Novel HIV Suppressive
Approaches with Integrase
Inhibitors
Mark A Wainberg
McGill University AIDS Centre
Montreal, Canada
1
Global distribution of HIV-1 subtypes
1.3 million
2 million
4.8 million
URF 4.2%
AE 3.1%
G 5%
D 3.6%
Rapid Selection of K65R Resistance
in Subtype C Isolates
6
Previous work in our lab
showed that MK-2048, a
Merck INSTI, selected G118R
followed by E138K. The latter
augmented levels of
resistance against MK-2048
and also restored replicative
fitness.
7
Major resistance pathways against INSTIs
(clinical and tissue culture data)
Resistance pathways
Y143 pathway
Y143C
Y143R
T97A/Y143C
T97A/Y143R
L74M/T97A/Y143G
L74M/T97A/E138A/Y143C
N155 pathway
N155H
E92Q/N155H
L74M/N155H
Q148 pathway
Q148H
Q148K
Q148R
E138K/Q148H
E138K/Q148K
E138K/Q148R
G140S/Q148H
G140S/Q148K
G140S/Q148R
E138A/G140S/Y143H/Q148H
RAL
Fold resistance
EVG
DTG
<10
<50
>100
>100
<50
<20
<2
<2
<2
<2
ND
ND
<2
<2
<2
<2
<2
<2
<50
<100
<50
<50
>100
<50
<2
<10
<2
<20
<100
<50
<10
>100
>100
>100
<10
>100
>100
<10
<100
<100
<20
>100
>100
>100
<100
>100
ND
<2
<2
<2
<2
<20
<10
<20
<2
<10
<50
Quashie et al., Curr. Opin. Infect. Diseases, in press
Secondary INSTI-resistance mutations often
restore HIV replication capacity
Effect on viral fitness
Secondary Mutations in the presence of
(pathway)
primary resistance
mutations
Y143 pathway
- (often)
L74M, T97A
+
N155H pathway
-
Q95K, T97Q, G163R/K
+
Q148 pathway
-
G140A/S/C, E138K/A
+
Mbisa et al., Infect. and drug resistance, 2011--Canducci et al., JAC, 2010--Reigadas et al., Plos One, 2010--Delelis et al., AAC, 2009
Dolutegravir activity on RALresistant clinical isolates (n=39)
(median IC50 for wild-type=1.07 nM)
Genotype
Median fold change
N155H
1.37
Y143R/T97A
1.05
Q148H/G140S
3.75
Q148R/G140S
13.3
Underwood et al., JAIDS, 2012
Resistance to INSTIs in clinical
trials
in treatment-naïve patients
Treatment
Major resistance mutations
detected by genotyping in
treatment-naïve patients failing
therapy
Minor
resistance
mutations
Raltegravir
Y143
N155H
Q148
Multiple
Elvitegravir
T66I
E92Q
N155H
Q148
Multiple
Dolutegravir
NONE
NONE
RALTEGRAVIR
Cooper et al., NEJM, 2008
Sichtig et al, JAC, 2009
Canducci et al, AIDS, 2009
Hatano et al, JAIDS, 2010
ELVITEGRAVIR
Sax et al, Lancet, 2012
DeJesus et al, Lancet, 2012
DOLUTEGRAVIR
vanLunzen et al., Lancet Infect. Dis., 2012
Selection results with DTG
Quashie, et al, Journal of Virology 2012
Selection results with DTG
Quashie, et al, Journal of Virology 2012
Selection results with DTG
Quashie, et al, Journal of Virology 2012
Subtype-specific mutations
selected in vitro with dolutegravir
HIV-1 subtype
Most common mutations
selected with dolutegravir
B
R263K, H51Y
C
G118R, H51Y
Quashie, Mesplède et al., Journal of Virology, 2012
The R263K mutation
confers low-level resistance to dolutegravir
in cell culture
Genotype
R263K
*Methodological differences
(EC50 for wild-type ≈1-6nM)
IC50 fold change*
2.5 to 6
Quashie, Mesplède et al., Journal of Virology, 2012
The R263K mutation decreases
integrase activity in cell-free assays
Quashie, Mesplède et al., Journal of Virology, 2012
The R263K mutation decreases
dolutegravir residency time
in an integrase-vDNA complex
The addition of H51Y to R263K
further decreases IN strand
transfer activity
A
B
The combination of H51Y and
R263K negatively impacts viral
fitness
Effects of G118R and H51Y on
in vitro strand transfer activity
IN protein
WT
H51Y
G118R
H51Y/G118R
Relative strand transfer
activity (RFU/hr)
Vmax
± SEM
7,751.2
480.7
7,590.0
265.3
6,138.5
621.5
3,223.0
130.2
Effects of H51Y, G118R and R263K
mutations
on susceptibility to dolutegravir in cell
culture
Genotype
IC50 fold change*
R263K
2.5 to 6
H51Y
1 (no change)
H51Y/R263K
6 to 12
G118R
3 to 7
H51Y/G118R
6 to 10
*Methodological differences
(EC50 for wild-type ≈1-6nM)
Dolutegravir resistance
associates with
a decrease in viral replication capacity
Genotype
Resistance
Effect on viral
fitness
R263K
+
-
H51Y
None
None
H51Y/R263K
++
--
G118R
+
-
H51Y/G118R
++
--
Conclusions
• Resistance mutations selected in vitro with
dolutegravir are: R263K or G118R plus H51Y
• R263K and G118R confer low-level resistance
against dolutegravir, e.g. 2.5-6 fold
• The addition of H51Y to either R263K or G118R
increases resistance against DTG but also further
decreases viral fitness
• These findings help to explain why resistance against
dolutegravir in INSTI-naïve patients has not been
observed
No compensatory mutations
in regard to DTG resistance
and viral fitness have
developed over more than
one year in culture. Might
there be other implications
for a drug that selects for an
unfit virus and can animal
Acknowledgements
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Bluma Brenner
Hongtao Xu
Dimitri Coutsinos
Jerry Zaharatos
Maureen Oliveira
Thibault Mesplède
Peter Quashie
MERCI