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

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HIV viral load testing in the era of ART

Christian Noah Labor Lademannbogen, Hamburg

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Life expectancy of patients on ART

May et al. (2014), AIDS, 28, 1193-1202

Successfully treated HIV patients have the chance of a normal life expectancy

Data from the UK Collaborative HIV Cohort (UK CHIC)

Requirements: ■ Early diagnosis ■ Timely initiation of ART ■ Adherence ■ Periodic monitoring

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HIV monitoring

CD4 cell count

Lymphocyte differentiation

Viral load

PCR ■ Marker of overall immune function ■ Predictor of disease progession ■ Urgency to initiate ART ■ Indication for prophylaxis against opportunistic infection ■ Marker of treatment success and adherence ■ Monitoring of the efficacy of ART ■ Detection of virologic failure ■ Selection of antivirals

Substances/combinations not recommended >100000 copies/ml:

Rilpivirin
Abacavir/Lamivudine +

Efavirenz or Atazanavir/r

Darunavir/r+Raltegravir

■ Risk of transmission

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Monitoring intervals

DAIG/DÖAG

2015

EACS

2015

IAS

2014

DHHS

2016

Viral load CD4 cells

pre ART: 2-3 months
at ART initiation/switch:

„more frequent“

if suppressed: 2-4 months
same as „viral load“
3-6 months
at ART initiation/switch:

„more frequent“

3-6 months
every 12 months

if stable on ART CD4 >350; VL <LOD

at least every 3 months
4 weeks after ART initiation
at least every 3 months
at least every 6 months

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
2-8 weeks after ART start/switch
every 6 months

(adherence, immunologically stable, <LOD >2 years)

every 3-6 months

first 2 years on ART, CD4 <300, viremia

every 12 months

after 2 years on ART, VL <LOD, CD4 >300

optional

CD4 >500

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Monitoring intervals

DAIG/DÖAG

2015

EACS

2015

IAS

2014

DHHS

2016

Viral load CD4 cells

pre ART: 2-3 months
at ART initiation/switch:

„more frequent“

if suppressed: 2-4 months
same as „viral load“
3-6 months
at ART initiation/switch:

„more frequent“

3-6 months
every 12 months

if stable on ART CD4 >350; VL <LOD

at least every 3 months
4 weeks after ART initiation
at least every 3 months
at least every 6 months

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
2-8 weeks after ART start/switch
every 6 months

(adherence, immunologically stable, <LOD >2 years)

every 3-6 months

first 2 years on ART, CD4 <300, viremia

every 12 months

after 2 years on ART, VL <LOD, CD4 >300

optional

CD4 >500

every 3 months
baseline before ART
every 1-2 months after

ART initiation until suppression

consider lower frequency

(every 6 months) if <LOD >2 years >350 CD4 cells adherence

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Ford et al. 2015; JIAS 18:20061

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

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1 2 3 Months after ART initiation

Viral load

[copies/ml]

■ ■ ■ ■ ■ ■ ■ 4 5 6

Limit of detection (LOD)

Definition of treatment response

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Definition of treatment response

defined by a technical cutoff: 50 copies/ml Cobas Amplicor (Roche Diagnostics)

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Cobas Amplicor Cobas Ampliprep/Taqman 400 (1995) 50 (1998) 40 (2005) 20 (2009) „ultrasensitive“ Version 1 Version 2 copies/ml

Limits of detection: the Roche history

20 (2015) Cobas 6800

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Roche COBAS Ampliprep/Taqman 20 Kopien/ml Siemens VERSANT kPCR Molecular System 37 Kopien/ml Abbott m2000rt Real Time PCR System 40 Kopien/ml Qiagen QIAsymphony RGQ 34 Kopien/ml

Roche Cobas 6800 20 Kopien/ml

Platforms for viral load measurement

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

Definition of optimal treatment response

■

DAIG/DÖAG

2015

EACS

2015

IAS

2014

DHHS

2016

<50
after 3-4 months
after 6 months

if viral load was high at baseline

<50
after 6 months
<LOD (<20-75)
after 6 months
<LOD (<20-75)
after 6 months

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1 2 3 Months after ART initiation

Viral load

[copies/ml]

■ ■ ■ ■ ■ ■ ■ 4 5 6

Treatment failure?

■ 99

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1 2 3 Months after ART initiation

Viral load

[copies/ml]

■ ■ ■ ■ ■ ■ ■ 4 5 6

Treatment failure? No, just a blip...

■ ■ Blip = transient viremia

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Biological causes of blips

Infections Vaccination

Syphilis:

27,6 % viremic during active infection

Palacios R (2007), J Acquir Immune Defic Syndr 44(3), 356-359.

Tuberculosis:

5-160 fold increase of viral load during active infection

Goletti D (1996), J Immunol 157(3), 1271-1278

Influenza:

20,6 % viremic 2-4 weeks after vaccination

Kolber MA (2002), AIDS 16(4), 537-542.

Tetanus

100 % viremic after vaccination

Stanley SK (1996) N Engl J Med 334(19), 1222-1230.

Pneumococi

Vigano A (1998), AIDS Res Human Retroviruses 14(9), 727-734.

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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

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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 [%]

60 40 30 20 15 10 5 126 186 126 126 59 126 125 126 126 185 125 124 53 108 66 100 99 99 98 90 86 53 PROBIT 95 % analysis: 16,5 copies/ml 95 %.confidence interval: 14,3-19,8

Definition of the limit of detection (LOD)

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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

Single Copy PCR

LOD 1 copy/ml

130 patients

3TC/d4T + LPV/r orNFV mit 3TC und d4T als Backbone

<50 copies/ml within 24 weeks
<50 copies/ml after 60 weeks

After 60 weeks: 83 % of the patients viremic Median 3,1 copies/ml

After 2 years:

No significant drop

f the viral load

After 7 years:

77 % of the patients viremic Median 3,34 copies/ml

After treatment intensification (Raltegravir):

No significant drop

f the viral load

Target not detected ≠ negative

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Viral load log10/ml Charge 1 Total SD (log) Charge 2 Total SD (log) Charge 3 Total SD (log) Charge 1-3 Total -SD (log) Total VC der Log- Normalverteilung (%)

2 3 4 5 6 7 0,19 0,07 0,07 0,04 0,10 0,11 0,16 0,09 0,07 0,05 0,09 0,12 0,17 0,07 0,06 0,07 0,10 0,14 0,17 0,08 0,07 0,06 0,10 0,13 41 20 16 15 25 33

Example: Viral load 102/ml = 100 copies/ml 102,17/ml = 148 copies/ml 101,83/ml = 68 copies/ml 15 runs 3 lots 3 replicates

Precision of viral load assays (Roche)

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Precision of viral load assays (Siemens)

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Precision of viral load assays (Abbott)

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Comparison of viral load assays

J Clin Microbiol (2014). 52(2), 517-523

Results from over 4000 paired plasma samples

Roche Taqman Version 1+2
Roche Amplicor
Abbott RealTime
Overall good correlation (0,90-0,97)
Low level viremia <200: 0,45-0,85

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Assay variation

Residual viremia <LOD Ability of commercial assays to detect HIV RNA <LOD Inaccurate quantification at low levels Overquantification

f residual viremia

= Blip

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1 2 3 Months after ART initiation

Viral load

[copies/ml]

■ ■ ■ ■ ■ ■ ■ 4 5 6

Treatment failure?

■ 99

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1 2 3 Months after ART initiation

Viral load

[copies/ml]

■ ■ ■ ■ ■ ■ ■ 4 5 6

Treatment failure? Maybe yes, maybe no...

■ ■ persistent viremia

low-level
very-low-level
high-level

Resistance development

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Risk factors for persistent viremia

Ryscavage R. et al. (2014), AAC, 58(7), 3585-3598

■ overall conflicting data ■ most cases multifactorial ■ no one factor is determinative Stage of infection

high baseline VL low CD4 cell count CDC state

Regimen PI>NNRTI

Very low level viremia

ADHERENCE Duration of suppression <50

Interactions Pharmaco- genomics

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■ How to manage viremia? ■ Which viral load is predictive for treatment failure?

Viral load level
Persistence

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Significance of persistent low-level viremia

Vandenhende 2015, CROI, Poster 1014

■ 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

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Significance of low-level viremia (LLV)

Ryscavage R. et al. (2014), AAC, 58(7), 3585-3598

■ LLV is common: blips: 70-82 % persistent LLV: 18-24 % high level viremia: 6-9 % ■ Persistent LLV associated with an increased risk of resistance 19 % resistance mutations at first LLV (50-1000) Risk correlated with viral load level Median VL in patients evolving resistance: 472 copies/ml vs. 369 copies/ml in patients not evolving resistance (p=0,067)

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Definition of treatment failure

DAIG/DÖAG

2015

EACS

2015

IAS

2014

DHHS

2016

Detectable viral load >50 copies/ml (confirmed)
Drop of <2 log10 after 4 weeks
Detectable viral load 6 months after ART start
Detectable viral load >50 copies/ml (confirmed)
„Depending on assay limit could be higher or lower“
Detectable viral load 6 months after ART start
Detectable viral load >50 copies/ml (confirmed)
Detectable viral load >200 copies/ml
Detectable viral load >200 copies/ml (confirmed)

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Management of viremia

Assessment of factors leading to suboptimal response Adherence (TDM?) Interactions (TDM?) Infections Vaccinations Pre-analytic issues (incl. sample confusion) ...

Confirmation

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Management of viremia

■ VL <50 (=very low-level viremia): No clinical relevance Regular follow-up 3 months later ■ VL >500: Virologic failure Resistance test Switch regimen as soon as possible No resistance mutations: assess adherence (again?) ■ VL 50-500 (=low-level viremia) Confirmation within 4 weeks a) Not confirmed: Blip No clinical relevance Regimen with low genetic resistance barrier: consider shorter follow-up interval b) Confirmed:

50-200

Weak association with virologic failure Regular Follow-up 3 months later Consider resistance test (optional)

200-500

Predictive for virologic failure Resistance test Switch of regimen No resistance mutations: assess adherence (again?)

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