Chronic infection with hepatitis C virus is an insidious and slow- progressing disease having a significant impact on the quality of life. It can eventually result in cirrhosis of the liver, decompensated liver disease and/or hepatocelluar carcinoma.

Combination treatment with interferon alfa-2b and ribavirin for chronic hepatitis C in patients. is disclosed by Reichard et al. (The Lancet 1998; 351; 83-87.

Various pilot studies using daily interferon-alfa-2b dosing in combination with ribavirin have been reported. See for example M. Buti et al. (Hepatology, October 1997, page A216, (Abstract# 351); S. J.

Hadziyanni et al (Hepatology, October 1997 page 420A, Abstract #1166); D. Tsantoulas et al (Hepatology, October 1998, AASLD ABSTRACTS, p 478A, Abstract #1263); and Elmar Zehnter (Hepatology, 1998, Vol. 28, No. 4, pt 2, page 717A, Abstract #2218).

None of these pilot studies disclose the method of the present invention T. Poynard et al. ( The Lancet, 1998, Vol. 352, Oct. 31, p 1426- 1432) disclose that treating chronic hepatitis C patients who had not been treated with interferon or ribavirin with 3 MIU of interferon alfa-2b TIW plus 1000-1200 mg of ribavirin per day for 48 weeks resulted in a sustained virological response at 24 weeks after treatment in 43% of the patients.

See also J. G. McHutchinson et al. (N. Engl. J. Med., 1998,339: 1485- 1492), G. L. Davis et al. (N. Engl. J. Med., 1998,339: 1493-1499) disclose that treating chronic hepatitis G patients who relapse after treatment with interferon with 3 MIU of interferon alfa-2b Tim plus 100-1200 mg of ribavirin per day for 48 weeks results in higher rates of sustained virologic response than treatment with interferon alone.

There is a need to provide an improved combination therapy for treating chronic hepatitis C patients to produce a sustained virological response in more patients than previously possible.

SUMMARY OF THE INVENTION The present invention provides the use of ribavirin for the manufacture of a pharmaceutical composition for treating a patient having chronic hepatitis C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of ribavirin in association with an effective amount of interferon alpha, characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and an therapeutically effective induction dosing amount of interferon-alfa are administered for a time period sufficient to sustantially lower detectable HCV-RNA serum levels, and (b) a second treatment time period of at least

20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective amount of interferon-alfa are administered sufficient to eradicate detectable HCV-RNA at least 20 to 30 weeks after the end of the first treatment time period and to maintain no detectable HCV-RNA for at least 24 weeks after the end of the second treatment time period.

The present invention aiso provides the use of interferon alpha for the manufacture of a pharmaceutical composition for treating a patient having chronic hepatitis C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of interferon alpha in association with an effective amount of ribavirin characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective induction dosing amount of interferon-alfa are administered for a time period sufficient to sustantially lower detectable HCV-RNA serum levels, and (b) a second treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective amount of interferon-alfa are administered sufficient to eradicate detectable HCV-RNA at least 20 to 30 weeks after the end of the first treatment time period and to maintain no detectable HCV-RNA for at least 24 weeks after the end of the second treatment time period.

The present invention also provides the use of both ribavirin and interferon alpha for the manufacture of pharmaceutical compositions for treating a patient having chronic hepatits C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of ribavirin in association with an effective amount of interferon

alpha characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective induction dosing amount of interferon-alfa are administered sufficient to sustantially lower detectable HCV-RNA serum levels, and by (b) a second treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective amount of interferon-alfa are administered sufficient to eradicate detectable HCV-RNA at least 20 to 30 weeks after the end of the first treatment time period and to maintain no detectable HCV-RNA for at least 24 weeks after the end of the second treatment time period.

The present invention also provides the use of ribavirin for the manufacture of a pharmaceutical composition for treating a patient having chronic hepatitis C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of ribavirin in association with an effective amount of interferon alpha, characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective induction dosing amount of interferon-alfa are administered sufficient to eradicate detectable HCV-RNA, and (b) a second treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective amount of interferon-alfa are administered sufficient to maintain no detectable HCV-RNA for at least 20-30 weeks after the end of the first treatment time period and to maintain no detectable HCV-RNA for at least 24 weeks after the end of the second treatment time period.

The present invention also provides the use of interferon alpha for the manufacture of a pharmaceutical composition for treating a patient having chronic hepatitis C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of interferon alpha in association with an effective amount of ribavirin characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective induction dosing amount of interferon-alfa are administered sufficient to eradicate detectable HCV-RNA, and (b) a second treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective amount of interferon-alfa are administered sufficient to maintain no detectable HCV-RNA for at least 20-30 weeks after the end of the first treatment time period and to maintain no detectable HCV-RNA for at least 24 weeks after the end of the second treatment time period.

The present invention also provides the use of both ribavirin and interferon alpha for the manufacture of pharmaceutical compositions for treating a patient having chronic hepatits C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of ribavirin in association with an effective amount of interferon alpha characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of at least 20 to 30 weeks wherein a therapeutically effective amount of ribavirin and a therapeutically effective induction dosing amount of interferon-alfa are administered sufficient to eradicate detectable HCV- RNA, and (b) a second treatment time period of at least 20 to 30 weeks a therapeutically effective amount of ribavirin and a therapeutically effective amount of interferon-alfa are administered sufficient to maintain no detectable HCV-RNA for at least 20-30 weeks after the end of the first treatment time period and to maintain no detectable HCV-RNA for at least 24 weeks after the end of the second treatment time period.

In a preferred embodiment, the present invention relates to the use of ribavirin for the manufacture of a pharmaceutical composition for treating a patient having chronic hepatitis C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of ribavirin in association with an effective amount of interferon alpha, wherein the patient is one having HCV genotype 1,2 or 3 characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of twenty-four weeks wherein about 800 to about 1200 mg per day of ribavirin and about 10 MIU daily of interferon-alfa are administered for two weeks, 5 MIU daily of interferon-alfa are thereafter administered for six weeks, and 3 MIU daily of interferon-alfa for are thereafter administered 16 weeks, and (b) a second treatment time period of twenty-four weeks wherein about 800 to 1200 mg per day of ribavirin and 3 MIU TIW of interferon-alfa are administered.

In another preferred embodiment, the present invention relates to the use of interferon alpha for the manufacture of a pharmaceutical composition for treating a patient having chronic hepatitis C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of ribavirin in association with an effective amount of interferon alpha, wherein the patient is one having HCV genotype 1,2 or 3 characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of twenty-four weeks wherein about 800 to about 1200 mg per day of ribavirin and about 10 MIU daily of interferon-alfa are administered for two weeks, 5 MIU daily of interferon-alfa are thereafter administered for six weeks, and 3 MIU daily of interferon-alfa for are thereafter administered 16 weeks, and (b) a second treatment time period of twenty-four weeks

wherein about 800 to 1200 mg per day of ribavirin and 3 MIU TIW of interferon-alfa are administered.

In another preferred embodiment, the present invention relates to the use of ribavirin and interferon alpha for the manufacture of pharmaceutical compositions for treating a patient having chronic hepatitis C infection to eradicate detectable HCV-RNA by a method comprising administering an effective amount of ribavirin in association with an effective amount of interferon alpha, wherein the patient is one having HCV genotype 1,2 or 3 characterised in that treating patients having chronic hepatitis C infections is effected in two treatment time periods: (a) a first treatment time period of twenty-four weeks wherein about 800 to about 1200 mg per day of ribavirin and about 10 MIU daily of interferon- alfa are administered for two weeks, 5 MIU daily of interferon-alfa are thereafter administered for six weeks, and 3 MIU daily of interferon-alfa for are thereafter administered 16 weeks, and (b) a second treatment time period of twenty-four weeks wherein about 800 to 1200 mg per day of ribavirin and 3 MIU TIW of interferon-alfa are administered.

The preferred interferon-alfa is interferon-alfa-2a or interferon-alfa-2b; use of or interferon-alfa-2b is more preferred.

The patients treated in accordance with the prefered embodiments have no detectable HCV-RNA at the end of said 48 week treatment period, also have no detectable HCV-RNA for at least 24 weeks after the end of said 48 week period.

DETAILED DESCRIPTION The present method of treating patients having chronic hepatitis C infections comprises two treatment time periods. In the first treatment time

period of at least 20 to 30 weeks, a therapeutically effective induction dosing amount of ribavirin and an therapeutically effective induction dosing amount of interferon-alfa is administered sufficient to substantially lower detectable HCV-RNA serum levels, preferrably by at least two powers of ten, i. e., at least 102 lower than the initial HCV-RNA serum level, and more preferably eradicate detectable HCV-RNA serum levels. i. e., lower them to less than 100 copies/mL. In the second treatment time period of at least 20 to 30 weeks, the method entails administering a therapeutically effective amount of ribavirin and an therapeutically effective amount of interferon-alfa sufficient to achieve no detectable HCV-RNA at least 20 to 30 weeks after the end of the first treatment time period as well as to maintain no detectable HCV-RNA for at least 24 weeks after the end of the second treatment time period; and preferably when detectable HCV-RNA serum levels are eradicated during, or at least by the end of, the first treatment time period, the method of treating patients having chronic hepatitis C in accordance with the present invention maintains no detectable HCV-RNA during the second treatment time period as well as maintains no detectable HCV-RNA for at least 24 weeks after the end of the second treatment time period. The sum of the first and second treatment time periods is about 40-50 weeks, and preferrably is 48 weeks.

The amount of ribavirin administered in the first treatment time period is from 400 to 1600 mg per day, preferrably 600 to 1200 mg/day or about 800 to 1200 mg day and most preferably about 1000 to 1200 mg/kg a day. The amount of ribavirin administered in the second treatment time period is in the range of from about 800 to 1200 mg per day, preferably from about 1000 to 1200 mg per day.

The following preferred embodiments for administering interferon alfa are presented.

When the interferon-alfa administered is selected from interferon alfa-2a, interferon alfa-2b, or a purified interferon alfa product, the therapeutically effective induction dosing amount of interferon-alfa administered in the first treatment time period is 10 MIU daily for 2 weeks, followed by 5 MIU daily for 6 weeks, followed by 3 MIU daily for 16 weeks, and the therapeutically effective amount of interferon-alfa administered in the second treatment time period is 3 MIU TIW for 24 weeks.

When the interferon-alfa administered is interferon-alfa-2b, the therapeutically effective induction dosing amount of interferon-alfa-2b administered in the first treatment time period is 10 MIU daily for 2 weeks, followed by 5 MIU daily for 6 weeks, followed by 3 MIU daily for 16 weeks, and the amount of interferon-alfa-2b administered in the second treatment time period is 3 MIU TIW for 24 weeks.

When the interferon-alfa administered is consensus interferon, the amount of consensus interferon administered in the first treatment period of twenty-four weeks is from 15 to 20 micrograms on a daily basis for two weeks, followed by 9 to15 micrograms on a daily basis for twenty-two and the amount of consensus interferon administered in the second treatment period is from 9 micrograms TIW for twenty-four weeks.

In a preferred embodiment of the present invention, the interferon- alfa is interferon-alfa-2a or-2b; use of interferon-alfa-2b is more preferred.

The term"interferon-alfa"as used herein means the family of highly homologous species-specific proteins that inhibit viral replication and cellular proliferation and modulate immune response. Typical suitable

interferon-alfas include, but are not limited to, recombinant interferon alfa- 2b such as Intron-A interferon available from Schering Corporation, Kenilworth, N. J., recombinant interferon alfa-2a such as Roferon interferon available from Hoffmann-La Roche, Nutley, N. J., recombinant interferon alfa-2C such as Berofor alpha 2 interferon available from Boehringer Ingelheim Pharmaceutical, Inc., Ridgefield, CT., interferon alfa-n1, a purified blend of natural alpha interferons such as Sumiferon available from Sumitomo, Japan or as Wellferon interferon alfa-nl (INS) available from the Glaxo-Wellcome Ltd., London, Great Britain, or a consensus alpha interferon such as those described in U. S. Patent Nos. 4,897,471 and 4,695,623 (especially Examples 7,8 or 9 thereof) and the specific product available from Amgen, Inc., Newbury Park, CA, or interferon alfa- 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 use of interferon alfa-2a or alpha 2b is preferred. Since interferon alfa 2b, among all interferons, has the broadest approval throughout the world for treating chronic hepatitis C infection, it is most preferred. The manufacture of interferon alfa 2b is described in U. S.

Patent No. 4,530,901.

A person suffering from chronic hepatitis C infection may exhibit one or more of the following signs or symptoms: (a) elevated ALT, (b) positive test for anti-HCV antibodies, (c) presence of HCV as demonstrated by a positive test for HCV- RNA, (d) clinical stigmata of chronic liver disease, (e) hepatocelluar damage.

To practice the invention, the combination therapy of interferon-alfa and ribavirin is administered to the patient exhibiting one of more of the

above signs or symptoms in amounts sufficient to eliminate or at least alleviate one or more of the signs or symptoms.

Ribavirin is administered to the patient in association with the interferon-alfa, that is, the interferon-alfa dose is administered during the same period of time that the patient receives doses of the ribavirin derivative of the present invention. Most interferon-alfa formulations are not effective when administered orally, so the preferred method of administering the interferon-alfa is parenterally, preferably by subcutaneous, IV, or IM, injection. Ribavirin may be administered orally in capsule or tablet form in association with the parenteral administration of interferon-alfa. Of course, other types of administration of both medicaments, as they become available are contemplated, such as by nasal spray, transdermally, by suppository, by sustained release dosage form, etc. Any form of administration will work so long as the proper dosages are delivered without destroying the active ingredient.

Pharmaceutical composition of interferon-alfa, suitable for parenteral administration may be formulated with a suitable buffer, e. g., Tris-HCI, acetate or phosphate such as dibasic sodium phosphate/monobasic sodium phosphate buffer, and pharmaceutically acceptable excipients (e. g., sucrose), carriers (e. g. human serum albumin), toxicity agents (e. g. NaCI), preservatives (e. g. thimerosol, cresol or benylalcohol), and surfactants (e. g. tween or polysorabates) in sterile water for injection. The interferon alfa-may be stored as lyophilized powders under a refrigeration at 2°-8°C. The reconstituted aqueous solutions are stable when stored between 2° and 8°C and used within 24 hours of reconstitution. See for example U. S. Patent Nos, 4,492,537; 5,762,923 and 5,766,582.

The term"patients having chronic hepatitis C infections"as used herein means any patient having chronic hepatitis C and includes treatment naive patients, relapses and non-responders.

These patients having chronic hepatitis C include those who are infected with mutiple HCV genotypes including type 1 as well as those infected with, interalia, HCV genotype 2 and/or 3.

The term"treatment naive patients"as used herein means patients with chronic hepatitis C who have never been treated with ribavirin or any interferon, including but not limited to interferon-alfa.

The term"no detectable HCV-RNA"in the context of the present invention means that there is less than 100 copies of HCV-RNA per ml of serum of the patient as measured by quantitative, multi-cycle reverse transcriptase PCR methodology. HCV-RNA is preferably measured in the present invention by the methodology described below. This methodology is referred to herein as HCV-RNA/qPCR.

The term"substantially lower detectable HCV-RNA serum levels" in the context of the present invention means that the HCV-RNA serum level is lower by at least a power of ten, preferably lower by two powers of ten and most preferably lower by at least three powers of ten, compared to the initial HCV-RNA serum level.

RNA is extracted from patient serum using a guaninidium thiocyanate-phenol-chloroform mister followed by ethanol-ammonium acetate precipitation. The precipitated RNA is centrifuged and the resulting pellet is dried in a Centrivap console (Labconco, Kansas City, Mo.). The dry pellet is then resuspended in 30 microliters of an Rnasin (Promega Corp., Madison, WI), dithiothritol, and diethylpyrocarbonate- treated water mixture. Samples are kept at or below-20°C (preferably below-70°C) until RNA reverse transcription (RT) and PCR.

In order to convert the entire RNA sequence into cDNA in the RT reaction, random hexadeoxyribonucleotides (Pharmacia Biotech, Piscataway, NJ) are used as primers for the first strand cDNA synthesis.

Two aliquots of 3 microliters of resuspended sample is added to 3 microliters of 1 OOng/pl random primers and denaturated at 70°C, then reverse transcribed at 40°C for one hour using M-MLV reverse transcriptase (USB, Cleveland, OH) in standard buffer containing 5 mM MgCI2. The final RT reaction volume is 26 lil. The PCR is started immediately following the reverse transcription.

A modified version of the PCR method is performed using heat- stable Taq polymerase to amplify the cDNA. Seventy-five microliters of <BR> <BR> <BR> PCR mix is added to the entire RT reaction volume (26 pu) to a final MgCI2 concentration of 1.5 mM in a total volume of 101, ul. Each 101, ul sample is then split into 50.5, ul, and a layer of mineral oil is placed on top to prevent evaporation.

The PCR cycle consists of annealing for 90 sec., extension for 90 sec., and denaturation for 90 sec., at 55°C, 74°C and 94°C, respectively.

Thermocycling samples is submitted to a final 74°C extension for 10 minutes. Four different cycle sets are used. By loading the sample in duplicate, and splitting these samples evenly after RT, there are four tubes from one sample. Each of the four tubes is given a different cycle number, enhancing sensitivity and accuracy in the quantitation process.

The thermocycling efficiency will be assessed by satisfactory amplification of known copy number RNA standards included in each set of 60 tubes.

Two primer sets are used for the amplification, both from the 5' untranslated region of the HCV genome. Both of these primer sets are highly conserved and detect all known subtypes of HCV. Primer set 1: upstream 5'-GTG GTC TGC GGA ACC GGT GAG T-3', downstream 5'- TGC ACG GTC TAC GAG ACC TC-3'which produced a 190 bp product.

Primer set 2: upstream 5'-CTG TGA GGA ACT ACT GTC TTC-3', downstream 5'-CCC TAT CAG GCA GTA CCA CAA-3'which produced a 256 bp product. <BR> <BR> <BR> <BR> <BR> <BR> <P> The amplified cDNA is then electrophorised in 3% agarose gel and<BR> <BR> <BR> <BR> <BR> transferred to nylon membrane. The target DNA is detected by Southern blotting and immunostaining using a nonradioactive digoxigenin-labeled DNA probe. These procedures are performed using automated

instruments for PCR thermocycling, agarose gel electrophoresis, vacuum- transfer Southern blot, hybridization, and immunostaining. Each membrane contains known copy number serially diluted standards which are used to construct standard curves for quantitative measurement of the specimen bands. Originally standard curves are made from carefully diluted HCV-RNA from transcribed clones. Radioactive incorporation studies, gel electrophoresis, and OD 260 are performed on the transcripts to determine that they are of the expected length. After the production of the RNA transcripts quantitated clone standards"pooled"standards are generated which better represent the heterogeneous nature of HCV, one would encounter in natural infection. These pools are made by combining large amounts of serum or plasma from known infected individuals. The serum/plasma pools are calibrated with PCR, against the clone transcripts and then diluted in the known PCR-negative fluids. Finally, the higher copy number samples of the pools are checked against the cDNA Quantiplex nucleic acid detection system from Chiron Inc. (Emeryville, CA). These"double quantitated"pools are aliquote and saved at-70°C.

Dilutions of 5,000,000,1,000,000,500,000,100,000,10,000, and 1000 copies/ml are used in each experiment.

Each Southern blot membrane is scanned into a computer using an automated scanner/densitometer, at intervals during development to determine when the standard curve is most linear. The resultant electronic images are then measured for band area and mean band density. All of the reading are standardized to integrated band density and compared to the standard curve to obtain a numerical value of viral copy number for each band.

The term"sustained virologic response"as used in the context of the present invention means that there is no detectable HCV-RNA in the patients treated in accordance with the present invention for at least 24 weeks after the end of the combined therapy treatment. Preferably, the period of sustained virologic response will be at least one year-or longer- after the end of treatment.

The following clinical protocol may be used to administer the combination therapy of the present invention: Overall Design and Plan of the Study A prospective, multicenter, randomized, double-blind, parallel- group should be used. The study should compare treatment with ! NATRON@ A 3 MU SC TIW plus ribavirin1000-1200 mg/Kg/day PO in two divided doses for 48 weeks to treatment with (a) ! NTRON@ A 10 MIU SC QD plus ribavirin 1000-1200 mg/Kg/day PO in two divided doses for 2 weeks; followed by (b)! NTRON@ A 5 MIU SC QD plus ribavirinl000-1200 mg/Kg/day PO in two divided doses for 6 weeks; followed by (c) INTRONO A 35 MIU SC QD plus ribavirinl000-1200 mg/Kg/day PO in two divided doses for 16 weeks; followed by (d) INTRONO A 3 MU SC TIW plus ribavirin 1000-1200 mg/Kg/day PO in two divided doses for 24 weeks. Eligible patients are male and females of 18 to 65 who should have chronic hepatitis C confirmed by positive serum HCV-RNA, liver biopsy, and laboratory tests.

Patients should be randomized tothe abovedescribed treatments.

Kg PO daily (based on weight) in two divided doses. Treatment group assignments should be made by a Central Randomization Center. The randomization procedure should be designed to attempt to balance the treatment groups, within and across sites, with respect to presence or absence of cirrhosis in the pretreatment liver biopsy, serum HCV- RNA/qPCR level, and HCV genotype.

During treatment and posttreatment follow-up, biochemical (ALT), virological (HCV-RNA), and histological (liver biopsy) examinations would be used to assess the nature and duration of response to study treatment.

The primary efficacy variable will be the overall response defined as loss of serum HCV-RNA/qPCR (<100 copies/mL) as measured at 24 weeks following the end of therapy. In addition, a decrease in hepatic inflammation, an improvement in posttreatment liver biopsy as measured by the Knodell Histology Activity index (HAI) and normalization of ALT will

also be examined as a secondary efficacy endpoints. The safety of the study treatments will be assessed by monitoring selected laboratory parameters and by also recording and evaluating the occurrence of any adverse events.

Treatment Regimens There are two study treatment regimens : 1. (a) INTRONO A 10 MIU SC QD plus ribavirin 1000-1200 mg/Kg/day PO in two divided doses for 2 weeks; followed by (b) INTRONO A 5 MIU SC QD plus ribavirin1000-1200 mg/Kg/day PO in two divided doses for 6 weeks; followed by (c) INTRON@ A 35 MIU SC QD plus ribavirinl 000-1200 mg/Kg/day PO in two divided doses for 16 weeks; followed by (d) NATRON@ A 3 MU SC TIW plus ribavirin 1000-1200 mg/Kg/day PO in two divided doses for 24 weeks; or 2.! NATRON@ A 3 MU SC TIW plus ribavirin 1000-1200 mg/Kg/day PO in two divided doses for 48 weeks.

Study treatments 1 and 2 should be administered for 48 weeks.

InStudy treatment 1, the standard INTRONO A (interferon alfa-2b, recombinant) regimen for hepatitis C should be administered as a fixed dose of 3 MU TIW. Each patient should receive instructions regarding the preparation and subcutaneous administration of INTRONO A. Ribavirin should be administered twice daily, morning and evening. The dose will be determined by the patient's body weight at the Entry visit.

The randomization procedure should be designed to balance the groups with respect to the following Baseline characteristics: pretreatment liver histology (cirrhosis or no cirrhosis); 'serum HCV-RNA/qPCR status (HCV-RNA/qPCR <2,000,000 or HCV-RNA/qPCR >2,000,000 copies/mL); and * HCV Genotype (1).

Patients with HCV Genotype (2 and/or 3).

Efficacv The primary efficacy objective will be the comparison of the treatment groups 1 and 2 with respect to the sustained virologic response rate defined as loss of (detectable) serum HCV-RNA/qPCR measured at 24 weeks following the end of therapy to an undetectable level or to a level <100 copies/mL. The following secondary efficacy Endpoints will also be examined using logistic regression: The secondary efficacy Endpoints: 'proportions of patients with normalization of ALT at 24 weeks of follow-up; 'proportions of patients with improvement in biopsy (Categories I + 11 +111 combined scores); changes from Baseline in the biopsy scores (Categories I + II + III combined scores); response rates at Endpoint of treatment based on HCV- RNA/qPCR; proportion of patients with normalization of ALT at Endpoint of treatment. response rates at 24 weeks of follow-up based on HCV- RNA/qPCR.

Virology: Entry Status and Change from Entry Serum HCV-RNA/qPCR testing and HCV genotype testing will be performed by a central laboratory. A positive HCV-RNA assay result will be required at Baseline; only patients positive for HCV-RNA will be eligible to participate. Repeat assays should be scheduled at Weeks 4,12,24, and if the patient is in the 48 week treatment groups at weeks 36 and 48.

All patients should have repeat assays scheduled for Follow-up Weeks 12 and 24.

Response will be assessed as defined below: Virologic Responder: A patient will be classifie as a responder at a given time point if HCV-RNA/qPCR is negative (<100 copies per mL) at that time point.

Sustained Virologic Responder: A patient will be classified as a sustained responder if the patient is a responder at 24 weeks of follow- up.

Note that patients who do not meet these criteria, including patients who discontinued before the required HCV-RNA/qPCR evaluations are obtained, will be classifie as non- responders.

Overall Responder: Based on both serum HCV- RNA/qPCR and change in liver histology as evaluated by the Knodell HAI Inflammation Score. A patient will be classifie as an overall responder to treatment if at 24 weeks of follow-up, he/she is a sustained virologic responder and has normal ALT.

Liver Histology Liver biopsy will be required within the six months preceding patient enrollment and at Follow-up Week 24 for all patients. Evaluation of the biopsies will be performed by a single pathologist using the Knodell Histology Activity Score. The central pathologist will be blinded with respect to patient identification, treatment group, and the time the biopsy will be obtained relative to treatment (Pre-or Posttreatment).

Efficacy of study treatments will be assessed by comparing the degree of

inflammatory activity observed at Baseline with that present at Follow-up Week 24.

The patient's weight and their baseline disease characteristics (HCV genotype and initial viral load) for all patients will be measured before the start of the study. HCV genotypes should be done on the patient serum samples subjected to HCV-RNA/qPCR testing.

This enhancement of efficacy included all aspects of the disease will result in: Sustained eradication of detectable HCV-RNA; Improvement in hepatic inflammation; Normalization of ALT; ') Improvement in HQL.