1st International Standard for HIV-1 RNA NIBSC Code 97/656 CBER, CLB and NIBSC collaborated in development of HIV-1 International Standard for NAT Three candidate standards evaluated in collaborative study WHO Expert Committee (ECBS) established candidate YY as 1st International Standard for HIV-1 RNA (code 97/656) Assigned a concentration of 100,000 IU per vial/ml (1IU ~ 0.58 copies/ml) YY was human HIV-1-positive plasmapheresis donation diluted in defibrinated plasma Has recently been found positive for HBV DNA WHO Expert Committee (ECBS) established candidate YY as 1st International Standard for HIV-1 RNA (code 97/656) Assigned a concentration of 100,000 IU per vial/ml Mean copy number in 20 quantitative assays was: 4.75 Log10 RNA copies/ml 56,000 RNA copies/ml 1 RNA copy equal to 1.78 IU Available from NIBSC 03 July 2003 SoGAT XVI

1st International Standard for HIV-1 RNA Code 97/656 In-house qualitative assay detected HBV DNA (David Padley, NIBSC) Nested PCR positive for HBV DNA – estimated viral load at 3.5 x 104 amplifiable copies/ml (Alison Hardie, University of Edinburgh) Procleix Triplex assay showed that 100 IU/ml dilution of HIV-1 International Standard contains 611 IU/ml HBV DNA (V Shyamala, Chiron Corporation) What are the implications of this? 03 July 2003 SoGAT XVI

1st International Standard for HIV-1 RNA: Implications of HBV Contamination For use in monovalent HIV-1 NAT or multivalent NAT assays that do not include HBV detection: International Standard may still be used as directed For use in multiplex assays that detect both HIV-1 RNA and HBV DNA : 1st international Standard for HIV-1 may not be suitable for the quantitation of HIV-1 RNA What difficulties will this cause for users? Do we need to establish a second International Standard calibrated on the first? If so, should we use candidate XX used in the collaborative study? 03 July 2003 SoGAT XVI

Development of 1st International Standard for HIV-1 RNA Candidate: XX YY Subtype: B Virus: Primary isolate Plasmapheresis donation Propagated: PBMCs No Copy number: High Medium Freeze-dried: Yes Diluent: Plasma Volume: 1ml 03 July 2003 SoGAT XVI

Development of 1st International Standard for HIV-1 RNA Candidate XX Candidate YY Candidate ZZ --- bDN --- Monitor --Nuclisens --- Abbott --- in-house 03 July 2003 SoGAT XVI

Distribution: Approx 240 vials/year On present trend, Std will run out in 4 years, possibly sooner 03 July 2003 SoGAT XVI

1st International Standard for HIV-1 RNA: Implications of HBV Contamination If it is agreed that candidate XX be brought in as a replacement for 1st international Standard (YY) we will need to carry out small comparability and stability study to confirm that performance is satisfactory This can be carried out over next 6 months in time for approval at WHO ECBS meeting in 2004 03 July 2003 SoGAT XVI