Christoph Sarrazin

1
Resistance is important? No
5th Paris Hepatitis Conference Paris, 31.01.2012
Christoph Sarrazin J. W. Goethe-University
Hospital Frankfurt am Main, Germany
2
Hepatitis C virus is an RNA virus
HIV HBV HCV
Genome RNA DNA RNA
Mutation rate Very High High Very High
Virions produced daily 1010 1013 1012
Viral genetic archiving YES YES NO
Drug targets Multiple One Multiple
Eradication with current therapy? NO (Integrated viral DNA) NO (cccDNA) YES
Therapeutic Goal Lifelong suppression Lifelong suppression clearance from plasma and liver
3
Selected resistant variants are not archived
Long-term follow-up
VX-950 Dosing Period
Post-Dosing
7
7
7
7
6
6
6
6
5
5
5
5
4
4
4
4
Median Log HCV RNA
Long-term follow-up 3-7 months post-dosing
3
3
3
3
Follow-Up 7/10 days post-dosing
2
2
2
2
EOD 14 days
Baseline
1
1
1
1
WT
IC50 fold change
WT
V36 M/A/L
R155 K/T/S/M
T54A
36/155
36/156
A156 V/T
Sarrazin et al. Gastroenterology 2007
4
Selected resistant variants are not archived
during long-term follow-up
Boceprevir (Phase 3)
Telaprevir (Phase 2/3) (median FU 29 months)
20
53
Patients (n)
Overall
36155
36
54
155
156
168
Population based sequencing
Sherman KE, et al. Hepatology 201154 (Suppl.
S1) Abstract 248
Barnard RJO, et al. Hepatology 201154 (Suppl.
S1) Abstract 164
5
Resistant variants at long-term FU are rarely
observed clonal / deep sequencing
Deep sequencing (Illumina) 5.7y after Telaprevir
(Phase 1)
4.5 years
V36A V36M T54A T54S
4.5 years
Patient
Susser et al., J Clin Virol 2011
Sarrazin et al., AASLD 2011
6
Re-Treatment of patients is not commonly
associated with treatment failure
108 107 106 105 104 103 102 101 100
1 Patient had a confirmed viral breakthrough at
Week 8 (V36M/V R155K/R)
Baseline 1 2 4 6 8
Time (weeks)
Sarrazin et al., AASLD 2011
7
Re-Exposure of patients is not commonly
associated with re-selection of same variants
1, GT 1a
2, GT 1a
3, GT 1b
4, GT 1b
Vermehren et al., J Viral Hepatitis 2012
8
Theoretically all possible single and double
variants exist - but
Hepatitis C virus 9600 nucleotides Error rate
during replication 10-4 10-5 per copied
nucleotide Viral turnover 1012 virions produced
every day
Number of nucleotide change Probability of generation after one round of replication Number of virions with nucleotide change(s) produced per day Number of all possible nucleotide mutants Fraction of all possible mutants created per day
0 91 9.1 x 1011
1 8.7 8.7 x 1010 2.9 x 104 1
2 0.4 4.2 x 109 4.1 x 108 1
3 0.001 1.3 x 108 4.0 x 1012 3.4 x 10-5

• Not all variants survive
• Dead mutations (variants that can not replicate)
• Immune sensitive mutations (variants that are
  eliminated by the immune system)

Rong L, et al, Sci Transl Med 2010230ra32
Neumann AU, et al. Science 19982821037Domingo
E, et al. Viral Hepatitis Rev 1996224761
Cuevas JM, et al. J Virol 20098357604
9
Presence of resistant variants at baseline is
rare (TVR/BOC) and at low frequencies has no
impact on SVR
Population based sequencing

• Study 1 (n570)0.9 V36M, 0.7 R155K, 0.2
  V170A, 0.2 R109K
• Study 2 (n507)0.32.2 dominant PI resistant
  mutations within NS3 protease
• Study 3 (n662)1.8 T54S, 0.6 R155K, 0.3 V36M
• Study 4 (n595)4 dominant PI resistant
  mutations within NS3 protease

cut-off 0.1 according to statistical test
based on Poissons law SVR sustained virologic
response NR non-responder RR
responder-relapser
Bartels DJ, et al. J Infect Dis
20081988007Kuntzen T, et al. Hepatology
200848176978 Vierling JM, et al. Hepatology
201052(Suppl.)702A De Meyer S, et al. J
Hepatol 201154(Suppl. 1)S475 Chevaliez S, et
al. J Hepatol 201154(Suppl. 1)S30
10
Presence of resistant variants at baseline at
high frequencies requires combination therapies
Cyclophilin inhibitors
Interferon alfa
NS5A inhibitors
Ribavirin
NS3/4A-protease- inhibitors
polymerase- inhibitors
3
C
E1
E2
p7
2
3
5B
5A
4B
4A
NS3-protease cofactor
RNA-dependent RNA-polymerase
metallo-/ cysteine-protease
membrane anchor
capsid
regulation of replication
envelope
NTPase/ helicase
serine- protease
11
Barrier to resistance depend on number and
probability of nucleotide exchanges
Main first generation NS3 Protease-Inhibitor
Resistance site (R155K)
One nucleotide exchange for subtype 1a versus two
nucleotide exchanges for subtype 1b
NS3 protease sequence 155 HCV-1a GIFRAAV HCV-
1b GIFRAAV HCV-1a AGG ? AAG (R155K) HCV-1b
CGG ? AAG (R155K)
Kieffer et al., Hepatology 2007 Sarrazin et al.,
Gastroenterology 2010
12
New Triple- / Quadruple-Therapies and all-oral
DAA therapies are highly effective
Treatment-naive non-cirrhotic genotype 2/3
patients, n50 (Nuc PSI-7977 /- PEG2a /- R for
a total duration of 12 weeks)
RVR EOT SVR
PSI-7977PEG12R 100 100 100
PSI-7977PEG8R 100 100 100
PSI-7977PEG4R 100 100 100
PSI-7977R 100 100 100
PSI-7977 mono 100 100 60
Gane et al., AASLD 2011, 34
13
Summary

• HCV is an RNA virus- treatment induced
  eradication of virus is possible- resistant
  variants can not be archived
• Frequency of resistant variants at baseline is-
  low for many DAA- has no importance for SVR at
  low levels
• Barrier to resistance is high for certain
  subtypes / isolates, and in general for
  nucleoside analogues
• Combination therapies are effective to avoid
  resistance- many DAAs / HTA without cross
  resistance in development- quadruple therapies
  shown to highly effective- proof of principle to
  achieve SVR with all oral treatment