Roche TaqMan v2 viral load (cp/mL)

Report
Simplification, cost-reduction
strategies and examples from the
field
Teri Roberts
Diagnostics Advisor
MSF Access Campaign
Virological Monitoring Detects Treatment Failure Early On
Adapted from Bartlett et al. Lancet Infect Dis 2009
Across programmes: 2% of treated patients are on 2nd-line ART
In South Africa (Khayelitsha), where routine virological monitoring is available: 12% on 2nd-line after 5 years
HIV Policy and Progress Indicators Across 16 Countries
Cameroon
CAR
DRC
Ethiopia
Guinea
India
VL for Tx
failure
OPT
OPT
OPT
NO
OPT
REQ
Routine VL
OPT
NO
NO
NO
NO
NO
Available
LTD
LTD
LTD
LTD
LTD
LTD
Kenya
Lesotho
Malawi Mozambique Myanmar
VL for Tx
failure
OPT
OPT
REQ
OPT
OPT
Routine VL
NO
NO
NO
REQ
NO
Available
YES
LTD
LTD
NO
LTD
South Africa Swaziland Uganda Zambia
Zimbabwe
VL for Tx
failure
REQ
OPT
OPT
OPT
OPT
Routine VL
REQ
NO
OPT
OPT
NO
LTD
LTD
OPT:Available
optional; REQ: required;
LTD: limited
YES
LTD
Lynch
LTDet al. Science 2012
How to increase access to virological monitoring?
• Reduce complexity
• Reduce price
– Market entry
– Volume
– Competition
– Open and polyvalent platforms
– Price transparency
• Field validate new and current tests (point of care and lab-based)
• Perform operational research to define best adapted and most feasible
tests for different settings
• Introduce viral load testing in a phased in approach
– Define testing frequency
– Replace CD4 monitoring with viral load monitoring
– Implement evidence-based algorithms to prioritise patients
Laboratory-based test
Point-of-care test
Sample
Plasma, DBS
Fingerstick, heelstick
Sample
volume
200 – 1000μl
≤100μl
Sample prep
Simple, no
contamination
Simple, part of POC test
Consumables
Minimal, open access
Minimal (1 lancet, 1 collection tube, 1
cartridge)
Reagents
No cold storage, stable
≥40°C for ≥18 months
Part of cartridge, no cold storage, stable ≥40°C
for ≥18 months
Power
AC and battery
AC, battery (≥8 hours), solar
Instrument
Open access and
polyvalent, 1 room, no
contamination
Closed system, automated, small and
lightweight, environmentally robust (heat,
humidity, rigorous movement)
Hands-on time
≤1 hour
≤10 minutes
Time to result
≤1 day
≤30 minutes
Range
Quantitative, all
subtypes, ≥50 copies/ml
Quantitative / semi-quantitative, all subtypes,
≥1000 copies/ml
Training / skill
Medium
Minimal, basic (≤2 days), no precision pipetting
Regulation
WHO PQ (opt CE, FDA)
WHO PQ (opt CE, FDA)
Simplifying sample transport by using DBS
•
•
•
•
•
•
•
•
•
Quick processing of whole blood
Inefficient sample networks
Alternative: dried blood spots
Long distances, ambient
temperature
Time to result: e-health, m-health
Fingerprick DBS
NucliSENS EasyQ® HIV-1 v2.0 viral
load test (bioMerieux) for DBS
MSF validation of fingerprick DBS
in Malawi
Other tests for use with DBS?
NucliSENS EasyQ® HIV-1 v2.0 (bioMérieux)
• Thyolo district hospital, Malawi
• DBS validated
• Real time NASBA (isothermal signal
amplification), RNA specific
• Logistical challenges:
–
–
–
–
–
–
laboratory infrastructure
unreliable power supply
unreliable water supply
provision of RNAse-free water
unreliable air-conditioning
non-adherence to cold chain
transportation, especially at customs
– inability to find local laboratory technicians
with molecular biology expertise
– lack of in-country trouble-shooting and
maintenance services
1. Extraction room
2. Amplification room
Generic HIV viral load assay (Biocentric)
• Nhlangano health center,
Swaziland
• Open system, low cost
• Real time RT-PCR (DNA and
RNA)
• Logistical challenges
• Use of plasma as a
sample type (use of DBS
is research use only)
• Most of the other
challenges as for the
NucliSENS test
ExaVirTM Load Version 3 (Cavidi)
• Yangon, Myanmar (field site is in Shan state)
• Subtype independent, relatively low cost, minimal lab
requirements, not as prone to contamination and not
as dependent on precision pipetting as molecular lab
tests
• ELISA of HIV reverse transcriptase activity
Challenges include:
•Must be performed on plasma
•Plasma must be frozen at -20°C
•Need for back-up vacuum pump
•Relatively low through-put for lab test
•Good water quality is essential
•Positive and negative controls must be
supplied in-house
•Sample preparation to isolate the reverse
transcriptase enzyme is labourintensive
For
more information,
please grab a copy of
our viral load report
(also available on our
website:
www.msfaccess.org)
Performance evaluation of
SAMBA semi-quantitative HIV viral load test
for therapy monitoring in resource-poor settings
Dr. Suna Balkan
MSF Aids Working Group
Scaling-up in the MSF project
Chiradzulu district, Malawi
7000
Task shifting
Need for a POC VL
6000
5000
4000
Decentralisation
3000
2000
1000
0
2001
2002
2003
Inclusions/month
2004
2005
Cumulated patients under ART
SAMBA system characteristics
MSF requirements
SAMBA
• All HIV1 subtypes & recombinants •
• Threshold 1,000 copies/ml
•
• Heat stability at 50°C
•
• Robust & simple instrument
•
•
•
•
•
No or minimum electricity
•
Minimum handling
•
No risk of contamination
Turn around time allowing same •
day result
• Affordable cost
Can detect Groups M, N, O &
recombinants
Cut-off at 1,000 copies/ml
Heat stable reagents; no cold
chain transport or storage
Isothermal amplification with
simple visual detection
Low power requirement 350W
Preloaded reagents in a closed
cartridge
Test time = 90 minutes with
throughput of 24/day at 6.5 hr
working day
Visual readout of SAMBA semi-quant VL test
<1,000 cp/ml
≥1,000 cp/ml
SAMBA system
SAMBA-prep
(sample extraction)
1 to 4 samples per run
SAMBA-amp
(amplification)
Evaluation of SAMBA London St Thomas & Royal
London Hospitals in 134 clinical samples
Roche Taqman v2 (copies/ml)
< 500
(<2.7 log)
500 – 2000
(2.7- 3.3 log)*
>2,000
(>3.3 log)
Total
SAMBA >1,000
2
2
34
38
SAMBA < 1,000
93
2
1
96
Total (%)
95 (71%)
4 (3%)
35 (26%)
134
* Roche TaqMan accuracy: +/- 0.3 Log per package insert
Concordance between SAMBA & Roche = 97.8 % (131/134)
MSF Chiradzulu project
background
• Malawi
– 13.2 million population mainly rural
– 1 million HIV-infected
• MSF project based in a rural district
– 1 hospital (laboratory),10 health centres
– HIV care in 2000,decentralisation in 2003
– 25 000 patients followed under ART
– 80% followed in the 10 decentralised health centres
– Integrated project with MOH
MSF Arua project background
• Northwestern Uganda
• Arua + catchment population :
1,5 M
• HIV prevalence 3%
• ART project since 2002
• Arua District Hospital
• 7000 patients followed under ART
• Integrated project with the MOH
SAMBA field trials in Malawi and Uganda
200 HIV+ patients in Malawi
154 HIV+ patients in Uganda recruited
from HIV clinic during routine visit
200 µl fresh plasma
SAMBA tested on-site
by MSF technician
Frozen plasma
shipped
directly
Roche TaqMan v2
at Royal London
Hospital
Results to MSF
All testing blinded to each other
Discordant
SAMBA/Roche
Abbott RealTime PCR
at Addenbrooke
Malawi results – SAMBA vs Roche TaqMan v2
Roche TaqMan version 2
Viral Load (cp/ml)
< 500
(<2.7 log)
500 – 2,000
(2.7- 3.3 log)*
>2,000
(>3.3 log)
Total
SAMBA >1,000
4
4
46
54
SAMBA < 1,000
142
4
0
146
Total (%)
146 (73%)
8 (4%)
46 (23%)
200
* Roche TaqMan accuracy is +/- 0.3 Log per package insert
Overall concordance with Roche v2 = 98% (196/200)
Uganda results – SAMBA vs Roche TaqMan v2
Roche TaqMan v2
Viral Load (cp/ml)
< 500
(<1.7 Log)
500 – 2,000*
(2.7-3.3 Log)
>2,000
>(3.3 Log)
Total
SAMBA >1,000
2
0*
56
58
SAMBA < 1,000
90
2*
4
96
Total (%)
92 (60%)
2 (1%)
60 (39%)
154
* Roche
TaqMan is 0.3 Log accuracy (package insert)
Overall concordance with Roche v2 = 96.1% (148/154)
Conclusion
•
SAMBA platform is much simpler than currently available molecular technologies
which require highly-trained personnel and sophisticated infrastructure only available
in centralised laboratories
•
SAMBA device is much easier to handle and being a closed system, prevents
contamination by amplicons
•
Staff training requirement for SAMBA is minimal
•
SAMBA can be implemented in lower healthcare levels such as district hospitals or
health centres with a basic laboratory but supplied with electricity
•
Routine use of Samba will be now implemented in Arua and Chiradzulu with on going
evaluation
•
Will improve HIV care in a decentralization & task shifting strategy
Virological efficacy of ART over time
at MSF sites in Arua and Chiradzulu
100%
% of patients
80%
<40
60%
<1000
40%
n = 284
20%
0%
<0.5
0.5-1
1-2
2-3
3-4
4-5
5-6
>6
Years on ART
> 65 % of patients on ART have VL < 40 cp/ml after 6 months
> 80 % of patients on ART have VL < 1,000 cp/ml after 6 months
Distribution of viral loads in treated and untreated
individuals in Malawi & Uganda
50%
1,000 cp/ml
% of patients
40%
30%
20%
10%
0%
> 1x106 1x105
1x104
1x103 1x102
<100
Roche TaqMan v2 viral load (cp/mL)
<40

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