HCV%20resistance%20Understanding%20the%20mechanism%20and%20Prevention

1
HCV resistanceUnderstanding the mechanism and
Prevention

• Fabien Zoulim
• Hepatology department, Hospices Civils de Lyon
• INSERM U1052, Viral Hepatitis Team
• Lyon University, France

2
Novel targets for antiviral intervention using
the HCV life cycle
IFN RBV
Other viral and cellular targets
Racanelli V, et a., Trends Immunol
200324456-64 Manns MP, et al. Nat Rev Drug
Discov 20076991-1000.
IFN Interferon, RBV - Ribavirin
3
Key concepts for HCV

• Viral persistence but a curable disease !
• Viral genome heterogeneity
• Resistance to polymerase protease inhibitors
• Selection of resistant mutants
• Key objective suppress resistance

4
The main differences between HIV, HBV and HCV
HBV
HIV
HCV
H
H
H
Host cell
Host cell
Host cell
HCV RNA
cccDNA
Host DNA
Host DNA
Proviral DNA
Integrated DNA
Nucleus
Nucleus
Nucleus
Life-long suppression of viral replication
Definitive viral clearance and SVR
Long-term suppression of viral replication
SVR Sustained viral response
Kieffer TL, et al. J Antimicrob Chemother
201065202-12 Garrido C, et al. J Antimicrob
Chemother 201065320-6 Clavel F, et al. New
Engl J Med 20043501023-5 Zoulim F, et al.
Gastroenterology 20091371593-608 Sarrazin C,
et al. Gastroenterology 2010138447-62.
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How does HCV resistance develop?
High replication rate with errors during
replication 1012 viruses produced per day 1
mistake per virus produced
Continual development of viral variants
Drug-resistant variantsexist before antiviral
therapy
Antiviral therapy
Suppression of wild-type and susceptible variants
Selection and expansion of drug-resistant mutants
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Definitions of treatment failure
Null-Response
Breakthrough
Relapse
Partial responder
Detection limit
Treatment including DAA
Resistance mutants
DAA Direct acting antiviral agents
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The virus and its environment

• The infected hepatocytes
• Virus replication in hepatocytes
• Hepatocyte response to infection
• Antiviral drugs
• Potency of antivirals
• Potency shift to mutant
• Barrier to resistance
• The virus
• Fitness of the resistant mutants
• Accumulation of compensatory mutations
• Cross-resistance profile

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Emergence of drug resistant mutants
All single mutations likely to be generated every
day
Resistant mutants less fit than wt
HCV RNA
Hepatocytes
Viral infection
Viral replication
Resistant mutant
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Emergence of drug resistant mutants
All single mutations likely to be generated every
day
Hepatocytes
HCV RNA
Viral replication
Viral infection
Resistant mutants more fit than wt
Resistant mutant
Antiviral treatment with DAA
DAA Direct acting antiviral agents, wt
wild-type
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Antiviral drug resistance testing

• Genotypic (sequence analysis) assays
• Detection of emerging mutants
• Population sequencing
• Clonal analysis
• Ultradeep sequencing
• HCV viral fitness assays
• Determination of fitness, infectivity and
  evolution of mutants
• Difficult to apply to clinical isolates
• HCV phenotypic assays
• Determination of drug susceptibility and
  cross-resistance profile / Replicon system

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Evolution of NS3 protease variants in patients
treated with telaprevir monotherapy
Sarrazin C, et al. Gastroenterology
20071321767-77
NS3 Non structural protein 3
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Towards the suppression of resistance

• Factors affecting the selection of resistant
  variants during antiviral treatment
• Drug selective pressure
• Antiviral potency
• Drug concentration at the site of replication
• Genetic barrier to resistance
• Number of mutations required for loss of activity
• Viral fitness Relative rate of replication of
  resistant strains
• IFN and ribavirin backbone to maintain antiviral
  pressure on resistant mutants

IFN Interferon
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Peg-IFN Ribavirin inhibit PI resistant mutant
replication
Peg-IFN Pegylated interferon, PI Protease
inhibitor
Kieffer TL, et al. AASLD 2006
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Failure of triple therapy is the result of the
failure of IFN Ribavirin to clear PI resistant
mutants !
IFN Interferon, PI Protease inhibitor
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Virologic monitoring of triple therapy
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Example of virologic breakthrough
DAA stopped sequencing
10 106 105 104 103 102 101 0
HCV - RNA (UI/ml)
0 N N
2 N N
4 Y Y
6 Y Y
8 Y Y
10 Y Y
12 Y Y
vBT Confirmed v BT
DAA Direct acting antiviral agents, v BT
Virologic breakthrough
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Example of virologic breakthrough
Importance of the timing of virologic monitoring
10 106 105 104 103 102 101 0
HCV - RNA (UI/ml)
0 N N
2 N N
4 Y Y
6 Y Y
8 Y Y
10 Y Y
12 Y Y
vBT Confirmed v BT
v BT Virologic breakthrough
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Example of virologic breakthrough
Importance of sequencing and mutation detection
10 106 105 104 103 102 101 0
HCV - RNA (UI/ml)
V36M R155K
0 N N
2 N N
4 Y Y
6 Y Y
8 Y Y
10 Y Y
12 Y Y
vBT Confirmed v BT
v BT Virologic breakthrough
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Loss of telaprevir resistant variants after
treatment cessation
1.0
0.9
Médiane de retour des variants sauvages en
séquençage direct 7 mois (IC95 5-8)
0.8
0.7
0.6
médiane
0.5
Probabilité
0.4
0.3
0.2
0.1
0.0
0
2
4
6
8
10
12
14
16
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Suivi après léchec thérapeutique (mois)
Sullivan J. et al. EASL 2011.
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Loss of telaprevir resistant variants after
treatment cessation
1.0
0.9
1a
0.8
0.7
0.6
médiane
Probabilité
0.5
0.4
1b
0.3
0.2
0.1
0.0
0
2
4
6
8
10
12
14
16
18
Suivi après léchec thérapeutique (mois)
Sullivan J. et al. EASL 2011.
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Optimizing anti-HCV regimens to maximize SVR and
minimize resistance

• The drugs
• Antiviral potency
• Pharmacokinetics (intracellular concentration of
  the inhibitor)
• The virus
• Genetic barrier to resistance
• Fitness of resistant variants
• Cross-resistance
• The host
• Treatment adherence
• IFN response
• Genetics / IL28B gene polymorphism others
• ISGs expression
• The treatment regimen
• Treatment duration / Dosage of the drug /Dosing
  interval
• Side effects

IFN Interferon, IL28 Interleukin 28B, ISGs
Interferon stimulated genes, SVR Sustained
virologic response
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All-oral HCV treatmentGT-1
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Site of action of BI compounds
NS3/4A Protease inhibitor BI 201335
NS5B pocket I Polymerase inhibitor BI 207127
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Cross-resistance between polymerase and protease
inhibitors is unlikely
NS2NS3 protease
NS3 protease
C
E1
E2
p7
NS2
NS3
NS4A
NS4B
NS5A
NS5B
Serine protease domain
Core
Envelope
T54 R155 A156 D168 V36
S96 N142 S282 C316 M414 M419 P495 T423
R1479(R1626)
Telaprevir SCH 503034
Telaprevir BI 201335
NM283
Telaprevir BI 201335 SCH 503034
HCV-796
BI 201335
Telaprevir
BI207127
nucleoside non-nucleoside
Sarrazin C, et al. Gastroenterol.
2007132176777 Tong X, et al. Antiviral Res.
2006702838 De Francesco R, et al. Nat.
200543695360 Le Pogam S, et al. Virol.
200635134959 Villano S, et al. 57th AASLD
2006, Boston, MA, October 2731, 2006
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BI 207127 BI 201335 Combination suppresses
emergence of resistance
BI 207127 X EC50
Long term selection of resistance in vitro is
effectively suppressed by BI 201335 and BI
207127 combination
BI 201335 X EC50
EC50 Median estimated concentration
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BI 201335 BI 207127 SOUND-C1
400 mg TID BI 207127 120 mg BI 201335
RBV(n15)
100000000 10000000 1000000 100000 10000 1000
100 10 1
GT-1a GT-1b
HCV RNA (IU/mL)
LLOQ
LLOD
0 4 8 12 16 20 24 28 32 36 40 44
Treatment day
BI 207127 400 mg/BI 201335/RBV
BI 201335/ PegIFN/RBV
LLOQ, lower limit of quantification LLOD, lower
limit of detection, GT - genotype
Zeuzem S, et al. Gastroenterology 20111412047-55
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SOUND-C1 trial

• Multi-centre, open-label, randomised phase Ib
  study in
• treatment-naïve, HCV genotype-1 (GT-1) patients

400 mg BI 207127 TID 120 mg BI 201335 QD RBV
PegIFN alfa 2a/RBVa
120 mg BI 201335 QD PegIFN alfa 2a/RBV
Follow-up
n 15 n 17
600 mg BI 207127 TID 120 mg BI 201335 QD RBV
PegIFN alfa 2a/RBVa
120 mg BI 201335 QD PegIFN alfa 2a/RBV
Follow-up
Day 1
Week 4
Week 24
Week 48
Week 72

• Futility rules
• Virological breakthrough (increase in HCV RNA by
  gt 1 log, or HCV RNA 100 IU/mL after lt 25 IU/mL)
• Lack of EVR (gt 2 log decrease at Week 12)
• Lack of undetectable HCV RNA at Week 24
• aPatients without eRVR (HCV RNA 25 IU/mL Week
  4, undetectable Weeks 5 to 18) continued
  PegIFN/RBVup to Week 48
• TID, three times daily QD, once daily

Zeuzem S, et al. AASLD 2010. Abstract LB-7
EVR Early virologic response, eRVR extended
Rapid virologic response, PegIFN/RBV Pegylated
interferon/ribavirin
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SOUND-C1Virologic response
400 mg TID 600 mg TID
100 80 60 40 20 0
Proportion of patients ()
17/17
4/15
17/17
11/15
11/15
12/17
14a/15
16b/17
RVR eRVR EoT SVR12
aIncludes patient 61102 switched to
Peg/RBV bPatient 41203 outstanding RVR, rapid
virologic response (after 4 weeks of treatment)
eRVR, HCV RNA lt 25 IU/mL at Week 4 and undetected
at Week 5 to 18 EoT, undetectable HCV RNA at the
end of all treatment
Zeuzem S, et al. AASLD 2011. Abstract 249
EOT End of treatment, SVR Sustained virologic
response
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SOUND-C2 trial
Multi-centre, open-label, randomised phase IIb
study in treatment-naïve, HCV genotype-1 (GT-1)
patients Including 15 cirrhotics
A(n81) B(n81) C(n81) D(n81) E(n81)
1335 7127TID RBV
Follow-up
1335 7127TID RBV
Follow-up
1335 7127TID RBV
1335 7127BID RBV
Follow-up
1335 7127TID no RBV
Follow-up
Day 1 Week 12 Week 16 Week 26 Week 40
Interim analysis
Zeuzem S, et al. AASLD 2010. Abstract LB-15
GT Genotype, RBV - Ribavirin
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Results Antiviral activity antiviral response
assessment up to week 12 (5)
patients with HCV RNA ltLLOD at Week 12 by IL28 GT
and viral subtype (per protocol analysis)
100 80 60 40 20 0
Proportion of patientswith HCV RNA ltLLODat Week
12 ()
C/C Non-C/C C/C Non-C/C
GT-1a GT-1b
1335 7127TID RBV 22/25 39/61 24/26 79/92 1335
7127BID RBV 6/7 10/22 10/11 32/36 1335
7127TID no RBV 3/3 2/9 7/7 13/20
LLOD Lower limit of detection, IL28b
Interleukin 28b, GT - genotype
Zeuzem S, et al. AASLD 2010. Abstract LB-15
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All-oral HCV treatment GT-1

• BMS-790052 BMS-650032

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BMS-790052 BMS-650032

• Phase IIa study of BMS-790052 plus BMS-650032
  for 24 weeks
• HCV GT-1b Japanese null responders

Follow-up
BMS-790052 60 mg QD BMS-650032 200 mg BID
n10 (GT-1b)
48
Week
72
24
GT Genotype
Chayama K, et al. Hepatology. 201154(Suppl. S1)
Abstract LB-4
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BMS-650032/BMS-790052 virologic response (in
GT1b only)

• One patient discontinued at Week 2 HCV RNA was
  undetectable after 24 weeks follow-up

Proportion of patients with undetectable HCV RNA
()
9/10
9/10
9/10
4/10
Week 4
EOT
SVR24
Week 12
EOT End of treatment, SVR Sustained virologic
response
Chayama K, et al. Hepatology. 201154(Suppl. S1)
Abstract LB-4
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All-oral HCV treatmentGT2/3

• PSI-7977

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PSI-7977 RBV (GT-2/3) (n10 per arm)
phase II, randomized, open-label trial of
PSI-7977 plus RBV, with or without PegIFN, in
treatment-naïve HCV GT-2 and GT-3 patients
cirrhotics excluded
PSI R12 weeks n10
PSI-7977 400 mg RBV
PSI PR4 weeks n10
PSI-7977 400 mg PegIFN/RBV
PSI-7977 400 mg RBV
PSI PR8 weeks n10
PSI-7977 400 mg RBV
PSI-7977 400 mg PegIFN/RBV
PSI PR12 weeks n10
PSI-7977 400 mg PegIFN/RBV
8
Week
12
4
Gane EJ, et al. AASLD 2011. Abstract 34
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PSI-7977 RBV (GT-2/3) (n10 per arm)

• No viral breakthrough observed
• PSI-7977 very well tolerated, with no
  attributable safety signal, no treatment
  discontinuations and no treatment emergent
  laboratory abnormalities

100
100
100
100
100
100
100
100
Gane EJ, et al. AASLD 2011. Abstract 34
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PSI-7977 RBV (GT-2/3) (n10 per arm)
100
100
100
100
60
Gane EJ, et al. AASLD 2011. Abstract 34
RBV - Ribavirin
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ConclusionsCurrent and future HCV treatment
regimens
HCV NS5A inhibitor
HCV NS5A inhibitor
OR
HCV NS5A inhibitor