national institute for biological standards and control assuring the quality of biological medicines...
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![Page 1: National Institute for Biological Standards and Control Assuring the quality of biological medicines Human Cytomegalovirus (HCMV) Proposed 1 st International](https://reader034.vdocuments.us/reader034/viewer/2022051215/56649efb5503460f94c0eb10/html5/thumbnails/1.jpg)
National Institute for Biological Standards and ControlAssuring the quality of biological medicines
Human Cytomegalovirus (HCMV) Proposed 1st International Standard
WHO/BS/08.2099
Jacqueline Fryer
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• Ubiquitous and persistent infection, causes disease in immunologically naïve (foetus and newborns) and suppressed (transplant recipients, AIDS patients).
• Leading infectious cause of deafness and brain damage in newborns, most significant viral pathogen after solid-organ transplantation.
• High viral load is most important risk factor for CMV disease in transplant recipients; HCMV DNA quantification assays are used to guide pre-emptive antiviral therapy to prevent viral load rising above critical disease threshold.
• Viral load measurements increasingly being used to predict sensorineural hearing loss congenitally-infected infants.
Rationale 1
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• Viral load measurements performed using NAT, particularly real-time PCR. Many assays developed in-house, although a number of new commercial assays have been developed.
• High level of inter-laboratory variability in viral load measurements (AST/CST study, EQA proficiency programmes).
• Cut-off thresholds for initiation of pre-emptive therapy are site-specific and vary significantly, therefore, difficult to compare clinical practice and standardise patient management.
• IHMF* recommendations (2004) called for ‘international quantification standard to compare studies using different PCR-based systems and facilitate patient management at multiple care centres’.
* International Herpes Management Forum
Rationale 2
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Rationale 3
Pang et al, Am J Transplant. 2009;9:258-68
Log 10
var
iatio
n in
repo
rted
resu
lts
(rel
ative
to e
xpec
ted)
Variability in performance of HCMV viral load assays
Plasma spiked with HCMV Merlin Clinical samples
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Source material for HCMV candidate
• Whole virus preparation of prototype clinical HCMV strain Merlin
• Produced in cell culture, formulated in universal buffer and freeze dried
• Concentration of ~1x107 copies/mL (IU when established)
• ~5000 vials to be filled (August 2009)
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Collaborative study protocol
• Candidate standard to be evaluated alongside frozen liquid preparations:
– Merlin liquid bulk
– Prototype laboratory HCMV strain AD169 (whole virus)
– Purified BAC-cloned Merlin DNA
• ~30 participants (clinical and research labs, assay manufacturers) performing range of NAT-based assays
• To ECBS 2010
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Intended use
• Calibration of secondary references used in routine HCMV viral load assays
• Calibration/validation of commercial NAT assays
• Evaluation of HCMV-positive materials distributed in molecular quality assurance programmes
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National Institute for Biological Standards and ControlAssuring the quality of biological medicines
Epstein-Barr Virus (EBV) Proposed 1st International Standard
WHO/BS/08.2099
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• EBV-associated Post Transplant Lymphoproliferative Disease (PTLD) affects 1-20% of allografts.
• Viral load measurements by NAT used to guide pre-emptive therapy in transplant recipients.
• High level of inter-laboratory variability in viral load measurements (AST/CST study, EQA proficiency programmes).
• Cut-off thresholds for initiation of pre-emptive therapy are site-specific and vary significantly, therefore, difficult to compare clinical practice and develop standardised treatment models.
• EBV Viral Load Standardisation Workshop (Third European Congress of Virology, Nürnberg, 2007) called for the development of an International Standard for EBV DNA.
Rationale 1
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Rationale 2Lo
g 10 v
aria
tion
in re
port
ed re
sults
(r
elati
ve to
exp
ecte
d)
Variability in performance of EBV viral load assays
Preiksaitis et al, Am J Transplant. 2009;9:269-79
Plasma spiked with Namalwa cells Clinical samples
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Source material for EBV candidate
• Whole virus preparation of prototype laboratory EBV strain B95-8
• Produced in cell culture, formulated in universal buffer and freeze dried
• Concentration of ~1x107 copies/mL (IU when established)
• ~5000 vials to be filled (August 2009)
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Collaborative study protocol
• Candidate standard to be evaluated alongside frozen liquid preparations:
– B95-8 liquid bulk
– EBV-positive Namalwa cells
– EBV-positive Raji cells
• ~30 participants (clinical and research labs, assay manufacturers) performing range of NAT-based assays
• To ECBS 2010
![Page 13: National Institute for Biological Standards and Control Assuring the quality of biological medicines Human Cytomegalovirus (HCMV) Proposed 1 st International](https://reader034.vdocuments.us/reader034/viewer/2022051215/56649efb5503460f94c0eb10/html5/thumbnails/13.jpg)
Intended use
• Calibration of secondary references used in routine EBV viral load assays
• Calibration/validation of commercial NAT assays
• Evaluation of EBV-positive materials distributed in molecular quality assurance programmes