1. John Frater University of Oxford
The UNICORN study - Whole blood finger-prick sampling for rapid and convenient PoC HIV viral load measurement
Poster MOPEB0264
 Monday, 24 July 2017, 12:30 – 14:30
John Frater
University of Oxford

2. Background PoC HIV diagnostics is widely available
PoC HIV plasma viral load (pVL) is not
PoC pVL testing would revolutionise the way we manage HIV:
In high burden settings
In low resource, low infrastructure settings
For clinical trials requiring rapid and regular monitoring
Eg Treatment Interruption studies for cure interventions

3. Rationale: the PITCH study
Prospective Interruption of Therapy Towards a Cure for HIV (PITCH)
Aim:
To prospectively study mechanisms of post-treatment control after ART in Primary HIV Infection
N=20; Pilot study
Intensively Monitored Treatment Interruption (IMTI)
IMTI Protocol involves pVL testing up to 3 times per week
HOW BEST TO DO THIS?

4. Protocol dilemma: Quantitative or Qualitative monitoring??
More data
?too much data
Only available from plasma
Needs central lab
1ml plasma
Qualitative
Simple read-out
Detectable:Yes/No
Need to define cut-off
Might be able to run from whole blood
? Could be done from a fingerprick

5. UNICORN
‘Use of Needleprick Investigation to Collate Objective Rebound Notifications’
Can we adapt Xpert HIV VL and HIV Qual cartridges for PoC needlestick pVL measurement?
Recruited participants at St Mary’s Hospital, London
N=40
20 WITH UNDETECTABLE pVL – all <20 copies/ml
20 WITH DETECTABLE pVL – wide range of values

6. Study Protocol: Each Participantx1 x4
4 CARTRIDGES: 100ul WB Finger-prick sample
SPIN
PVL assay
Roche Taqman
Certified clinical lab
HIV-1 Qual x2
HIV-1 Viral Load x2

7. The ‘SPIN’ step
Microcentrifuge
Portable
Cheap
3 minute spin

8. Finger-Prick Sample Prep
HIV-1 Qual Cartridge
HIV-1 Viral Load Cartridge
100µl blood
ADD TO
1000µl buffer
ADD TO CARTRIDGE
100µl blood
ADD TO
100µl PBS
SPIN for 3 mins
REMOVE 100µl
1000µl buffer
ADD TO CARTRIDGE
100µl blood
ADD TO
900 µl PBS
ADD TO CARTRIDGE
100µl blood
ADD TO
1000 µl PBS in EPPENDORF
SPIN for 3 mins
REMOVE 1000µl
ADD TO CARTRIDGE

9. WHAT ABOUT FOR DETECTABLE VIRAEMIA?

10. Range of Detectable Viraemia (n=20)
Mean 95,219 copies/ml
Range 33-1,514,378 copies/ml

12. What does this tell us? (Part 1)
Can’t do pVL from WB using standard protocols
Introducing spin allows accurate indentification of undetectable viraemia
Introducing spin impacts sensitivity for quantification of detectable viraemia
With HIV Viral load assay a finger-prick PoC approach Can we still use this protocol, accepting a higher LLD?

13. Analysis according to Roche pVL

14. Analysis according to Roche pVL
SPIN STEP PRESERVES CONCORDANCE WITH ROCHE AT PVL > 1000 COPIES/ML

15. Excellent concordance for all pVL >1000 copies/ml

16. What does this tell us? (Part 2)
Can’t do pVL from WB using standard protocols
Introducing spin allows accurate identification of undetectable viraemia
Introducing spin impacts sensitivity for quantification of detectable viraemia
For UNDETECTABLE viraemia: PoC approach gives 100% agreement with Roche
For DETECTABLE viraemia: PoC approach is accurate for pVL >1000 copies/ml

17. Acknowledgements Participants of UNICORN
Peter Medawar Building, Oxford
Jodi Meyerowitz
Imperial College, London
Heather Lewis
Kristen Kuldanek
John Thornhill
Panagiotis Pantelidis
David Muir
Sarah Fidler
Cepheid
Georgina Timson
Alice Bonnissent
Poster MOPEB0264
 Monday, 24 July 2017, 12:30 – 14:30