Transcript Slide 1

ARV Drug Resistance
Dr Pontiano Kaleebu
Pontiano Kaleebu MBchB PhD
MRC/UVRI Uganda Research
Unit on AIDS
Summary of presentation
•
•
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Mechanisms of ARV resistance
How do we look for resistance
Clinical implications
Some review of resistance in Uganda (Including
Dart)
• National HIVDR Drug Resistance Prevention,
Monitoring and Surveillance Plan
Mechanisms of Drug Resistance and
Diversity
• HIV-1 genetic variability is generated by the lack of
proof-reading ability of reverse transcription
• Rapid turnover of HIV in vivo
• Host selective immune pressures
• Recombination events during replication
• Of the 10 billion new viruses produced, 1/1000 (10
million) viruses per day will have one new "error"
(mutation) some of which make the virus resistant
to ART drugs
Selective Pressures of Therapy
Copies/mL
Treatment begins
900,000
(CD4 <200 cells/mm3)
Drug-susceptible quasispecies
Drug-resistant quasispecies
Selection of resistant
quasispecies
Viral load
100,000
Incomplete suppression
• Inadequate potency
• Inadequate drug levels
• Inadequate adherence
• Pre-existing resistance
< 400
Time
V. Failure
Other factors
• Genetic barrier:
– Some drugs like lamivudine and NNRTIs
have a low genetic barrier in that they only
require a single mutation to cause resistance.
– On the other hand drugs like abacavir and
indinavir require at least three mutations
before significant loss of activity
• Half life:
– Long half life e.g Tenofovir
Patterns of mutation
• Degree of resistance by a mutation differs
• E.g M184V mutation:
– <5 fold resistance to abacavir and didanosine
>1000 fold resistance to lamuvidine
– K103R leads to 20-30 fold resistance to
NNRTI
• Cross-resistance; 151M arises primarily
with DDI but leads to resistance to most
NRTIs
Patterns of mutation
• K65R causes tenofovir resistance but
increases sensitivity to AZT
• NVP Y181C can suppress effect of AZT
215 mutation
• Mutation patterns observed in combination
treatment have become complex and
interpretation needs experience
Measurement of HIV Drug
Resistance
• Genotypic assays: Commercial e.g ViroSeq Kit (Abbot
Diagonostics), TrueGene Kit; In house
• Phenotypic assays: Virco Laboratories (Belgium, USA)
• “Virtual” phenotype
– Use of genotype results to predict phenotypic
susceptibility based originally on database of paired
genotype and phenotype data or, more recently, through
scores derived from linear regression analysis
Genotyping assays
Acquire consensus sequences
And save them as text files
Cross-check for contamination from
older samples by phylogenetic analysis
Phenotypic assays
• “Culture and sensitivity”
• In vitro determination of drug susceptibility:
compare the concentration at which virus
replication is inhibited by 50% (IC50) compare
with a reference strain
• Cost: about US $300
ZDV/3TC/ABC: Example of Slow Stepwise Appearance of
Mutations in Subjects With Virologic Failure
WT
4
5000 c/mL
28 weeks of
M184V only
3.5
3
2.5
ABC=6.2,
ZDV=12.2 fold
400 c/mL
ABC=5.9, ZDV=4.1fold
2
1.5
50 c/mL
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
60
64
68
72
76
80
84
88
92
96
Plasma HIV-1 RNA Log
4.5
M184V
D67N/D, K70R/K, M184V
M184V, T215T/Y
M41L/M, M184V, T215Y
M41L, M184V, T215Y
M41L, M184V, L210L/W, T215Y
Study week
Should we worry about drug
resistance
• USA: 1999 an estimated 87% of patients with
detectable viremia receiving treatment with
ARVs had evidence of genotypic mutations
associated with HIV resistance to at least one
drug (70% for NRTI, 31% for NNRTI and 42%
for protease inhibitors)
• In recently infected individuals resistance
prevalence ranges between 10-25% in some
communities in Europe and USA
Review of drug resistance
in Uganda
Some information on resistance in
Uganda
• Drug naïve:
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Becker-Pergola et al. AIDS Res Hum Retro 2000
Weidle PJ et ak JAIDS 2001
Richard N et al. ARHR 2004
Gale C et al. ARHR 2006
NO resistant mutations but appreciable
polymorphisms-minor mutations that could have
relevance in resistance development
• Transmitted resistance:
– Ndembi N et al ARHR In press (No resistance
mutations)
POTENTIAL IMPLICATIONS OF ART WITHOUT VIROLOGICAL
MONITORING: FAILURE OF THERAPY
CD4 count
Viral load
VL 1000
YEARS
MONTHS
Treatment
onset
Virological
failure
(>1000 c/ml)
Clinical failure
(AIDS events)
INCREASING RESISTANCE
Dart virology studies
• 300 patients on Combivir + Tenofovir
– 100 in each of 3 clinical sites in Uganda (2)
and Zimbabwe (1)
– 50 with baseline CD4 <100 cells/mm3, 50
CD4 (100-199)
• Plasma HIV-1 RNA assayed on stored
specimens at 0, 4, 12, 24 and 48 weeks
after initiation of CBV+TDF
• Genotyping of those with VL >1000c/ml is
underway
Evolution of resistance 24-48 weeks (n=7)
AZT + 3TC + TDF
Patient
Mutations at week 24
Additional mutations by week 48
A
184V
67N,70R,215F
B
41L,67N,70R,184V,215Y
210W
C
184V
41L,67N,210W,215Y
D
67N,70R,184V
41L,215Y,219Q
E
67N,70R,215F
184V,219E
F
67N,70R,184V,215N
41L,215Y
G*
41L,67N,181I,184V,215Y
70R
Impact of viral subtype on resistance
mutations
Mutation
Subtype
A(A1) (n=33)
M184V/I
K65R
# TAMs
0
1-3
4-6
C (n=14)
P-value
D (n=12)
24(73%)
9 (64%)
9 (75%)
0.8
5 (15%)
3 (21%)
1 (8%)
0.7
0.9
10 (30%)
17 (52%)
6 (18%)
4 (29%)
6 (43%)
4 (29%)
5 (42%)
5 (42%)
2 (17%)
Differences in the dynamics of viral rebound
and evolution of resistance between
CBV/NVP and CBV/ABC (NORA sub study of
DART Trial) uncovered in the absence of
viral load monitoring in real-time.
Nicaise Ndembi1, Deenan Pillay2, Ruth Goodall3, Adele McCormick4,
Andy Burke3, Fred Lyagoba1, Paula Munderi1, Pauline Katundu5,
Stefano Tugume5, Pontiano Kaleebu1 on behalf of the DART Virology
and Trial Teams
1
Med Res Council/Uganda Virus Res Inst Prgm on AIDS, Entebbe, Uganda; 2 UCL/Health Protection
Agency, London, UK; 3 Med Res Council Clin Trials Unit, London, UK; 4 UCL, London, UK; and 5 Joint
Clin Res Ctr, Kampala, Uganda;
Table 1: Prevalence of individual and class specific mutations
Individual Mutations*
M41L
D67NG
K70R
K103N
Y181CI
M184V
G190AS
T215FY
K219QEN
Class mutations
TAMs
none
1-2
3+
NNRTI
none
1+
Permutations of mutations
None
TAMs only
M184V only
NNRTI only
TAMs & M184V
TAMs & NNRTI
M184V & NNRTI
TAMs & M184V & NNRTI
* occurring with >5% prevalence
ABC
(n=56)
NVP
(n=31)
3 (5%)
21 (38%)
24 (43%)
3 (5%)
0
49 (88%)
1 (2%)
11 (20%)
8 (14%)
2 (6%)
6 (19%)
3 (10%)
7 (23%)
6 (19%)
23 (74%)
9 (29%)
4 (13%)
1 (3%)
25 (45%)
23 (41%)
8 (14%)
52 (93%)
4 (7%)
22 (71%)
7 (23%)
2 (6%)
9 (29%)
22 (71%)
6 (11%)
1 (2%)
18 (32%)
0
27 (48%)
0
1 (2%)
3 (5%)
5 (16%)
0
2 (6%)
3 (10%)
2 (6%)
0
12 (39%)
7 (23%)
On treatment in clinics (JCRC and
UNAIDS HIV drug access initiative
clinics)
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Weidle PJ et al. JAIDS 2001
Weidle PJ et al. Lancet 2002
Weidle P.J et al. AIDS 2003
Richard N et al. ARHRetro 2004
Oyugi JH et al. AIDS 2007
Note late 1990s some were on dual NRTI therapy, most paying and price high
Summary findings: Resistance detected in those with
virological failure, mutations were similar to subtype B;
phenotypic resistance corresponded to genotypic
resistance; treatment interruptions lead to resistance
Resistance under PMTCT
(HIVNET 006 & 012)
• Jackson JB et al. AIDS 2000; Eshleman SH et al. AIDS
2001; Eshleman SH et al. JAIDS 2004; Eshleman SH et
al. ARHR 2004; Eshleman SH et al. JID 2005
• Summary: In women K103N NVP mutation 6-8 weeks
after delivery and fades by 12-24 months!! Minor
population missed
• In infants: Y181C
• What will happen when these women and infants start
HAART will NVP containing regimens be effective
Is it possible to prevent HIV Drug Resistance?
No, NOT ENTIRELY
Some degree of HIV drug resistance
(HIVDR) is inevitable
high rate of mutation
treatment is life long
The Country HIVDR Package
National HIVDR strategy elements for
countries scaling up ART
A.
B.
C.
D.
E.
F.
G.
H.
Development of a national HIVDR
strategy working group, plan and budget
HIVDR prevention activities
Regular evaluation of HIVDR "early
warning" indicators from all ART
treatment sites
HIVDR transmission threshold surveys:
geographic areas, populations, timing
Sentinel monitoring of HIVDR emerging
in treated populations and related ART
programme factors
HIVDR database development
A designated HIVDR genotyping
laboratory
Preparation of national annual HIVDR
report and recommendations
23rd -24th January 2007, Kampala, Uganda
Goal of Plan
• To support ART program practices and country
planning in order to minimize the unnecessary
emergence of HIV drug resistance, and to
restrict the extent to which emerging resistance
jeopardizes the effectiveness of the limited ART
regimens available, within the context of the
national HIV prevention and treatment plan.
Specific Objectives and key
activities
• Develop an support capacity for HIVDR
prevention, monitoring and surveillance
• Develop a list of EWI that will be regularly
evaluated
• Support and coordinate surveillance of HIVDR
transmission in different geographical regions
• Support and coordinate the monitoring of HIVDR
arising in paediatric and adult populations
starting and continuing treatment
Objectives continue
• Accredit and support local laboratories to
support HIVDR activities
• Develop and maintain a data management
system
• ***Develop and maintain a system to
disseminate program findings and results for
evidence based HIV drug resistance
containment strategies ( translate into policy
Some achievements so far
• Consensus workshop Jan 2007
• HIVDR working group created
• HIVDR transmitted Threshold survey (In press
ARHR)
• Early Warning Indicators (Pilot completed)
• UVRI National reference laboratory final stages of
WHO Accreditation
• Some equipments and reagents obtained from The
Global Fund
QCMD 2007 ENVA7 HIV Drug Resistance Typing
Proficiency Programme
Next activities
• Sentinel HIVDR monitoring at selected treatment
sites
• Repeat Threshold transmitted resistance in
Kampala and later Mbarara
• Collaborate with other partners such as
PharmAccess
Data on Early Warning Indicators for
HIV Drug Resistance In Uganda
December 2007
Dr Wilford Kirungi, Dr Elizabeth Madraa, Dr
Norah Namuwenge, Dr Frank Lule, Dr
Beatrice Crahay, Miss Marion Acieng, Dr
Pontiano Kaleebu
and
The National HIVDR Technical Working
group
WHO Recommended HIVDR EWI
• The HIVDR TWG prioritised 6 HIVDR EWI and set
thresholds for each
– Indicator 1: Prescribing practices
– Indicator 2: Defaulter rates during the first 12 months
of ART
– Indicator 3: Retention on first-line during the first 12
months of ART
– Indicator 4: Appointment keeping over a 12 months
period
– Indicator 5: Pill count adherence
– Indicator 6: Continuity of ARV drug supply in facilities
Methods
• Sample of 41 ART sites during Nov – Dec 2007
• Sampled from all regions, various partners,
different levels and modes of ART service delivery
that had had ART established for at least 1 year
• Trained field workers and constituted 6 teams of 2
• 5 teams comprised of persons with medical
training and clinical experience of ART – 28 sites
• One team of 2 data managers with IT background
and experience in EMRS - 13 sites
Composite Scores
Site
%
Firstline
T=100
%
% Lost % Retained
FU Yr 1 First-line,
T < 20% Yr 1
T > 70%
% Kept
Appointmen
t
T > 80%
Quarters
with
continuous
ARV supply
NI Hosp
100
0
65
71
1
N2 Hosp
100
2
81
100
3
N3 RRH
99.4
0
83
ND
2
N4 Hosp
100
0
73
97
4
N5 Hosp
94
2
79
ND
0
N6 RRH
100
79
18
ND
1
N7 Hosp
100
0
52
97
0
N8 RRH
97.0
0
69
63
0
N9 Hosp
100
52.9
24
85
4
C1 HC
100
0
94
ND
1
C2 HC
100
0
85
22
0
C3 Hosp
100
2
93
77
3
C4 Hosp
100
ND
ND
ND
0
Composite Scores (ctd)
Site
% Firstline
T=100%
% Lost
FU Yr 1
T < 20%
% Retained
First-line, Yr
1
T > 70%
% Kept
Appointme
nt
T > 80%
Quarters with no
continuous ARV
supply
C5 CCE
100
0
87
ND
ND
C6 Comm
78
2
63
ND
3
C7 HC
100
5
36
36
4
C8 RRH
99
0
83
54
4
C9 Hosp
98
1.6
81
ND
0
C10 Hosp
97
0
55
43
0
C11 HC
100
0
80
61
3
C12 Hosp
98
0
80
ND
0
E1 Hosp
78
0
50
55
2
E2 RRH
100
8.5
74
40
0
E3 HC
100
0
96
64
1
E4 Hosp
100
0
79
66
1
E5 NGO
100
0
91
ND
0
Composite Scores (ctd)
Site
% Firstline
T=100%
% Lost % Retained
FU Yr 1 First-line,
T < 20% Yr 1
T > 70%
% Kept
Appointmen
t
T > 80%
Quarters
with no
continuous
ARV supply
E7 CE
99
ND
ND
ND
0
E8 CE
100
0
81
ND
4
W1 RRH
100
4
95
74
0
W2 Hosp
100
0
76
31
3
W3 NGO OR
100
24
76
38
4
W4 Hosp
100
5
76
29
0
W5 Hosp
100
24
62
74
0
W6 Hosp
100
10
83
59
3
W7 HC
100
0
97
53
2
W8 RRH
100
2.0
78
61
0
W9 Hosp
97
5
90
44
0
W10 H
100
0
72
66
0
W11 Hosp
100
0
90
ND
0
W12 HC
100
7.7
73
47
1
Conclusions
• Resistance develops in those who do not suppress virus
• We need to study more how resistance develops in absence of
virological monitoring
• A national ART prevention and monitoring plan is operational
• A small study has not demonstrated transmitted resistant
viruses
• A significant proportion of patients in ART treatment centers
start on appropriate ART regimens
• Drug stock-out afflict many centers and poses a danger for poor
adherence and resistance development
Acknowledgements
Dart team: MRV-UVRI; JCRC; IDI; University
of Zimbabwe, MRC-CTU; UCL, Imperial
College
National HIVDR working group
WHO
MRC
Dart virology supported by Roche,
GSK, Abbot, Gilead, Boehringer
Ingelheim