What are the determinants of HIV persistence?

1. Cell- and Tissue-based Measures of Viral Persistence Are Associated with Immune Activation and PD-1-Expressing CD4+ T cells H Hatano1, V Jain1, PW Hunt1, JN Martin1, TH Lee2, E Sinclair1, JM McCune1, F Hecht1, MP Busch1,2, SG Deeks1 1University of California, San Francisco, CA, USA 2Blood Systems Research Institute, San Francisco, CA, USA

2. What are the determinants of HIV persistence? • Determinants of HIV persistence during long-term HAART remain unknown, but may include: • Ongoing viral replication (Buzon, Nat Med 2010) • Potency of HIV-specific responses • Mucosal HIV-specific T cell responses(Hatano, JID 2011)

3. Higher Levels of GALT HIV-specific CD8+ T Cells Are Associated with Lower Levels of Proviral DNA CD8 CD4 rho = - 0.50, p = 0.03 rho = - 0.42, p = 0.07 Hatano et al, JID 2011

4. What are the determinants of HIV persistence? • Determinants of HIV persistence during long-term HAART remain unknown, but may include: • Persistent immune activation • Immune activation levels remain elevated despite effective HAART-mediated viral suppression • Negative regulators that reverse activated state (PD-1) (Chomont, Nat Med 2009) • PD-1high CD4+ T cells have high levels of proviralDNA • Triggering of PD-1 inhibits HIV transcription, and inhibiting the PD-1/PD-L1 interaction increases HIV production • PD-1 expressing CD4+ T cells → Preferential reservoir for HIV • Understanding the causes of persistent inflammation are important for preventing non-AIDS morbidity and for strategies towards cure

5. Study Objectives • To assess the relationship between measurements of viral persistence and immune activation • Plasma RNA • Cell-associated RNA and proviral DNA • Tissue-associated RNA and proviralDNA • To determine the relationship between treatment response and • T cell activation/dysfunction • Viral persistence • To identify potential interventions to decrease HIV persistence

6. Methods • 190 HAART-suppressed subjects identified from UCSF SCOPE/OPTIONS cohorts • Ultrasensitive plasma HIV RNA • Modified Roche CAP/CTM v2.0 (LOD <5 copies/mL) • Cell-associated RNA • Proviral DNA • Immune activation (% CD4+ and CD8+ T cells) • CD38+HLA-DR+, PD-1 • Gut-associated lymphoid tissue (GALT) samples were obtained from 14 subjects

7. Baseline Characteristics

8. No Association Between Low-Level Plasma RNA Levels and T Cell Activation All p-values > 0.20

9. Modest Association Between Cell-Based Measures of Viral Persistence and T Cell Activation rho = 0.23, p = 0.014 rho = 0.16, p = 0.057 rho = 0.22, p = 0.008 rho = 0.14, p = 0.088

10. Highly Significant Association between Proviral DNA Levels and Frequency of PD-1 Expressing CD4+ T Cells rho = 0.28, p = 0.0005 These observations are consistent with PD-1 being a marker of latently infected CD4+ T cells (Chomont et al, Nature Med 2009)

11. Strong Association Between Viral Persistence in GALT and T Cell Activation

12. What is the relationship between treatment response and…-Viral Persistence? -T Cell Activation/Dysfunction? Will treated subjects with a low CD4+ T cell count require unique curative strategies?

13. Plasma RNA Levels Similar in Low and High CD4+ Groups p = NS

14. Cell-Associated RNA and Proviral DNA Levels Are Higher in Low CD4+ Group p = 0.008 p = 0.001

15. CD4+ T Cell Activation and PD-1 Expression are Higher in Low CD4+ Group p < 0.0001 p < 0.0001 p < 0.0001 p < 0.0001

16. Higher Frequencies of PD-1 Expressing TCM CD4+ T Cells in Low CD4+ Group p < 0.0001 p < 0.0001 p < 0.0001

17. Conclusions I. • No associations between ultrasensitive plasma HIV RNA levels and immune activation • Cell-based measurements of viral persistence were modestly but consistently associated with markers of immune activation/dysfunction and frequency of PD-1 expressing CD4+ T cells • Stronger positive correlation between tissue-based measurements of viral persistence and immune activation

18. Potential Eradication Strategies • Highly significant association between proviral DNA levels and frequency of PD-1 expressing CD4+ T Cells • Phase I study of an anti-PD-1 monoclonal antibody aimed at clearing the latent reservoir is in development (ACTG 5301)

19. ACTG 5301 Study Schema • Study Design: Single arm, dose-finding study • Population: • HIV-infected female and male subjects ≥ 18 years of age. Females of reproductive potential are excluded from the study. • Screening CD4+ T cell count > 350 cells/mm3 • Plasma HV RNA < 75 copies/mL while taking HAART for previous 36 months • Sample size: 40 (10 subjects in each dose cohort) • Study duration: 16 weeks • Intervention: Single IV dose of open-label MK3475 at dose of 0.1, 1, 3, or 10 mg/kg

20. Conclusions II. • Treated patients with a low CD4+ T cell count had: • Higher cell-based measures of viral persistence • Expansion of CD4+ T cells expressing PD-1 • Most consistently observed in the central memory compartment  • Treated individuals with low CD4+ T cell counts may be more difficult to cure and/or will require unique interventions

21. Implications • Understanding the causes of viral persistence and inflammation in the setting of HAART are necessary to develop new strategies towards cure • Future studies of viral persistence should focus on cell- and tissue-based measurements of viral persistence, not on plasma RNA(Chun, JID 2008; Yukl, JID 2010; Hatano, JID 2011)

22. Acknowledgements UCSF/SFGH/PHPUCSF/SFGH/DEMFunding VivekJainElizabeth Sinclair NIAID K23AI075985 Peter Hunt Joseph M. McCune Ma Somsouk Jeffrey MartinVGTI Florida Frederick Hecht Nicolas Chomont Steven DeeksRafickSekaly UCSF/SFVAMCRoche, Inc. Steven Yukl Tri Do Joseph Wong UCSF/BSRI Tzong-Hae Lee Michael Busch