HIV viral load testing in the era of ART Christian Noah Labor - PowerPoint PPT Presentation

HIV viral load testing in the era of ART Christian Noah Labor Lademannbogen, Hamburg 1

Life expectancy of patients on ART Data from the UK Collaborative HIV Cohort (UK CHIC) Requirements: ■ Early diagnosis ■ Timely initiation of ART ■ Adherence ■ Periodic monitoring Successfully treated HIV patients have the chance of a normal life expectancy May et al. (2014), AIDS, 28, 1193-1202 2

HIV monitoring CD4 cell count Viral load Lymphocyte differentiation PCR ■ Marker of treatment success ■ Marker of overall immune function and adherence ■ Monitoring of the efficacy of ART ■ Predictor of disease progession ■ Urgency to initiate ART ■ Detection of virologic failure ■ Indication for prophylaxis ■ Selection of antivirals Substances/combinations not recommended against opportunistic infection >100000 copies/ml: ● Rilpivirin ● Abacavir/Lamivudine + Efavirenz or Atazanavir/r ● Darunavir/r+Raltegravir ■ Risk of transmission 3

Monitoring intervals Viral load CD4 cells ● pre ART: 2-3 months ● same as „viral load“ DAIG/DÖAG ● at ART initiation/switch: 2015 „more frequent“ ● if suppressed: 2-4 months ● 3-6 months ● 3-6 months EACS ● every 12 months ● at ART initiation/switch: 2015 if stable on ART „more frequent“ CD4 >350; VL <LOD ● at least every 3 months ● at least every 3 months IAS ● 4 weeks after ART initiation ● at least every 6 months 2014 if stable on ART CD4 >350; VL <LOD >1 year ● optional if stable on ART CD4 >500; VL <LOD >2 years ● every 3-4 months ● every 3-6 months DHHS first 2 years on ART, CD4 <300, ● 2-8 weeks after ART start/switch 2016 viremia ● every 6 months ● every 12 months (adherence, immunologically stable, after 2 years on ART, VL <LOD, <LOD >2 years) CD4 >300 ● optional CD4 >500 4

Monitoring intervals Viral load CD4 cells ● pre ART: 2-3 months ● same as „viral load“ DAIG/DÖAG ● at ART initiation/switch: 2015 „more frequent“ ● if suppressed: 2-4 months ● every 3 months ● 3-6 months ● 3-6 months EACS ● every 12 months ● at ART initiation/switch: ● baseline before ART 2015 if stable on ART „more frequent“ CD4 >350; VL <LOD ● every 1-2 months after ● at least every 3 months ● at least every 3 months IAS ART initiation until ● 4 weeks after ART initiation ● at least every 6 months 2014 suppression if stable on ART CD4 >350; VL <LOD >1 year ● optional ● consider lower frequency if stable on ART CD4 >500; VL <LOD >2 years (every 6 months) if <LOD >2 years ● every 3-4 months ● every 3-6 months DHHS >350 CD4 cells first 2 years on ART, CD4 <300, ● 2-8 weeks after ART start/switch 2016 viremia ● every 6 months adherence ● every 12 months (adherence, immunologically stable, after 2 years on ART, VL <LOD, <LOD >2 years) CD4 >300 ● optional CD4 >500 5

Future role of CD4 cell count in HIV monitoring ● Metaanalysis (13 studies) ● 20000 virologically suppressed patients ● Proportion of an unexplained, confirmed CD4 decline: 0,4 % (95 % CI 0,2-0,6) ● No adverse events among patients experiencing CD4 declines Ford et al. 2015; JIAS 18:20061 6

Definition of treatment response Viral load [copies/ml] ■ ■ ■ Limit of detection ■ (LOD) ■ ■ ■ 0 1 2 3 4 5 6 Months after ART initiation 7

Definition of treatment response Cobas Amplicor (Roche Diagnostics) defined by a technical cutoff: 50 copies/ml 8

Limits of detection: the Roche history Cobas Amplicor Cobas Ampliprep/Taqman Cobas 6800 „ultrasensitive“ 400 Version 1 50 Version 2 (1995) (1998) 40 20 (2005) copies/ml 20 (2009) (2015) 9

Platforms for viral load measurement Abbott m2000rt Roche COBAS Siemens VERSANT kPCR Real Time PCR System Ampliprep/Taqman Molecular System 20 Kopien/ml 37 Kopien/ml 40 Kopien/ml Qiagen QIAsymphony RGQ Roche Cobas 6800 20 Kopien/ml 34 Kopien/ml 10

Definition of optimal treatment response ● <50 DAIG/DÖAG Viral load ● after 3-4 months [copies/ml] 2015 ● after 6 months if viral load was high at baseline EACS ● <50 ■ ● after 6 months 2015 ■ ● <LOD (<20-75) IAS ■ ● after 6 months 2014 Limit of detection (LOD) ■ ■ ■ ■ ■ DHHS ● <LOD (<20-75) 0 1 2 3 4 5 6 ● after 6 months 2016 Months after ART initiation 11

Treatment failure? Viral load [copies/ml] ■ ■ ■ 99 ■ ■ ■ ■ ■ 0 1 2 3 4 5 6 Months after ART initiation 12

Treatment failure? No, just a blip... Viral load [copies/ml] ■ ■ Blip = transient viremia ■ ■ ■ ■ ■ ■ ■ 0 1 2 3 4 5 6 Months after ART initiation 13

Biological causes of blips Vaccination Infections ● Influenza: ● Syphilis: 20,6 % viremic 2-4 weeks after vaccination 27,6 % viremic during active infection Kolber MA (2002), AIDS 16(4), 537-542. Palacios R (2007), J Acquir Immune Defic Syndr 44(3), 356-359. ● Tetanus 100 % viremic after vaccination ● Tuberculosis: Stanley SK (1996) N Engl J Med 334(19), 1222-1230. 5-160 fold increase of viral load during active infection ● Pneumococi Vigano A (1998), AIDS Res Human Retroviruses 14(9), Goletti D (1996), J Immunol 157(3), 1271-1278 727-734. 14

Technical causes of blips 1. Pre-analytical errors proviral DNA avoid hemolysis Plasma should be separated from cells within 24 h after blood withdrawal 2. Assay variation 15

Definition of the limit of detection (LOD) Viral load detected with a probability of 95 % Example: COBAS AmpliPrep/COBAS Taqman HIV-1-Test, v. 2,0 LOD 20 copies/ml Concentration [copies/ml] Replicates Positive Detection (WHO standard) rate [%] 126 100 126 60 185 99 186 40 125 99 126 30 124 98 126 20 59 53 90 15 108 86 126 10 66 53 125 5 0 0 126 0 PROBIT 95 % analysis: 16,5 copies/ml 95 %.confidence interval: 14,3-19,8 16

Target not detected ≠ negative 130 patients 3TC/d4T + LPV/r orNFV mit After 2 years: 3TC und d4T als Backbone No significant drop ● <50 copies/ml within 24 weeks of the viral load ● <50 copies/ml after 60 weeks After 7 years: 77 % of the patients viremic Single Copy PCR Median 3,34 copies/ml LOD 1 copy/ml After treatment intensification (Raltegravir): No significant drop After 60 weeks: of the viral load 83 % of the patients viremic Median 3,1 copies/ml Maldarelli F et al. (2007), PLoS Pathogens, 3(4), 46 Palmer S et al. (2008) PNAS, 105 (10), 3879 Gandhi RT et al. (2010). PLoS Medicine 7(8), e1000321 17

Precision of viral load assays (Roche) 15 runs 3 lots 3 replicates Viral load Charge 1 Charge 2 Charge 3 Charge 1-3 Total VC der Log- log10/ml Total SD (log) Total SD (log) Total SD (log) Total -SD (log) Normalverteilung (%) 2 0,19 0,16 0,17 0,17 41 3 0,07 0,09 0,07 0,08 20 4 0,07 0,07 0,06 0,07 16 5 0,04 0,05 0,07 0,06 15 6 0,10 0,09 0,10 0,10 25 7 0,11 0,12 0,14 0,13 33 Example: Viral load 10 2 /ml = 100 copies/ml 10 2,17 /ml = 148 copies/ml 10 1,83 /ml = 68 copies/ml 18

Precision of viral load assays (Siemens) 19

Precision of viral load assays (Abbott) 20

Comparison of viral load assays Results from over 4000 paired plasma samples ● Roche Taqman Version 1+2 ● Roche Amplicor ● Abbott RealTime J Clin Microbiol (2014). 52(2), 517-523 ● Overall good correlation (0,90-0,97) ● Low level viremia <200: 0,45-0,85 21

Assay variation Ability of commercial Inaccurate Residual viremia assays to detect HIV quantification <LOD RNA <LOD at low levels Overquantification of residual viremia = Blip 22

Treatment failure? Viral load [copies/ml] ■ ■ ■ 99 ■ ■ ■ ■ ■ 0 1 2 3 4 5 6 Months after ART initiation 23

Treatment failure? Maybe yes, maybe no... Viral load [copies/ml] Resistance development ■ persistent viremia ● low-level ■ ● very-low-level ● high-level ■ ■ ■ ■ ■ ■ ■ 0 1 2 3 4 5 6 Months after ART initiation 24

Risk factors for persistent viremia Pharmaco- Interactions ADHERENCE genomics Very low level viremia Stage of infection ■ overall conflicting data ■ most cases multifactorial high baseline VL low CD4 cell count ■ no one factor is determinative CDC state Duration of suppression <50 Regimen PI>NNRTI Ryscavage R. et al. (2014), AAC, 58(7), 3585-3598 25

■ How to manage viremia? ■ Which viral load is predictive for treatment failure? ● Viral load level ● Persistence 26

Significance of persistent low-level viremia ■ Data from 18 cohorts including 17902 patients No LLV 93,8 % LLV 50-199 3,5 % LLV 200-499 2,7 % ■ Virologic failure (VL ≥ 500 copies/ml): 1903 patients (10.6 %) No LLV 1745 (10,4%) LLV 50-199 49 (7,9 %) LLV 200-499 109 (22,6 %) 91,7 % of patients with VF without any previous LLV ■ LLV 200-499 strongly associated with VF (adjusted HR 3,97) LLV 50-199 weakly associated with VF ■ No association with VF: type of regimen duration of LLV Vandenhende 2015, CROI, Poster 1014 27