Reduced Viremia Following Immunotherapy of SIV with Peptide Pulsed Blood Robert De Rose, University of Melbourne, Australia O verlapping P eptide-pulsed A utologous L eukocytes

OPAL - what is involved PBMC 18 mL blood draw Vaccinated or Infected IV infuse PBMC back into same animal Pulse PBMC with Overlapping 15mer peptides 1 h at 37 o C ABCDEFGHIJKLMNO EFGHIJKLMNOPQRS IJKLMNOPQRSTUV MNOPQRSTUVWXYZ BEFORE treatment 2 weeks AFTER treatment Intracellular IFN  Assay IFN  CD8 CD4 Chea et al, J.Virol 2005

Aims 1. Does OPAL reduce viral load? Macaque efficacy study tat Pol Env SIV mac239 b: “OPAL (All)” - broad Vif VpxVpr Gag Nef Tat Rev Gag SIV mac Compare a: “OPAL (Gag)” - narrow

Week after infection Experimental Design * Pigtail macaque/SIVmac251 model * 36 macaques

Week after infection Experimental Design * Pigtail macaque/SIVmac251 model * 36 macaques * Infected with SIVmac251

Week after infection Experimental Design * Pigtail macaque/SIVmac251 model * 36 macaques * Infected with SIVmac251 * Randomised into 3 groups according: - peak VL - weight, gender - MHC I

Week after infection Experimental Design * Pigtail macaque/SIVmac251 model * 36 macaques * Infected with SIVmac251 * Randomised into 3 groups according: - peak VL - weight, gender - MHC I * Daily Tenofovir and FTC TDF + FTC

Week after infection OPAL Experimental Design * Pigtail macaque/SIVmac251 model * 36 macaques * Infected with SIVmac251 * Randomised into 3 groups according: - peak VL - weight, gender - MHC I * Daily Tenofovir and FTC * OPAL - (w4, w6, w8, w10)

Primary endpoint  VL (w10  w20) Trial Endpoints

Secondary 1.  VL (w10  w36) 2. Safety 3. T cell immunogenicity

T cell immunogenicity (SIV Gag) CD4CD8 % IFN  + T cells FTC+TDF OPAL FTC+TDF OPAL

(Gag) OPAL (All) Env Pol Accessory CD4 OPAL (Gag) OPAL (All) CD8 50% IFN  Animal N o Gag

 VL = 0.5 log 10 ( p = 0.04 ) (n = 8) (n = 10) (n = 8)

 VL = 0.7 log 10 ( p = 0.01 ) (n = 8) (n = 10) (n = 8)

Conclusions  OPAL Gag: Strong Gag responses  OPAL All: Broad responses to all proteins, BUT some reduction of Gag responses  0.5 log 10 reduction in average VL over first 10 weeks (primary endpoint)  0.9 log10 reduction in VL at end of study  Gag equivalent to All peptides: suggests Gag is an effective immunogen  OPAL therapy was safe

Future plans Pulsing PBMC vs whole blood Boosting - further reduce VL? Clinical trials 1. Patient catheterized and 60mL blood allowed to flow into blood bag. 2. OPAL peptides (HIV Gag) reconstituted and delivered to blood bag. 3. Peptides allowed to mix (pulse) with blood at room temp for 60min. 4. Blood infused directly back into patient. Safety, Immunogenicity, Efficacy

Acknowledgments Stephen Kent Lab (University of Melbourne) Stephen Kent SheilaJen Alcantara Miranda Smith Caroline Fernandez Viv Peut C. Jane Batten Erik Rollman Liyen Loh Rosemarie Mason Janette Reece Roberta Goli Collaborators Matthew Law (UNSW) Amanda Handley (OPAL Therapeutics) NIH Reference and Reagent Program Peptides