Transcript R155K

Future Treatment: is resistance
important?
Philippe Halfon
Laboratoire Alphabio
Hôpital Ambroise Paré, Marseille, France
PHC 2012
Risk of selection of resistant virus
MINIMAL
INCOMPLETE
MAXIMAL
Potency
IC 50 nM
1-10
10-1000
NS5A Inhibitors
0.01-0.1
10-100
Genetic Barrier for HCV Direct Antiviral Agents
High
Nucleos(t)ide
Analog Inhibitors
2 st generation
Protease
Inhibitors
n
Non Nucleos(t)ide
Analog Inhibitors
:
NS5 A
Inhibitors
1 st generation
Protease
Inhibitors
Low
Halfon P J Hepatol 2011
Resistance to DAA
Monotherapy
What we learned?
32
Resistant virus is rapidly selected with Telaprevir alone
CI50 x fold
WT
1
Telaprevir
T54A
6
V36A/M
7
R155K/T
7-29
36/155
57
A156V/T
>74
36/156
> 74
Treatment regimen :PEG-IFNα-2a + RBV
8
Log10 ARN-VHC (UI/ml)
Viral decrease
> 5 000 000 fold
6
4
2
Detection limit (100 UI/ml)
ARN-VHC LID (10 UI/ml)
0
0
10
20
50
100 days
Kieffer et al.Hepatology 2007
Virologic Escape during Danoprevir
(ITMN-191/RG7227)Monotherapy
Lim S et al. AAC 2012
Genetic barrier can be overcome
by combination with PEG+Riba
DAA Monotherapy
Basal Status
DAA + Peg-IFN+RBV
Sensitive Virus
Resistant Virus
Dynamics of the viral breakthrough
during Telaprevir Monotherapy
Single resistant variants associated with
Boceprevir resistant variants4,5
T54A/S
V36M/A, T54S
V36A/M, R155K/T, A156S
V55A, R155K/T,
V170A, T54A, A156S
Medium
A156V/T
A156T
*Double mutants have also been reported with
telaprevir and boceprevir; †Measured by fold
change in IC50 in the HCV replicon assay
Low
Telaprevir resistant variants1–3
High
Increase in resistance†
telaprevir and boceprevir*
1. Kieffer T, et al. Hepatology 2007;46:631–9
2. Kieffer T, et al. Hepatology 2010;52(Suppl.):879A; 3. De Meyer S, et al. J Hepatol 2011;54(Suppl. 1): S475
4. Susser S, et al. Hepatology 2009;50;1709–18; 5. Zeuzem S, et al. J Hepatol 2011;54(Suppl. 1):S4
Location of NS3/4A protease amino acid substitutions
conferring decreased sensitivity to Telaprevir
Active
Site
Val36
Halfon P et al J Hepatol 2011
Home messages from Resistance
to DAA Monotherapy
• The HCV NS3,NS5A, Pol (NNI) mutations occurred quickly (less
than 15 days) and longer for Nucleosides Inhbibitors in
monotherapy.
• Genetic barrier can be overcome by combination with PEG+Riba
• There is a long term persistence of HCV NS3 Protease mutations
after the end of Therapy
• Monotherapy will lead to selection of resistant variants that, in turn,
could produce cross-resistance to whole class of drugs wit
overlapping resistance profiles
• Telaprevir and Boceprevir has a well-characterized and consistent
resistance profile
– Subtype 1a was associated with V36M and R155K variants, while
subtype 1b was associated with V36A, T54A/S, and A156S/T variants.
Resistance to SOC+DAA
(Triple Therapy)
Do we need a resistance test before treatment
with direct-acting antiviral agents?
Emergence of Viral Resistance to DAA Agents
Pre-existing Resistance Associated Variants within Quasispecies
Wild Type HCV
Viral Load
Resistance Associated Variants (RAVs)= 0.3-2.8%
Time on DAA Therapy
19
Adapted from Lok ASF, McMahon BJ. Hepatology. 2009;50:1-36.
Resistance to DAA detection
“Detection depends on how carefully
you look for it”
Clinical significance of RA minority mutants detection
Sequencing : 15-20%
Pyrosequencing : 1-10 %
Ultradeepsequencing : < 1%
Sarrazin C et al. AASLD 2011
Pyrosequencing assay
Focus on R155 and A156
C/AGG
GCT
Arginine R
Alanine A
Wild-type cells
R155
A156
Patient with
2 mutations
AAG
ACT
Lysine K
Threonin T
R155K
A156T
Baseline mutations 1-10 % !
Clinical significance of baseline
mutations on SVR using DAA
• 39 genotype 1 naïve patients (24 SVR and 15 NR) treated by a
protease inhibitor (Boceprevir and/or Telaprevir).
• 24 Non responders :
- 5/13 have one alone RAV at D0
- 9/13 have more one RAVs at D0
- 10/13 have multiples RAVs (2-4)
• None of the 15 complete responders have baseline mutations
• The presence of telaprevir/boceprevir-resistant variants was
found at baseline in all patients who had not achieved an SVR.
• These preliminary data suggest that treatment failure can be
predicted using a sensitive and standardized assay ( 1-10%)
Halfon P , Oules V, Bourliere M et al Liver International 2012
Post-Dosing
Peg-Riba – Telaprevir Dosing Period
Baseline
Week 4
Week 12
Week 24
WT
41%
WT
9%
R155K
100%
R155K
100%
R155K
91%
R155K
59%
Halfon P, Oules V, Bourliere M et al , Liver International 2012
Does resistance develop in all patients who do
not achieve an SVR?
REALIZE: TVR-resistant variants associated with
virologic failure in the TVR/Pbo treatment phase
Genotype 1a
Genotype 1b
25
Number of patients
Number of patients
25
20
15
10
5
0
20
15
10
5
0
T12/PR48
(n=136)
LI T12/PR48
(n=149)
Not available
Wild-type (no TVR-resistant variants)
Analysis used population-based sequencing
On-treatment virologic failure: patients who had discontinued due to a
virologic stopping rule and/or patients with viral breakthrough
T12/PR48
(n=126)
LI T12/PR48
(n=113)
Lower-level
Higher-level
V36A/M
T54A/S
R155I/K/M/T
A156S
Combinations
V36M+R155K
A156T/V
Combinations
De Meyer S, et al. J Hepatol 2011;54(Suppl. 1):S475
Subtype Matter
with Telaprevir Therapy
Genotype 1a (n = 6)
V36M
Genotype 1b (n = 14)
R155K/T
A156V/T
• 1 nucleoside substitution
in relevant codons of 1a
• 2 substitutions needed in 1b
• Less fit than
other variants
Implication: subtype distinctions may become
more important with DAA agents
than with PEG IFN + RBV alone
Kieffer TL, et al. Hepatology. 2007;46:631.
Do resistance mutations persist?
Samples from patients with no
detectable resistant variants (%)
EXTEND: 89% of patients no longer have
detectable resistant
variants
100
100
100
89
92
88
85
80
60
40
Population
Sequencing
20
0
n/N = 50/56
Overall
34/37
12/12
29/33
5/5
22/26
patients
36
54
155
156
36+155
variants
Variants at HCV NS3 position
Median follow-up time from end of prior study of 25 months (range 7–36)
Variant categories are not mutually exclusive
Zeuzem S, et al. Hepatology 2010;52(Suppl.):436A
Probability
Telaprevir Phase III trials: loss of resistant
variants according to NS3 position
Analysis includes only patients with follow-up data and a
resistant variant(s) at treatment failure (probability starts at 100%)
1.0
0.9
0.8
0.7
0.6
0.5
Common 1a variants
Common 1b variants
R155K
T54A
0.4
0.3
0.2
0.1
0.0
V36M
A156S/T
V36A
0
2
4
6
8
10
12
14
16
18
Time after treatment failure (months)
Median months
to loss (95% CI)
V36M
R155K
V36A
T54A
A156S/T
9 (8,11)
10 (9,11)
4 (3,4)
3 (2,4)
4 (3,6)
the time taken for resistant HCV variant populations to return to WT is longer for patients with genotype 1a versus genotype 1b.
Boceprevir long-term follow-up (2 years)*
174 patients who did not achieve SVR were followed for ≥2 years
Cumulative rate of
reversion to wild-type (%)
100
91%
80
71%
62%
59%
60
40
V36M
T54S
R155K
Any mutation
20
0
0
0.5
1.0
1.5
2.0
Years after end of therapy
Analysis used population-based sequencing
*Data from one Phase I study (N=22 previous non-responders), one Phase II
dose-ranging study (P03659; N=357 previous non-responders), and the
Phase II SPRINT-1 Study (P03523; N=520 treatment-naïve patients)
Vierling JM, et al. J Hepatol 2010;52(Suppl. 1):S470
HCV Resistance and Polymerase Inhibitors?
Could the patient be re-treated with the same
medication in the same regimen?
Amino acid positions within the NS3/4A protease associated
with resistance mutations to different NS3 protease inhibitors
V36A/M
Telaprevir
(linear)
Boceprevir
(linear)
SCH900518
(linear)
T54A
V55A
Q80R/K
R155K/T/Q
A156S
A156V/T
D168A/V/T/
H
V170A
*
*
*
BILN-2061
(macrocyclic)
ITMN191
(macrocyclic)
*
MK7009
(macrocyclic)
*
TMC435350
(macrocyclic)
*
*
*
BI-201335
(linear)
MK5172
(macrocyclic)
GS-9256
(macrocyclic)
ABT 450
(macrocyclic)
BMS-791325
(macrocyclic)
* Mutations associated with resistance in vitro only
Halfon et al J Hepatol 2011
Could the patient be re-treated with the same
medication in the same regimen?
Peg-Riba – DAA Dosing Period
Post-Dosing
RAVs : 3-20 months
DO NOT RE-TREATED
WITH THE SAME
MEDICATION IN THE
SAME REGIMEN
Resistance to IFN-Free Regimen
59
INFORM-1 :
Mediane log10 ARN VHC (log UI/ml)
Protease Inhibitor+Polymerase Inhibitor
7
Decrease median of Viral load
Virological response
at Day 14
6
RG7227 + PEG-IFN + RBV
RG7227/RG7128 (naïfs)
RG7227/RG7128 (NRC)
5
4
3
2
DIL
1
0 1
3
5
7
Days
9
11
13
RG7128 1000 mg x 2/j + RG7227 900 mg x 2/j
DIL < 15 UI/ml
Gane EJ.,Lancet 2011
for Hepatitis C Genotype 1
Lock A , NEJM N Engl J Med 2012;366:216-24.
When to test for resistance mutation?
• Before starting any Protease, NS5A and
NNPol inhibitors? at a level of 1-10%? SO FAR
UNKNOWN AND NEED TO BE EXPLORED
• At treatment failure? YES
• Before Re-starting any Protease , NS5A and
NNPol inhibitors : YES
Boceprevir in non responders
HCV RNA monitoring can predict HCV Protease resistance
ARN VHC log
6
Non responders
mutations = 49 %
4
Relapsers
Mutations = 58 %
Virological breaktrough
Mutations = 82 %
2
LID
SVR
0
Weeks of treatment
SVR
Partial virological responders
Folow up
Breaktrough
Relapsers
Non responders
Most frequent mutations : V36M, T54S, R155K, V36L, V170A, T54A.
EASL 2008 – Schiff –Abstract 104
Treatment failure and resistance may be detected by
frequent monitoring of HCV RNA levels
Baseline HCV RNA
Start treatment
HCV RNA
Viral breakthrough
Before treatment
Sensitive virus
Time on treatment
Resistant virus
Li F JAMA 2011
Lessons learned from HIV
• Genotypic Resistance testing in standard of care in
HIV Management
• HIV resistance testing recommended :
- At Baseline: a diagnosis or prior initiation of HAART
•To detect transmitted drug resistance
- When rebound occurs
*
Unknown
Not for Nuc*
Is resistance important? YES?
• SOC+DAA : Protease , NNI and NS5A inihbitors : YES
• IFN-Free Regimen : MAYBE
• DAA resistance is Partially abrogated by addition of
Peginterferon : in QUAD therapy ?
• Subtypes 1a and 1b are associated with different resistance
profiling : for RAV 1a >1b: YES
• Issues on HCV archived mutations are not solved
• Effect of ribavirin important seems limit the DAA resistance
Cross-resistance will probably occur for each target
Courtesy of Dr J Courcambeck