Download TB diagnostics

TB Diagnostics: Update on
Policies and Pipeline
Thomas M. Shinnick, Ph.D.
Chair, Global Laboratory Initiative
Associate Director for Global Laboratory Activities
Division of TB Eliminations, NCHHSTP
9th WPRO Meeting of National TB Program Managers
Manila Philippines
December 9, 2014
National Center for HIV/AIDS, Viral Hepatitis, STD & TB Prevention
Division of Tuberculosis Elimination
Current Laboratory Diagnostic Gaps
• Only about 53% of all new cases and 63% of
new smear-positive cases are detected
• AFB smear-based testing is inadequate in
high HIV settings
• Only 28% of MDR TB cases lab confirmed
• Many XDR TB cases are not detected due to
the lack of second-line DST
TB Laboratory Services
Key needs:
• Quality assured testing for patient care
• rapid, reliable detection and DST
• Access to diagnostic tests for all patients
• 2007 WHA call for universal access to
culture and drug susceptibility testing
• Lab systems and tests appropriate for the
setting
• Safe lab working environment (Biosafety)
Courtesy WHO and FIND
WHO-Endorsed Technologies
• LED Microscopy
• Peripheral laboratory and higher
• Culture (liquid and solid)
• Regional or national level laboratory
• Phenotypic DST
• Regional or national level laboratory
• Molecular Line Probe Assay (LPA)
• Regional or national level laboratory
• Xpert MTB/RIF
• Sub-district and district level laboratory
Culture
• Culture in liquid media
• Culture positives – 2-3 weeks
• Culture negative – 6 weeks
• Culture on solid media
• Culture positives – 3-4 weeks
• Culture negative – 8 weeks
• Culture is most sensitive tool for detection
• Diagnostic delay limits the usefulness of
culture as a diagnostic tool
• Culture needed for phenotypic DST and
monitoring of the response to therapy
Role of the Laboratory in DST
• Detect drug resistance to enable clinician to
design effective multidrug regimen
• Initial M. tuberculosis isolate should be
tested against primary drugs
• INH, RIF, PZA, EMB
• For Rif-R isolates, test secondary drugs as
needed
• FQ, AMI, KAN, CAP
Drug Susceptibility Testing
• Culture-based methods
• Proportion method
• solid media
• liquid media
• Absolute concentration method
• Relative ratio method
• Test critical concentrations — the lowest
concentration that inhibits growth of all
susceptible strains and allows growth of
all resistant strains
• Molecular methods
Updated Critical Concentrations
Ciprofloxacin
MGIT 960
LJ
7H10
7H11
removed
removed
removed
removed
Ofloxacin
4 μg/ml
Levofloxacin
1.5 μg/ml
1μg/ml
Moxifloxacin
0.5, 2.0 μg/ml
0.5, 2.0 μg/ml
Amikacin
30 μg/ml
Capreomycin
Kanamycin
Cycloserine
4 μg/ml
4 μg/ml
2.5 μg/ml
30 μg/ml
removed
WHO-Endorsed Molecular Tests for TB
• Molecular Line Probe Assays (LPA)
• Xpert MTB/RIF Assays
Line-Probe Assays
• LPA can be used to detect rifampicin and
isoniazid resistance conferring mutations
• AFB-smear positive specimens
• Positive TB cultures
• Results can be available in 24 hrs
• Second-line LPA NOT recommended
• Needs sophisticated laboratory
• Needs good referral mechanisms
• Suitable for high throughput testing at
Central or Regional laboratory level
Xpert MTB/RIF Assay
• Can detect rifampicin-resistance conferring
mutations in
• AFB-smear positive specimens
• AFB-smear negative specimens
• Positive TB cultures
• Results can be available in 2 hrs
• Minimal infrastructure and facility needs
• Suitable for testing at sub-district/district
hospital level laboratory
WHO Recommendations – Xpert
• Xpert should be used rather than conventional
microscopy, culture and DST as the initial
diagnostic test in persons presumed to have
pulmonary MDR TB or HIV-associated TB
• Xpert may be used as a follow-on test to
microscopy in persons, where MDR TB or HIV
is of lesser concern, especially in further
testing of smear-negative specimens
• Xpert may be used rather than conventional
microscopy, culture and DST as the initial
diagnostic test in all persons presumed to have
TB
WHO Recommendations – Xpert
Paediatric TB
• Xpert should be used rather than conventional
microscopy, culture, and DST in children
presumed to have MDR TB or HIV-associated
TB
• Xpert may be used rather than conventional
microscopy, culture, and DST in all other
children presumed to have pulmonary TB
WHO Recommendations - Xpert
Extrapulmonary TB
• Xpert should be used in preference to
conventional microscopy, culture and DST as
the initial diagnostic test in testing CSF from
patients presumed to have TB meningitis
• Xpert may be used as a replacement test for
usual practice including conventional
microscopy and culture in testing lymph nodes
and tissues from patients presumed to have
extrapulmonary TB
Scale-up PMDT Program in Parallel
with Xpert MTB/RIF Scale-up
• Laboratory capacity
• conventional culture and DST
• other molecular methods – e.g. LPA
• specimen referral and reporting results
• Treatment capacity
• hospital based and ambulatory care
• patient support and palliative care
• infection control
• Second-line drug management
• Forecasting and ordering
DST Questions
• What is gold standard DST method?
• genotypic? phenotypic?
• Correlation with treatment outcomes?
• “Borderline” rifampicin resistance
• prevalence
• geographic distribution
• Genotypic DST
• not all mutations known for all drugs
• silent mutations, polymorphisms
• mutations of unknown significance
• What is role of next generation DNA
sequencing in determining DST
WHO-Endorsed Technologies
• LED Microscopy
• Peripheral laboratory and higher
• Culture (liquid and solid)
• Regional or national level laboratory
• Phenotypic DST
• Regional or national level laboratory
• Molecular Line Probe Assay (LPA)
• Regional or national level laboratory
• Xpert MTB/RIF
• Sub-district and district level laboratory
An overview of progress in the development and
evaluation of TB diagnostics
Volatile organic compounds
BreathLink, Menssana Research, USA
Prototype breathanalyzer device, Next
Dimensions Technology, USA
Molecular technologies
Alere Q, Alere, USA
B-SMART, LabCorp, USA
Gendrive MTB/RIF ID, Epistem, UK
LATE-PCR, Brandeis University, USA
GeneXpert XDR cartridge, Cepheid, USA
TruArray MDR-TB, Akkoni, USA
INFINITIMTB Assay, AutoGenomics, USA
FluoroType MTB / FluoroType MTB RNA,
Hain Lifesciences, Germany
Molecular technologies
TB LAMP, Eiken, Japan
Molecular technologies for genotypic
DST (including sequencing technologies)
Line probe assays
Non-molecular technologies
Alere Determine TB-LAM, Alere, USA
Molecular technologies
Culture-based technologies
BNP Middlebrook, NanoLogix, USA
iCubate System, iCubate, USA
TREK Sensititre MYCOTB MIC plate, Trek
TB drug resistance array, Capital Bio, China
Diagnostic Systems/ Thermo Fisher Scientific,
EasyNAT TB Diagnostic kit, Ustar
USA
Biotechnologies, China
Truelab/Truenat MTB, Molbio/bigtec
Other technologies
Diagnostics,
India
TB Rapid Screen, Global BioDiagnostics,
a
USA
TBDx, Signature Mapping Medical Sciences,
USA
Commercial serodiagnostics (all
manufacturers)
Interferon-gamma release assays for
the detection of active TB (all settings)
This is not an exhaustive list of technologies in development. Those listed are the ones documented in
Molecular technologies
Xpert MTB/RIF (pulmonary ,
extrapulmonary and paediatric samples)
Lineprobe assays for the detection of MTB
and rifampicin resistance conferring
mutations in AFB smear positive sputum or
MTB cultures
Microscopy
Light and LED Microscopy
Same-day -diagnosis
Culture-based technologies
Commercial liquid culture systems and
rapid speciation
Non-commercial culture and DST (MODS,
NRA, CRI)
Evidence required for WHO review
Phase 5
Scale-up
and policy
refinement
Phase 1
Research and
Development
Phase 4
Phased uptake
and collection
of evidence for
scale-up
Phase 2
Evaluation
and
Demonstration
Phase 3
WHO evidence
assessment
GRADE
Phase 1: Research and Development
WHO
•Upstream research
andrecommended
development to definediagnostics
and validate a prototype
•Laboratory validation under international standards, design-locked product
•WHO interact with developers to discuss end-user requirements
Phase 2: Evaluation and Demonstration
• Controlled trials at 3-5 trial sites in high-burden TB and HIV countries
• Product registration with global and/or national regulatory authorities
• Specifications, performance validated in trials at 5-10 sites of intended use
Phase 3: WHO evidence assessment using GRADE
New technologies/new indications for use: Dossier with Phase 1 and 2 data
• Generic technologies: ISO13:485 standards; equivalence shown in 2-3 SRLs
• WHO is not a regulatory authority
• WHO does not recommend technologies for individual country use
•
Phase 4: Phased uptake & evidence for scale-up
Implementation in routine TB services in high-burden TB and HIV countries
• Systematic evaluation: algorithms, workload, operational issues, CE
• Lessons learnt by early implementers used for country adaptation
•
Phase 5: Scale-up & policy refinement
• Scale-up, with subsequent data to inform and refine WHO policy guidance
Challenges for Adopting a New Test
• Incorporate new test into national TB
strategic plans and testing algorithms
• coordination of implementing partners
• education of clinicians, program, patients
• coordination of lab and treatment scale-up
• sustainability and affordability
• Which services are needed for patient care?
• access to DST for all relevant drugs
• Specimen or patient referral system
Implementation of New Technologies
and Diagnostic Algorithms
• Decided by Ministries of Health
• Coordinate partners and funding to
avoid duplication and maximize
resources
• Phased approach as part of national
strategic plans for laboratory, program,
PMDT, TB/HIV
• Linked to drug access and program
capacity
• Based on local epidemiology
Improve Entire Path of Work
• A new lab test, e.g., Xpert®, is just one tool
• A systems approach is needed
• Must strengthen all processed from
specimen collection to reporting results
A Systems Approach
• Emphasizes access to services
• Ensures timely flow of specimens and
information
• Uses appropriate methods to provide
prompt, high quality results
• Relies on a well-trained workforce
• Involves a network of quality-assured public
and private laboratories
Summary
• New tests and diagnostic algorithms decided
by Ministries of Health
• Favor integrated technology and broad
laboratory network development
• Phased implementation as part of national
strategic plan for lab and program
• Use a systems approach to develop a
network of laboratories that provide reliable,
quality-assured testing
• Build the system on quality principles and
emphasize access to services and timely
flow of specimens and information
Thank You
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of TB Elimination
Target Product Profiles
•
•
•
•
Point-of-care, non-sputum based test
Point-of-care, triage test
Point-of-care sputum based test as a replacement for microscopy
Point-of-care drug susceptibility testing (at microscopy center level)
The clinical purpose of the test (e.g. triage,
detection, DST, other)
Goal to be met (e.g. start TB treatment on that
day; refer for confirmatory testing)
Target population (children, adults, community
or HIV-clinic)
Intended level of implementation in the health
care system (home, community, clinic, peripheral
microscopy center, hospital)