1. Latency reversing agents
HIV Cure Research Training Curriculum
Latency Reversing Agents Module by:
Scientific Leads: David M. Margolis (CARE) and Sharon Lewin (DARE) Community Leads: Cipri Martinez (DARE) and David Palm (CARE)
The HIV CURE training curriculum is a collaborative project aimed at making HIV cure research science accessible to the community and the HIV research field.

2. Predicted survival if HIV+ at 25 yrs
US military cohort (n = 2327, mean age 35) who started ART after 2000, 5-year mortality 0.3%
Marconi 2010

3. Reduce the number of new HIV infections
Combination
HIV
Prevention
Treatments
that clear Infection
Reduce the number of
HIV-infected people
Reduce the number of new HIV infections

4. Last public appearance of the entire AIDS Quilt, 1996
Prevention
Diagnosis
Treatment
Prevention
Diagnosis
Treatment
Cure
Last public appearance of the entire AIDS Quilt, 1996

5. Transient “remission” is possible
Two Boston Patients1,2
The Mississippi Child3
Treatment
CCR5+/+
bone marrow transplant
Early ART
Remission off ART
3 months and
7 months
2.5 years
Lesson
Delayed viral rebound is achievable
But unknown biomarkers for HIV remission
Henrich et al., J Infect Dis 2013, 207(11): Henrich et al., Ann Intern Med Jul 22; Persaud et al., N Engl J Med 2013 Nov 7;369(19):

6. Aiming for sustained “remission” off ART
Cohen J. Science 2014 July

7. Latently infected T-cells
cART
Homeostatic
proliferation

8. The persistent pool of HIV-1 antiretroviral therapy can prevent the creation of new latently infected cells, but it does not affect cells in which latency was initially established.
The persistent pool of HIV-1.Antiretroviral therapy can prevent the creation of new latently infected cells, but it does not affect cells in which latency was initially established. Intermittent bursts of viremia originate in part from this latent reservoir. Forcing these cells to exit the latent state without enhancing new infection could make the virus vulnerable to clearance by an HIV-targeted immune response. Blocking the proliferation of these latently infected T cells could deplete the pool if its stability is driven by such multiplication.
Science 2014

9. Residual viral expression
cART
Evidence for residual viral expression in about one third of patients on cART
Buzon et al., Nature Med 2010; 16: 460; Hatano et al, J Infect Dis 2013

10. Anatomical reservoirs

11. A model using the exposure to viremia over time in early infection predicts the frequency of latent infection (“…size of the reservoir…”)
Archin et al. 2012

12. Very early ART significantly reduces reservoir size
14%
74%
100%
Duration of HIV before ART N
Ananworanich et al, 20th International AIDS Conference AIDS2014, Melbourne, Australia, 2014

13. Very early ART reduces reservoirs but…rebound still occurs in SIV
Time to viral rebound, days
Log HIV DNA in PBMC
Day of ART initiation post infection
N=20, SIVmac251 infected macaques treated with tenofovir/FTC/dolutegravir for 24W
Whitney et al., Nature 2014, July 20

14. Balance between reservoir and immunity
latent
virus
Boston patients
Mississippi child
VISCONTI patients
(EM>CM) ?
Lewin SR. Ann Int Med 2014 July 22

15. Activating latent HIV
The Economist, July 17, 2011

16. A first step to eliminate latent HIV infection
A second step to eliminate latent HIV infection
Immunotherapy
Anti-latency
therapy
Current paradigm that is beginning to be tested
Other Challenges:
Clearance of infected cells
Clearance of virions
Complete block of new infection

17. Activating latent infection: in vitro
“activate”
HIV US RNA
HIV DNA
HIV proteins
HIV virions
HIV DNA
Cell death
Latent infection
HDACi
Methylation inh
Cytokines eg., IL7
disulfiram
quinolines
Histone methyl transf inh
BET inh

18. Identifying latency reversing agents (LRA) in vitro
Resting CD4+ T-cells
from HIV-infected patients
on ART
Often needs leukapharesis
Frequency of latency low
Mechanistic studies difficult
Highly variable responses
Latently infected
primary T-cells
Resting cells
High frequency of latency
Pre and post activation models
Latently infected cell lines
e.g., J-Lat, ACH2, U1
Constantly dividing
Clonal
Integrate in heterochromatin

19. No model ideally represents latently infected ells from patients
T-cell activation
PKC
Cytokines
HDACi
other
Spina et al., Plos Pathogens 2013 Dec;9(12):e

20. Histone deacetylase inhibitors turn HIV genes “on”
HDACi
OFF TF

21. Latency “activating” agent
Activating latent infection: clinical trials
“activate”
HIV US RNA
HIV DNA
HIV proteins
HIV virions
HIV DNA
Cell death
Latent infection
cART
Latency “activating” agent
cART>3 years
HIV RNA<50 c/ml
CD4>350 cells/ml

22. HDACi: activity in cancer and HIV
Clinical development
HIV latency
Vorinostat
Pan HDACi
Licensed - CTCL
Single dose1 Intermittent2 Continuous3
Panobinostat
Phase III – multiple myeloma
Intermittent dose4
Romedepsin
Class I HDACi
Weekly dose5
Entinostat
Phase III – breast cancer
TBD6
CTCL – cutaneous T-cell lymphoma
1 Archin et al., Nature 2012; 487: 482–85; 2 Archin et al., J Infect Dis 2014; 210: 728–35; 3Elliott J et al., Plos
Pathogens 2014 (in press); 4Rasmussen et al., Lancet HIV 2014; epub Sept 16; 5Sogaard et al., 20th International
AIDS Conference (AIDS2014), Melbourne, 2014; 6Wightman et al., AIDS Nov 28;27(18):

23. A single dose of HDACi vorinostat activates HIV transcription in vivo
Baseline cART
800
600
400
200 60 40 20
Pt 1
Pt 2
Pt 3
Pt 4
Pt 5
Pt 6
Relative HIV-1 gag RNA copies
100
Pt 7
Pt 8
Vorinostat 400 mg
Archin et al., Nature 2012; 487: 482

24. Can continuous doses of vorinostat “activate” latent infection?
day 1 3 7 14 21 28 84
cART>3 years
HIV RNA<50 c/ml
CD4>500 cells/ml
cART
Vorinostat 400 mg/day *
Rectal biopsy * *
Single site, single arm, non-randomised observational study
Elliott et al., Plos Pathogens 2014

25. Vorinostat induces a significant increase in unspliced HIV RNA
Median fold change max = 7.4 (IQR 3.4, 9.1)
Fold increase CA-US HIV RNA above baseline
Elliott et al., Plos Pathogens 2014

26. But…no change in plasma HIV RNA or HIV DNA

27. Panobinostat: a more potent HDACi
cART
M/W/F 28 49
n=16
day
cART>3 years
HIV RNA<50 c/ml
CD4>350 cells/ml 21 7 14 35 42
Panobinostat 20mg/day, 3 times a week
(Monday, Wednesday, Friday)

28. The HDACi panobinostat activates latent HIV and produces some virus
Fold increase in CA-US RNA
ANOVA p<0.0001
days
Some increase in virus in plasma in some patients
No change in the reservoir ie no change in HIV DNA
Rasmussen et al., Lancet HIV 2014

29. The HDACi romidepsin is more potent and activates virus release
HIV RNA in plasma, copies/ml
Days post first infusion
No change in HIV DNA following romidepsin x 3
Sogaard et al., 20th International AIDS Conference, Melbourne, 2014

30. What we have found so far:
A single dose of VOR induces expression of full- length HIV RNA within latently infected resting CD4+ T cells.
The optimal dosing schedule of VOR, and its ability to repeatedly and completely perturb latency in all relevant infected cells, must be established
Separately, the potential for VOR to induce antigen expression in (some or all) latently infected cells must be established

31. Will HDACi be enough?
Not all studies show induction of viral expression by HDACi ex vivo
Combinations of anti-latency compounds with different mechanism of action may be more effective
Latently infected cells that express HIV-1 RNA may not all die

32. Latently infected cells are rare

33. HIV DNA, RNA, antigen & viruses
HIV Antigen
(protein)
detector
QVOA
growing virus
The “Real”
Reservoir

34. Where can HIV eradication approaches be tested?
“HUMANIZED” MICE

35. When latency is disrupted, mechanisms to kill virus- expressing cells may be needed
INFUSE BROADLY NEUTRALIZING ANTIBODY OR ANTIBODY PRIMED FOR ADCC
IMPROVE HIV-1 SPECIFIC CD8 RESPONSE THROUGH EX VIVO MANIPULATION
EXPANSION or
TCR ENHANCEMENT
Dual function Ab to recruit immune effectors without the need for HIV-specific cells
AUGMENT HIV-1 SPECIFIC IMMUNE RESPONSE WITH HIV-1 VACCINE PRIOR TO “KICK”
Wake up “exhausted” HIV-1 specific cells
eg. Checkpoint inhibitors

36. Blocking PD1-PDL1 to boost immune function
Mason et al., CROI 2014

37. Anti-PDL1 led to successful virus control following ART in half the monkeys
isotype n=5; anti-PDL1 n=9
responders n=4, non-responders n=5
ACTG: single infusion of anti PDL-1 (BMS) to start in 2014

38. Current clinical trials to eliminate latently infected cells
Agent
Design
PI (location)
Status
HDACi
Vorinostat + vaccine
10 days (acute treated HIV)
Frater (UK)
Approved
Rhomedepsin
Single dose
ACTG (US)
Rhomedepsin + vaccine
Ostergaard (Denmark)
Rhomedepsin alone (complete)
Other
Disulfiram
14 days 500mg/day
Deeks (US)
Transient increase in plasma RNA (Spivak CID 2014)
3 days
500mg-2g/day
Elliot/Lewin (Australia)
Enrolment complete
Anti-PDL1 (BMS)
Eron (US/ACTG)
Enrolling

39. Managing the hope and hype
Danish breakthrough for HIV cure expected 'within months'
April 29th, 2013

40. Expectations of study participants
20 participants with \ HIV infection in vorinostat (HDACi) trial
Top priority in cure research (%)
McMahon et al., AIDS 2014 (in press)

41. Conclusions
We are assembling the tools to design, discover, and test anti-latency therapy
Rational design based on biological understanding of latency
Screen-based discovery
Harnessing the immune response, or other cellular pathways, or new technology to assist in the clearance of persistently infected cells is the next step
Developing platforms and novel assays to allow these developments to be efficiently validated, and safely tested in the clinic

42. Acknowledgements

43. Module Collaborators