described by formula (Va) or (Vb):

wherein,

A, R4, R5, R6, and Y are as defined above; and

R7 is an optionally substituted C1-C6 alkyl,

or a pharmaceutically acceptable salt thereof.

15. The compound of any one of claims 1 -14, wherein each of R4, R5, and R6 is CH3.

16. The compound of claim 1 , wherein said compound has the formula:

or a pharmaceutically acceptable salt thereof.

17. The compound of claim 1 , wherein said compound has the formula:

or a pharmaceutically acceptable salt thereof.

18. The compound of claim 1 , wherein said compound has the formula:

or a pharmaceutically acceptable salt thereof.

19. A pharmaceutical composition comprising a compound of any of claims 1 -18, armaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.

20. A method of treating a fungal infection in a subject, said method comprising administering to said subject a pharmaceutical composition of claim 19 in an amount sufficient to treat said infection.

21 . The method of claim 20, wherein said pharmaceutical composition is

administered intravenously.

22. The method of claim 20, wherein said pharmaceutical composition is

administered topically.

23. The method of claim 20, wherein said pharmaceutical composition is

administered orally.

24. The method of claim 20, wherein said pharmaceutical composition is

administered subcutaneously or intramuscularly.

25. The method of any one of claims 20-24, wherein said pharmaceutical composition is administered to treat a blood stream infection or tissue infection in said subject.

26. The method of claim 25, wherein said infection is selected from tinea capitis, tinea corporis, tinea pedis, onychomycosis, perionychomycosis, pityriasis versicolor, oral thrush, vaginal candidosis, respiratory tract candidosis, biliary candidosis, eosophageal candidosis, urinary tract candidosis, systemic candidosis, mucocutaneous candidosis, aspergillosis, mucormycosis, paracoccidioidomycosis, North American blastomycosis, histoplasmosis, coccidioidomycosis, sporotrichosis, fungal sinusitis, or chronic sinusitis.

27. The method of claim 20, wherein said fungal infection is an infection of Candida albicans, C. parapsilosis, C. glabrata, C. guilliermondii, C. krusei, C. tropicalis, C. lusitaniae, Aspergillus fumigatus, A. flavus, A. terreus, A. niger, A. candidus, A. clavatus, or A.

ochraceus.

28. A method of stabilizing or inhibiting a fungal infection in a subject, said method comprising administering to said subject a pharmaceutical composition of claim 19 in an amount sufficient to prevent said infection.

29. The method of claim 28, wherein said pharmaceutical composition is

administered intravenously.

30. The method of claim 29, wherein said subject is being prepared for an invasive medical procedure, said subject is immunocompromised, or said subject is undergoing long term antibiotic therapy.

31 . The method of any one of claims 20-30, wherein said pharmaceutical composition comprises compound 1 , compound 22, compound 23, or a pharmaceutically acceptable salt thereof.

32. A method of stabilizing or inhibiting the growth of fungi, or killing fungi, said method comprising contacting said fungi or a site susceptible to fungal growth with a compound of any of claims 1 -18, or a pharmaceutically acceptable salt thereof.