1. BioLife Plasma Services Experience with HBV NAT Testing
Gerold Zerlauth Director Plasma Sourcing Europe BioLife Plasma Services--Baxter Healthcare SA
FDA Blood Products Advisory Committee Meeting
28 April 2011

2. BioLife NAT Donor Screening—Source Plasma
BioLife Plasma Services (US FDA License #1640)
Baxter owned—Testing performed on minipools of 512 samples
HIV – Human Immunodeficiency Virus, Type 1 (HIV-1) Reverse Transcription (RT) Polymerase Chain Reaction (PCR) assay (STN BLA )
HCV – Hepatitis C Virus (HCV) Reverse Transcription (RT) Polymerase Chain Reaction (PCR) assay (STN BLA )
HBV – Hepatitis B Virus (HBV) Deoxynucleic Acid (DNA) Polymerase Chain Reaction (PCR) assay (BB-IND-9465)
NGI (US FDA License #1582)
Contract Testing Laboratory—Testing performed on minipools of 512 samples
HIV – UltraQual™ HIV-1 RT-PCR Assay (STN BL103902)
HCV – UltraQual™ HCV RT-PCR Assay (STN BL103902)
HBV – UltraQual™ HBV PCR Assay (BB-IND-8629)

3. BioLife HBsAg Donor Screening / NAT Pooling
BioLife Plasma Services Testing Lab--Hoover, Alabama
HBsAg Donor Screening—History
Until November 27, 2007
Round Lake, IL (closed 12/04)—Abbott Auszyme Monoclonal
North Brunswick, NJ (closed 12/04)—Abbott Auszyme Monoclonal
Hoover, AL facility--Genetic SystemsTM HBsAg EIA 2.0 and 3.0
Since November 28, 2007
Hoover , AL facility--Abbott PRISMTM HBsAg
NAT Pooling (Minipools of 512 samples)--History
Until September 6, 2004
Pooling performed at the Round Lake, IL facility
Since September 7, 2004
Pooling performed at the Hoover, AL facility

4. Yield of HBV NAT positive / HBsAg negative donors BioLife BB-IND-9465
BioLife HBV NAT Screening
BioLife BB-IND-9465
HBsAg Screening Test
Donations tested in minipools of 512
Total number of HBV NAT only positive donors
Rate of HBV NAT only positive donors/per tested donations
Abbott Auszyme or
Genetic SystemsTM
5,435,228 27
1 in 232,451
Abbott
PRISMTM
10,222,462 8
1 in 1,277,808
Abbott PRISM has reduced the NAT only yield by 5.5-fold

5. Yield of HBV NAT positive / HBsAg negative donors NGI BB-IND-8629
HBV NAT Screening
NGI BB-IND-8629
HBs Ag Screening Test
Donations tested in minipools of 512
Total number of HBV NAT only positive donors
Rate of HBV NAT only positive donors/per tested donations
Genetic SystemsTM
3,333,665 18
1 in 185,204
Abbott
PRISMTM
4,248,168 4
1 in 1,062,042
Abbott PRISM has reduced the NAT only yield by 5.7-fold

6. PRISM HBsAg screening has reduced the HBV NAT-only yield
The implementation of the Abbott PRISMTM HBsAg donor screening assay with no changes to the HBV NAT testing (BioLife BB-IND and NGI BB-IND-8629) has led to a reduction in the number of HBV NAT only positive donors by nearly 6-fold as compared to the previously used HBsAg donor screening assay.

7. Sensitivity Definitions for HBV NAT
Analytical Sensitivity
95% cut-off: Concentration of HBV DNA that is detected positive in 95% of NAT tests
Sensitivity on single donation level
NAT testing is performed in minipools. Due to the inherent dilution factor in a pool, a single donation needs to contain a certain concentration of virus to be detected positive in the minipool.
Calculation: 95% cut-off multiplied by the number of samples in a minipool
Example
BioLife BB—IND-9465
Analytical Sensitivity
11 IU/ml
Samples per Minipool
512
Sensitivity on the single donation level
11 x 512 = 5,632 IU/ml

8. Factors influencing NAT sensitivity on single donation level
Factors influencing NAT sensitivity on the level of the individual donation are:
Analytical sensitivity (95% cut-off) of the assay
Number of samples in the minipool tested (dilution factor)
Example
Analytical Sensitivity [IU/ml]
Minipools size (dilution factor)
Sensitivity on single donation [IU/ml]
BioLife BB-IND-9465 11
512
5,632
Novartis UltrioTM*
10.4 16
166.4
*Stramer,S.L. et al. Nucleic acid testing to detect HBV infection in blood donors. N. Engl. J. Med. 364, (2011).

9. HBV NAT at different pool size
Plasma for fractionation in minipools of 512
Serological Screening: HBsAg Abbott PRISMTM
NAT Assay: BioLife BB-IND-9465
Yield HBV NAT only: 1 in 1,277,808 donations
Blood for transfusion in minipools of 16 or ID NAT*
Serological Screening: HBsAg Abbott PRISMTM
NAT Assay: Procleix Ultrio Assay and Tigris Automated Platform (Gen-Probe and Novartis)
Yield HBV NAT only: 1 in 410,540 donations
Blood for transfusion in minipools of 24, 6 or ID NAT**
Serological Screening: Abbott HBsAg Auszyme or Ortho HBsAg test system 2 and test system 3, index samples tested using HBsAg Abbott PRISMTM
NAT Assay: COBAS Ampliscreen HBV, Cobas TaqScreen MPX (Roche Molecular Systems)
Yield HBV NAT only: 1 in 610,488 donations
*Stramer,S.L. et al. Nucleic acid testing to detect HBV infection in blood donors. N. Engl. J. Med. 364, (2011).
**Linauts,S. et al. PRISM hepatitis B surface antigen detection of hepatitis B virus minipool nucleic acid testing yield samples. Transf. 48, (2008)

10. HBV NAT pool size – is there a benefit for the patient?
Blood Products intended for transfusion
HBV NAT in small pools adds value for the patient by preventing transfusion of the few very low level HBV DNA positive units that escaped HBsAg screening and potentially preventing Transfusion Transmitted Hepatitis B.
Plasma intended for fractionation
HBV NAT in smaller pools adds little to no value as the very low viral load of HBV DNA entering the production pool is reliably inactivated by the validated viral inactivation processes during production
The current HBV NAT 512 minipool assay assures that the maximum level of virus potentially entering a production pool cannot exceed the validated safety level of the virus inactivation measures
E.g., pasteurization, dry heat, solvent/detergent, etc.
Virus reduction/inactivation capacity for HBV in order of 9 log 10 or greater

11. Conclusion
The introduction of HBsAg screening with the PRISM assay has reduced the number of HBV NAT only donors nearly 6-fold.
Testing in small minipools increases yield of HBV NAT only donors 2-3 fold compared to mini pools of 512.
For patients who receive blood products for transfusion, testing in small minipools appears to provide additional benefit.
For manufactured plasma derived therapeutics, testing in small minipools provides no additional benefit over the current processes with pathogen inactivation while at the same time it will result in additional complexity and expense with the handling and testing of small pool sizes.
Therefore, the intended use of the product (direct transfusion or further manufacture) should determine the most suitable testing regimen.