Infectious diseases related reference materials WHO International Standards

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Infectious diseases related reference
materials-----WHO International Standards
Micha Nübling, PEI
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Paul-Ehrlich-Institut

• Governmental Authority for biological medicinal
  products
• Vaccines
• Blood and blood products
• Assessment of IVDs for CE marking (NB)IVD batch
  release testing
• WHO Collab. Center
• IVDs Blood Products

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Dir 98/79/ECAnnex I -Essential RequirementsPart
A. General Requirements, Clause 3"The
traceability of values assigned to calibrators
and/or control materials must be assured through
available reference measurement procedures and/or
available reference materials of a higher
order..
Standardization of IVDs

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Standardization of IVDs
common languageInterchangeability of data
between different IVDs Therapy
guidelines RegulationsComparison / competition
between IVDs Quality goalsLong-term-performance
stabilityProficiency testing

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Metrological Traceability Chain
Reference system Reference Materials Reference
Method Reference Lab
ISO 17511
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Standardization of IVDs

• Diagnosis of infectious diseases often
  characterized by
• ...Complex analytes
• antibodies interindividual variation
• antigens posttranslational modifications
• viruses genotypes, variants
• analytes heterogenous mixture of related
  structures
• not traceable to SI units

• ...Complex matrix
• plasma/serum proteins may interfere,
  anticoagulants, ...
• ...Complex design of assays
• high intra / inter assay variation
• no reference method

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Traceability Chain of Biological Reference
Preparations
WHO IS
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Standardization of IVDs
Traceability to materials of higher order
WHO is mandated by it's Member States to
"develop, establish and promote international
standards for biological products to ensure their
quality and efficacy. biological product is
a substance which cannot be completely
characterized by physico-chemical means alone,
and which therefore requires the use of some form
of bioassays

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WHO Biological Reference Preparations
Recommendations for the preparation,
characterization and establishment of
international and other biological reference
standards (revised 2004)Annex 2, WHO TRS, No
932, 2005
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Standardization of IVDs
Traceability to materials of higher order

• In practice, WHO biological standards cover
• Vaccines
• Blood and blood products
• Biological therapeutics
• In vitro diagnostic devices

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Standardization of IVDs
Traceability to materials of higher order

• In practice, WHO biological standards cover
• Vaccines
• Blood and blood products
• Biological therapeutics
• In vitro diagnostic devices

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Standardization of IVDs
WHO Biological Reference Preparations

• International Standard expressed in IU
• Reference Reagent
• International Reference Panel
• endorsed and adopted by Expert Committee on
  Biological Standardization (ECBS decision making
  body)
• Catalogue on the website
• www.who.int/medicines
• www.who.int/bloodproducts/ivd/infectious_markers

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Standardization of IVDs
WHO Biological Reference Preparations
International Standard International
Units/ml IU arbitrary unitage accepted in
international therapy guidelines (e.g. HBV,
HCV) Issues commutability (to routine clinical
samples) replacement of International Standards,
continuity of the IU

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Standardization of IVDs
Preparation of WHO IS
Work programs agreed between WHO Collaborating
Centers (IVDs) FDA/CBER (USA), NIBSC (UK),
PEI (D) Priorities determined by annual ECBS

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Standardization of IVDs
Use of WHO IS

• Tool for regulatory bodies, manufacturers,
  product users (physicians/scientists) to
  communicate in a "common language
• Validation, quality control and comparability of
  IVD tests (e.g. analytical sensitivity)
• Tool for identifying unsuitable diagnostic kits
• Tool for global regulation and harmonization in
  the IVD area
• Underpin the appropriate diagnoses of the disease

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Standardization of NAT assays
NAT standards Desired Features suitable for
all NAT technologies PCR, TMA, NASBA,
branched DNA, .... reflect measuring
range of quantitative NATs reflect target
material comparability with conventional
IVDs, e.g. HIV RNA / p24 one unitage (IU
/ ml)
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Standardization of NAT assays
WHO International NAT Standards lyophilised
preparations of biologicals high
concentration of target gold standard for
secondary standards and working reagents
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Standardization of NAT assays
WHO International Standards NIBSC Targ
et Concentration 1 IU code HCV RNA 105
IU/ml 3 - 8 cps 96/798 HBV DNA 106 IU/ml 2 -
7 cps 97/746 HIV-1 RNA 106,1 IU/ml 0.5
cps 97/650 B19 DNA 106 IU/ml 0.8
cps 99/800 HAV RNA 105 IU/ml gt10 cps 00/560
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Standardization of NAT assays
WHO / (NIBSC / PEI) Genotype / Subtype Reference
Panels Target Geno-/Subtypes HCV RNA
1, 2, 3, 4, 5, 6 HBV DNA A, B, C, D, E, F,
G (in preparation, PEI WHO CC) HIV-1 RNA A,
B, C, D, AE, F, G, AG-GH, N, O B19 DNA 1, 2,
3a, 3b (in preparation, FDA, NIBSC WHO CCs) HAV
RNA
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Reference to WHO IS
Common Technical Specifications (CTS) for NAT
assays
Traceability quantitative NAT assays to be
calibrated with WHO IS detection limit of
qualitative NATs to be expressed as 95 c/o
value, in IU/ml
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Secondary standards
Biological Reference Preparation for
HCV-RNA (PhEurBRP) Background CHMP
requirement for plasma pool HCV-NAT OMCLs confirm
manufacturers testing (batch release) Need for a
common reference material
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Biological Reference Preparation
HCV-RNA(PhEurBRP)
WHO IS (96/790) BRP Candidate Material
HCV-RNA pos plasma HCV genotype
I antiHCV pos antiHCV neg diluted in neg
pool 100.000 IU/ml 4.000 - 10.000
gEq/ml freeze dried (0.5 ml)
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Biological Reference Preparation HCV-RNA
(PhEurBRP)
Collaborative calibration study Calibration
against WHO standard Assignation of unitage
(IU/ml) Suitability for OMCLs plasma pool
testing
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Biological Reference Preparation HCV-RNA
(PhEurBRP)
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WHO IS
PhEurBRP
105 IU/ml
Estimated potency 103.55 IU / ml
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Mean Potency 102.97 IU / ml
1.000 IU / ml
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NAT Secondary standards
Ph. Eur. BRP HCV-RNA 103 IU/ml Ph. Eur.
BRP B19-DNA 105,8 IU/ml PEI Ref
Prep HCV-RNA 104,9 IU/ml PEI Ref Prep
HIV1-RNA 104,9 IU/ml PEI Ref
Prep HBV-DNA 104,9 IU/ml
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Alternatives to Biological Standards ?
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Alternatives to Biological Standards ?
WHO Consultation on International Standards for
In Vitro Clinical Diagnostic of Viral Nucleic
Acids (April 2002) use of synthetic nucleic
acid as a reference material for biological
assays should be considered.
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Alternatives to Biological Standards ?
Feasibility Studies by manufacturers of
qtHCV-NATs (Roche, Bayer, Abbott) Phase I
(September 2002- July 2003) in-vitro HCV RNA
(Bayer) as proof of principle Samples
quantified in different assays using the
synthetic materials as a mathematical calibrator
were within 0.6 log10 between different assays
(presented to SoGAT in 2003) Phase I I (draft
protocol 08/05) Commutability of two candidate
synthetic materials (in vitro HCV RNAs, armoured
HCV-RNA) to biological materials comparison with
respect to assay linearity Proposal of
procedures for the calibration of subsequent lots
of WHO HCV International Standards
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Standardisation of Molecular Diagnostics

biological NAT standards
synthetic NAT standards
Extraction of Nucleic Acids
Amplification
Detection of Amplification Products
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Conclusions
IVD Dir traceability to standards of higher
orderreference system reference material,
reference method, SI units often not feasible
for biological markers WHO IS International
Units well-established for standardization
of assays therapy guidelines regulations,
e.g. on blood and blood products