Susane Crowe

Affordable Point-of-Care Diagnostic Test for Monitoring CD4 in resource limited settings

Transcript

1. Affordable Point-of-Care Diagnostic Test for Monitoring CD4 in Resource Limited Settings Professor Suzanne Crowe, AM Associate Director, Burnet Institute, Professor of Infectious Diseases Monash University Consultant Physician The Alfred Hospital Melbourne Director, St Vincent’s Health Australia Catholic AIDS Conference Melbourne, 2014
2. OUR MISSION AT BURNET is to achieve better health for poor and vulnerable communities in Australia and internationally through research, education and public health.
3. MATERNAL AND CHILD HEALTH Working with communities we are improving access to health care services such as family planning, post-natal and newborn care, vaccinations, management of childhood illnesses and nutrition.
4. SEXUAL AND REPRODUCTIVE HEALTH An important global issue, sexually transmitted infections (STIs), including HIV, impacts on the health of all communities and is often related to alcohol and drug misuse.
5. YOUNG PEOPLE’S HEALTH Our research focuses on the health issues arising from risky behaviours by young people such as alcohol and drug use, as well as STIs and mental disorders.
6. INFECTIOUS DISEASES We have expertise in specific infectious diseases of global health significance – HIV, hepatitis viruses, influenza, malaria and emerging infectious diseases.
7. ALCOHOL, OTHER DRUGS AND HARM REDUCTION The focus on risky behaviours associated with drug and alcohol misuse aims to develop community-level education and preventative public health programs.
8. IMMUNITY, VACCINES AND IMMUNISATION Developing vaccines for preventing major infectious diseases such as HIV, influenza and malaria requires an understanding of the way the immune system functions in health and disease.
9. UNAIDS challenges by 2015 • Reduce sexual transmission of HIV by 50% • Reduce transmission of HIV in IDUs by 50% • Eliminate HIV infections among children • Provide access to treatment to 15 million HIV+ • Reduce TB deaths in HIV+ by 50% • Eliminate gender inequalities, gender-based abuse • Eliminate HIV-related stigma, discrimination UNAIDS’ vision Zero new HIV infections. Zero discrimination. Zero AIDS-related deaths. UNAIDS 2013: Getting to Zero: 2011-2015 Strategy
10. UNAIDS challenges by 2015 • Reduce sexual transmission of HIV by 50% • Reduce transmission of HIV in IDUs by 50% • Eliminate HIV infections among children • Provide access to treatment to 15 million HIV+ • Reduce TB deaths in HIV+ by 50% • Eliminate gender inequalities, gender-based abuse • Eliminate HIV-related stigma, discrimination UNAIDS’ vision Zero new HIV infections. Zero discrimination. Zero AIDS-related deaths. UNAIDS 2013: Getting to Zero: 2011-2015 Strategy
11.  CD4 testing is a requirement to start ART in every country  In resource limited countries access to CD4 testing is a barrier to treatment • Financial barrier • Geographical barrier What is CD4 testing? CD4 testing is a major barrier to access treatment for HIV
12. T lymphocyte with CD4 on its surface This is a measure of immune damage caused by HIV CD4 test measure the number of these CD4 T cells in blood
13. Flow Cytometry – “standard of care” in developed countries to measure CD4 T cells Not widely available in resource limited countries Burnet CD4 test (Omega Visitect®) Point-of-care CD4 test with optional handheld instrument
14. Point-of-care CD4 testing improves access to ART HIV Dx (rapid test) at clinic POC CD4 test if HIV+ Start ART Point-of-care CD4 1 visit + results HIV Dx (rapid test) at clinic Blood drawn for CD4 test if HIV+ Blood sent to central lab for flow cytometry Wait for results Can take weeks Staging by CD4 count ? Needs ART Find patient & return them to clinic Can take weeks Loss to follow up Start ART Current Standard of Care Days or weeks to therapy
15. Clinical scenario #1  Flow cytometric CD4 in lab often not available  Machine broken  Test too expensive  Reagents not available  Electricity failure  Trained laboratory technician sick or gone Critical clinical need •To have an affordable test that does not require a laboratory or instrument or a trained scientist
16. Clinical scenario #2  Few large ART clinics in remote areas  HIV+ people live 25km+ away  Means travelling up to 3 days, often by foot  CD4 testing not available at the clinic  Blood sent to central laboratory  Patient must return for results  Loss to follow-up can exceed 50% Critical clinical need • Link clinic visit with same-day results to prevent loss to follow-up
17. Today’s presentation UNAIDS goal: • Provide access to treatment (cART) for 15 million – Reduce barrier to access – Decentralize CD4 testing to clinic level – Link clinic visit with same day results. – Provide “one stop” service of testing, counselling, – Patients can qualify for cART on 1st clinic visit – Prevent loss to follow up  via introduction of point-of-care (POC) tests to monitor the immune system and guide when to start treatment  via introduction of point-of-care (POC) tests to monitor the immune system and guide when to start treatment
18. Today’s presentation UNAIDS goal: • Provide access to treatment (cART) for 15 million – Reduce barrier to access – Decentralize CD4 testing to clinic level – Link clinic visit with same day results. – Provide “one stop” service of testing, counselling, initiation of therapy – Patients can qualify for cART on 1st clinic visit – Prevent loss to follow up  via introduction of point-of-care (POC) tests to monitor the immune system and guide when to start treatment via introduction of point-of-care CD4 tests to monitor the immune system & guide treatment
19. Four health clinics in Mozambique  Assessed impact of introducing POC CD4 testing  Loss to follow up decreased  57% to 21%  Proportion of patients initiating ART increased  12% to 22%  Median turnaround time from enrolment to ART decreased  48 to 20 days (p <0.0001)  Time for CD4 staging decreased  32 to 3 days (p< 0.0001) Jani IV et al Lancet 2011 378 902 Clear evidence that point-of-care CD4 testing improves patient care
20. Alere PIMA Daktari CD4 Counter Mbio CD4 Zyomyx MYT4 BD FACS Presto Visitect® POC CD4 2010 - 2011 2014 - 2015 Low Cost Point-of-care CD4 Technology Pipeline
21. Resource Limited? 21
22. Resource Limited? …..maybe But Resource-full (sic) 22
23.  Solves the geographic problem  Can be performed anywhere  Provides an answer in 40 minutes  no return visit needed  Solves the financial problem  No instrument  No highly trained personnel needed Visitect® CD4 test
24. for use in remote sites Uses finger prick blood Semi-quantitative: 350 cells/ul cut-0ff No laboratory or technical expertise No instrument needed No electricity or cold chain Visual answer within 40 mins Stable 12 months, 40C, high humidity Funded by Bill and Melinda Gates Foundation (The CD4 Initiative), Doris Duke Foundation , (Australian) Medical Research Commercializaton Fund Visitect CD4™ test
25. A bit about the science
26. Outside the cell Extracellular domain: • 4 immunoglobulin-like domains Transmembrane domain Cellular CD4 T-cell plasma membrane S-S S-S S-S S-S S-S S-S Soluble CD4 Discrimination between T-cell CD4 and soluble CD4 Inside the cell Cytoplasmic domain
27. Outside the cell Extracellular domain: • 4 immunoglobulin-like domains Transmembrane domain Cellular CD4 T-cell plasma membrane S-S S-S S-S S-S S-S S-S Soluble CD4 Target with PAIR of antibodies A bit more about the science: the way our test works Inside the cell Cytoplasmic domain
28. How we started to develop our CD4 test CD4 extracellular CD4 intracellular Anti-CD4cyto mAb Biotinylated Anti-CD4extracellular MAb ELISA detects cell-associated CD4, but not soluble CD4 Capture cell-associated CD4 with CD4 ab directed against cytoplasmic domain of CD4 *
29. Proof of concept: Cellular CD4 Capture ELISA CD4 extracellular CD4 intracellular Anti-CD4cyto mAb Biotinylated Anti-CD4extracellular MAb ELISA detects cell-associated CD4, but not soluble CD4 Capture cell-associated CD4 with CD4 ab directed against cytoplasmic domain of CD4 Then detect with CD4 ab directed against extracellular domain of CD4
30. Proof of concept: Cellular CD4 Capture ELISA CD4 extracellular CD4 intracellular Anti-CD4cyto mAb Biotinylated Anti-CD4extracellular MAb ELISA detects cell-associated CD4, but not soluble CD4 Flow CD4 vs Burnet ELISA CD4 n= 28 R 2 = 0.9248 0 200 400 600 800 1000 1200 1400 10 0 200 400 600 800 1000 1200 1400 1600 Estimated CD4 counts (ELISA) cells/ul CD4 counts (Flow) cells/ul Once we showed this worked we …….
32. 2000 1000 500 250 125 62.5 31.2 0 CD4 +ve T cells Test line . 500 cells/ µL 250 cells/µL Test line 2000 1000 500 250 125 62.5 31.2 CD4 +ve T cells Then the slow part started… thousands of these
33. Finally…..VISITECT® CD4 • 3 steps, minimal training • Need only 30uL whole blood • Disposable device • Instrument free • Visual result “<350” or “>350” CD4+ T cells/uL • Result in 40 mins
34. VISITECT® Result Interpretation 1 2 3 Invalid T same as 350 <350 cells/ul (treat) T stronger than 350 >350 cells/ul (no treat) Results are interpreted visually by comparing the colour intensity of the Test (T) line with the reference (350) line T line equal/weaker than 350 ref CD4 count is <350 cells/ul T line stronger than 350 reference CD4 count is >350 cells/ul C (control) line absent/irregular Test invalid Repeat test T weaker than 350 <350 cells/ul (treat)
35. 0 200 400 600 800 1000 1200 1400 1 4 7 10 13 16 19 22 25 28 31 34 37 40 CD4 T-cells (Flow cytometry) Sample, ranked by CD4 count 96% (24/25) correct for “treat” (<200)* 94% (16/17) correct for “don’t treat” (≥200) 6% (1/17) incorrect “treat” (≥200) 4% (1/25) incorrect “don’t treat” (<200) •95% CI 79-99% (81-99.99% pooled with Alfred data •Slide: courtesy D Anderson) Evaluation by PATH Seattle, original test (200 cut-off)
36. Where are we up to with the development of Visitect CD4?
37.  Removes subjective analysis of test line intensity  Runs on battery power  Provides print-out of results and down-loads results onto USB  Enhances training  Instruction program  Useful for manufacturing QC CD4 Test Instrument to complement stand-alone CD4 test
38. June 2012 Burnet Institute licenses CD4 point-of- care test to Omega Diagnostics, UK
39. June 2012 Burnet institute licenses CD4 point-of- care test to Omega Diagnostics, UK Technology transfer for large-scale manufacturing completed 2014
40. Results can be sent from the remote clinic to a central database
41. 41 Collaborating Partners Laboratory and Field Validation Studies of Visitect CD4 Funding Bodies Mombasa, Kenya Johannesburg South Africa Chennai, India Training for validation studies has commenced
42. Our training programs for validation are performed in the heart of Africa & other remote places • “Trucks line up looking for parking • Loud music pounds out of the bars • Alcohol flows freely • and half-dressed sex workers gather around seeking clients. • This is the common scene at the busy border town of Busia” “The Star” Wednesday, May 30, 2012 - 00:00 -- BY MONICAH MWANGI
43. Burnet Visitect CD4 training • Recent program, May 2014 • Busia, 450 km west of Nairobi • A border-town, (Uganda& Kenya) • HIV is rife – (7.4% prevalence)
44. Training programs are not glamorous Scientists and clinicians are grateful for the training & highly motivated
45. • Point of care CD4 testing is starting to increase in remote parts of resource limited countries • Burnet CD4 test initially validated in laboratories in Australia, USA and UK • Licenced to Omega Diagnostics as Visitect® CD4 POC test Current Visitect® CD4 has 350 cells/ul cut-off • In-country laboratory & field validation studies in 2014-15 • India (YRGCARE); South Africa; Myanmar; China; Kenya; PNG • Funded by UNITAID, NHMRC, Gates Foundation Conclusions
46. Point-of-care Visitect® CD4 monitoring Will result in better ART access
47. To acknowledge my colleagues •My colleagues at Burnet Inst •Assoc Prof David Anderson •Ms Mary Garcia •Ms Adele Lee Wriede •Ms Robyn Lloyd •Ms Eman Aleksic •Ms Serina Cucuzza •Dr Alison Greenway •Dr Stanley Luchters •Dr Imogen Elsum •Axxin, Melbourne •Mr Andrew Lysikatos •Mr Bill Hopper •Rush Univ, Chicago •Prof Alan Landay •Duke University, NC •Prof Tom Denny •YRG Care, Chennai •Ass Professor P Balakrishnan •Prof Suniti Soloman •University of Witwatersrand •Prof Wendy Stevens •Prof Leslie Scott •Kirby Institute, Sydney •David Wilson • Doris Duke Foundation , Bill & Melinda Gates Foundation ACH2, NHMRC, UNITAID Omega Diagnostics Group PLC Andrew Shepherd Mike Iddon