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BioLife Plasma Services Experience with HBV NAT Testing

Gerold ZerlauthDirector Plasma Sourcing Europe BioLife Plasma Services--Baxter Healthcare SA

FDA Blood Products Advisory Committee Meeting

28 April 2011

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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 125100)

• HCV – Hepatitis C Virus (HCV) Reverse Transcription (RT) Polymerase Chain Reaction (PCR)

assay (STN BLA 125101)

• 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)

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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

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Yield of HBV NAT positive / HBsAg negative donors BioLife BB-IND-9465

BioLife HBV NAT Screening 2001 - 2010BioLife 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 orGenetic SystemsTM

5,435,228 27 1 in 232,451

AbbottPRISMTM

10,222,462 8 1 in 1,277,808

Abbott PRISM has reduced the NAT only yield by 5.5-fold

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Yield of HBV NAT positive / HBsAg negative donors NGI BB-IND-8629

HBV NAT Screening 2007 - 2010NGI 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

AbbottPRISMTM 4,248,168 4 1 in 1,062,042

Abbott PRISM has reduced the NAT only yield by 5.7-fold

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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- 9465 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.

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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

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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)

ExampleAnalytical 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, 236-247 (2011).

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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, 236-247 (2011).**Linauts,S. et al. PRISM hepatitis B surface antigen detection of hepatitis B virus minipool nucleic acid testing yield samples. Transf. 48, 1376-1382 (2008)

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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

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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.