WO2011088126A2

WO2011088126A2 - Treatment of viral infection with prenyltransferase inhibitors

Info

Publication number: WO2011088126A2
Application number: PCT/US2011/020998
Authority: WO
Inventors: David Cory; Ingrid Choong; Brian Murphy; Wenjin Yang; Jeffrey S. Glenn
Original assignee: Eiger Biopharmaceuticals, Inc.
Priority date: 2010-01-13
Filing date: 2011-01-12
Publication date: 2011-07-21
Also published as: WO2011088126A3

Abstract

Inhibitors of prenylation such as farnesyl transferase inhibitors can be used to treat HDV infection.

Description

TREATMENT OF VIRAL INFECTION WITH PRENYLTRANSFERASE INHIBITORS

FIELD OF THE INVENTION

The present invention provides compositions and methods for treating viral infection and so relates to the fields of chemistry, medicinal chemistry, medicine, molecular biology, and pharmacology.

BACKGROUND

Hepatitis delta virus (HDV) causes the most severe form of viral hepatitis, and there is no effective medical therapy (see Lau, 1999, Hepatology 30:546-549). The HDV large delta antigen protein contains a CXXX box rendering it a substrate for prenylation (see Zhang and Casey, 1996, Annu. Rev. Biochem. 65:241-269) by the prenyl lipid farnesyl (see Glenn et al, 1992, Science 256: 1331-1333, and Otto and Casey, 1996, J. Biol. Chem. 271 :4569-4572). Farnesylation of proteins catalysed by FTase is an essential step in processing of a variety of proteins and occurs by transfer of the farnesyl group of farnesyl pyrophosphate to a cysteine at the C-terminal tetrapeptide of a protein in a structural motif sometimes referred to as the CAAX box. Further post-translational modifications of a farnesylated protein, including proteolytic cleavage at the cysteine residue of the CAAX box and methylation of the cysteine carboxyl, generally follow farnesylation. Molecular genetic experiments demonstrated that specific mutation of the prenylation site in large delta antigen prevents both its prenylation and HDV particle formation (see Glenn et al, 1992, supra).

The hypothesis that pharmacologic inhibition of prenylation could achieve the same end result has now been demonstrated in a variety of experimental systems including: the HDV virus-like particle (VLP) assembly model (see Glenn et al, 1998, J. Virol. 72:9303-9306); a cell culture model of infectious HDV (see Bordier et al, 2002, J. Virol. 76:10465-10472); and a small animal model of HDV viremia (see Bordier et al., 2003, J. Clin. Invest. 112:407-414). This has been possible because, fortuitously, the oncogene Ras also undergoes prenylation and plays a role in a variety of tumors, prompting the development of specific inhibitors of Ras prenylation (see Barinaga, 1997, Science 278: 1036-1039, and Sebti and Hamilton, 1997, Current Opinion in Oncology 9:557-561; James et al, J. Biol. Chem. 269:27705-27714; Dalton et al, 1995, Cancer Research 55:3295-3304; Rowinsky et al, 1999, J. Clin. Oncol. 17:3631-3652; and Sebti et al, 2000, Oncogene 19:6584-6593). Since the discovery that the farnesylation of Ras oncoproteins (which are associated with up to a quarter of all human cancers including 90% of all pancreatic cancers and 50% of colon cancers) is essential for their

transforming activity, FTase has been an anti-cancer drug target. Inhibitors of FTase (FTIs) can cause tumor regression in animals and have been evaluated in clinical trials for the treatment of human cancers. A large number of articles and applications have been published relating to the use of FTIs and other prenyltransferase inhibitors for treatment of cancers. See, e.g., PCT Pub. Nos. WO 95/10516, WO 97/23478, WO 98/54966, WO 01/45740, WO 01/56552, WO 01/62234, and WO 01/64199; US Pat. Nos. 5,874,442; 6,096,757; 6,232,338; 7,101,897; and 7,342,016. To date, however, none of these agents has been approved for the treatment of human cancer.

Although solely inhibiting Ras prenylation may be insufficient to cure cancer, published experimental data suggests that inhibition of delta antigen prenylation may be sufficient to break the HDV life cycle at the key step of particle assembly.

Importantly, a range of structurally diverse farnesyl trasferase inhibitors (FTIs) have been used for these experiments, with their only common feature being inhibition of farnesyl transferase, and they have all been able to effectively inhibit HDV particle assembly in model systems. Collectively, the experimental data provides a compelling rationale for the hypothesis that FTIs can form the basis for a potential practical clinical therapy, and proteins involved in prenylation have been identified as targets of anti-viral therapies (see US Pat. Nos. 5,503,973; 5,876,920; 6,159,939; and 6,627,610). Key prenylation proteins include CAAX prenyltransferases, e.g., farnesyl protein transferase (FTase) and geranylgeranyl protein transferase (GGTase), which catalyze the posttranslational attachment of an isoprenoid lipid group (prenylation) to many signal transduction proteins, including members of the Ras GTPase superfamily. Moreover, others have speculated that viral infection with viruses that do not have prenylated proteins can be treated by administering prenylation inhibitors (see US Pat. No. 7,223,787). However, to date no prenylation inhibitor has been demonstrated to be efficacious for the treatment of HDV or other virus infection in humans.

Thus, there is an ongoing need in the art for agents that treat HDV and other viral, bacterial, protozoal, and other pathogen infections and for identifying, among the many prenylation inhibitors, including FTIs, studied to date, those that will be efficacious in humans infected with HDV. The present invention meets these needs by providing pharmaceutical formulations and methods for treating HDV and other viral infections with inhibitors of prenylation.

SUMMARY

In a first aspect, this invention provides a method of inhibiting HDV replication in a cell or tissue comprising administering to the cell or tissue comprising HDV a therapeutically effective dose of a farnesyl transferase inhibitor (FTI) selected from the group consisting of EBP921 (also known as AZD3409; see U.S. Patent Nos. 6,232,338 and 7,101,897, incorporated herein by reference) and its active metabolites EBP919 and EBP975 (EBP921 is a pro-prodrug that is converted in vivo first to EBP919 and then to the most active FTI EBP975, which does not efficiently penetrate cells; the prodrugs EBP921 and EBP919 penetrate cells more efficiently) and EBP994 (also known as lonafarnib, SCH66336, and Sarasar) and its active metabolites (see U.S. Patent Nos. 5,874,442; 6,632,455; 7,049,440; 7,271,174, incorporated herein by reference) and pharmaceutically acceptable salts of any of the foregoing. In one embodiment the administration is in vitro. In another embodiment the method is practiced in vivo in a human subject or in an animal model. In another embodiment, the method is practiced in a human subject known to be co-infected with HBV and HDV.

In one embodiment, the method comprises orally administering a therapeutically effective dose of EBP921 (AZD3409) to a human subject known to be co- infected with HBV and HDV at a total daily dose of between about 200 mg to about 2 g for a period of at least 28 consecutive days. For example and without limitation, suitable administration schedules for EBP921 include: about 250 mg (malate salt or equivalent amount of HC1 or other salt) BID for a total daily dose of about 500 mg; about 500 mg (malate salt or equivalent amount of HC1 or other salt) BID for a total daily dose of about 1 g; and about 750 mg (malate salt or equivalent amount of HC1 or other salt) BID for a total daily dose of about 1.5 g. In various embodiments, the drug EBP921 is administered as a capsule comprising about 250 mg of the malate salt (or equivalent amount of HC1 or other salt) of EBP921. In various embodiments, EBP921 is co-administered with EBP994 and/or one or more drugs currently approved or otherwise used for treatment of HBV or HDV and/or EBP921 therapy is followed by a currently approved or otherwise used therapy or by EBP994 therapy. In one embodiment, the method comprises orally administering a therapeutically effective dose of EBP994 (lonafarnib) to a human subject known to be co- infected with HBV and HDV at a total daily dose of between about 50 mg to about 1 g for a period of at least about 28 consecutive days. In various embodiments, the EBP994 is administered BID; for example and without limitation, EBP994 can be administered at a dose of about 25 mg BID for a total daily dose of about 50 mg; about 50 mg BID for a total daily dose of about 100 mg; about 100 mg BID for a total daily dose of about 200 mg; about 200 mg BID for a total daily dose of about 400 mg; and about 300 mg BID for a total daily dose of about 600 mg. In various embodiments, EBP994 is co-administered with EBP921 and/or one or more drugs currently approved or otherwise used for treatment of HBV or HDV and/or EBP994 therapy is followed by a currently approved or otherwise used therapy or by EBP921 therapy.

In another aspect, the present invention provides a method of inhibiting in a cell a delta antigen prenylation comprising contacting the cell comprising the delta antigen with an effective amount EBP921 or EBP994, thereby inhibiting delta antigen prenylation. As used herein, an effective amount EBP921 or EBP994, refers to an amount of EBP921 or EBP994 that is sufficient to inhibit delta antigen prenylation, for example, by at least about 50%. In one embodiment, the contacting is in vitro or in vivo. As also used herein, delta antigen includes, without limitation, Hepatitis Delta large antigen protein and the like.

In another aspect, the present invention provides a method of inhibiting hepatitis D virus proliferation in a cell comprising contacting the cell comprising the hepatitis D virus with an effective amount of EBP921 or EBP994, thereby inhibiting the hepatitis D virus. As used herein, an effective amount EBP921 or EBP994, refers to an amount of EBP921 or EBP994 that is sufficient to inhibit hepatitis D virus proliferation, for example, by at least about 50%. In one embodiment, the contacting is in vitro or in vivo. As used herein, hepatitis D virus proliferation, includes, without limitation, hepatitis D virus-like particle production.

In another aspect, the present invention provides pharmaceutical formulations and unit dose forms of the compounds and pharmaceutical formulations useful in the methods of the invention. In another aspect, the present invention provides the use of EBP921 or EBP994, or a metabolite or salt of each thereof in the preparation of a medicament for the treatment of HDV infection.

In another aspect, the present invention provides a kit comprising a therapeutically effective dose of an FTI which is EBP921 or EBP994, or a salt or metabolite of each thereof, and an instruction for administration of the therapeutically effective dose for the treatment of HDV.

These and other aspects and embodiments of the invention are described in more detail below.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the results of the HDV viral-like particle (VLP) assay conducted with EBP921, as described in Example 1, and demonstrates that the compound is a potent inhibitor of HDV particle formation.

Figure 2 demonstrates that EBP921 inhibits HDV particle formation in a dose-dependent manner.

Figure 3 shows the results of the HDV viral-like particle assay conducted with EBP994, as described in Example 2, and demonstrates that the compound is a potent inhibitor of HDV particle formation.

Figure 4, in parts a and b, shows the EC₅o values for EB921 and five HBV drugs against HBV DEI 9 cells (part a) and summarizes the synergy/antagonism observed in combination studies together with the MacSynergy volume plots (part b).

Figure 5, in parts a and b, shows the EC50 values for EB994 and five HBV drugs against HBV DEI 9 cells (part a) and summarizes the synergy/antagonism observed in combination studies together with the MacSynergy volume plots (part b).

DETAILED DESCRIPTION OF THE INVENTION

This detailed description of the invention is divided into sections for the convenience of the reader. In Section I, definitions of terms used herein are provided. In Section II, various compounds useful in the methods of the invention are described. In Section III, conditions amenable to treatment in accordance with the methods of the invention are described. In Section IV, pharmaceutical compositions and unit dose forms useful in accordance with the methods of the invention are described. In Section V, methods for administering the compounds, pharmaceutical compositions, and unit dose forms useful in accordance with the methods of the invention are described. In Section VI, combination therapies of the invention are described. This section is followed by examples illustrating how the anti-viral activity of various illustrative compounds useful in the methods of the invention can be measured.

All publications and patents cited in this specification are herein incorporated by reference as if each individual publication or patent were specifically and individually indicated to be incorporated by reference and are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior disclosure. Further, the dates of publication provided could be different from the actual publication dates that may need to be independently confirmed.

As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure. Any recited method can be carried out in the order of events recited or in any other order that is logically possible. Embodiments of the present disclosure will employ, unless otherwise indicated, techniques of synthetic organic chemistry, biochemistry, biology, molecular biology, recombinant DNA techniques, pharmacology, and the like, which are within the skill of the art. Such techniques are explained fully in the literature. This disclosure is not limited to particular embodiments described, and the embodiment of the invention in practice may, of course, vary from that described herein.

I. Definitions

The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, because the scope of the present invention will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In this specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings unless a contrary intention is apparent. In some cases, terms with commonly understood meanings are defined herein for clarity and/or for ready reference, and the inclusion of such definitions herein should not be construed as representing a substantial difference over the definition of the term as generally understood in the art.

Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods, devices, and materials are now described. All technical and patent publications cited herein are incorporated herein by reference in their entirety. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.

All numerical designations, e.g., pH, temperature, time, concentration, and molecular weight, including ranges, are approximations which are varied ( + ) or ( - ) by increments of 0.1 or 1.0, as appropriate. It is to be understood, although not always explicitly stated that all numerical designations are preceded by the term "about".

The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a compound" includes a plurality of compounds.

The term "administration" refers to introducing a compound, a composition, or an agent of the present disclosure into a host. One preferred route of administration of the agents is oral administration. Another preferred route is intravenous administration. However, any route of administration, such as topical, subcutaneous, peritoneal, intraarterial, inhalation, vaginal, rectal, nasal, introduction into the

cerebrospinal fluid, or instillation into body compartments can be used.

The term "comprising" is intended to mean that the compounds, compositions and methods include the recited elements, but not excluding others.

"Consisting essentially of when used to define compounds, compositions and methods, shall mean excluding other elements that would materially affect the basic and novel characteristics of the claimed invention. "Consisting of shall mean excluding any element, step, or ingredient not specified in the claim. Embodiments defined by each of these transition terms are within the scope of this invention.

The terms "host," "subject," "patient," or "organism" include humans and mammals (e.g., mice, rats, pigs, cats, dogs, and horses). Typical hosts to which compounds of the present disclosure may be administered will be mammals, particularly primates, especially humans. For veterinary applications, a wide variety of subjects will be suitable, e.g., livestock such as cattle, sheep, goats, cows, swine, and the like; poultry such as chickens, ducks, geese, turkeys, and the like; and domesticated animals particularly pets such as dogs and cats. For research applications, a wide variety of mammals will be suitable subjects, including rodents (e.g., mice, rats, hamsters), rabbits, primates, and swine such as inbred pigs and the like. The term "living host" refers to a host noted above or another organism that is alive and refers to the entire host or organism and not just a part excised (e.g., a liver or other organ) from the living host.

The term "pharmaceutical composition" is meant to encompass a composition suitable for administration to a subject, such as a mammal, especially a human. In general a "pharmaceutical composition" is sterile, and preferably free of contaminants that are capable of eliciting an undesirable response within the subject (e.g., the compound(s) in the pharmaceutical composition is pharmaceutical grade).

Pharmaceutical compositions can be designed for administration to subjects or patients in need thereof via a number of different routes of administration including oral,

intravenous, buccal, rectal, parenteral, intraperitoneal, intradermal, intracheal, intramuscular, subcutaneous, inhalational and the like.

The terms "pharmaceutically acceptable excipient," "pharmaceutically acceptable diluent," "pharmaceutically acceptable carrier," or "pharmaceutically acceptable adjuvant" means an excipient, diluent, carrier, and/or adjuvant that are useful in preparing a pharmaceutical composition that are generally safe, non-toxic and neither biologically nor otherwise undesirable, and include an excipient, diluent, carrier, and adjuvant that are acceptable for veterinary use and/or human pharmaceutical use. "A pharmaceutically acceptable excipient, diluent, carrier and/or adjuvant" as used in the specification and claims includes one and more such excipients, diluents, carriers, and adjuvants. The term "pharmaceutically acceptable salt" refers to those salts that retain the biological effectiveness and optionally other properties of the free bases and that are obtained by reaction with inorganic or organic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, malic acid, maleic acid, succinic acid, tartaric acid, citric acid, and the like. In the event that embodiments of the disclosed agents form salts, these salts are within the scope of the present disclosure. Reference to an agent of any of the formulas herein is understood to include reference to salts thereof, unless otherwise indicated. The term "salt(s)", as employed herein, denotes acidic and/or basic salts formed with inorganic and/or organic acids and bases. In addition, when an agent contains both a basic moiety and an acidic moiety, zwitterions ("inner salts") may be formed and are included within the term "salt(s)" as used herein. Pharmaceutically acceptable (e.g., non-toxic, physiologically acceptable) salts are preferred, although other salts are also useful, e.g., in isolation or purification steps which may be employed during preparation. Salts of the compounds of an agent may be formed, for example, by reacting the agent with an amount of acid or base, such as an equivalent amount, in a medium such as one in which the salt precipitates or in an aqueous medium followed by lyophilization. Embodiments of the agents that contain a basic moiety may form salts with a variety of organic and inorganic acids. Exemplary acid addition salts include acetates (such as those formed with acetic acid or trihaloacetic acid, for example, trifluoroacetic acid), adipates, alginates, ascorbates, aspartates, benzoates,

benzenesulfonates, bisulfates, borates, butyrates, citrates, camphorates,

camphorsulfonates, cyclopentanepropionates, digluconates, dodecylsulfates,

ethanesulfonates, fumarates, glucoheptanoates, glycerophosphates, hemisulfates, heptanoates, hexanoates, hydrochlorides (formed with hydrochloric acid), hydrobromides (formed with hydrogen bromide), hydroiodides, 2-hydroxyethanesulfonates, lactates, maleates (formed with maleic acid), methanesulfonates (formed with methanesulfonic acid), 2-naphthalenesulfonates, nicotinates, nitrates, oxalates, pectinates, persulfates, 3- phenylpropionates, phosphates, picrates, pivalates, propionates, salicylates, succinates, sulfates (such as those formed with sulfuric acid), sulfonates (such as those mentioned herein), tartrates, toluenesulfonates such as tosylates, undecanoates, and the like.

Embodiments of the agents that contain an acidic moiety may form salts with a variety of organic and inorganic bases. Exemplary basic salts include ammonium salts, alkali metal salts such as sodium, lithium, and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salts with organic bases (for example, organic amines) such as benzathines, dicyclohexylamines, hydrabamines (formed with N,N- bis(dehydroabietyl)ethylenediamine), N-methyl-D-glucamines, N-methyl-D-glucamides, t-butyl amines, and salts with amino acids such as arginine, lysine, and the like. Basic nitrogen-containing groups may be quaternized with agents such as lower alkyl halides (e.g., methyl, ethyl, propyl, and butyl chlorides, bromides and iodides), dialkyl sulfates (e.g., dimethyl, diethyl, dibutyl, and diamyl sulfates), long chain halides (e.g., decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides), aralkyl halides (e.g., benzyl and phenethyl bromides), and others. Solvates of the agents of the disclosure are also contemplated herein. To the extent that the disclosed active compounds, and salts thereof, may exist in their tautomeric form, all such tautomeric forms are contemplated herein as part of the present disclosure. To the extent that the disclosed active compounds, and salts thereof, may exist as their N-oxides, all such N-oxides are contemplated herein as part of the present disclosure; methods of preparing such N-oxides are within the skill of one in the art. All stereoisomers of the agents, such as those that may exist due to asymmetric carbons on the various substituents, including enantiomeric forms (which may exist even in the absence of asymmetric carbons) and diastereomeric forms, are contemplated within the scope of this disclosure. Individual stereoisomers of the compounds of the disclosure may, for example, be substantially free of other isomers, or may be admixed, for example, as racemates or with all other, or other selected, stereoisomers. The stereogenic centers of the compounds of the present disclosure can have the S or R configuration as defined by the IUPAC 1974 Recommendations.

The term "prodrug" refers to an inactive (or less active, and in each case, depending on how activity is measured) precursor of an agent that is converted into a biologically active form in vivo. Prodrugs are often useful because, in some situations, they may be easier to administer than the parent compound. They may, for instance, be bioavailable by oral administration whereas the parent compound is not. The prodrug may also have improved solubility in pharmaceutical compositions over the parent drug. A prodrug may be converted into the parent drug by various mechanisms, including enzymatic processes and metabolic hydrolysis. The terms "prophylactically treat" or "prophylactically treating" refers completely or partially preventing a disease or symptom thereof and/or may be

therapeutic in terms of a partial or complete cure for a disease and/or adverse effect attributable to the disease.

The term "therapeutically effective amount" as used herein refers to that amount of an embodiment of the agent (which may be referred to as a compound, an inhibitory agent, and/or a drug) being administered that will treat to some extent a disease, disorder, or condition, e.g., relieve one or more of the symptoms of the disease, i.e., infection, being treated, and/or that amount that will prevent, to some extent, one or more of the symptoms of the disease, i.e., infection, that the host being treated has or is at risk of developing.

The terms "treatment", "treating", and "treat" are defined as acting upon a disease, disorder, or condition with an agent to reduce or ameliorate the pharmacologic and/or physiologic effects of the disease, disorder, or condition and/or its symptoms. "Treatment," as used herein, covers any treatment of a disease in a host (e.g., a mammal, typically a human or non-human animal of veterinary interest), and includes: (a) reducing the risk of occurrence of the disease in a subject determined to be predisposed to the disease but not yet diagnosed as infected with the disease, (b) impeding the development of the disease, and/or (c) relieving the disease, i.e., causing regression of the disease and/or relieving one or more disease symptoms. "Treatment" is also meant to encompass delivery of an inhibiting agent to provide a pharmacologic effect, even in the absence of a disease or condition. For example, "treatment" encompasses delivery of a disease or pathogen inhibiting agent that provides for enhanced or desirable effects in the subject (e.g., reduction of pathogen load, reduction of disease symptoms, etc.).

The term "unit dosage (or dose) form," as used herein, refers to physically discrete units suitable as unitary dosages for human and/or animal subjects, each unit containing a predetermined quantity of a compound (e.g., an anti-viral compound, as described herein) calculated in an amount sufficient to produce the desired treatment effect in association with a pharmaceutically acceptable diluent, carrier or vehicle. In other words, "unit dosage form," as used herein, refers to physically discrete units suitable as unitary dosages for human and/or animal subjects, each unit containing a

pharmaceutically acceptable composition of a predetermined quantity of a compound. The specifications for unit dosage forms depend on the particular compound employed, the route and frequency of administration, and the effect to be achieved, and the pharmacodynamics associated with each compound in the host.

II. Compounds Useful in the Invention

The present invention provides methods for treating certain viral, bacterial, protozoal, and other pathogen-induced infections comprising administering a

therapeutically effective amount of an inhibitor of prenylation to a patient in need of treatment. In various embodiments, the compound is an inhibitor of prenylation described in Section VI, subsection 12, below. Inhibitors of particular interest include

prenyltransferase inhibitors, particularly FTIs and GGTIs (GGTase inhibitors). In various embodiments, the inhibitor is a compound with FTase and/or GGTase inhibitory activity in the nanomolar range, i.e., having an IC₅₀ of less than 1 micromolar for either (or both) enzyme(s). In one embodiment, the inhibitor is EBP921 (AZD3409) or one of its metabolites EBP919 and EBP975 (see Table 1 below). EBP921 is a pro-prodrug that is converted in vivo first to EBP919 and then under the action of esterases to EBP975, which is a dual inhibitor of FTase and GGTase. In another embodiment, the inhibitor is EBP994 (lonafarnib, also known under the trade name Sarasar (Schering); see Table 1 below), which is an FTase inhibitor with little or no GGTase inhibitory activity. In various embodiments, the compound is a compound described in any of U.S. Pat. Nos. 5, 874,442; 6,232,338; 7,101,897; and 7,342,016. In various embodiments, the compound is EBP888, EBP889, or EBP890.

Table 1

Compounds Useful in the Methods of the Invention

Preferred compounds for use in the methods of the invention are EBP921 (AZD3409), which is the pro-pro-drug of EPB975; EBP919, which is the pro-drug of EBP975; EBP975, although EPB921 is typically the form administered to humans; and EBP994 (lonafarnib). Preferred methods for treating HDV involve the administration of EBP921 or EBP994. HDV infection and other conditions amenable to treatment in accordance with the methods of the invention are described in the following section. III. Conditions Amenable to Treatment

The present invention provides methods for treating diseases relating to HDV infection. HDV always presents as a co-infection with HBV, but a co-infected patient is much more likely to die of complications of viral infection than a patient infected with HBV alone. Currently available anti-HBV agents include the following nucleotide or nucleoside reverse transcriptase (RT) inhibitors: Lamivudine, Adefovir, Entecavir, Telbivudine, Clevudine, and Tenofovir. HBV/HDV co-infection may be treated with alpha interferon therapy or therapy with pegylated interferon alpha 2a (alone or in combination with one of the foregoing RT inhbitors). In accordance with the methods of this invention, an FTI, for example EBP921 , EBP994, EBP888, EBP889, and EBP890, are administered alone or in combination with another prenyltransferase inhibitor or other therapeutic for the treatment of HBV and/or HDV infection, including treatment in combination with one or more of the foregoing RT inhibitors and/or interferon (see the combination therapy section, below). In one embodiment, the subject is not known to have cancer and/or is not known to be infected with any virus other than HDV and HBV.

One exemplary method of treating a host infected with HDV provided by the invention, among others, includes administering to the host a therapeutically effective amount of an inhibitor of prenylation to reduce the HDV viral load in the host. In various embodiments, the inhibitor of prenylation is a prenyltransferase inhibitor such as an FTI, a GGTI, or a dual-acting FTI/GGTI. In various embodiments, the prenyltransferase inhibitor is EBP921 and/or EBP994.

In an embodiment, prenyltransferase inhibitors as described herein are used in combination with another agent (e.g. an anti-viral agent) to treat HDV infection. In an embodiment, prenyltransferase inhibitors described herein are used in combination with another agent (e.g. an anti-viral agent) to treat HDV infection prophylactically. In various embodiments, the prenyltransferase inhibitor used in the combination therapy is EBP921 and EBP994 (or both) and the other agent is an agent used to treat HBV or HDV infection. In an embodiment, an effective amount of the prenyltransferase inhibitor is an amount that, when administered in one or more doses to a host (e.g., human) in need thereof, reduces HDV viral load in the individual by at least about 10%, at least about 50%), at least about 75%, at least about 80%>, or at least about 90%>, or more, compared to the viral load in the individual not treated with the prenyltransferase inhibitor.

HDV can severely damage the liver of infected patients. Accordingly, the present invention provides methods for preventing liver damage and, in some patients, restoring liver function. Thus, in some embodiments, an effective amount of the prenyltransferase inhibitor is an amount that, when administered in one or more doses to a host (e.g., human) in need thereof, increases liver function in the individual by at least about 10%), at least about 25%, at least about 50%>, at least about 75%, at least about 90%>, or more, compared to the liver function in the individual not treated with the

prenyltransferase inhibitor. In some embodiments, an effective amount of the

prenyltransferase inhibitor is an amount that, when administered in one or more doses to a host (e.g., a human) in need thereof, reduces liver fibrosis in the host by at least about 10%), at least about 25%, at least about 50%, at least about 75%, at least about 90%, or more, compared to the degree of liver fibrosis in the individual not treated with the prenyltransferase inhibitor.

Liver fibrosis reduction is determined by analyzing a liver biopsy sample. An analysis of a liver biopsy comprises assessments of two major components:

necroinflammation assessed by "grade" as a measure of the severity and ongoing disease activity, and the lesions of fibrosis and parenchymal or vascular remodeling as assessed by "stage" as being reflective of long-term disease progression. See, e.g., Brunt, 2000, Hepatol. 31 :241-246; and METAVIR (1994) Hepatology 20: 15-20. Based on analysis of the liver biopsy, a score is assigned. A number of standardized scoring systems exist which provide a quantitative assessment of the degree and severity of fibrosis. These include the transient elastography, METAVIR, Knodell, Scheuer, Ludwig, and Ishak scoring systems.

The transient elastography fibrosis scoring system is suitable for use in determining whether a patient is in need of treatment or is responding to treatment in accordance with the methods of the invention and was developed by Thierry Poynard and marketed primarily in the EU but also in the US. It is often used when an invasive liver biopsy is risky. The marketed product for this scoring system is called FibroScan, and the system provides a measure of liver stiffness.

The METAVIR scoring system is based on an analysis of various features of a liver biopsy, including fibrosis (portal fibrosis, centrilobular fibrosis, and cirrhosis); necrosis (piecemeal and lobular necrosis, acidophilic retraction, and ballooning degeneration); inflammation (portal tract inflammation, portal lymphoid aggregates, and distribution of portal inflammation); bile duct changes; and the Knodell index (scores of periportal necrosis, lobular necrosis, portal inflammation, fibrosis, and overall disease activity). The definitions of each stage in the METAVIR system are as follows: score: 0, no fibrosis; score: 1, stellate enlargement of portal tract but without septa formation; score: 2, enlargement of portal tract with rare septa formation; score: 3, numerous septa without cirrhosis; and score: 4, cirrhosis.

Knodell's scoring system, also called the Hepatitis Activity Index, classifies specimens based on scores in four categories of histologic features: I. Periportal and/or bridging necrosis; II. Intralobular degeneration and focal necrosis; III. Portal inflammation; and IV. Fibrosis. In the Knodell staging system, scores are as follows: score: 0, no fibrosis; score: 1, mild fibrosis (fibrous portal expansion); score: 2, moderate fibrosis; score: 3, severe fibrosis (bridging fibrosis); and score: 4, cirrhosis. Thus, the scoring is such that higher the score, the more severe the liver tissue damage. See

Knodell, 1981, Hepatol. 1 :431.

In the Scheuer scoring system scores are as follows: score: 0, no fibrosis; score: 1, enlarged, fibrotic portal tracts; score: 2, periportal or portal-portal septa, but intact architecture; score: 3, fibrosis with architectural distortion, but no obvious cirrhosis; score: 4, probable or definite cirrhosis. See Scheuer, 1991, J. Hepatol. 13:372.

The Ishak scoring system is described in Ishak, 1995, J. Hepatol. 22:696-

699. Stage 0, No fibrosis; Stage 1, Fibrous expansion of some portal areas, with or without short fibrous septa; stage 2, Fibrous expansion of most portal areas, with or without short fibrous septa; stage 3, Fibrous expansion of most portal areas with occasional portal to portal (P-P) bridging; stage 4, Fibrous expansion of portal areas with marked bridging (P-P) as well as portal-central (P-C); stage 5, Marked bridging (P-P and/or P-C) with occasional nodules (incomplete cirrhosis); stage 6, Cirrhosis, probable or definite. The benefit of a therapy provided by the invention can also be measured and assessed by using the Child-Pugh scoring system which comprises a multicomponent point system based upon abnormalities in serum bilirubin level, serum albumin level, prothrombin time, the presence and severity of ascites, and the presence and severity of encephalopathy. Based upon the presence and severity of abnormality of these parameters, patients may be placed in one of three categories of increasing severity of clinical disease: A, B, or C.

IV. Pharmaceutical Compositions and Unit Dose Forms

The present invention provides pharmaceutical compositions comprising, or consisting essentially of, or consisting of one or more prenyltransferase inhibitors (and pharmaceutically acceptable salts thereof) and optionally one or more other anti-viral agents as identified herein and formulated with one or more pharmaceutically acceptable excipients, diluents, carriers and/or adjuvants. In addition, embodiments of the pharmaceutical compositions of the present invention include such prenyltransferase inhibitors formulated with one or more pharmaceutically acceptable auxiliary substances. In particular, one or more prenyltransferase inhibitors can be formulated with one or more pharmaceutically acceptable excipients, diluents, carriers, and/or adjuvants to provide an embodiment of a pharmaceutical composition of the invention.

In an embodiment, the prenyltransferase inhibitor is combined with another anti-viral agent to prepare a pharmaceutical composition of the invention, and the pharmaceutical composition can include one or more pharmaceutically acceptable excipients, diluents, carriers and/or adjuvants.

In an embodiment, a prenyltransferase inhibitor (referred to below as "a subject active agent"; or "a drug") can be formulated with one or more pharmaceutically acceptable excipients, diluents, carriers, and/or adjuvants to provide a formulation useful in the methods of the invention.

A wide variety of pharmaceutically acceptable excipients are known in the art. Pharmaceutically acceptable excipients have been amply described in a variety of publications, including, for example, A. Gennaro (2000) "Remington: The Science and Practice of Pharmacy," 20th edition, Lippincott, Williams, & Wilkins; Pharmaceutical Dosage Forms and Drug Delivery Systems (1999) H.C. Ansel et al, eds., 7^th ed., Lippincott, Williams, & Wilkins; and Handbook of Pharmaceutical Excipients (2000) A.H. Kibbe et al., eds., 3^rd ed. Amer. Pharmaceutical Assoc.

The pharmaceutically acceptable excipients, such as vehicles, adjuvants, carriers or diluents, are readily available to the public. Moreover, pharmaceutically acceptable auxiliary substances, such as pH adjusting and buffering agents, tonicity adjusting agents, stabilizers, wetting agents and the like, are readily available to the public.

In an embodiment of the present invention, the prenyltransferase inhibitor is formulated into pharmaceutical compositions by combination with appropriate, pharmaceutically acceptable carriers or diluents, and is formulated into preparations in solid, semi-solid, liquid or gaseous forms, such as tablets, capsules, powders, granules, ointments, solutions, suppositories, injections, inhalants and aerosols.

In pharmaceutical dosage forms, the prenyltransferase inhibitor may be administered in the form of its pharmaceutically acceptable salts, or a subject

prenyltransferase inhibitor may be used alone or in appropriate association, as well as in combination, with other pharmaceutically active compounds. The following

pharmaceutical formulations, unit dose forms, methods for their preparation, and excipients are merely exemplary and are in no way limiting.

For oral preparations, the prenyltransferase inhibitor can be used alone or in pharmaceutical formulations of the invention comprising, or consisting essentially of, or consisting of the prenyltransferase inhibitor in combination with appropriate additives to make tablets, powders, granules or capsules, for example, with conventional additives, such as lactose, mannitol, corn starch or potato starch; with binders, such as crystalline cellulose, cellulose derivatives, acacia, corn starch or gelatins; with disintegrators, such as corn starch, potato starch or sodium carboxymethylcellulose; with lubricants, such as talc or magnesium stearate; and if desired, with diluents, buffering agents, moistening agents, preservatives and flavoring agents.

In one embodiment, the pharmaceutical formulation of the invention contains the malate salt of EBP921 formulated for oral administration. The malate salt can be prepared as described in Bergin et al, 2007, J. Label Comp. Radiopharm. 50: 426, incorporated herein by reference. In another embodiment, the pharmaceutical formulation contains the EBP921 HC1 salt formulated for oral administration. One unit dose form useful in the methods of the invention contains 250 mg of the EBP921 malate salt or an equivalent amount of the EBP921 HC1 salt. The EBP921 HC1 salt can be conveniently formulated in a capsule. The EBP921 malate salt is readily compressible into tablets.

In one embodiment, the pharmaceutical formulation of the invention contains EBP994 formulated for oral administration. In various embodiments, the unit dose form useful in the methods of the invention contains 25 mg, 50 mg, 75mg, 100 mg, and 200 mg of EBP994.

Pharmaceutical formulations and unit dose forms suitable for oral administration are particularly useful in the treatment of chronic conditions, bacterial infections, and therapies in which the patient self-administers the drug. For acute infections and life -threatening conditions, particularly those requiring hospitalization, intravenous formulations are desirable, and the present invention provides such formulations as well.

The invention provides pharmaceutical formulations in which the prenyltransferase inhibitor can be formulated into preparations for injection in accordance with the invention by dissolving, suspending or emulsifying them in an aqueous or nonaqueous solvent, such as vegetable or other similar oils, synthetic aliphatic acid glycerides, esters of higher aliphatic acids or propylene glycol; and if desired, with conventional additives such as solubilizers, isotonic agents, suspending agents, emulsifying agents, stabilizers and preservatives.

Aerosol formulations provided by the invention can be administered via inhalation. For example, embodiments of the pharmaceutical formulations of the invention comprise the prenyltransferase inhibitor formulated into pressurized acceptable propellants such as dichlorodifluoromethane, propane, nitrogen and the like.

Suppositories of the invention can be prepared by mixing the prenyltransferase inhibitor with any of a variety of bases such as emulsifying bases or water-soluble bases. Embodiments of this pharmaceutical formulation of the

prenyltransferase inhibitor can be administered rectally via a suppository. The suppository can include vehicles such as cocoa butter, carbowaxes and polyethylene glycols, which melt at body temperature, yet are solidified at room temperature.

Unit dosage forms for oral or rectal administration, such as syrups, elixirs, and suspensions, may be provided wherein each dosage unit, for example, teaspoonful, tablespoonful, tablet or suppository, contains a predetermined amount of the composition containing one or more prenyltransferase inhibitors. Similarly, unit dosage forms for injection or intravenous administration may comprise the prenyltransferase inhibitor in a composition as a solution in sterile water, normal saline or another pharmaceutically acceptable carrier. Appropriate amounts of the API for unit dose forms of EBP921 and EBP994 are provided above.

Embodiments of the pharmaceutical formulations of the invention include those in which a prenyltransferase inhibitor is formulated in an injectable composition. Injectable pharmaceutical formulations of the invention are prepared as liquid solutions or suspensions; or as solid forms suitable for solution in, or suspension in, liquid vehicles prior to injection. The preparation may also be emulsified or the active ingredient (prenyltransferase inhibitor) encapsulated in liposome vehicles in accordance with other embodiments of the pharmaceutical formulations of the invention.

In an embodiment, the prenyltransferase inhibitor is formulated for delivery by a continuous delivery system. The term "continuous delivery system" is used interchangeably herein with "controlled delivery system" and encompasses continuous (e.g., controlled) delivery devices (e.g., pumps) in combination with catheters, injection devices, and the like, a wide variety of which are known in the art.

Mechanical or electromechanical infusion pumps can also be suitable for use with the present disclosure. Examples of such devices include those described in, for example, U.S. Pat. Nos. 4,360,019; 4,487,603; 4,692, 147; 4,725,852; 5,820,589;

5,643,207; and 6,198,966, incorporated herein by reference. In general, delivery of the prenyltransferase inhibitor can be accomplished using any of a variety of refillable, pump systems. Pumps provide consistent, controlled release over time. In some embodiments, the prenyltransferase inhibitor is in a liquid formulation in a drug-impermeable reservoir, and is delivered in a continuous fashion to the individual.

In one embodiment, the drug delivery system is an at least partially implantable device. The implantable device can be implanted at any suitable implantation site using methods and devices well known in the art. An implantation site is a site within the body of a subject at which a drug delivery device is introduced and positioned.

Implantation sites include, but are not necessarily limited to, a subdermal, subcutaneous, intramuscular, or other suitable site within a subject's body. Subcutaneous implantation sites are used in some embodiments because of convenience in implantation and removal of the drug delivery device.

Drug release devices suitable for use in the disclosure may be based on any of a variety of modes of operation. For example, the drug release device can be based upon a diffusive system, a convective system, or an erodible system (e.g., an erosion- based system). For example, the drug release device can be an electrochemical pump, osmotic pump, an electroosmotic pump, a vapor pressure pump, or osmotic bursting matrix, e.g., where the drug is incorporated into a polymer and the polymer provides for release of drug formulation concomitant with degradation of a drug-impregnated polymeric material (e.g., a biodegradable, drug-impregnated polymeric material). In other embodiments, the drug release device is based upon an electrodiffusion system, an electrolytic pump, an effervescent pump, a piezoelectric pump, a hydrolytic system, etc.

Drug release devices based upon a mechanical or electromechanical infusion pump can also be suitable for use with the present disclosure. Examples of such devices include those described in, for example, U.S. Pat. Nos. 4,360,019; 4,487,603; 4,692,147; and 4,725,852, incorporated herein by reference. In general, a subject treatment method can be accomplished using any of a variety of refillable, non- exchangeable pump systems. Pumps and other convective systems are generally preferred due to their generally more consistent, controlled release over time. Osmotic pumps are used in some embodiments due to their combined advantages of more consistent controlled release and relatively small size (see, e.g., PCT Pub. No. WO 97/27840 and U.S. Pat. Nos. 5,728,396 and 5,985,305). Exemplary osmotically-driven devices suitable for use in the disclosure include those described in U.S. Pat. Nos. 3,760,984; 3,845,770; 3,916,899; 3,923,426; 3,987,790; 3,995,631 ; 4,016,880; 4,036,228; 4,111,202; 4,111,203; 4,203,440; 4,203,442; 4,210,139; 4,327,725; 4,627,850; 4,865,845; 5,057,318; 5,059,423; 5,112,614; 5,137,727; 5,234,692; 5,234,693; and 5,728,396.

In some embodiments, the drug delivery device is an implantable device. The drug delivery device can be implanted at any suitable implantation site using methods and devices well known in the art. An implantation site is a site within the body of a subject at which a drug delivery device is introduced and positioned. Implantation sites include, but are not necessarily limited to a subdermal, subcutaneous, intramuscular, or other suitable site within a subject's body. Thus, in some embodiments, a prenyltransferase inhibitor is delivered using an implantable drug delivery system, e.g., a system that is programmable to provide for administration of the agent. Exemplary programmable, implantable systems include implantable infusion pumps, as described in, for example, U.S. Pat. Nos. 4,350,155; 5,443,450; 5,814,019; 5,976,109; 6,017,328; 6,171,276; 6,241,704; 6,464,687; 6,475,180; and 6,512,954. A further exemplary device that can be adapted for the present disclosure is the Synchromed infusion pump

(Medtronic).

Suitable excipient vehicles for the prenyltransferase inhibitor are, for example, water, saline, dextrose, glycerol, ethanol, or the like, and combinations thereof. In addition, if desired, the vehicle may contain minor amounts of auxiliary substances such as wetting or emulsifying agents or pH buffering agents. Methods of preparing such dosage forms are known, or will be apparent upon consideration of this disclosure, to those skilled in the art. See, e.g., Remington's Pharmaceutical Sciences, Mack Publishing Company, Easton, Pennsylvania, 17th edition, 1985. The composition or formulation to be administered will, in any event, contain a quantity of the prenyltransferase inhibitor adequate to achieve the desired state in the subject being treated.

Compositions of the present invention include those that comprise a sustained-release or controlled release matrix. In addition, embodiments of the present invention can be used in conjunction with other treatments that use sustained-release formulations. As used herein, a sustained-release matrix is a matrix made of materials, usually polymers, which are degradable by enzymatic or acid-based hydrolysis or by dissolution. Once inserted into the body, the matrix is acted upon by enzymes and body fluids. A sustained-release matrix desirably is chosen from biocompatible materials such as liposomes, polylactides (polylactic acid), polyglycolide (polymer of glycolic acid), polylactide co-glycolide (copolymers of lactic acid and glycolic acid), polyanhydrides, poly(ortho)esters, polypeptides, hyaluronic acid, collagen, chondroitin sulfate, carboxcylic acids, fatty acids, phospholipids, polysaccharides, nucleic acids, polyamino acids, amino acids such as phenylalanine, tyrosine, isoleucine, polynucleotides, polyvinyl propylene, polyvinylpyrrolidone and silicone. Illustrative biodegradable matrices include a polylactide matrix, a polyglycolide matrix, and a polylactide co-glycolide (co-polymers of lactic acid and glycolic acid) matrix. In another embodiment, the pharmaceutical compositions of the present disclosure (as well as combination compositions) are delivered in a controlled release system. For example, the prenyltransferase inhibitor may be administered using intravenous infusion, an implantable osmotic pump, a transdermal patch, liposomes, or other modes of administration. In one embodiment, a pump may be used (see Sefton, 1987. CRC Crit. Ref. Biomed. Eng. 14:201 ; Buchwald et al, 1980, Surgery 88:507; and Saudek et al, 1989, N. Engl. J. Med. 321 :574). In another embodiment, polymeric materials are used. In another embodiment, a controlled release system is placed in proximity of the therapeutic target, i.e., the liver, thus requiring only a fraction of the systemic dose. In another embodiment, a controlled release system is placed in proximity of the therapeutic target, thus requiring only a fraction of the systemic dose. Other controlled release systems are discussed in Langer, 1990, Science 249: 1527-1533.

In another embodiment, the compositions of the present invention (as well as combination compositions separately or together) include those formed by

impregnation of an inhibiting agent described herein into absorptive materials, such as patches, sutures, bandages, and gauze, or coated onto the surface of solid phase materials, such as surgical staples, zippers and catheters to deliver the compositions. Other delivery systems of this type will be readily apparent to those skilled in the art in view of the instant disclosure.

Thus, the invention provides a variety of pharmaceutical formulations, unit dose forms, and drug delivery devices for administering prenyltransferase inhibitors in accordance with the methods of the invention. These include, but are not limited to, tablets, capsules, and suspensions suitable for oral administration; formulations suitable for intramuscular and/or intravenous administration; lotions, creams, suspensions, gels, and treated patches and/or bandages suitable for topical application; and pumps and implantable depot formulations and devices for continuous administration of the prenyltransferase inhibitor.

V. Administration

As is clear from the previous section, the present invention provides methods and compositions for the administration of a prenyltransferase inhibitor to a host (e.g., a human) for the treatment of HDVinfection. In various embodiments, these methods of the invention span almost any available method and route suitable for drug delivery, including in vivo and ex vivo methods, as well as systemic and localized routes of administration. Generally, however, EBP921 and EB994 are administered orally.

Typical oral administration schedules for these schedules are BID administration schedules. For patients in which GI side effects are expected or have been demonstrated to be problematic, however, or for convenience, the methods of the invention can be practiced using patch technology, particularly patch technology that employ microneedles, to administer the drug subcutaneously, and thereby avoid or at least ameliorate GI and other side effects.

Thus, routes of administration applicable to the methods of the invention include intranasal, intramuscular, intratracheal, subcutaneous, intradermal, topical application, intravenous, rectal, nasal, oral, and other enteral and parenteral routes of administration, although oral administration is generally the preferred route of

administration. Routes of administration may be combined, if desired, or adjusted depending upon the agent and/or the desired effect. An active agent can be administered in a single dose or in multiple doses. Embodiments of these methods and routes suitable for delivery include systemic or localized routes. In general, routes of administration suitable for the methods of the invention include, but are not limited to, enteral, parenteral, or inhalational routes.

Parenteral routes of administration other than inhalation administration include, but are not limited to, topical, transdermal, subcutaneous, intramuscular, intraorbital, intracapsular, intraspinal, intrasternal, and intravenous routes, i.e., any route of administration other than through the alimentary canal. Parenteral administration can be conducted to effect systemic or local delivery of the inhibiting agent. Where systemic delivery is desired, administration typically involves invasive or systemically absorbed topical or mucosal administration of pharmaceutical preparations.

The prenyltransferase inhibitor can also be delivered to the subject by enteral administration. Enteral routes of administration include, but are not limited to, oral and rectal {e.g. , using a suppository) delivery.

Methods of administration of the inhibiting agent through the skin or mucosa include, but are not limited to, topical, transdermal, injection, and epidermal administration. For transdermal transmission, absorption promoters or iontophoresis are suitable methods. Iontophoretic transmission may be accomplished using commercially available "patches" that deliver their product continuously via electric pulses through unbroken skin for periods of several days or more.

In various embodiments of the methods of the invention, the prenyltransferase inhibitor will be administered orally on a continuous, daily basis, at least once per day (QD), and in various embodiments two (BID), three (TID), or even four times (QID) a day. Typically, the therapeutically effective daily dose will be at least 10 mg, usually at least 100 mg, often 200-500 mg, and sometimes, depending on the prenyltransferase inhibitor, up to as much as 750 mg, 1 g, or even up to 2.5 g.

For example and without limitation, EBP994 (lonafarnib) can be employed in accordance with the methods of the invention by orally administering to a patient in need of treatment at least 25 mg per day and up to 1000 mg per day. In various embodiments of the methods of the invention, EBP994 is administered twice per day, in equal doses, and each dose is in the range of 25 mg to 400 mg, so the daily dose is in the range of 50 to 800 mg. In one embodiment, EBP994 is administered orally at 100 mg BID. In another embodiment, EBP994 is administered orally at 200 mg BID.

For example and without limitation, EBP921 (AZD3409) can be employed in accordance with the methods of the invention by orally administering to a patient in need of treatment at least 50 mg per day and up to 2500 mg per day. In various embodiments of the methods of the invention, EBP921 is administered twice per day, in equal doses, and each dose is in the range of 25 mg to 1250 mg, so the daily dose is in the range of 50 to 2500 mg. In one embodiment, EBP921 is administered 500 mg BID. In another embodiment, EBP921 is 750 mg BID. In various embodiments, EBP921 is administered in a unit dose form of 250 mg, and at least one, two, or three unit doses is administered at least once or twice daily.

Dosing of prenyltransferase inhibitors like EBP994 and/or EBP921 can be accomplished in accordance with the methods of the invention using capsules, tablets, oral suspension for oral administration; patches for transdermal administration;

suspension for intra-muscular, intravenous, or intra-articular infusion or injection; and gel or cream for topical application. In one embodiment, EBP921 is administered orally in a tablet containing the malate salt. In another embodiment, EBP994 is administered orally in a tablet or capsule. Treatment dosages (or doses) generally may be titrated to optimize safety and efficacy. Typically, dosage-effect relationships from in vitro and/or in vivo tests initially can provide useful guidance on the proper doses for patient administration. For example, and without limitation, one may desire to administer an amount of the compound or composition of the present invention to decrease viral proliferation as compared to a suitable control. Determination of these parameters is well within the skill of the art.

In one embodiment of the invention, a prenyltransferase inhibitor is administered to a patient in need of therapy to treat HDV infection (HDV infection generally occurs only in patients co-infected with HBV). In one embodiment, the prenyltransferase inhibitor is EBP921 (AZD3409), which is administered as described above. In another embodiment, the prenyltransferase inhibitor is EBP994 (lonafarnib), which is administered as described above. Various combination therapies of the invention for the treatment of HBV and HDVcoinfection are described in Section VI, below.

A proof of concept (POC) trial demonstrating the antiviral effect of

EBP921 or EBP994 against HDV can be conducted in a cohort of 15 to 25 patients with chronic HDV infection. Patients will undergo pre-study screening, which may include the following assessments: liver biopsy within one-year of study enrollment; hematological assessment and monitoring throughout the study; blood chemistry assessment and monitoring throughout the study; screening for concomitant viral infections, including HBV, HCV, and HIV, as well as HDV viral loads; cancer assessment and screening, including liver carcinoma; patients co-infected with HCV, HIV, or who have received an experimental drug within the prior six months, or who have been recently

diagnosed/treated for cancer may be excluded from the study to facilitate demonstration of improved health upon treatment as described herein.

Once a patient is qualified to enter the clinical trial, baseline HDV viral load levels will be determined. Patients will then receive active dosing with EBP921 or EBP994. For EBP994, a first cohort of patients may receive EBP994 at a dose of 100 mg BID for 28 days. If good tolerability and safety are observed in this cohort, but it appears that efficacy can be increased by a higher dosage, then a second cohort may receive dosing of EBP994 at 200 mg BID for 28 days. If tolerability and safety signals are observed in the first cohort, and/or it appears that equal efficacy can be achieved by a lower dosage, then a second cohort may receive dosing of EBP994 at 25 or 50 mg BID for 28 days.

For EBP921, a first cohort of patients may receive EBP921 at a dose of 500 mg BID for 28 days. If good tolerability and safety are observed in this cohort, then a second cohort may receive dosing of EBP921 at a dose of 750 mg or 1000 mg BID for 28 days. If tolerability and safety signals are observed in the first cohort, and/or it appears that equal efficacy can be achieved by a lower dosage, then a second cohort may receive dosing of EBP921 at 150 or 250 mg BID for 28 days.

HDV viral load levels can be assessed throughout the active therapy phase of the study, with heightened viral surveillance occurring at six time-points during the first 72 hours of therapy to gauge initial virologic response. Follow-up HDV viral load assessment will occur approximately every fourth day during the last 24 days of active therapy. Safety and pharmacokinetic data will be collected during the dosing phase, as well as examination of PBMC farnesyl transferase activity. In addition, patients will undergo post-treatment monitoring for six -months to assess HDV viral load as well as safety assessments.

VI. Combination Therapies

The pharmaceutically acceptable compositions or pharmaceutical formulations and unit dose forms described herein can be used in combination with other drugs, including other anti-viral drugs. Thus the methods of the invention include methods for treating a virus-induced (or other pathogen-induced) disease comprising administering two or more drugs, at least one of which is a prenyltransferase inhibitor and at least one of which is selected from the group consisting of (1) nucleotide and nucleoside analogs; (2) interferons; (3) thiazolides, including but not limited to nitazoxanide; (4) protease inhibitors; (5) polymerase inhibitors (both nucleoside and non- nucleoside inhibitors); (6) helicase inhibitors; (7) class C CpG toll-like receptor 7 and/or 9 antagonists; (8) amphipathic helix disruptors; (9) statins; (10) immunomodulators (including steroidal and non-steroidal immunomodulators); (11) anti-inflammatories; (12) other inhibitors of prenylation, including prenyltransferase inhibitors, including but not limited to another FTI, GGTI, or dual-acting FTI/GGTI, or inhibitors of post-prenylation reactions; and/or (13) other agents for the treatment of side effects and/or pain relief. In various embodiments, inhibitors of the HDV ribozyme, ligase, and/or polymerase activities are co-administered with a prenyltransferase inhibitor and/or one or more additional agents. In various embodiments of these various combination therapies of the invention, at least one of the drugs co-administered is EBP921 or EBP994. Each of these classes of other drugs that can be used in the combination therapies of the invention are discussed below.

(1) Nucleoside and Nucleotide Analogs

Nucleoside and nucleotide analogs that are suitable for use in a

combination therapy of this invention include, but are not limited to, lamivudine, adefovir, entecavir, telbivudine, clevudine, and tenofovir. Other suitable such analogs include lagociclovir valactate, elvucitabine, LB-80380, pradefovir, and valtorcitabine.

Other suitable such analogs include ribavirin, levovirin, taribavirin, compounds disclosed in U.S. Pat. Nos. 5,559,101; 6,277,830; and 6,423,695; U.S. Pat. App. Pub. No.

20020058635; and PCT Pub. Nos. WO 01/90121, WO 02/057425, WO 02/057287, and WO 02/069903. Certain nucleoside analogs are DNA polymerase inhibitors, which are also discussed as a class below.

(2) Interferons

Current medical practice to treat HBV and/or HBV and HDV co-infection sometimes employs either interferon-alpha monotherapy (including treatment with interferon alpha 2b or a pegylated interferon, such as Pegasys, marketed by Roche, or PEG-Intron, marketed by Schering Plough) or combination therapy with interferon alpha and a nucleoside or nucleotide analogue, such as adefovir (Hepsera®), entecavir

(Baraclude®), lamivudine (Epivir-HBV®, Heptovir®, Heptodin®), telbivudine

(Tyzeka®), tenofivir (Viread®), and ribavirin (such as Rebetol® or Copegus®). In accordance with the methods of the present invention, a prenyltransferase inhibitor is used in combination with one of these standard therapies to treat HDV infection (i.e., HBV and HDV co-infection). In various embodiments an interferon of any of Types I-IV is used in combination with a prenyltransferase inhibitor, such as EBP921 and/or EBP994, to treat HDV infection.

Thus, the present invention provides combination therapies in which an interferon, e.g., interferon-alpha (IFN-a) is used in combination with a prenyltransferase inhibitor. Any known IFN-a can be used in the treatment methods of the invention. The term "interferon-alpha" as used herein refers to a family of related polypeptides that inhibit viral replication and cellular proliferation and modulate immune response. The term "IFN-a" includes naturally occurring IFN-a; synthetic IFN-a; derivatized IFN-a (e.g., PEGylated IFN-a, glycosylated IFN-a, and the like); and analogs of naturally occurring or synthetic IFN-a. Thus, essentially any IFN-a that has antiviral properties, as described for naturally occurring IFN-a, can be used in the combination therapies of the invention.

Suitable alpha interferons for purposes of the invention include, but are not limited to, naturally-occurring IFN-a (including, but not limited to, naturally occurring IFN-a2a, IFN-a2b); recombinant interferon alpha-2b such as Intron-A interferon available from Schering Corporation, Kenilworth, NJ; recombinant interferon alpha-2a such as Roferon interferon available from Hoffmann-La Roche, Nutley, NJ; recombinant interferon alpha-2C such as Berofor alpha 2 interferon available from Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT; interferon alpha-nl , a purified blend of natural alpha interferons such as Sumiferon available from Sumitomo, Japan or as Wellferon interferon alpha-nl (INS) available from the Glaxo-Wellcome Ltd., London, Great Britain; and interferon alpha-n3 a mixture of natural alpha interferons made by Interferon Sciences and available from the Purdue Frederick Co., Norwalk, CT, under the Alferon tradename.

The term "IFN-a" also encompasses consensus IFN-a. Consensus IFN-a (also referred to as "CIFN" and "IFN-con" and "consensus interferon") encompasses, but is not limited to, the amino acid sequences designated IFN-coni, IFN-con₂ and IFN-con₃ which are disclosed in U.S. Pat. Nos. 4,695,623 and 4,897,471 ; and consensus interferon as defined by determination of a consensus sequence of naturally occurring interferon alphas (e.g., Infergen®, Three Rivers Pharmaceuticals, Warrendale, PA). IFN-coni is the consensus interferon agent in the Infergen® alfacon-1 product. The Infergen® consensus interferon product is referred to herein by its brand name (Infergen®) or by its generic name (interferon alfacon-1). DNA sequences encoding IFN-con may be synthesized as described in the aforementioned patents or other standard methods. In an embodiment, the at least one additional therapeutic agent is CIFN.

In various embodiments of the combination therapies of the invention, fusion polypeptides comprising an IFN-a and a heterologous polypeptide are used.

Suitable IFN-a fusion polypeptides include, but are not limited to, Albuferon-alpha™ (a fusion product of human albumin and IFN-a; Human Genome Sciences; see, e.g., Osborn et al., 2002, J. Pharmacol. Exp. Therap. 303:540-548). Also suitable for use in the present methods are gene-shuffled forms of IFN-a. See, e.g., Masci et al, 2003, Curr. Oncol. Rep. 5: 108-113. Other suitable interferons include Multiferon (Viragen), Medusa Interferon (Flamel Technology), Locteron (Octopus), and Omega Interferon (Intarcia/Boehringer Ingelheim).

The term "IFN-a" also encompasses derivatives of IFN-a that are derivatized (e.g., are chemically modified relative to the naturally occurring peptide) to alter certain properties such as serum half-life. As such, the term "IFN-a" includes glycosylated IFN-a; IFN-a derivatized with polyethylene glycol ("PEGylated IFN-a"); and the like. PEGylated IFN-a, and methods for making same, is discussed in, e.g., U.S. Pat. Nos. 5,382,657; 5,951,974; and 5,981,709. PEGylated IFN-a encompasses conjugates of PEG and any of the above-described IFN-a molecules, including, but not limited to, PEG conjugated to interferon alpha-2a (Roferon, Hoffman La-Roche, Nutley, N.J.), interferon alpha 2b (Intron, Schering-Plough, Madison, N.J.), interferon alpha-2c (Berofor Alpha, Boehringer Ingelheim, Ingelheim, Germany); and consensus interferon as defined by determination of a consensus sequence of naturally occurring interferon alphas (Infergen®, InterMune, Inc., Brisbane, CA.).

Thus, in some embodiments of the combination therapies of the invention, the IFN-a has been modified with one or more polyethylene glycol moieties, i.e.,

PEGylated. The PEG molecule of a PEGylated IFN-a polypeptide is conjugated to one or more amino acid side chains of the IFN-a polypeptide. In an embodiment, the PEGylated IFN-a contains a PEG moiety on only one amino acid. In another embodiment, the PEGylated IFN-a contains a PEG moiety on two or more amino acids, e.g., the IFN-a contains a PEG moiety attached to two, three, four, five, six, seven, eight, nine, or ten different amino acid residues. IFN-a may be coupled directly to PEG (i.e., without a linking group) through an amino group, a sulfhydryl group, a hydroxyl group, or a carboxyl group.

(3) Thiazolides

A number of thiazolide derivatives are in development for the treatment of viral infection, and in accordance with the methods of the present invention, coadministration of a prenyltransferase inhibitor and a thiazolide, including, but not limited to, nitazoxanide (Alinia, Romark Laboratories, or other sustained release formulations of nitazoxanide or other thiazolides) is efficacious in the treatment of HDV. Nitazoxanide administration in accordance with the combination therapies of the invention can be, for illustration and without limitation, 500 mg po BID. In one embodiment, an interferon alpha and/or a nucleoside analog such as ribavirin is/are also employed in this

combination therapy. Other doses, other thiazolides, or other formulations of nitazoxanide or another thiazolide, such as sustained release formulations, can also be used in the combination therapies of the invention.

(4) Protease Inhibitors

A number of HCV protease inhibitors are in development for the treatment of

HCV infection, and in accordance with the methods of the present invention, coadministration of a prenyltransferase inhibitor and an HCV protease inhibitor is efficacious in the treatment of patients co-infected with HDV and HBV, including but not limited to such patients that are also co-infected with HCV or another Flaviviridae virus. Suitable HCV protease inhibitors include, but are not limited to, telaprevir (VX-950, Vertex), BILN 2061 and BI 12202 (Boehringer Ingelheim), boceprevir (SCH 503034, Schering Plough), ITMN191 (Roche/InterMune/Array BioPharma), MK-7009 (Merck), TMC435350 (Tibotec/Medivir), ACH-1095 and ACH-806 (Achillion/Gilead), and other inhibitors of NS3/NS4A protease.

(5) Polymerase Inhibitors

DNA and RNA polymerase inhibitors may also be used in the combination drug therapies of the invention for the treatment of HDV infection. A number of HCV RNA polymerase (NS5B) inhibitors are in development for the treatment of HCV infection, and in accordance with the methods of the present disclosure, co-administration of a prenyltransferase inhibitor and an HCV RNA polymerase inhibitor is efficacious in the treatment of patients co-infected with HDV and HBV, including but not limited to such patients that are also co-infected with HCV. In one embodiment, an interferon alpha and/or a nucleoside analog such as ribavirin and/or an HCV protease inhibitor is/are also employed in this combination therapy. Suitable HCV RNA polymerase inhibitors include, but are not limited to, valopicitabine (NM283, Idenix/Novartis), HCV-796

(Wyeth/ViroPharma), R1626 (Roche), R7128 (Roche/Pharmasset), GS-9190 (Gilead), MK-0608 (Merck), PSI-6130 (Pharmasset), and PFE-868,554 (PFE). (6) Helicase Inhibitors

A number of agents targeting HCV NS3 helicase are in development, and compounds that suppress the HSV helicase-primase enzyme complex (such as ASP2151) are known and can be used in combination with a prenyltransferase inhibitor to treat HDV infection in accordance with the methods of the invention.

(7) Class C CpG Toll-like Receptor 7 and/or 9 Antagonists

A number of toll-like receptor (TLR) agonists are in development for the treatment of HCV infection, and in accordance with the methods of the present disclosure, co-administration of a prenyltransferase inhibitor and a TLR agonist can be efficacious in the treatment of patients co-infected with HDV and HBV, including but not limited to such patients who are also co-infected with HCV. In one embodiment, an interferon alpha and/or a nucleoside analog such as ribavirin and/or an HCV protease inhibitor and/or an HCV RNA polymerase inhibitor is/are also employed in this combination therapy.

Suitable TLR agonists include, but are not limited to, TLR7 agonists (i.e., ANA245 and ANA975 (Anadys/Novartis)) and TLR9 agonists (i.e., Actilon (Coley) and IMO-2125 (Idera)).

(8) Amphipathic Helix Disruptors and NS4B Inhibitors

In various embodiments of the invention, a prenyltransferase inhibitor of the invention is used in combination with an amphipathic helix disruptor and/or NS4B inhibitor to treat HDV infection. Such compounds are disclosed in PCT Pub. Nos. WO 2002/089731, WO 2009/0014615, WO 2009/039248 (including but not limited to clemizole); WO 2010/107739; WO 2010/107742; and WO 2010/039195; PCT App. Nos. US 10/053255 and US 10/053256, each of which is incorporated herein by reference.

(9) Statins and other HMG CoA Reductase Inhibitors

HMG CoA reductase inhibitors, including but not limited to statins, exert an antiviral effect (see Delang et al., 2009, Hepatology 50(1): 6-16; and Amet et al., Microbes and Infection 10(5): 471-480, both of which are incorporated herein by reference). In one embodiment of the combination therapies of the invention, an HMG CoA reductase inhibitor is used in combination with a prenyltransferase inhibitor to treat HDV infection. Thus, in an embodiment of the present invention, the prenyltransferase inhibitor is co-formulated with an inhibitor of HMG-CoA reductase into pharmaceutical compositions by combination with appropriate, pharmaceutically acceptable carriers and/or diluents, and is formulated into preparations in solid, semi-solid, liquid or gaseous forms, such as tablets, capsules, powders, granules, ointments, solutions, suppositories, injections, inhalants and aerosols. In various embodiments, the HMG Co A reductase inhibitor is a statin, including but not limited to lovastatin, simvastatin, atorvastatin, fluvastatin, and pravastatin.

(10) Immunomodulators

Steroid based immunomodulating therapies, including but not limited to treatment with methyprednisolone, are useful in the combination therapies of the invention, as are non-steroid immunomodulating therapies.

Non-steroid immunomodulating therapies useful in the combination therapies of the invention include administration of drugs from the following classes: inhibitors of inosine monophosphate dehydrogenase (IMPDH) and pro-drugs of inhibitors of IMPDH (mycophenolate mofetil); di-hydro orotate dehydrogenase inhibitors

(teriflunomide; fmgolimod; leflunomide) or pro-drugs of di-hydro orotate dehydrogenase inhibitors; monoclonal antibodies that target receptors on B-lymphocytes and/or T- lymphocytes (rituximab); compounds which cause selective apoptosis in dividing and non-dividing lymphocytes including purine nucleoside analog prodrugs (leustatin);

compounds which can modulate the immune response resulting in a conversion from a Thl to a Th2 response (glatiramer acetate); and inhibitors of folate metabolism

(methotrexate).

(11) Anti-inflammatories

Anti-inflammatory therapies useful in the combination therapies of the invention include steroid-based therapies (methylprednisolone); treatment with tumor necrosis factor (TNF) antagonists (etanercept); and treatment with pyrimidine synthesis inhibitors (leflunomide)

(12) Prenylation Inhibitors

Within the context of the combination therapies of this invention, a prenylation inhibitor (an inhibitor of prenylation) designates any compound, agent or treatment that inhibits (e.g., reduces or abolishes) the prenylation of proteins, more specifically the prenylation of proteins required for viral replication. Such inhibitors include more specifically any compound (e.g., antagonist) that inhibits a prenylation enzyme, particularly a prenyltransferase enzyme, more particularly a CAAX- prenyltransferase. Specific and preferred examples of such enzymes include

geranylgeranyl transferase(s) ("GGTase") and farnesyl transferase(s) ("FTase").

In a preferred embodiment, the FTase inhibitors ("FTIs") or GGTase inhibitors ("GGTIs") have an IC₅o for the FTase or GGTase, respectively, which is below 1 mM and, more preferably, below 100 iiM. The inhibitors can inhibit either GGTase or FTase, or both (i.e., dual inhibitors). Alternatively, a combination comprising, or consisting essentially of, or consisting of a GGTase inhibitor and an FTase inhibitor can be used. Most preferred GGTase or FTase inhibitors are selective inhibitors, i.e., they are essentially active on GGT or FT with no substantial specific activity on other enzymes (IC₅₀ > 20 uM). Most preferred prenyltransferase inhibitors for use in the present invention are EBP921 and EBP994, but other prenyltransferase inhibitors can be used in combination with one or both of these drugs in the methods of the invention.

Illustrative GGTIs include FTI-277 and GGTI-298. Illustrative FTIs include 3 -hydroxy-3 -methyl glutaryl coenzyme A reductase inhibitors and HMG-CoA inhibitors (including the statins, discussed above). Other FTIs useful in the combination therapies of the invention include those described in the following publications: PCT Pub. Nos. WO 95/10516; WO 95/25086; WO 97/16443; WO 97/23478;WO 98/54966; WO 01/45740; WO 01/56552; WO 01/62234; and WO 01/64199; US Pat. Nos. 5,874,442; 6,096,757; 6,232,338; 7,101,897; and 7,342,016; EP Pub. Nos. EP 534546, EP 696593, and EP 1162201; and Reiss, 1990, Cell 62: 81-8; James, 1993, Science 260: 1937-1942; Lerner, 1995, J. Biol. Chem. 270: 26802; and Shih et al., Cancer Chemother. Pharmacol, 2000, 46: 387-393.

More specifically, FTIs useful in the combination therapies of the inventions include, but are not limited to: A-87049, A-176120, A-197574, A-228839, A- 228839.25, A-345665, A-345877, A-373857, A-409100; ABT-100, ABT-839; Arglabin; Arglabin-DMA HC1; Arteminolide C; Artemisolide; 2-Benzoyloxycinnamaldehyde (BCA); BIM-46068; BMS-191563, BMS-193269, BMS-214662, BMS-225975, BMS- 316810; BNG-1; CH-222422; CP-609754, CP-663427; Dimethylaminoarglabin HC1; DMNQ-533; ER-51784, ER-51785; FTI-276, FTI-277, FTI-2148, FTI-2153, FTI-2600; Isorhamnetin; Isorhamnetol; J-104126, J-104134, J-104871; L-778123, L-779575; LB- 42908; 3'-Methoxyquercetin; Methylflucidone; NSC-702818 (Tipifarnib), NSC-712392; OSI-754; PD-161956, PD-169451; R-l 15777 (also identified Tipifarnib or Zamestra®, whose FTase IC₅₀ is 0.86 nM); RPR-115135, RPR- 130401, RPR-201764; SCH-400, SCH-207758, SCH-211618, SCH-226374, SCH-44342, SCH-54429, SCH-59228, EBP994 (SCH-66336, lonafarnib; Sarasar), SCH-69955, SCH-69956, SCH-704742; TAN-1813; and XR-3054.

Rl 15777 is a suitable prenyltransferase inhibitor for use in the methods of the invention that has the following structure:

R11 5777

EBP994 is (+)-4-[2-[4-(8-Chloro-3,10-dibromo-6,l l-dihydro-5H-benzo- [5,6]cycloh- epta[ 1 ,2-b]-pyridin- 11 (R)-yl)- 1 -piperidinyl]-2-oxo-ethyl]- 1 - piperidinecarboxamide (also identified as Sch-66336, lonafarnib, SCH 66336 or

Sarasar®, whose FTase IC₅₀=1.9 nM) and related compounds (see U.S. Pat. Nos.

5,874,442 and 7,342,016) are suitable prenyltransferase inhibitors for use in the methods of the invention. EBP994 (SCH-66336) has the following structure:

SCH-66336

(R)-7-Cyano-2,3 ,4,5 -tetrahydro- 1 -( 1 H-imidazol-4-ylmethyl)-3 - (phenylmethyl)-4-(2-thienylsulfonyl)-lH-l,4-benzodiazepine (also identified as BMS- 214662, whose FTase IC₅o=0.7 nM) is a suitable prenyltransferase inhibitor for use in the methods of the invention (see Hunt et al, J. Med. Chem., 2000, 43, 3587-3595) and has the following structure:

BMS-214662

EBP921 is isopropyl (2S)-2-({2-(4-fluorophenetyl)-5-[({(2S,4S)-4-[(3- pyridinylcarbonyl)sulfanyl]tetrahydro-lH-pyrrol-2-yl}methyl)amino]benzoyl}amino)-4- (methylsufanyl)- butanoate, also identified as AZD-3409 (see PCT Pub. No. WO

01/46137), is a preferred prenyltransferase inhibitor for use in the methods of the invention.

2,3,4,5-Tetrahydro- 1 -(1 H-imidazol-4-ylmethyl)-4-(l -naphthalenylcarbo- nyl)-lH-l,4-benzodiazepine, hydrochloride, described in PCT Pub. No. WO 97/30992, is suitable for use in the methods of the invention and has the following structure:

1 -(3-Chlorophenyl)-4-[ 1 -(4-cyanobenzyl)-5-imidazolylmethyl]-2-pipera- zinone (also identified as L-778,123, FTase IC₅o=2 nM; see Lobell, 2002, Mol. Cancer Ther. 1 : 747) is suitable for use in the methods of the invention and has the following

L-778,123

1(R), 10(S)-Epoxy-5(S),5(S),7(S)-guaia-3(4),l l(13)-dien-6,12-olide, also identified as Arglabin (see PCT Pub. No. WO 98/48789), is a prenyltransferase inhibitor suitable for use in the methods of the invention. L-Methionine, N-[[(4R)-3-[(2S,3S)-2-[[(2R)-2-amino-3- mercaptopropyl] amino] -3 -methylpentyl] -5 ,5 -dimethyl-4-thiazolidinyl] carbonyl] -, methyl ester, also identified as BIM-46068 (see PCT Pub. No. WO 98/00409) is a

prenyltransferase inhibitor suitable for use in the methods of the invention.

L-Methionine, N- [ [5 - [ [( 1 H-imidazol-4-ylmethyl)amino]methyl] -2'- methyl[l,l'-biphenyl]-2-yl]carbonyl] or also called FTI-2148 and its methyl ester, FTI- 2153 (see PCT Pub. No. WO 97/17070), are prenyltransferase inhibitors suitable for use in the methods of the invention.

4-[(4-Cyano-2-arylbenzyloxy)-(3-methyl-3H-imidazol-4-yl)methyl]benzo- nitriles, referred as A315493 (FTase IC₅₀=0.4 nM and GGTase IC₅₀=24 nM); A313326 (FTase IC₅₀=0.3 nM and GGTase IC₅₀=118 nM); and 5-cyano-2-[(4-cyanophenyl)-(3- methyl-3H-imidazol-4-yl)methoxymethyl]-N-phenylbenzamide (see Wang et al, 2004, J. Med. Chem. 47: 612) are prenyltransferase inhibitors suitable for use in the methods of the invention and have the following structures:

A31 5493: X = N

A31 3326: X = CH

FTI-276 (or EBP887; FTase IC₅₀=0.5 nM) and FTI-277 (or EBP888; FTase IC₅₀=100 nM), are described in Lerner et al, 1995, J. Biol. Chem. 270(45): 26770, and Lerner et al., 1995, J. Biol. Chem., 270(45): 26802, and are suitable prenyltransferase inhibitors for use in the methods of the invention that have the following structures:

FTI-276 R = H

FTI-277 R = CH3

(2S)-2-[[(2S)-2-[[(2S,3S)-2-[[(2R)-2-Amino-3-mercaptopropyl]amino]-3- - methylpentyljoxy]- 1 -oxo-3-phenylpropyl] amino] -4-(methylsulfonyl)-butanoic acid 1 - methylethyl ester, also identified as EBP 1673 and L-744,832 (see Law et al, 2000, J.

Biol. Chem. 275: 10796, is a prenyltransferase inhibitor suitable for use in the methods of the invention. L-744,832 has the following structure:

L-744,832 Other prenyltransferase inhibitors suitable for use in the methods of the invention include: 1 -[ 1 - [1 -(1 ,3-benzodioxol-5-ylmethyl)-l H-imidazol-5-ylmethyl]-4-(l - naphthyl)-lH-pyrrol-3-yl]-l-(4-methyl-l-piperazinyl)methanone, also called LB-42908, described in W09928315; 2-(3-pyridyl)-N-(2,2-diphenyl-ethyl)-N-((cis)-3- sulfanylpyrrolidin-2-ylmethyl)acetamide described in PCT Pub. No. WO 98/07692; (7,8- dichloro-5H-dibenzo[b,e][l,4]diazepin-l l-yl)-pyridin-3-yl methylamine described in PCT Pub. No. WO 97/00252; (2 alpha)-2-hydroxy-24,25-dihydroxylanost-8-en-3-one or clavarinone and clavaric acid and lanost-8,24-dien-3-one described in PCT Pub. No. WO 96/35707; L-erythro-L-glycero-D-altro-7-trideculo-7,4-furanosonic acid, 2,7-anhydro- 3 ,4-di-C-carboxy-8,9, 10,12, 13-pentadeoxy- 10-methylene- 12-(phenylmethyl)- 11 -acetate 5-(4,6-dimethyl-2-octenoate), [5(2E,4S,6S),7S] or zaragozic acid A described in PCT

Pub. No. WO 94/04144 (Zaragozic acid FTase IC₅₀=50 nM); 2,4-decadienamide, N-(5- hydroxy-5 -(7-((2-hydroxy-5 -oxo- 1 -cyclopenten- 1 -yl)amino-oxo- 1 ,3 ,5 -heptatrienyl)-2- oxo-7-oxabicyclo(4.1.0)hept-3-en-3-yl)-2,4,6-trimethyl-(lS-(lalpha,3(2E,4E,6S^!i:),5 alpha, 5(1E,3E,5E),6 alpha)) or Manumycin A or also called UCFl-C, described in EP Pub. No. EP 456474; and N-Acetyl-N-naphthylmethyl-2(S)-[(l-(4-cyanobenzyl)-lH- imidazol-5-yl)-acetyl]amino-3(S)-methylpentamine, described in PCT Pub. No. WO 96/39137.

4,9-Ethano-3aH-benz[fJisoindole-3a-carboxylicacid, 1,2,3,4,9,9a- hexahydro-2-[2-(2-methoxyphenyl)-l-oxo-2-propenyl]-9-(4-methylphenyl)-,

(3aR,4S,9S,9aR) or also identified as RPR- 130401 (see PCT Pub. No. WO 98/29390) is a prenyltransferase inhibitor suitable for use in the methods of the invention and has the following structure:

RPR-1 30401

(lalpha,2beta,3beta,4alpha)-l,2-di[N-Propyl-N-(4-phenoxybenzyl)amino- carbonyl]cyclobutane-3,4-dicarboxylate, also identified as A-87049 (see PCT Pub. No. WO 96/34851), is a prenyltransferase inhibitor suitable for use in the methods of the invention.

1-Cyclohexene-l -methanol, 4-(l -methyl ethenyl), also named perillyl alcohol (see U.S. Pat. No. 5,110,832), is a prenyltransferase inhibitor suitable for use in the methods of the invention and has the following structure:

Cys-Val-Phe-Met (or CVPM, see Reiss et al, 1990, Cell 62: 81) is a prenyltransferase inhibitor suitable for use in the methods of the invention that has the following structure:

H-Cys-Val-2-Nal-Met-OH (Nal = naphthylalanine), also identified as (S)-2-((S)-2- ((S)-2-((R)-2-amino-3 -mercaptopropanamido)-3 -methylbutanamido)-3 -(naphthalen-2- yl)propanamido)-4-(methylthio)butanoic acid and EBP889 (see Hamilton and Sebti, 1995. Drug News Perspect. 8: 138, and Leftheris et al, 1994. Bioorg. Med. Chem. Lett. 4: 887 (FTase ICso=12 nM for p21^ras)) is a prenyltransferase inhibitor suitable for use in the methods of the invention and has the following structure:

(S)-2-((S)-2-((S)-2-((R)-2-Amino-3-mercaptopropanamido)-3-methylbutylamino)- 3-phenylpropanamido)-4-(methylthio)butanoic acid, also identified as EBP 1674 (see Yamaguchi et al, 2004, Stroke 35: 1750; Cox et al, 1994, J. Biol. Chem. 269: 19203; and Garcia et al., 1993, J. Biol. Chem. 268: 18415 (FTase ICso=21 nM)) is a prenyltransferase inhibitor suitable for use in the methods of the invention and has the following structure:

(S)-4-(5-{[l-(3-Chlorobenzyl)-2-oxopyrrolidin-3-ylamino]methyl}imida- zol-l-ylmethyl)benzonitrile (see Bell, 2001, J. Med. Chem. 44:, 2933 (FTase IC₅₀=1.9 nM)) is a prenyltransferase inhibitor suitable for use in the methods of the invention that has the following structure:

FTI-205, FTI-232 (Cys-4-ABA-Met, also identified as EBP 1675, FTase

IC₅₀=50 nM) and FTI-249 (FTase IC₅₀=50 nM; see Quian et al, 1994, J. Biol. Chem. 269 12410) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

FTI-2287 and FTI-2312 (FTase IC₅₀=430 nM; see Ohkandha, 2002, Med. Chem. 45: 177) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

J-104,134 (FTase IC₅₀=5 nM) and J-104,135 (FTase IC₅₀=3.9 nM; see Aoyama et al., 1998, J. Med. Chem. 41 : 143) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

J-104,134 4S, 5S, 8R, 9R

J-104,135 4R, 5S, 8R, 9R

BZA-2B (FTase IC₅₀=0.85 iiM), BZA-4B (FTase IC₅₀=1.3 iiM), and BZA- 5B (FTase IC₅o⁼41 iiM; see Stadley et al, 1993, Biochemistry 32: 12586; James et al, 1993, Science 260: 1937 are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

BZA-2B R = H BZA-4B

BZA-5B R = CH3

L-739,750 (FTase IC₅₀=1.8 iiM) and L-739,749 (see Kohl et al, 1994, Proc. Natl. Acad. Sci. USA 91 : 9141) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

L-739,749 R = CH₃

L-739,750 R = H

(R*)-N-[[l,2,3,4-Tetrahydro-2-[N-[2-(lH-imidazol-4-yl)ethyl]-L-valyl]-3- isoquinolinyl]carbonyl]-L-methionine ([imidazol-4-yl-ethyl]-Val-Tic-Met) or BMS- 193269 (FTase IC₅₀=0.79 nM; see Hunt, 1996, Med. Chem. 39: 353) is a prenyltransferase inhibitor suitable for use in the methods of the invention that has the followin structure:

BMS-1 93269

RPR 113829 (FTase IC₅₀=1.8 nM) and its methyl ester prodrug RPR 114334 (see Clerc et al., 1995, Bioorg. Med. Chem. Lett. 5: 1779) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

RPR 1 13829 R = H

RPR 1 14334 R = Me

B956 (FTase IC₅₀=11 nM) and its methyl ester B1086 (see Nagasu et al, 1995, Cancer Res. 55: 5310) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

B 956 R = H

B 1 088 R = Me

BMS-186511 (FTase IC₅₀=10 nM; see Patel et al, 1995, J. Med Chem. 38: 2906) is a prenyltransferase inhibitors suitable for use in the methods of the invention that has the following structure:

Methyl N-benzoyl-N-(piperidin-4-yl-N-(R)-cysteinyl)-(S)-methioninate (FTase IC₅₀=20 nM; see Houssin et al, 2002, J. Med. Chem., 45: 533) is a

prenyltransferase inhibitor suitable for use in the methods of the invention that has the following structure:

N- [3 -Benzoyl -4- [(4-methylphenyl)acetylamino]phenyl] -5 -phenylvaleryl amide (FTase IC₅₀=390 nM; see Bohm et al, 2001, J. Med. Chem. 44: 3117) is a prenyltransferase inhibitor suitable for use in the methods of the invention that has the following structure:

(+)-4-(4-Chloro-3,6,7,12-tetrahydro-l-methylpyrido[2',3':4,5]cyclohepta :]indol-12-yl)-l-(4-pyridinylacetyl)piperidine N-oxide (or Sch-207758; FTase 7.4 nM; see Taveras et al., 2001, J. Med. Chem. 44: 3117) is a prenyltransferase nhibitor suitable for use in the methods of the invention that has the following structure:

Sch-207758

(+)-4-(2-Bromophenyl)-2-(3,4-dihydroxyphenyl)-3-nitro-l-(3-pyridylme- thyl)piperidine (FTase IC₅o=l .9 nM); see Nara et al, 2003, J. Med. Chem. 46: 2467) is a prenyltransferase inhibitor suitable for use in the methods of the invention that has the following structure:

L-Leucine, N-[4-[[(2R)-2-amino-3-mercaptopropyl]amino]-2-(l- naphthalenyl)benzoyl] -methyl ester (or GGTI-298) and the corresponding acid (GGTI- 297 (GGTase-I IC₅₀=50 nM; see McGuire et al, 1996, J. Biol. Chem. 271 : 27402) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

(S)-Methyl 2-(5-((R)-2-amino-3-mercaptopropylamino)biphenyl-2- ylcarboxamido)-4-methylpentanoate (or GGTI-286) and its corresponding acid (GGTI- 287 or EBP1676; GGTase-I IC₅₀=5 nM; see Lerner et al, 1995, J. Biol. Chem. 270(45): 26770, and Lerner et al., 1995, J. Biol. Chem. 270(45): 26802) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following

4-((5-((4-(3-chlorophenyl)-3-oxopiperazin- 1 -yl)methyl)- lH-imidazol-1 - yl)methyl)-2-phenoxybenzonitrile is a prenyltransferase inhibitor suitable for use in the methods of the invention that has the following structure:

GGTI-2154 (GGTase IC₅₀=21 nM; see Vasudevan et al, 1999, J. Med. Chem. 42: 1333) and GGTI-2166 (see Sun et al, 1999, Cancer Res. 59: 4919) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

4-[[N-(Imidazol-4-yl)methyleneamino]-2-(l-naphthyl)benzoyl]leucine, also identified as GGTI2133 (GGTase IC₅₀ = 38 nM; see Collisson et al. 2003. Mol. Cancer Ther. 2, 941), and 4-[[N-(imidazol-4-yl)methyleneamino]-2-(l-naphthyl)benzoyl]leucine methyl ester, also identifed as GGTI-2147 and EBP 1677 (GGTase IC₅₀ = 500 nM for RaplA; see Bernot et al., 2003, J. Cardiovasc. Pharmacol. 41 : 316; and Vasudevan et al., 1999, J. Med. Chem. 42: 1333) are prenyltransferase inhibitors suitable for use in the methods of the invention that have the following structures:

GGTI-2133 R=H

GGTI-2147 R=Me

The present invention also includes, as prenylation inhibitors, the optical and geometrical isomers, racemates, tautomers, salts, hydrates and mixtures of the above cited compounds. Also, the present invention is not limited to the compounds identified above, but shall also include any compound and derivative thereof cited in the references mentioned above, as well as all farnesyltransferase or geranylgeranyl transferase inhibitors (FTls or GGTIs) known to one skilled in the art, which are appropriate for use in human subjects. Furthermore, the prenyltransferase inhibitors also include prodrugs of compounds cited above which, after administration to a subject, are converted to said compounds. They also include metabolites of compounds cited above which display similar therapeutic activity to said compounds.

(13) Other Agents In other embodiments of the methods of the present invention, coadministration of a prenyltransferase inhibitor and a compound from one of the following classes of compounds is used to treat HDV infection: cyclophilin inhibitors (i.e., NIM- 811 and DEBIO-025); alpha-glucosidase inhibitor (i.e., Celgosivir); agents targeting NS5 A, including, but not limited to, A-831 , AZD2836, and agents in PCT Pub. Nos. WO 06/133326 and WO 08/021928, incorporated herein by reference); agents targeting TBC1D20 and/or NS5A's interaction with TBC1D20 (see PCT Pub. No. WO 07/018692 and U.S. Pat. App. No. 11/844,993, incorporated herein by reference); agents targeting NS4B's GTPase activity (see PCT Pub. No. WO 2005/032329 and US Pat. App. Pub. No. 2006/0199174, incorporated herein by reference); agents targeting PIP2 or BAAPP domains, such as those found in NS4B and NS5A (see PCT Pub. No. WO 2009/148541); agents targeting HDV entry, assembly, or release, including antibodies to co-receptors; siRNAs, shRNAs, antisense RNAs, or other RNA-based molecules targeting sequences in HDV; agents targeting microRNAs modulating HDV replication; agents targeting PD-1, PD-L1 , or PD-L2 interactions or pathway (see US Pat. App. Pub. Nos. 20080118511, 20070065427, 20070122378, incorporated herein by reference); any agent approved for the treatment of HIV; any agent useful in the treatment of HBV (see Lok et al., 2007, Gastroenterology 132: 1586-1594); and side effect management agents, including but not limited to agents that are effective in pain management; agents that ameliorate

gastrointestinal discomfort; analgesics, anti-inflammatories, antipsychotics, antineurotics, anxiolytics, hematopoietic agents, and any agent for palliative care of patients suffering from pain or any other side effect in the course of treatment with a subject therapy, including but not limited to palliative agents such as acetaminophen, ibuprofen, other NSAIDs, H2 blockers, proton pump inhibitors, and antacids.

In preferred combination therapies of the invention, one or more prenylation inhibitors is combined with an antiviral medication directed against HBV. In these combination therapies, any prenylation inhibitor described herein can be used. In various embodiments of these methods, EBP921 and/or EBP994 is the prenylation inhibitor employed.

Anti-HBV medications that are currently approved inhibit reverse transcriptase and are nucleoside/-tide analogues. These medications, while effective against HBV, are not effective against HDV as they do not lower HBsAg, which HDV needs to replicate; however, when used in the combination therapies of the invention, improved patient outcomes can be achieved. Currently approved anti-HBV medications include: lamivudine, adefovir, entecavir, telbivudine, clevudine (Korea/Asia), and tenofovir. Truvada, which is a combination of tenofovir and emtricitabine, is not yet approved but has been shown to be effective in reducing HBV viral titers in early clinical trials and is useful in the combination therapies of the invention.

Another class of anti-HBV drugs that can be combined with a prenylation inhibitor in the management of HDV in accordance with the combination therapies of the invention is the class of pro-drug nucleotide/-side analogues that inihibit viral reverse transcriptase. Compounds in this class include, but are not limited to lagociclovir, elvucitabine, LB-80380, pradefovir, and valtorcitabine.

A preferred class of compounds that can be combined with a prenylation inhibitor in the management of HDV in accordance with the combination therapies of the invention is the class of non-nucleoside HBV inhibitors (i.e., compounds described in Tables 3 and 4 of Kim et al, 2010, Molecules 15:5878-5908, incorporated herein by reference, including but not limited to alisol A derivatives, ellagic acid, and

pyranocoumarin derivatives). This class is designed to attack HBV by either targeting viral antigens or viral replication. Compounds that attack HBV viral antigens by inhibiting HBsAg secretion are ideal for combination therapy with prenylation inhibitors for the management of HDV. Compounds that inhibit the replication of HBsAg are also useful for combination therapy with prenylation inhibitors for the management of HDV, optionally in combination with compounds that inhibit HBsAg secretion. Thus, drug "cocktails" provided by the invention for use against HDV include those comprising one or more prenylation inhibitor(s) in combination with an inhibitor of HBsAg secretion and/or an inhibitor of HBsAg replication. Dual or triple therapy is valuable against HDV given the reliance of the delta antigen on HBsAg.

Another class of drugs that can be combined with a prenylation inhibitor in the management of HDV in accordance with the combination therapies of the invention is the class of alfa-interferons. Pegylated interferon has been used in the management of HDV as a monotherapy, albeit with clearance of HDV in no more than a quarter of those treated. A combination therapy provided by the invention comprises administering one or more prenylation inhibitors as direct antivirals with an immune modulator such as interferon (optionally in combination with other antiviral medications, as described above). Illustrative interferons include those discussed above. In one embodiment of these combination therapies, pegylated interferon alfa-2a is administered weekly in dosages of 180 meg subcutaneously (SQ). In other embodiments of these methods, alfa-interferons are used as follows: consensus interferon (Infergen) administered at 9 meg to 15 meg SQ daily or thrice weekly; interferon-alfa 2a recombinant 3 MIU to 9 MIU SQ administered thrice weekly; interferon-alfa 2b recombinant 3 MIU to 25 MIU SQ administered thrice weekly; and pegylated interferon lambda (IL-28) 80 meg to 240 meg SQ weekly.

In addition, any compound that stimulates the secretion of interferon can be used in combination with prenylation inhibitors for the management of HDV in accordance with the methods of the invention. For example, toll-like receptor agonists are immune enhancers useful in these methods.

The methods and compositions of the invention having now been described in detail, the following examples are provided to illustrate methods by which the anti-viral activity of the prenylation inhibitors of the invention can be demonstrated. Activity against HDV can be demonstrated in vitro through cell-based assays assessing the cytotoxicity and IC₅₀ of the prenyltransferase inhibitor alone, and then in combination with other antiviral compounds. The cell lines used for these assays may be laboratory- derived and/or patient-derived cell lines. The examples herein are put forth so as to provide those of ordinary skill in the art with an illustrative disclosure and description of how to perform the methods and use the compounds disclosed and claimed herein. Efforts have been made to ensure accuracy with respect to numbers {e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C, and pressure is at or near atmospheric. Standard temperature and pressure are defined as 20 °C and 1 atmosphere. Any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

EXAMPLES

Example 1. Virus-Like Particle Inhibition Assay with EBP921

EBP921 was tested in the hepatitis D virus-like particle assay described by

Glenn et al, 1998, J. Virol. 72: 9303, incorporated herein by reference, to demonstrate that delta antigen prenylation can be pharmacologically inhibited by the prenylation inhibitor EBP921.

Huh7 cells were transfected with a combination of plasmids coding for Hepatitis Delta large antigen (HDLAg) and Hepatitis B surface antigen (HBsAg) or HDLAg and an empty DNA plasmid (negative control). The cells expressing HBsAg and HDLAg were treated daily with EBP921 at increasing concentrations. As a control one plate was treated with high dose FTI-2153, which is known to inhibit virus-like particle (VLP) production. Three days post transfection the media was collected and debris and floating cells were removed by low speed centrifugation (4000 rpm at 4 °C for 15 min). The resulting supernatant was overlaid on a 20% sucrose cushion and centrifuged for 16 hours at 30000 rpm I °C.

The pellet was resuspended in 40 μΐ of SDS-PAGE sample buffer and heated for 5 min at 98 °C. The samples were resolved over a 12%> SDS-PAGE gel, which was then blotted onto a PVDF membrane. To detect the HDLAg, IgG's isolated from hepatitis Delta patient serum were used and then detected with a secondary anti-human antibody conjugated to an infrared dye followed by scanning of the membrane in LICOR- Odyssey scanner. The resulting bands were quantified using the Odyssey software. The graph (middle panel, Figure 1) represent the percent VLP detected (top panel, Figure 1) relative to non-treated control. The HDLAg transfection (without HBsAg) served for background subtraction.

HBsAg secretion was determined using an ELISA kit. The cell media was diluted 1 : 100 and 100 μΐ was used to determine the level of HDsAg. The HBsAg secretion level was normalized to non-treated control using the HDLAg transfection (without HBsAg) for background subtraction.

Upon expression, HDLAg is retained inside the cells when it is expressed alone. When co-expressed with HBsAg, VLPs are produced and HDLAg and HBsAg are secreted in these VLPs. However, because HBsAg is secreted via a second pathway as well, inhibition of VLPs is not expected to inhibit secretion of HBsAg. As seen in Figure 1, VLPs (and HDLAg secretion) are not produced upon expression of HDLAg alone (lane 1). Co-expression of HDLAg with HBsAg results in VLP production as indicated by the presence of secreted HDLAg in the media (lane 2). Treatment with 0.1 μΜ EBP921 results in over 50% inhibition of VLP production (lane 3) and 1 μΜ completely inhibits VLP production (lane 4), similar to treatment with 10 μΜ FTI-2153 (lane 5). Treatment with either inhibitor has no effect on HBsAg secretion. The results presented in this Example demonstrate that delta antigen prenylation can be pharmacologically inhibited by the prenylation inhibitor EBP921. Furthermore, EBP921 specifically abolishes particle production in a dose-dependent manner (EC50 = 0.12 uM; see Figure 2)·

Example 2. Virus-Like Particle Inhibition Assay with EBP994

EBP994 was studied in the VLP assay described in Example 1 to demonstrate that delta antigen prenylation can be pharmacologically inhibited by the prenylation inhibitor EBP994. As seen in Figure 3, treatment with 50 pM EBP994 results in over 50% inhibition, and treatment with 100 pM completely inhibits VLP production.

The results demonstrate that delta antigen prenylation can be pharmacologically inhibited by the prenylation inhibitor EBP994. Furthermore, EBP994 specifically abolishes particle production in a dose-dependent manner (EC50 = 34.7 pM).

Example 3. Combination Therapies

EBP921 and EBP994 were tested in in vitro combination studies in HBV

DEI 9 cell assays to illustrate combination therapies of the invention and to evaluate synergies/antagonisms with anti-HBV drugs.

EC50 values for EBP921, EBP994, and five anti-HBV drugs (tenofovir, adefovir, lamivudine, entecavir, telbivudine) were determined by ten (lO)-point titration

(1 :3 serial dilutions), in a 96-well assay format (see Figures 4a, 5a). The final DMSO concentration in the cell culture medium was 0.5% (v/v). The medium/compound mixtures were refreshed after three days followed by an additional three-day incubation.

Cell culture supernatant of each assay well was collected on day 6 followed by HBV DNA extraction. HBV DNA titer in each sample was quantified by TaqMan PCR, and the data were used for EC50 calculation.

All the agents (i.e., EBP921, EBP994, and each of the 5 anti-HBV drugs) were diluted based on the EC50 values obtained in the above assay. EBP921 and EBP994 were combined with each of the five drugs. The supernatant from each well was harvested on day 4, followed by HBV DNA extraction and real time PCR quantification of HBV

DNA in the culture supernatant. For each combination, the data were analyzed using

MacSynergy II for this analysis (see Figure 4b, 5b). In combinations of EBP921 and EBP994 with the five HBV drugs, no significant synergy or antagonism was observed. In addition, EBP921 and EBP994 did not show significant inhibitory activity against HBV replication under the assay conditions.

While certain embodiments have been illustrated and described, changes and modifications can be made thereto in accordance with ordinary skill in the art without departing from the present technology in its broader aspects as defined in the following claims.

Claims

1. A method of treating a hepatitis delta virus (HDV) infection in a subject, said method comprising administering to the subject in need of such treatment a

therapeutically effective dose of a farnesyl transferase inhibitor (FTI) which is EBP921 or EBP994, or a salt or metabolite of each thereof, thereby treating the HDV infection.

2. The method of Claim 1 , wherein the FTI is EBP921.

3. The method of Claim 2, wherein the therapeutically effective dose is a total daily dose of between about 200 mg to about 2 g that is administered for at least about 28 consecutive days.

4. The method of Claim 3, wherein the total daily dose is about 500 mg,

administered about 250 mg BID.

5. The method of Claim 3, wherein the total daily dose is about 1 g, administered about 500 mg BID.

6. The method of Claim 3, wherein the total daily dose is about 1.5 g, administered about 750 mg BID.

7. The method of any one of Claims 2-6, wherein EBP921 is administered as a tablet comprising about 250 mg of a malate salt of EBP921.

8. The method of Claim 1 , wherein the FTI is EBP994.

9. The method of Claim 8, wherein the therapeutically effective dose is a total daily dose of between about 50 mg to about 1000 mg that is administered for at least about 28 consecutive days.

10. The method of Claim 9, wherein the therapeutically effective dose is a total daily dose of between about 100 mg to about 500 mg.

11. The method of Claim 10, wherein the total daily dose is about 100 mg, administered about 50 mg BID.

12. The method of Claim 10, wherein the total daily dose is about 200 mg, administered about 100 mg BID.

13. The method of Claim 10, wherein the total daily dose is about 400 mg, administered about 200 mg BID.

14. The method of any one of Claims 1-13, wherein the FTI is co-administered with an anti-viral agent that is not EBP921 and EBP994 or a metabolite or salt thereof.

15. A method of treating HDV infection in a subject, said method comprising administering to the subject in need of such treatment a therapeutically effective dose of a farnesyl transferase inhibitor (FTI) in combination with a second drug, thereby treating the HDV infection.

16. The method of claim 15, wherein the FTI is EBP887, EBP888, EBP889, EBP890, EBP919, EBP921, EBP975, or EBP994, or a metabolite or a salt of each thereof, and the second drug is lamivudine, adefovir, entecavir, telbivudine, clevudine, tenofovir, emtricitabine, lagociclovir, elvucitabine, LB-80380, pradefovir, valtorcitabine, a non- nucleoside HBV inhibitor, an HMG CoA reductase inhibitor, or an alfa-interferon, or a salt thereof.

17. A method of inhibiting delta antigen prenylation in a cell comprising contacting the cell comprising the delta antigen with an effective amount EBP921 or EBP994 or a metabolite or salt of each thereof, thereby inhibiting delta antigen prenylation in the cell.

18. A method of inhibiting hepatitis D virus proliferation in a cell comprising contacting the cell comprising the hepatitis D virus with an effective amount of EBP921 or EBP994 or a metabolite or salt of each thereof, thereby inhibiting the hepatitis D virus proliferation in the cell.

19. The method of claim 17 or 18, wherein the contacting is in vitro or in vivo.

20. Use of EBP921 or EBP994, or a metabolite or salt of each thereof in the preparation of a medicament for the treatment of HDV infection.

21. A kit comprising a therapeutically effective dose of an FTI which is EBP921 or EBP994, or a salt or metabolite of each thereof, and an instruction for administration of the therapeutically effective dose for the treatment of HDV.