THERAPY OF HEPATITIS C: BASIC APPROACHES AND CLINICAL APPLICATIONS

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THERAPY OF HEPATITIS CBASIC APPROACHES AND
CLINICAL APPLICATIONS

• Erik DE CLERCQ
• Rega Institute for Medical Research,
  K.U.LeuvenB-3000 Leuven, Belgium

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Flaviviridae
Flaviviruses Pestiviruses
Hepaciviruses
Yellow fever virus Dengue virus West Nile
virus Japanese encephalitis virus Tick-borne
encephalitis virus St. Louis encephalitis virus
Bovine viral diarrhea virus Classical swine
fever Border disease virus
Hepatitis C virus (HCV)
. . .
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Hepatitisviruses
HAV HBV HCV HDV HEV
Enterovirus type 72 Hepadnavirus Hepacivirus ?-agens circular (-)RNA Calicivirus
Picornaviridae Hepadnaviridae Flaviviridae Picornaviridae
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Transmission of hepatitisviruses
HAV HBV HCV HDV HEV
Faeco-oral Parenteral Sexual Perinatal Parenteral Sexual (Perinatal) Parenteral Sexual (Perinatal) Faeco-oral
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Hepatitisvirus infections
HAV HBV HCV HDV HEV
Acute hepatitis ? ? ? ? ?
Chronic carrier (risk) O ? ? ? O
Chronic hepatitis (risk) O ? ? ? O
Cirrhosis (risk) O ? ? ? O
Hepatocellular carcinoma (risk) O ? ? ? O
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Hepatitisvirus infections vaccination
HAV HBV HCV HDV HEV
Yes Yes No No No
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Features of hepatitis C virus infection
Average 6-7 weeks Range 2-26 weeks
Incubation period
Mild (? 20)
Acute illness (jaundice)
Low
Case fatality rate
60-85
Chronic infection
10-70
Chronic hepatitis
lt 5-20
Cirrhosis
1-5
Mortality from CLD
Centers for Disease Control and Prevention
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Centers for Disease Control and Prevention
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Centers for Disease Control and Prevention
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Evolution of chronic hepatitis C
Primary hepatocellular carcinoma
Cirrhosis 42
Average 3 years (0-15 years)
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Global distribution of HCV infection
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Transmission routes for HCV
Centers for Disease Control and Prevention
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Hepatitis C Risk groups

• Blood transfusion before 1990
• Injecting drug use
• Household transmission of HCV
• Health care workers
• Tattooing, body piercing
• Promiscuity
• Unknown

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Centers for Disease Control and Prevention
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Other transmission issues

• HCV not spread by kissing, hugging, sneezing,
  coughing, food or water, sharing eating utensils
  or drinking glasses, or casual contact
• Do not exclude from work, school, play, childcare
  or other settings based on HCV infection status

Centers for Disease Control and Prevention
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GENERAL STRUCTURE OF A FLAVIVIRUS
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HCV GENOME ORGANIZATION
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(No Transcript)
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HCV genome and sites for current drug development
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At the 5 untranslated region resides the
internal ribosomal entry site (IRES), which
is highly conserved and represents a site for
development of translation inhibitors such as
antisense oligonucleotides and ribozymes. NS3
encodes for a specific helicase and the NS5B
region encodes for an RNA-dependent RNA
polymerase enzyme, both important in viral
replication. These also represent sites for the
development of specific viral enzyme inhibitors.
Other potential enzyme targets include the HCV
specific proteases (NS2/3 and NS3/4). These
enzymes are involved in processing the viral
polyprotein at specific sites as indicated.
McHutchison and Patel, Hepatology 36 S245-S252
(2002)
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Schematic representation of the HCV genome and
encoded viral proteins
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002)
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Schematic representation of the organization of
the HCV genome and the structure of a subgenomic
replicon
Bartenschlager, Nature Reviews/Drug Discovery 1
911-916 (2002)
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Proposed replicative cycle of HCV and potential
sites of therapeutic intervention
Tan et al., Nature Revievs/Drug Discovery 1
867-881 (2002)
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Crystal structure of HCV NS3 protease-inhibitor
complex
Ribbon conformation of the three-dimensional
crystal structure of two hepatitis C virus
(HCV) non-structural protein 3 (NS3)
serine-protease domains complexed with an NS4A
cofactor peptide (residues 956-967 red) and the
tripeptide inhibitor (inhibitor I ball-and-stick
model) L-BOC,L-Glu,L-Leu-(difluoro)aminobutyric
acid. BOC, tert-butyloxycarbonyl group.
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002)
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Macrocyclic inhibitor of HCV NS3 protease
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002) Tsantrizos et al., Int. Patent
Appl. WO 00/59929 (2000)
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Crystal structure of HCV NS3 helicase complexed
with single-stranded DNA
Ribbon diagram of the hepatitis C virus (HCV)
non-structural protein 3 (NS3) helicase
RNA-helicase domain complexed with a deoxyuridine
octamer (dU8 yellow)
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002) Kim et al., Structure 6 89-100
(1998)
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Crystal structure of HCV NS5B polymerase
Ribbon representation of the first 570 residues
from the amino terminus of hepatitis C
virus (HCV) non-structural protein 5B (NS5B),
with ?-helices and ?-strands represented in red
and cyan, respectively.
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002)
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Benzimidazole derivative Analogue of JTK-003, an
orally active inhibitor of non-structural protein
5B (NS5B)
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002) Hashimoto et al., Int. Patent
Appl. WO 01/47883 (2001)
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Iminosugar derivatives based on the glucose
analogue DNJ
Deoxynojirimycin
N-butyl-DNJ
N-nonyl-DNJ
Durantel et al., J. Virol. 75 8987-8998 (2001)
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Iminosugar derivatives based on the galactose
analogue DGJ
Deoxygalactonojirimycin
N-butyl-DGJ
N-nonyl-DGJ
Durantel et al., J. Virol. 75 8987-8998 (2001)
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Mechanism of action of short- and
long-alkyl-chain DNJ and DGJ derivatives against
BVDV (Bovine Viral Diarrhea Virus)

• Reduction in viral secretion and reduction in
  infectivity of newly released viral particles.
• No correlation between antiviral effect and
  inhibition of ?glucosidases at the endoplasmic
  reticulum (ER).

Durantel et al., J. Virol. 75 8987-8998 (2001)
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PEG Polyethylene glycol CH3(OCH2CH2)nOH CH3OCH2
CH2OCH2CH2.......OCH2CH2OCH2CH2OH
Glycol HOCH2CH2OH
Polyethylene -(CH2CH2)n- Ethylene -CH2-CH2-
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NHS
Branched polyethylene glycol (PEG) that was
created by coupling a monofunctional PEG
(mPEG)-benzatriazole carbonate of molecular mass
40 kDa to lysine. Conjugation of this PEG moiety
to interferon-?2a (IFN-??2a) results in an agent
with a significantly longer half-life, which
requires less frequent administration and has an
improved toxicity profile. NHS,
N-hydroxysuccinimide.
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002)
33
Pegylated interferon ?-2b plus ribavirin compared
with interferon ? 2b plus ribavirin for the
initial treatment of chronic hepatitis
CVirological response at the end of treatment
and follow-up
Endpoint Sustained viral response (SVR) rate (number responding/total treated) Sustained viral response (SVR) rate (number responding/total treated) Sustained viral response (SVR) rate (number responding/total treated)
Higher-dose peginterferon 1.5 µg/kg/week Lower-dose peginterferon 0.5 µg/kg/week Interferon 3 MU x 3/week
Ribavirin (800 mg/day) Ribavirin (1000-1200 mg/day) Ribavirin (1000-1200 mg/day)
Overall End of treatment all patients SVR at end of follow-up all patients 65 (333/511) 54 (274/511) 56 (289/514) 47 (244/514) 54 (271/505) 47 (235/505)
SVR by genotype 1 2/3 4/5/6 42 (145/348) 82 (121/147) 50 (8/16) 34 (118/349) 80 (122/153) 33 (4/12) 33 (114/343) 79 (115/146) 38 (6/16)
Manns et al., Lancet 358 958-965 (2001)
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Peginterferon ?-2b plus ribavirin for initial
treatment of chronic hepatitis C Logistic
regression analyses Sustained virological
response (SVR) as a function of ribavirin dose
(mg/kg) and dose of peginterferon alfa-2B
Manns et al., Lancet 358 958-965 (2001)
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Pegylated interferon ?-2b compared to interferon
?-2b for the initial treatment of chronic
hepatitis C Virologic response at end of
treatment and end of follow-up
HCV-negative patients
Lindsay et al., Hepatology 34 395-403 (2001)
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Pegylated interferon ?-2a, as compared to
interferon ?-2b, plus ribavirin for the treatment
of chronic hepatitis C virus infection
Fried et al., N. Engl. J. Med. 347 975-982 (2002)
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Pegylated interferon ?-2a, as compared to
interferon ?-2b, plus ribavirin for the treatment
of chronic hepatitis C virus infection
Fried et al., N. Engl. J. Med. 347 975-982 (2002)
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Pegylated interferon ?-2a, as compared to
interferon ?-2b, plus ribavirin for the treatment
of chronic hepatitis C virus infection Proportion
of patients with a sustained virologic response
as a function of HCV genotypea
Peginterferon alfa-2a plus ribavirin (N 453) Interferon alfa-2b plus ribavrin (N 444) Peginterferon alfa-2a plus placebo (N 224)
No./total no. ()
HCV genotypeb
All patients 255/453 (56) 197/444 (44) 66/224 (29)
Genotype 1 138/298 (46) 103/285 (36) 30/145 (21)
Genotype 2 or 3 106/140 (76) 88/145 (61) 31/69 (45)
Genotype 4 10/13 (77) 4/11 (36) 4/9 (44)
aA sustained virologic response was defined as no detectable hepatitis C virus (HCV) RNA 24 weeks after the cessation of therapy. bSix patients had other genotypes aA sustained virologic response was defined as no detectable hepatitis C virus (HCV) RNA 24 weeks after the cessation of therapy. bSix patients had other genotypes aA sustained virologic response was defined as no detectable hepatitis C virus (HCV) RNA 24 weeks after the cessation of therapy. bSix patients had other genotypes aA sustained virologic response was defined as no detectable hepatitis C virus (HCV) RNA 24 weeks after the cessation of therapy. bSix patients had other genotypes
Fried et al., N. Engl. J. Med. 347 975-982 (2002)
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Pegylated interferon ?-2a plus ribavirin for the
treatment of chronic hepatitis C virus
infection Predictability of sustained virologic
response
Fried et al., N. Engl. J. Med. 347 975-982 (2002)
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Kinetics of HCV RNA and proportions of patients
who became HCV RNA negative at different times
with the high and low doses of peginterferon
?-2b plus ribavirin
Buti et al., Hepatology 35 930-936 (2002)
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Adverse events in 453 patients with chronic
hepatitis C virus infecton who received
peginterferon alfa-2a plus ribavirin(percentage
of patients in parentheses)
Adverse events Peginterferon alfa-2a plus ribavirin
Fatigue 242 (54)
Headache 211 47)
Pyrexia 195 (43)
Myalgia 189 (42)
Insomnia 168 (37)
Nausea 130 (29)
Alopecia 128 (28)
Arthralgia 121 (27)
Irritability 109 (24)
Rigors 106 (24)
Pruritus 101 (22)
Depression 100 (22)
Decreased appetite 96 (21)
Dermatitis 95 (21)
This symptom is one of the influenza-like
symptoms often seen with interferon treatment
Fried et al., N. Engl. J. Med. 347 975-982 (2002)
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Ribavirin
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Viramidine
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LevovirinL-Ribavirin
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VX-497
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Mycophenolic acid
Mycophenylate mofetil (Cellcept) 2-Morpholinoethy
l ester of mycophenolic acid
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Amantadine
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Rimantadine
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Current clinical hepatitis C drug development
Drug type Compound Phase of development Comments
Alternative interferons Natural interferon Albuferon Oral interferons Oral interferon inducers II I I Preclinical/I Leukocyte-derived interferon alfa, alternative to recombinant interferons Fusion of interferon with albumin to increase half-life Oral absorption of interferon Drugs that induce interferon production
Nucleoside analogues Levovirin Viramidine I/II I/II L-isomer of ribavirin, reported to cause less hemolysis Ribavirin prodrug with preferential liver uptake
IMPDH inhibitors VX-497 Mycophenylate mofetil II II Specific inhibitor, no hemolysis, further trials with interferons in progress Evaluation of efficacy combined with interferon alfa in nonresponders in progress
Broad spectrum antivirals Amantadine Rimantadine II II Numerous clinical trials evaluating efficacy with interferon or interferon and ribavirin in naive and nonresponder populations
McHutchison and Patel, Hepatology 36 S245-S252
(2002)
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Current clinical hepatitis C drug development
(continued)
Drug type Compound Phase of development Comments
Small molecule targets and viral enzyme inhibitors
NS3 protease inhibitors BILN-2061 Preclinical/I A multitude of agents from different classes is in preclinical development. One agent has entered phase I trials (BILN-2061)
NS3 helicase inhibitors Preclinical/I Numerous agents in preclinical stages. Development of one compound halted in early dose ranging studies
NS5B polymerase inhibitors JTK-003 Preclinical/I Several compounds in development. A single drug in phase I trials (JTK-003)
Antisense oligonucleotides ISIS-14803 II
McHutchison and Patel, Hepatology 36 S245-S252
(2002)
51
Selected IFN-based therapies for the treatment of
HCV infection
Drug name Company Clinical phase
Monotherapy
Intron A (IFN-?2b, recombinant) Schering-Plough FDA approval, 1995
Roferon A (IFN-?2a, recombinant) Roche FDA approval, 1996
Infergen A (IFN alfacon-1) InterMune Pharmaceuticals FDA approval, 1997
Welferon (lymphoblastoid IFN-?n1) GlaxoSmithKline FDA approval, 1999
PEG-INTRON (PEGylated IFN-?2b) Schering-Plough FDA approval, 2001
Pegasys (PEGylated IFN-?2a) Roche FDA approval, 2001
Omniferon (natural IFN-?) Viragen (Scotland) Phase II
Omega IFN (IFN-?) BioMedicines Phase II
Albuferon- ? (albumin-IFN-?2b) Human Genome Sciences Phase I
Rebif (IFN-?1a) Serono Preclinical
Combination therapies
Rebetron (Intron A and ribavirin) Schering-Plough FDA approval, 1998
PEG-INTRON and ribavirin Schering-Plough FDA approval, 2001
Pegasys and ribavirin Roche FDA application, submitted
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002)
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A sample of the drug pipeline for hepatitis C and
related treatments
Target/indication Drug name Mechanism/drug category Company
IRES ISIS 14803 Antisense ISIS Pharmaceuticals/Elan Corporation
Heptazyme Ribozyme Ribozyme Pharmaceuticals
NS3 BILN-2061 Serine-protease inhibitor Boehringer Ingelheim
VX-950/LY-570310 Serine-protease inhibitor Vertex Pharmaceuticals/Lilly
NS5B JTK-003 RdRp inhibitor Japan Tobacco
IMPDH VX-497 IMPDH inhibitor Vertex Pharmaceuticals
Levovirin IMPDH inhibitor Ribapharm
Viramidine IMPDH inhibitor Ribapharm
Tan et al., Nature Reviews/Drug Discovery 1
867-881 (2002)