Salts and Polymorphs of Sulfamide NS3 Inhibitors

The present invention relates to salts and polymorphs of (5R,8S)-7-

[(2S)-2- {[(2S)-2-cyclohexyl-2-({[(2S)-l-isopropylpiperidin-2-yl]carb onyl}amino)acetyl]amino} -3,3-dimethylbutanoyl]-N- {(lR,2R)-2-ethyl- 1 -[(pyrrolidin- 1 -ylsulfonyl)carbamoyl]cyclopropyl} -10,10-dimethyl-7-azadispiro[3.0.4. l]decane-8-carboxamide, pharmaceutical compositions containing them and their use in therapy.

Background

Chronic hepatitis C virus (HCV) infection is a major global health burden, with an estimated 170 million people infected worldwide and an additional 3 to 4 million infected each year (See e.g. World Health Organization Fact Sheet No.164. October 2000). Although 25% of new infections are symptomatic, 60-80% of patients will develop chronic liver disease, of whom an estimated 20% will progress to cirrhosis with a 1 -4% annual risk of developing hepatocellular carcinoma (See e.g. World Health Organization Guide on Hepatitis C. 2002; Pawlotsky, J-M. (2006) Therapy of Hepatitis C: From Empiricism to Eradication. Hepatology 43:S207-S220). Overall, HCV is responsible for 50-76% of all liver cancer cases and two thirds of all liver transplants in the developed world (See e.g. World Health Organization Guide on Viral Cancers. 2006). And ultimately, 5-7% of infected patients will die from the consequences of HCV infection (See e.g. World Health Organization Guide on Hepatitis C. 2002).

The current standard therapy for HCV infection is pegylated interferon alpha (IFN-a) in combination with ribavirin. However, only up to 50% of patients with genotype 1 virus can be successfully treated with this interferon-based therapy. Moreover, both interferon and ribavirin can induce significant adverse effects, ranging from flu-like symptoms (fever and fatigue), hematologic complications (leukopenia, thrombocytopenia), neuropsychiatric issues (depression, insomnia, irritability), weight loss, and autoimmune dysfunctions (hypothyroidism, diabetes) from treatment with interferon to significant hemolytic anemia from treatment with ribavirin. Therefore, more effective and better tolerated drugs are still greatly needed.

NS3, an approximately 70 kDa protein, has two distinct domains: a N-terminal serine protease domain of 180 amino acids (AA) and a C-terminal helicase/NTPase domain (AA 181 to 631). The NS3 protease is considered a member of the chymotrypsin family because of similarities in protein sequence, overall three-dimensional structure and mechanism of catalysis. The HCV NS3 serine protease is responsible for proteolytic cleavage of the polyprotein at the NS3/NS4A, NS4A/NS4B, NS4B/NS5A and NS5A/NS5B junctions (See e.g. Bartenschlager, R., L. et al. (1993) J. Virol. 67:3835-3844; Grakoui, A. et al. (1993) J. Virol. 67:2832-2843; Tomei, L. et al. (1993) J. Virol. 67:4017-4026). NS4A, an approximately 6 kDa protein of 54 AA, is a co-factor for the serine protease activity ofNS3 (See e.g. Failla, C. et al. (1994) J. Virol. 68:3753-3760; Tanji, Y. et al. (1995) J. Virol. 69: 1575-1581). Autocleavage of the NS3/NS4A junction by the NS3/NS4A serine protease occurs intramolecularly (i.e., cis) while the other cleavage sites are processed intermolecularly (i.e., trans). It has been demonstrated that HCV NS3 protease is essential for viral replication and thus represents an attractive target for antiviral chemotherapy.

There remains a need for new treatments and therapies for HCV infection, as well as HCV- associated disorders. There is also a need for compounds useful in the treatment or prevention or amelioration of one or more symptoms of HCV, as well as a need for methods of treatment or prevention or amelioration of one or more symptoms of HCV. Furthermore, there is a need for new compounds capable of modulating the activity of HCV-serine proteases, particularly the HCV NS3/NS4a serine protease and using said compounds to treat, prevent or ameliorate HCV infection.

Unpublished patent application no. PCT/IB2010/000784 describes a novel class of compounds useful in the treatment of HCV-associated disorders. One such compound is

(5R,8S)-7-[(2S)-2- {[(2S)-2-cyclohexyl-2-({[(2S)-l-isopropylpiperidin-2-yl]carb onyl}amino)acet yljamino} -3,3-dimethylbutanoyl]-N- {(1 R,2R)-2-ethyl- 1 -[(pyrrolidin- 1 -ylsulfonyl)carbamoyl]cy clopropyl}-10,10-dimethyl-7-azadispiro[3.0.4.1]decane-8-carb oxamide, having the structure shown below. This compound is referred to herein as Compound X.

Compound X

In the manufacture of pharmaceutical formulations, it is important that the active compound be in a form in which it can be conveniently handled and processed in order to obtain a commercially viable manufacturing process. Accordingly, the chemical stability and the physical stability of the active compound are important factors. The active compound, and formulations containing it, must be capable of being effectively stored over appreciable periods of time, without exhibiting any significant change in the physico-chemical characteristics (e.g. chemical composition, density, hygroscopicity and solubility) of the active compound.

Furthermore, if the active compound is to be incorporated into a dosage form for oral administration, such as a tablet, it is desirable that the active compound be readily micronised to yield a powder with good flow properties to aid manufacture.

It is generally found that there are advantages in manufacturing a particular solid-state form of a pharmaceutical ingredient and these are described in "Handbook of Pharmaceutical Salts;

Properties, Selection and Use", P. Heinrich Stahl, Camille G. Wermuth (Eds.) (Verlag Helvetica Chimica Acta, Zurich). Methods of manufacturing solid-state forms are also described in "Practical Process Research and Development", Neal G. Anderson (Academic Press, San Diego) and "Polymorphism: In the Pharmaceutical Industry", Rolf Hilfiker (Ed) (Wiley VCH).

The present inventors have discovered a number of salts and crystalline polymorphs of

Compound X. Salt and crystal formation has the potential to improve yields as the resultant new physical form may exhibit lower solubility in organic solvents. This can lead to an improved manufacturing process. Additionally, the salts may be easier to isolate and purify. Thus, in one aspect, the invention provides Compound X hydrochloride salt, or a pharmaceutically acceptable derivative thereof. In an embodiment, the purity of the salt is at least 98%. In another embodiment, the purity of the salt is at least 99%. In another aspect, the invention provides Compound X hemi-hydrochloride salt, or a pharmaceutically acceptable derivative thereof. In another aspect, the invention provides Compound X methanesulfonic acid salt, or a

pharmaceutically acceptable derivative thereof. In yet another aspect, the invention provides Compound X succinic acid salt, or a pharmaceutically acceptable derivative thereof.

Furthermore, in accordance with the present invention, there are provided a number of crystalline polymorphs of Compound X and its salts.

Thus, in one aspect, the invention provides a crystalline form of Compound X hydrochloride salt (Form A) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 7.7, 8.9, 1 1.8, 15.5 and 18.0. In one embodiment, Form A exhibits at least the following characteristic X-ray powder diffraction peaks: 7.7, 8.9, 1 1.8, 15.5, 17.3, 18.0 and 19.9. In another embodiment, Form A exhibits at least the characteristic X-ray powder diffraction peaks shown in Table A. In yet another embodiment, Form A exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 1.

In another aspect, the invention provides a crystalline form of Compound X hydrochloride salt (Form B) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 7.8, 8.6, 1 1.3, 15.8 and 18.2. In one embodiment, Form B exhibits at least the following characteristic X-ray powder diffraction peaks: 7.8, 8.6, 9.5, 1 1.3, 14.8, 15.8 and 18.2. In another embodiment, Form B exhibits at least the characteristic X-ray powder diffraction peaks shown in Table B. In yet another embodiment, Form B exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 2.

In another aspect, the invention provides a crystalline form of Compound X hydrochloride salt (Form C) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 9.2, 14.4, 15.3, 17.7 and 20.0. In one embodiment, Form C exhibits at least the following characteristic X-ray powder diffraction peaks: 8.0, 9.2, 14.4, 15.3, 17.7, 19.3 and 20.0. In another embodiment, Form C exhibits at least the characteristic X-ray powder diffraction peaks shown in Table C. In yet another embodiment, Form C exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 3.

In another aspect, the invention provides a crystalline form of Compound X hydrochloride salt (Form D) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 8.0, 8.3, 14.3, 15.9 and 18.2. In one embodiment, Form D exhibits at least the following characteristic X-ray powder diffraction peaks: 8.0, 8.3, 9.1, 10.0, 10.7, 14.3, 14.8, 15.9, 17.2 and 18.2. In another embodiment, Form D exhibits at least the characteristic X- ray powder diffraction peaks shown in Table D. In yet another embodiment, Form D exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 4.

In another aspect, the invention provides a crystalline form of Compound X hydrochloride salt (Form E) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 7.5, 8.8, 9.2, 15.6 and 17.8. In one embodiment, Form E exhibits at least the following characteristic X-ray powder diffraction peaks: 7.5, 8.8, 9.2, 15.6, 17.8, 18.2 and 19.5. In another embodiment, Form E exhibits at least the characteristic X-ray powder diffraction peaks shown in Table E. In yet another embodiment, Form E exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 5.

In another aspect, the invention provides a crystalline form of Compound X hemi-hydrochloride salt (Form F) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 6.9, 1 1.3, 14.8, 16.0 and 18.2. In one embodiment, Form F exhibits at least the following characteristic X-ray powder diffraction peaks: 6.9, 7.8, 9.1, 1 1.3, 14.8, 16.0, 17.4 and 18.2. In another embodiment, Form F exhibits at least the characteristic X-ray powder diffraction peaks shown in Table F. In yet another embodiment, Form F exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 6.

In another aspect, the invention provides a crystalline form of Compound X methanesulfonic acid salt (Form G) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 5.8, 6.5, 7.8, 10.4 and 15.7. In one embodiment, Form G exhibits at least the following characteristic X-ray powder diffraction peaks: 5.8, 6.5, 7.8, 10.4, 12.9, 15.7 and 17.2. In another embodiment, Form G exhibits at least the characteristic X-ray powder diffraction peaks shown in Table G. In yet another embodiment, Form G exhibits an X- ray powder diffraction pattern substantially the same as that shown in Figure 7.

In another aspect, the invention provides a crystalline form of Compound X (Form H) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 5.7, 6.9, 7.8, 14.4 and 18.5. In one embodiment, Form H exhibits at least the following characteristic X-ray powder diffraction peaks: 5.7, 6.9, 7.8, 9.2, 10.3, 12.4, 14.4, 15.5, 16.3, 16.7 and 18.5. In another embodiment, Form H exhibits at least the characteristic X-ray powder diffraction peaks shown in Table H. In yet another embodiment, Form H exhibits an X- ray powder diffraction pattern substantially the same as that shown in Figure 8.

In another aspect, the invention provides a crystalline form of Compound X (Form I) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 9.5, 13.3, 14.5, 19.0 and 19.7. In one embodiment, Form I exhibits at least the following characteristic X-ray powder diffraction peaks: 6.8, 7.4, 7.9, 9.5, 13.3, 14.0, 14.5, 16.1, 17.9, 19.0 and 19.7. In another embodiment, Form I exhibits at least the characteristic X-ray powder diffraction peaks shown in Table I. In yet another embodiment, Form I exhibits an X- ray powder diffraction pattern substantially the same as that shown in Figure 9. In another aspect, the invention provides a crystalline form of Compound X (Form J) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 6.9, 8.3, 12.5, 13.6, 16.0, 16.8, and 17.1. In one embodiment, Form J exhibits at least the following characteristic X-ray powder diffraction peaks: 6.9, 8.3, 9.2, 12.5, 13.6, 16.0, 16.8, 17.1, 19.8 and 20.9. In another embodiment, Form J exhibits at least the characteristic X- ray powder diffraction peaks shown in Table J. In yet another embodiment, Form J exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 10.

In another aspect, the invention provides a crystalline form of Compound X (Form K) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 6.1, 7.4, 8.3, 22.1, 23.7, 24.1, and 24.6. In one embodiment, Form K exhibits at least the following characteristic X-ray powder diffraction peaks: 5.2, 6.1, 7.4, 8.3, 9.7, 18.2, 19.6, 22.1, 23.2, 23.7, 24.1, and 24.6. In another embodiment, Form K exhibits at least the characteristic X-ray powder diffraction peaks shown in Table K. In yet another embodiment, Form K exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 1 1.

In another aspect, the invention provides a crystalline form of Compound X (Form L) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 5.7, 8.2, 16.9, 18.4 and 18.5. In one embodiment, Form L exhibits at least the following characteristic X-ray powder diffraction peaks: 5.7, 7.0, 8.2, 15.4, 16.0, 16.9, 18.4 and 18.5. In another embodiment, Form L exhibits at least the characteristic X-ray powder diffraction peaks shown in Table L. In yet another embodiment, Form L exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 12.

In another aspect, the invention provides a crystalline form of Compound X (Form M) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 6.7, 7.6, 7.7, 9.5, and 19.0. In one embodiment, Form M exhibits at least the following characteristic X-ray powder diffraction peaks: 6.7, 7.6, 7.7, 9.5, 13.1, 14.4, 15.4, 16.0, 17.8, 18.3, 19.0 and 19.6. In another embodiment, Form M exhibits at least the characteristic X- ray powder diffraction peaks shown in Table M. In yet another embodiment, Form M exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 13.

In another aspect, the invention provides a crystalline form of Compound X (Form N) which exhibits at least the following characteristic X-ray powder diffraction peaks (expressed in degrees 2Θ): 6.3, 7.7, 8.7, 16.0, 18.1, and 20.5. In one embodiment, Form N exhibits at least the following characteristic X-ray powder diffraction peaks: 6.3, 7.7, 8.7, 10.2, 1 1.4, 13.8, 16.0, 17.2, 18.1, 18.6, 19.0 and 20.5. In another embodiment, Form N exhibits at least the characteristic X- ray powder diffraction peaks shown in Table N. In yet another embodiment, Form N exhibits an X-ray powder diffraction pattern substantially the same as that shown in Figure 14.

In one aspect of the invention, the polymorphs of the invention have crystalline properties and are preferably at least 50% crystalline, more preferably at least 60% crystalline, still more preferably at least 70% crystalline and most preferably at least 80% crystalline. Crystallinity can be estimated by conventional X-ray diffractometry techniques or by infra-red spectroscopic techniques.

In one aspect of the invention, the polymorphs of the invention are from 50%, 60%, 70%, 80% or 90% to 95%, 96%, 97%, 98%, 99% or 100% crystalline.

In the present specification, X-ray powder diffraction peaks (expressed in degrees 2Θ) are measured using copper X-rays with a wavelength of 1.5406 A (alpha 1) and 1.5444 A (alpha2).

The crystalline forms of the present invention can exist in both unsolvated and solvated forms. The term 'solvate' is used herein to describe a molecular complex comprising the compound of the invention and an amount of one or more pharmaceutically acceptable solvents. Examples of pharmaceutically acceptable solvents include ethanol and water. The term 'hydrate' is employed when the solvent is water.

In one aspect, the invention provides a salt or crystalline form defined herein for use in therapy. In another aspect, the invention provides a method of treatment by therapy, comprising administering to a subject in need thereof a pharmaceutically acceptable amount of a salt or crystalline form of the invention.

In one aspect, the invention provides the use of a salt or crystalline form defined herein in the manufacture of a medicament for use in therapy.

In one embodiment, the therapy is the treatment of an HCV-associated disorder. In another embodiment, the therapy is the treatment of an HIV infection. In another embodiment the therapy is the treatment, inhibition or prevention of the activity of HCV. In another embodiment, the therapy is the inhibition of the activity of the NS2 protease, the NS3 protease, the NS3 helicase, the NS5a protein, and/or the NS5b polymerase. In another embodiment, the therapy is the disruption of the interaction between the NS3 protease and NS4A cofactor. In another embodiment, the therapy is the prevention or alteration of the severing of one or more of the NS4A-NS4B, NS4B-NS5A and NS5A-NS5B junctions of the HCV. In another embodiment, the therapy is inhibition of the activity of a serine protease. In another embodiment, the therapy is reduction of the HCV RNA load of a subject.

In one aspect, the salts and crystalline forms of the invention exhibit HCV protease activity. In one embodiment, the salts and crystalline forms are HCV NS3-4A protease inhibitors.

In one aspect, the invention provides a method of inhibiting hepatitis C virus replication in a cell, comprising contacting said cell with a salt or crystalline form of the invention.

In another aspect, the invention provides a packaged HCV-associated disorder treatment, comprising a salt or crystalline form of the invention, packaged with instructions for using an effective amount of the salt or crystalline form to treat an HCV-associated disorder.

In certain embodiments, the HCV-associated disorder is selected from the group consisting of HCV infection, liver cirrhosis, chronic liver disease, hepatocellular carcinoma,

cryoglobulinaemia, non-Hodgkin's lymphoma, liver fibrosis and a suppressed innate intracellular immune response.

In another embodiment, the invention provides a method of treating HCV infection, liver cirrhosis, chronic liver disease, hepatocellular carcinoma, cryoglobulinaemia, non-Hodgkin's lymphoma, liver fibrosis and/or a suppressed innate intracellular immune response in subject in need thereof comprising administering to the subject a pharmaceutically acceptable amount of a salt or crystalline form of the invention.

In one embodiment, the HCV to be treated is selected of any HCV genotype. In another embodiment, the HCV is selected from HCV genotype 1, 2 and/or 3.

HCV-associated states are often associated with the NS3 serine protease of HCV, which is responsible for several steps in the processing of the HCV polyprotein into smaller functional proteins. NS3 protease forms a heterodimeric complex with the NS4A protein, an essential cofactor that enhances enzymatic activity, and is believed to help anchor HCV to the endoplasmic reticulum. NS3 first autocatalyzes hydrolysis of the NS3-NS4A juncture, and then cleaves the HCV polyprotein intermolecularly at the NS4A-NS4B, NS4B-NS5A and NS5A- NS5B intersections. This process is associated with replication of HCV in a subject. Inhibiting or modulating the activity of one or more of the NS3, NS4A, NS4B, NS5A and NS5B proteins will inhibit or modulate replication of HCV in a subject, thereby preventing or treating the HCV- associated state. In a particular embodiment, the HCV-associated state is associated with the activity of the NS3 protease. In another particular embodiment, the HCV-associated state is associated with the activity of NS3-NS4A heterodimeric complex.

The invention also provides processes for the preparation of the crystalline forms described herein. Thus, in one aspect, the invention provides a process for the preparation of any of Forms A, B, C, D, E, F, G, H and I comprising the crystallisation of the Form from a solution of Compound X.

In the context of the present invention, references herein to "treatment" include references to curative, palliative and prophylactic treatment, unless there are specific indications to the contrary. The terms "therapy, "therapeutic" and "therapeutically" should be construed in the same way.

The salts and crystalline forms of the present invention may be administered alone or in combination with one or more other drugs. Generally, they will be administered as a formulation in association with one or more pharmaceutically acceptable excipients. The term "excipient" is used herein to describe any ingredient other than the compound(s) of the invention which may impart either a functional (i.e., drug release rate controlling) and/or a non-functional (i.e., processing aid or diluent) characteristic to the formulations. The choice of excipient will to a large extent depend on factors such as the particular mode of administration, the effect of the excipient on solubility and stability, and the nature of the dosage form.

Pharmaceutical compositions suitable for the delivery of the salts and crystalline forms of the present invention and methods for their preparation will be readily apparent to those skilled in the art. Such compositions and methods for their preparation may be found, for example, in Remington's Pharmaceutical Sciences, 19th Edition (Mack Publishing Company, 1995).

For administration to human patients, the total daily dose of the salt or crystalline form is typically in the range 0.01 mg and 1000 mg, or between 0.1 mg and 250 mg, or between 1 mg and 50 mg depending, of course, on the mode of administration. The total daily dose may be administered in single or divided doses and may, at the physician's discretion, fall outside of the typical range given herein. These dosages are based on an average human subject having a weight of about 60kg to 70kg. The physician will readily be able to determine doses for subjects whose weight falls outside this range, such as infants and the elderly.

The pharmaceutical compositions may be administered topically (e.g. to the skin or to the lung and/or airways) in the form, e.g., of creams, solutions, suspensions, heptafluoroalkane (HFA) aerosols and dry powder formulations; or systemically, e.g. by oral administration in the form of tablets, capsules, syrups, powders or granules; or by parenteral administration in the form of solutions or suspensions; or by subcutaneous administration; or by rectal administration in the form of suppositories; or transdermally.

In an embodiment of the invention, the active ingredient is administered orally. Oral administration may involve swallowing, so that the compound enters the gastrointestinal tract, and/or buccal, lingual, or sublingual administration by which the compound enters the blood stream directly from the mouth.

Formulations suitable for oral administration include solid plugs, solid microparticulates, semisolid and liquid (including multiple phases or dispersed systems) such as tablets; soft or hard capsules containing multi- or nano-particulates, liquids, emulsions or powders; lozenges (including liquid- filled); chews; gels; fast dispersing dosage forms; films; ovules; sprays; and buccal/mucoadhesive patches.

Formulations suitable for oral administration may also be designed to deliver the salts and crystalline forms in an immediate release manner or in a rate-sustaining manner, wherein the release profile can be delayed, pulsed, controlled, sustained, or delayed and sustained or modified in such a manner which optimises the therapeutic efficacy of the active agent. Means to deliver compounds in a rate-sustaining manner are known in the art and include slow release polymers that can be formulated with the said compounds to control their release.

Examples of rate-sustaining polymers include degradable and non-degradable polymers that can be used to release the said compounds by diffusion or a combination of diffusion and polymer erosion. Examples of rate-sustaining polymers include hydroxypropyl methylcellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, sodium carboxymethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, xanthum gum, polymethacrylates, polyethylene oxide and polyethylene glycol.

Liquid (including multiple phases and dispersed systems) formulations include emulsions, suspensions, solutions, syrups and elixirs. Such formulations may be presented as fillers in soft or hard capsules (made, for example, from gelatin or hydroxypropylmethylcellulose) and typically comprise a carrier, for example, water, ethanol, polyethylene glycol, propylene glycol, methylcellulose, or a suitable oil, and one or more emulsifying agents and/or suspending agents. Liquid formulations may also be prepared by the reconstitution of a solid, for example, from a sachet.

The salts and crystalline forms of the invention may also be used in fast-dissolving, fast- disintegrating dosage forms such as those described in Liang and Chen, Expert Opinion in Therapeutic Patents, 2001, 11 (6), 981-986.

The formulation of tablets is discussed in Pharmaceutical Dosage Forms: Tablets, Vol. 1, by H. Lieberman and L. Lachman (Marcel Dekker, New York, 1980).

Brief Description of the Figures

The invention will now be illustrated by the following non-limiting examples. In the examples the following figures are presented: jure 1 : X-ray powder diffraction pattern of Form A, defined herein.

F¾ jure 2: X-ray powder diffraction pattern of Form B, defined herein

F¾ jure 3: X-ray powder diffraction pattern of Form C, defined herein.

F¾ jure 4: X-ray powder diffraction pattern of Form D, defined herein.

F¾ jure 5: X-ray powder diffraction pattern of Form E, defined herein.

F¾ jure 6: X-ray powder diffraction pattern of Form F, defined herein.

F¾ jure 7: X-ray powder diffraction pattern of Form G, defined herein.

F¾ jure 8: X-ray powder diffraction pattern of Form H, defined herein.

F¾ jure 9: X-ray powder diffraction pattern of Form I, defined herein.

F¾ jure 10: X-ray powder diffraction pattern of Form J, defined herein

F¾ jure 11 : X-ray powder diffraction pattern of Form K, defined herein

F¾ jure 12: X-ray powder diffraction pattern of Form L, defined herein

F¾ jure 13: X-ray powder diffraction pattern of Form M, defined herein Figure 14: X-ray powder diffraction pattern of Fonn N, defined herein

General Experimental Details

LIST OF ABBREVIATIONS

Ac acetyl

ACN Acetonitrile

AcOEt / EtOAc Ethyl acetate

AcOH acetic acid

aq aqueous

Ar aryl

Bn benzyl

Bu butyl (nBu = n-butyl, tBu = tert-butyl)

GDI Carbonyldiimidazole

CH ₃ CN Acetonitrile

DBU 1 ,8-Diazabicyclo[5.4.0]-undec-7-ene

DCE 1 ,2-Dichloroethane

DCM Dichloromethane

DIPEA N-Ethyldiisopropylamine

DMAP Dimethylaminopyridine

DMF N,N'-Dimethylformamide

DMSO Dimethylsulfoxide

EI Electrospray ionisation

Et ₂ 0 Diethylether

Et ₃ N Triethylamine

Ether Diethylether

EtOH Ethanol

FC Flash Chromatography

h hour(s)

HATU 0-(7-Azabenzotriazole-l -yl)-N,N,N'N'- tetramethyluronium hexafluorophosphate

HBTU 0-(Benzotriazol- 1 -yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate

HC1 Hydrochloric acid

HOBt 1 -Hydroxybenzotriazole

HPLC High Performance Liquid Chromatography H ₂ 0 Water

IPA Isopropyl alcohol

L liter(s)

LC-MS Liquid Chromatography Mass Spectrometry

Me methyl

Mel Iodomethane

MeOH Methanol

mg milligram

min minute(s)

mL milliliter

MS Mass Spectrometry

Pd/C palladium on charcoal

PG protecting group

Ph phenyl

Prep Preparative

Rf ratio of fronts

RP reverse phase

Rt Retention time

rt Room temperature

Si0 ₂ Silica gel

TBAF Tetrabutylammonium fluoride

TEA Triethylamine

TFA Trifluoroacetic acid

THF Tetrahydrofurane

TLC Thin Layer Chromatography

X-Ray Powder Diffraction (XRPD) patterns were collected using sample weights of approximately 2-10 mg, which was gently compressed on the XRPD zero background single obliquely cut silica sample holder. The sample was then loaded into a Bruker GADDS and analysed using the following experimental conditions:

Tube anode: (Cu)

Generator tension: 40 kV

Tube current: 40 mA

Start angle [2 Θ]: 3

End angle [2 Θ]: 4 Scan time 2 minutes

All starting materials, building blocks, reagents, acids, bases, dehydrating agents, solvents, and catalysts utilized to synthesis the compounds of the present invention are either commercially available or can be produced by organic synthesis methods known to one of ordinary skill in the art (Houben-Weyl 4th Ed. 1952, Methods of Organic Synthesis, Thieme, Volume 21). Further, the compounds of the present invention can be produced by organic synthesis methods known to one of ordinary skill in the art as shown in the following examples.

Method B:

HPLC

Instrument: Agilent system

Column: Waters Symmetry C18, 3.5 microm., 2.1 x 50 mm, flow 0.6 mL/min

Solvent: CH ₃ CN (0.1 % CF ₃ C0 ₂ H), H ₂ 0 (0.1% CF ₃ C0 ₂ H)

Gradient: 0-3.5 min: 20-95% CH ₃ CN, 3.5-5 min: 95% CH ₃ CN, 5.5-5.55 min 95% to 20% CH ₃ CN

Method G:

LCMS

Instrument: Agilent system

Column: Halo CI 8, 2.7 microm., 2.1 x 30 mm, flow 1.1 mL/min

Solvent: CH ₃ CN (0.1 % HC0 ₂ H), H ₂ 0 (0.1% HC0 ₂ H)

Gradient: 0-2 min: 5-95% CH ₃ CN, 2-2.6 min: 95% CH ₃ CN, 2.6-2.65 min 95% to 5% CH ₃ CN, 2.65-3 min 5% CH ₃ CN

Method J :

MS

Instrument: Agilent system

Method: Flow injection

Detection: API-ES, positive/negative Compound X

The preparation of (5R,8S)-7-[(2S)-2-

{[(2S)-2-cyclohexyl-2-({[(2S)-l-isopropylpiperidin-2-yl]c arbonyl}amino)acetyl]amino}-3,3-dim ethylbutanoyl]-N- {(lR,2R)-2-ethyl- 1 -[(pyrrolidin- 1 -ylsulfonyl)carbamoyl]cyclopropyl} - 10, 10- dimethyl-7-azadispiro[3.0.4. l]decane-8-carboxamide, as described in unpublished patent application no. PCT/IB2010/000784, is detailed below.

Preparation of Reactant A

Step la:

Compound 1a

A suspension of N-(tert-butoxycarbonyl)-N-[4- (dimethylazaniumylidene)- 1 ,4-dihydropyridin- 1 - ylsulfonyljazanide (3 g; 9.955 mmol) prepared according to the procedure from Winum et al (Organic Letters 2001, 3, 2241) in DCM (24 mL) was treated with pyrrolidine (0.864 mL;

10.453 mmol) and stirred at rt for 24 h. The reaction mixture was chromatographed by FC on silica gel (eluent: CH ₂ Cl ₂ /EtOAc 100: 1) to give [N-(tert-butoxycarbonyl)]-pyrrolidine-l -sulfonic acid amide. TLC: Rf (DCM/EtOAc 100: 1) = 0.40. A solution of [N-(tert-butoxycarbonyl)]- pyrrolidine- 1 -sulfonic acid amide (57.09 g; 223 mmol) in DCM (450 mL) was treated with TFA (120 mL; 1.56 mol) and stirred at rt for 7 h. The reaction mixture was concentrated in vacuo and the residual oil was triturated with diisopropylether. The resulting powder was washed with diisopropylether and dried under high vacuum to provide Compound la. TLC: Rf (DCM/EtOAc 50: 1) = 0.10.

Step lb:

A solution of (lR,2S)- l-tert-butoxycarbonylamino-2-vinyl-cyclopropanecarboxylic acid prepared according to the procedure described in WO2000/09558 (8.24 g; 36.3 mmol) in THF (160 mL) was treated with CDI (9.09 g; 54.4 mmol) and heated to reflux for 1 h. The resulting reaction mixture was cooled to rt and treated with Compound la (7.62 g; 50.8 mmol) followed by DBU (8.28 g; 54.4 mmol). After 16 h at rt the reaction mixture was concentrated, the residue was taken up in DCM and washed with a saturated aq solution of KHSO ₄ (3x). The aq phases were extracted with DCM, the organics were combined, dried over Na ₂ S0 ₄ and concentrated in vacuo. The residue was chromatographed on silica gel (eluent: hexane/EtOAc 4: 1) to give Compound lb. LCMS (method F) Rt = 3.21 min; MS (method J): M/z = 358 [M-l ]

Step lc:

Compound lb (7.84 g; 21.81 mmol) was treated with 4N HC1 in dioxane (84 mL) at rt. After 1.5 h the reaction mixture was concentrated under high vacuum to give Compound lc as its hydrochloride salt. LCMS (method E) Rt = 1.10 min; MS (method J): M/z = 260 [M+l ]

Preparation of Intermediate II:

Intermediate II

Step 2a

(5R,8S)-10,1 0-Dimethyl-7-aza-dispiro

[3.0.4.1]decane-7,8-dicarboxylic acid Compound 2a

7-tert-butyl ester

(5R,8S)- 10, 10-Dimethyl-7-aza-dispiro[3.0.4.1]decane-7,8-dicarboxylic acid 7-tert-butyl ester (32.84 g; 106 mmol - prepared by the procedure described in WO2009/047264) in DMF (1 L) was treated with K ₂ C0 ₃ (22.00 g; 159 mmol) followed by methyliodide (9.93 mL; 159 mmol). The reaction mixture was stirred at rt for 18 h, concentrated in vacuo. The resulting residue was partitioned between water and EtOAc and extracted with EtOAc. The organics were combined, washed with brine, dried over Na ₂ S0 ₄ and concentrated. The residue was chromatographed on silica gel (eluent DCM/Ethylether 120: 1) to give Compound 2a. TLC: Rf (DCM/Ethylether 120: 1) = 0.22; MS (method J): M/z = 346 [M+Na]

Step 2b:

Compound 2b

Compound 2b hydrochloride was obtained from Compound 2a (6.3 g; 19.48 mmol) by treatment with 4N HC1 in dioxane (84 mL) at rt. After 1.5 h the reaction mixture was concentrated under high vacuum to give Compound 2b as its hydrochloride salt MS (method J): M/z = 224 [M+l]

Step 2c:

Compound 2c

Compound 2c was obtained from a solution of Compound 2b hydrochloride (7.33 g; 27.93 mmol) and BOC-L-tert-leucine (0.248 g; 1.072 mmol) in DCM (15 mL) which was cooled to 0 °C and treated with DIPEA (0.46 mL; 2.68 mmol) and HATU (0.61 1 g; 1.608 mmol). The reaction mixture was stirred at rt for 20 h, concentrated in vacuo and the residue was purified by preparative HPLC (method K). After workup (Workup 2 = fractions were treated with NaHCOs and concentrated; residue partitioned between water and EtOAc, extracted with EtOAc; organics combined, dried over Na ₂ S0 ₄ and concentrated) TLC: Rf (hexane/EtOAc 4: 1) = 0.37; MS (method J): M/z = 437 [M+l]

Step 2d:

Compound 2d

Compound 2d hydrochloride was obtained from Compound 2c (10.55 g; 24.16 mmol) by treatment with 4N HC1 in dioxane (84 mL) at rt. After 1.5 h the reaction mixture was

concentrated under high vacuum to give Compound 2d hydrochloride. TLC: Rf (DCM/MeOH 95:5) = 0.39; MS (method J): M/z = 337 [M+l]

Step 2e:

Compound 2e

Compound 2e was obtained from Compound 2d (0.2 g; 0.456 mmol) and BOC-L- cyclohexylglycine (1.582 g; 6.15 mmol) in DCM (65 mL) which was cooled to 0 °C and treated with DIPEA (2.68 mL; 15.37 mmol) followed by HATU (3.51 g; 9.22 mmol). After 16 h at rt the reaction mixture was partitioned between DCM and IN HCl, the organics were extracted with saturated aq NaHC0 ₃ , dried over Na ₂ S0 ₄ and concentrated. Purification by preparative HPLC (method K) followed by workup (Workup 2) afforded Compound 2e. LC-MS (method G): Rt = 2.21 min; M/z = 598 [M+Na]

Step 2f:

Compound 2f

A mixture of Compound 2e (1.136 g; 1.973 mmol) and LiOH.H ₂ 0 (0.09 g; 2.17 mmol) in THF/MeOH/water (6 mL; 2: 1 : 1) was stirred at rt 16 h. The reaction mixture was partitioned between water and EtOAc. The aq phase was acidified with IN HCl and extracted with EtOAC. Organics were combined, dried over Na ₂ S0 ₄ and concentrated to a residue that was

chromatographed on silica gel (DCM/MeOH 100% to 9: 1) to afford Compound 2f. LC-MS (method G): Rt = 1.99 min; M/z = 562 [M+l ]

Step 2g:

A solution of Compound 2f (0.050 g; 0.089 mmol) and pyrrolidine- 1 -sulfonic acid ((1R,2R)-1- amino-2-ethyl-cyclopropanecarbonyl)-amide - Reactant A (0.030 g; 0.093 mmol - prepared as set out in the procedure herein) in DCM (2 mL) was cooled to 0 °C and treated with DIPEA (0.078 mL; 0.445 mmol) and HATU (0.102 g; 0.267 mmol). The reaction mixture was stirred at rt for 2 h, partitioned between DCM and IN HCl. The organics were washed with a saturated aq NaHC0 ₃ solution, dried over Na ₂ S0 ₄ and concentrated in vacuo to a residue that was purified by preparative HPLC. After workup Compound 2g was obtained. LC-MS (method G): Rt = 2.25 min; M/z = 828 [M+Na]

Step 2h:

Intermediate II hydrochloride was obtained from Compound 2g (0.02 g; 0.025 mmol) by treatment with 4N HCl in dioxane (84 mL) at rt. After 1.5 h the reaction mixture was concentrated under high vacuum to give Intermediate II hydrochloride. LC-MS (method G): Rt = 1.59 min; M/z = 706 [M+l]

Synthesis of Compound X

Intermediate II

Compound X

A suspension of (S)-l-isopropyl-piperidine-2-carboxylic acid (1.39 g; 8.1 1 mmol) in DMF (150 mL) was treated with HATU (3.86 g; 10.14 mmol) and DIPEA (3.54 mL; 20.29 mmol) and stirred at RT. The resulting solution was treated with Intermediate II hydrochloride ((0.28 g; 0.378 mmol) and stirred at RT under Argon for lh. The reaction mixture was taken up in EtOAc, washed with water. The aqueous phase was extracted with EtOAc. The organics were combined, washed with saturated aq NaHC0 ₃ , dried over Na ₂ S0 ₄ and concentrated to a brown oil.

Purification by FC on silica gel (eluent: cyclohexane to cyclohexane/aceton 3:2) afforded Compound X hydrochloride. HPLC (method B): Rt = 3.70 min; MS (method J) M/z = 858 [M+l] 1H-NMR (400 MHz, methanol-d4): δ (ppm) = 8.4 (d, 1H), 4.75 (d, 1H), 4.3 (d, 1H), 4.2 (t, 1H), 3.95 (bs, 1H), 3.4-3.7 (m, 9H), 3.0 (m, 1H), 2.15 (m, 1H), 1.05-2.1 (m, 43H), 1.05 (s, 9H), 0.9 (s, 3H), 0.95 (s, 3H).

Compound X HC1 salt (Form A)

Dissolve free base in IPA and add 1 equivalent HC1. IPA is evaporated and the solids are equilibrated in acetonitrile at room temperature to give an di-hydrate form. The crystalline form (referred to herein as Form A) displayed the X-ray power diffraction peaks shown in Table A below. Figure 1 shows the X-ray powder diffraction pattern of Form A.

Table A

No. Position Intensity No. Position Intensity

1 7.7 31 8 19.9 28

2 8.9 53 9 22.0 19

3 1 1 .8 32 10 23.9 17

4 13.4 16 1 1 24.7 15

5 15.5 46 12 26.2 17

6 17.3 29 13 27.1 16

7 18.0 56 14 28.4 14 Compound X HCl salt (Form B)

Dissolve 600 mg of fee base in 3 ml ethyl acetate/acetonitrile (2: 1) and add 700 μΐ 6N HCl. Solution was equilibrated for 1 hour then evaporated. The solids were resuspended in acetonitrile and slurried for 1 hour before isolation to give an anhydrous form. The crystalline form (referred to herein as Form B) displayed the X-ray power diffraction peaks shown in Table B below. Figure 2 shows the X-ray powder diffraction pattern of Form B.

Table B

No. Position Intensity No. Position Intensity

1 7.8 87 5 13.7 20

2 8.6 62 6 14.8 32

3 9.5 30 7 15.8 45

4 1 1 .3 40 8 18.2 61

Compound X HCl salt (Form C)

2.54g of free base are dissolved in 3 ml acetone. 1.075 ml of 2.75 N HCl are added to the drug substance solution. This solution is equilibrated for 2 hours then solids were collected by filtration to give an anhydrous. The crystalline form (referred to herein as Form C) displayed the X-ray power diffraction peaks shown in Table C below. Figure 3 shows the X-ray powder diffraction pattern of Form C.

Table C

No. Position Intensity No. Position Intensity

1 8.0 19 8 16.7 17

2 8.5 14 9 17.7 96

3 9.2 43 10 19.3 22

4 12.0 12 1 1 20.0 28

5 14.4 22 12 23.4 16

6 15.3 27 13 25.2 12

7 16.2 15 14 26.0 13

Compound X HCl salt (Form D) The HC1 salt (Form C) was equilibrated in ethyl acetate for 72 hours to give a di-hydrate form. The crystalline form (referred to herein as Form D) displayed the X-ray power diffraction peaks shown in Table D below. Figure 4 shows the X-ray powder diffraction pattern of Form D.

Table D

No. Position Intensity No. Position Intensity

1 8.0 39 1 1 15.9 26

2 8.3 39 12 16.6 18

3 9.1 24 13 17.2 21

4 10.0 18 14 18.2 64

5 10.7 23 15 19.1 17

6 13.3 1 1 16 20.3 1 1

7 13.9 17 17 21 .1 9

8 14.3 39 18 22.5 10

9 14.8 20 19 24.4 9

Compound X HC1 salt (Form E)

The HC1 salt was isolated after equilibration of Form B in water for 72 hours to give a tri-hydrate from. The crystalline form (referred to herein as Form E) displayed the X-ray power diffraction peaks shown in Table E below. Figure 5 shows the X-ray powder diffraction pattern of Form E. Table E

No. Position Intensity No. Position Inten sity

1 7.5 32 8 14.4 9

2 7.9 12 9 15.6 27

3 8.8 52 10 16.7 13

4 9.2 47 1 1 17.8 38

5 10.4 8 12 18.2 19

6 12.6 10 13 19.5 16

Compound X hemi-HCl salt (Form F)

Dissolved 91 mg free base in 0.5 ml THF, added 53 μΐ 6N HC1. Added 2 ml acetonitrile and equilibrated the system for 4 hours before collecting solids to give a di-hydrate. The crystalline form (referred to herein as Form F) displayed the X-ray power diffraction peaks shown in Table F below. Figure 6 shows the X-ray powder diffraction pattern of Form F. Table F

No. Position Intensity No. Position Intensity

1 6.9 38 10 13.6 8

2 7.8 19 1 1 14.8 30

3 8.6 18 12 16.0 26

4 9.1 19 13 17.4 21

5 9.4 16 14 18.2 127

6 1 1.3 30 15 20.6 10

Compound X MeSChH salt (Form G)

Dissolved 50 mg free base in methyl i-butyl ketone, added 1 equivalent methanesulfonic acid and equilibrated for 2 hours before collecting solids. The crystalline form (referred to herein as Form G) displayed the X-ray power diffraction peaks shown in Table G below. Figure 7 shows the X-ray powder diffraction pattern of Form G.

Table G

No. Position Intensity No. Position Intensity

1 5.8 40 10 12.9 17

2 6.5 86 1 1 14.0 12

3 7.8 62 12 15.7 28

4 8.9 1 1 13 17.2 17

5 9.3 14 14 18.6 12

6 10.4 20 15 20.3 1 1

Compound X free base (Form H)

Compound X free base is precipitated from iso propyl acetate (clear solution) during solvent- exchange with CH ₃ CN (suspension) and stirred at 20 °C for 24h. The final drug substance was isolated from suspension of CH ₃ CN and washed by CH ₃ CN to give an anhydrous form. The crystalline form (referred to herein as Form H) displayed the X-ray power diffraction peaks shown in Table H below. Figure 8 shows the X-ray powder diffraction pattern of Form H.

Table H No. Position Intensity No. Position Intensity

1 4.9 1 1 10 13.9 12

2 5.7 21 1 1 14.4 19

3 6.9 16 12 15.5 17

4 7.8 60 13 16.3 17

5 9.2 14 14 16.7 18

6 10.3 15 15 18.5 32

7 12.0 9 16 19.2 15

8 12.4 15 17 19.8 16

9 13.3 10 18 20.3 12

Compound X (Form I)

Form I is prepared by dissolving the drug substance in ethanol and precipitating with water to a final ratio of 1 : 1 to give a mono-hydrate form. The crystalline form (referred to herein as Form I) displayed the X-ray power diffraction peaks shown in Table I below. Figure 9 shows the X-ray powder diffraction pattern of Form I.

Table I

No. Position Intensity No. Position Intensity

1 5.5 9 15 16.5 23

2 6.3 9 16 17.3 31

3 6.8 76 17 17.8 61

4 7.3 21 18 18.4 43

5 7.8 69 19 19.0 90

6 9.6 100 20 19.6 49

7 1 1.0 24 21 20.0 42

8 1 1.7 20 22 20.5 15

9 13.3 64 23 20.7 15

10 13.8 36 24 21.5 9

1 1 14.6 79 25 22.5 8

12 15.2 15 26 23.0 9

13 15.7 18 27 23.5 10

14 16.1 45 28 26.4 12

Compound X (Form J))

Form J obtained from methanol by equilibrating form H at 50°C. Solids are collected by filtration and dried at 50C.

Table J

No. Position Relative I No. Position Relative I

1 6.9 28 12 17.1 10

2 8.3 100 13 17.7 5

3 9.2 9 14 19.1 3

4 10.0 4 15 19.8 9

5 10.7 3 16 20.9 9

6 12.5 18 17 21 .6 3

7 13.6 10 18 23.0 4

8 14.3 3 19 23.2 4

9 15.4 4 20 25.0 4

10 16.0 1 1 21 26.9 3

1 1 16.8 10 22 29.1 3

Compound X (Form K)

Form K was crystallized from ethanol (100%) after the addition of acetonitrile. Solids were collected by centrifugation and dried under nitrogen flow.

Table K No. Position Relative I No. Position Relative I

1 5.2 26 10 16.3 16

2 6.1 42 1 1 18.2 20

3 7.4 76 12 19.6 24

4 8.3 100 13 22.1 30

5 9.7 24 14 23.2 20

6 10.9 16 15 23.7 36

7 12.1 14 16 24.1 33

8 13.2 14 17 24.6 31

9 14.7 17 18 28.5 19

Compound X (Form L)

Form L is the hydrated form of form H produced from acetonitrile and solids dried at 50C. Exposing the solid to elevated humidity generates form L.

Table L

No. Position Relative I No. Position Relative I

1 5.0 29 16 16.4 26

2 5.7 46 17 16.9 57

3 7.0 31 18 17.6 23

4 7.8 25 19 17.9 25

5 8.2 100 20 18.1 29

6 8.7 12 21 18.4 42

7 9.2 27 22 18.5 43

8 10.4 20 23 19.1 24

9 1 1.4 13 24 19.9 28

10 12.1 21 25 20.4 18

1 1 12.7 16 26 20.9 13

12 13.7 24 27 22.1 10

13 14.7 24 28 22.4 1 1

14 15.4 30 29 23.3 1 1

15 16.0 30 30 24.4 12

Compound X (Form M)

Form M is isolated from ethanol by precipitation with water. Solids are isolated by filtration and dried at 50C. Exposing the solid to elevated humidity generates form M.

Table M No. Position Relative I No. Position Relative I

1 5.6 9 17 17.4 29

2 6.7 63 18 17.8 32

3 7.3 18 19 18.3 38

4 7.6 67 20 19.0 88

5 7.7 69 21 19.6 43

6 9.5 100 22 20.4 21

7 1 1 .0 27 23 20.8 17

8 1 1 .7 19 24 21.6 1 1

9 13.1 46 25 22.5 14

10 13.8 21 26 22.9 19

1 1 14.0 25 27 23.5 13

12 14.4 35 28 23.9 18

13 15.4 32 29 24.6 13

14 16.0 37 30 26.3 20

15 16.6 23 31 27.2 14

16 17.0 20 32 29.1 12

Compound X (Form N)

From N was crystallized from ethanol (100%) after the addition of acetonitrile. Solids were collected by centrifugation and dried under nitrogen flow.

Table N

No. Position Relative I No. Position Relative I

1 5.4 12 1 1 14.8 13

2 6.3 25 12 15.5 14

3 7.7 29 13 16.0 28

4 8.7 100 14 17.2 20

5 9.2 12 15 17.7 15

6 10.2 22 16 18.1 26

7 1 1 .4 23 17 18.6 22

8 12.6 14 18 19.0 22

9 13.3 10 19 19.4 19

10 13.8 22 20 20.5 34

Biological Activity

HCV NS3-4A protease assay

The inhibitory activity of Compound X against HCV NS3-4A serine protease is determined in a homogenous assay using the full-length NS3-4A protein (genotype la, strain HCV-1) and a commercially available internally-quenched fluorogenic peptide substrate as described by Taliani, M., et al. 1996 Anal. Biochem. 240:60-67, which is incorporated by reference in its entirety.

Luciferase-based HCV replicon assay The antiviral activity and cytotoxicity of Compound X is determined using a subgenomic genotype lb HCV replicon cell line (Huh-Luc/neo-ET) containing a luciferase reporter gene, the expression of which is under the control of HCV RNA replication and translation. Briefly, 5,000 replicon cells are seeded in each well of 96-well tissue culture plates and are allowed to attach in complete culture media without G418 overnight. On the next day, the culture media are replaced with media containing serially diluted Compound X in the presence of 10% FBS and 0.5% DMSO. After a 48-h treatment with the compound, the remaining luciferase activities in the cells are determined using BriteLite reagent (Perkin Elmer, Wellesley, Massachusetts) with a LMaxII plate reader (Molecular Probe, Invitrogen). Each data point represents the average of four replicates in cell culture. IC ₅ o is the concentration of the compound at which the luciferase activity in the replicon cells is reduced by 50%. The cytotoxicity of the compound is evaluated using an MTS-based cell viability assay.

Compound X has been tested in the protease assay above. The IC ₅ o value is provided below. Compound X has also been tested in the replicon assay above and exhibits an IC ₅ o of less than about 100 nM or less.