DEVELOP AND TEST STRATEGIES TO ENHANCE THE CAPACITY OF THE HOST IMMUNE RESPONSE TO CONTROL ACTIVE VIRUS REPLICATION

Giuseppe Pantaleo, M.D.Professor of MedicineHead, Division of Immunology and AllergyExecutive Director, Swiss Vaccine Research InstituteLausanne University Hospital, Lausanne, Switzerland

HIV Replication Cycle and Sites of Drug ActivityAZT (Zidovudine-Retrovir)ddl (Didanosine-Videx)ddC (Zalcitabine-Hivid)d4T (Stavudine-Zerit)3TC (Lamivudine-Epivir)ABC (Abacavir-Ziagen)FTC (Emtricitabine, Emtriva)

Capsidproteinsand viralRNA

Protease

Nucleus

IntegraseReverse

Transcriptase

NRTIs

Tenofovir DF(Viread)

nTRI

Efavirenz (Sustiva)Delavirdine (Rescriptor)Nevirapine (Viramune)Etravirine (Intelense)

NNRTIs

Cellular DNA

HIV Virons

Indinavir (Crixivan)Ritonavir (Norvir)Saquinavir (Fortovase)Nelfinavir (Viracept)Lopinavir/ritonavir (Kaletra)Atazanavir (Reyataz)Fos Amprenavir (Aptivus)Darunavir (Prezista)

Protease Inhibitors

CD4 Receptor

Fusion InhibitorT-20 (enfuvirtide,Fuzeon)

New HIVParticles

CCR5 AntagonistMaraviroc (Celsentri)

Integrase InhibitorRaltegravir (Isentress)

Unintegrateddouble strandedViral DNA

ViralRNA

gag polpolyprotein

ViralmRNA

IntegratedViral DNA

Attachment UncoatingReverse

Transcription Integration Transcription TranslationAssembly and

Release

1 2 3 4 5 6

Why Does HIV Persist In Infected Individuals?Two Main Hypotheses

Latent HIV Reservoir

• Size: 105-107 cells• Half life memory• CD4 T cells: 43 months• Estimated time for

eradication: ~70 years under full virus suppression by ART

• Not susceptible to ART• Not susceptible to the

immune system

Residual HIV Replication

• Covert cellular reservoir• Priveleged anatomic

compartment• Resistant to HIV cytopathic effect• Poorly accessible to cytotoxic CD8

T cells• Minimal virus spreading• Replenishment of the latent

cellular reservoir

TCM/TTM CD4 T cells

CD4 T cells?Macrophages?DCs?

Immunological Measures Associated with Control of HIV Replication - I Functional profile

Proliferation capacity (Migueles et al. Nat Immunol 2002, Zimmerli , PNAS, 2005; Day, J Virol, 2007)

Polyfunctional cytokines profile (Pantaleo and Koup, Nat Med 2004, Harari et al. , Blood 2004; Harari et al., J Immunol 2004, Betts et al., Blood, 2006)

Cytotoxic profile Perforin/GrmB expression (Hersperger, PLoS Path, 2010; Migueles et al.,

Immunity 2008) Inhibition of virus replication (Freel et al., J Virol, 2010; Yang, JID, 2012

TCR avidity (Almeida et al., J Exp Med, 2008)

TCR clonotypes and protective role of HLA class I molecules (Chen et al. Nat Immunol, 2012)

Lack of exhaustion markers (Day, Nature, 2006; Trautmann, Nat Med, 2006)

Immunological Measures Associated with Control of HIV Replication - II

Epitopes targeted More Gag- and fewer Env-epitopes (Kiepiela, Nature, 2006) Conserved among strains (Turnbull, J Immunol, 2006) Mutations having a fitness cost (Martinez-Picardo, J Virol, 2006)

Immune Activation (lack of immune activation) (Many, Many Investigators)

Genetic Factors Long-term nonprogressors (LTNP) and ‘Elite controllers’ (EC): spontaneous control of

HIV-1 replication and preservation of high CD4 T-cell counts in the absence of ART HLA-B*57, HLA-B*27 and HLA-B*5801 genotypes are associated with viral control

(Carrington M, Annu Rev Immunol 2003) Genome-wide association studies indicate that:

The HLA-viral peptide interaction is the main determinant of HIV-1 control (Pereyra F, Science 2010)

Specific amino acids in the HLA-B peptide-binding groove are important in HIV-1 control (The international HIV controllers study, Science 2010)

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Immunological Measures Associated with Control of HIV Replication

Based on the immunological measures associated with control of HIV replication, the immunological interventions should :

a) induce recovery of proliferation capacity of CD4 and CD8 T-cells

b) induce polyfunctional T-cell responses

c) reduce immune activation

d) reduce T-cell exhaustion

e) induce predominantly CD8 T-cells specific to Gag epitopes

f) induce protective TCR clonotypes

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Immunological Strategies to Modify the Host Immune Response

Vaccination Cytokines Blockade of regulatory receptors Inhibitors of chronic immune activation

Immunological Strategies to Modify the Host Immune Response: Vaccines

Therapeutic vaccine clinical trials performed in the last 15 years: Number of clinical trials: n = 29 Number of subjects enrolled: n = 4376 (3000 in one trial) Type of vaccine:

recombinant proteins/peptides (used alone): 5 trials (n=460 subjects)

altered/killed HIV: 1 trial (n = 3000 subjects) DNA-based vaccines: 5 trials (n = 121 subjects) Viral vector-based vaccines (used alone): 14 trials (ALVAC canarypox

vector used in 8 trials, MVA poxvirus vector in 1 trial, NYVAC poxvirus vector in 1 trial, Fowlpox vector in 1 trial, Ad5 vector in 1 trial) ( n = 698 subjects)

Dendritic cell-based vaccines: 4 trials (n = 97 subjects)

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Immunological Strategies to Modify the Host Immune Response: Vaccines

Therapeutic vaccine clinical trials performed in the last 15 years: Number of clinical trials: n = 29 Number of subjects enrolled: n = 4376 (3000 in one trial) Clinical efficacy: effect on viral load (HIV RNA copies/ml in plasma)

9 clinical trials: no therapeutic efficacy 6 clinical trials: therapeutic efficacy not measured 1 clinical trial (ongoing) 13 clinical trials: modest therapeutic efficacy measured (delayed viral

load rebound in 5 trials, prolongation ART free time in 4 trials, 0.5 log reduction in plasma viremia in 3 trials and 0.26 reduction in plasma viremia in 1 trial)

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Immunological Strategies To Modify The Host Immune Response: Cytokines

Clinical clinical trials performed in the last 15 years: Number of clinical trials: n = 4 Number of subjects enrolled: n = 6007 (5806 in 1 trial) Type of cytokine (IL-2 in 3 trials and IL-7 in 1 trial) Clinical efficacy: effect on viral load (HIV RNA copies/ml in plasma)

2 clinical trials: no therapeutic efficacy 1 clinical trial: therapeutic efficacy not measured 1 clinical trial: modest therapeutic efficacy measured (prolongation

ART free time)

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Immunological Strategies to Modify the Host Immune Response

What went wrong ? Skepticism in the field Limited understanding of the immune correlates of protection from HIV

disease when most of these studies were performed The large majority of the studies were not appropriately powered to

measure clinical efficacy Challenges in the assessment of the HIV latent cell reservoir Limited resources Mono therapy approach

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Combination Strategies To Purge The HIV Reservoir

Latent ReservoirTCM/TTM CD4 cells

Reactivation

of replication

HDAC Inhibitors,

SAHA,Prostratin,Bryostatin 1,5-azathidine,anti-PD-1

Therapeutic vaccine,

anti-PD-1,

Cytokines (IL-2, IL-7),

Inhibitors of immune

activation

Potentiation of

immune

response

APOPTOSIS APOPTOSIS

Killing by effector CD8 T cells

HIVcytopathic

effect

Potentiation ofimmune response

Covert Cellular Reservoir with

Residual Replication

APOPTOSIS

Selective

targeting

Antibody coupled with toxins

Therapeutic vaccine programmeFrom POC to Clinical and surrogate end points

Accurate quantification of the therapeutic effect, i.e.

immunogenicity (broad polyepitopic and polyfunctional T cell responses)

Biomarkers associated with residual replication (markers of Immune activation and inflammation)

reduction of the latent cell reservoir over time (decrease of viral DNA levels in blood and gut; integrated/non integrated DNA; frequency of latent replicating cells)

Development of mathematical model to monitor the immune responses (integrated analysis) durability of the therapeutic effect over time (effect of repeated

boosts) prediction (correlates)

0 4 8 12

HAART plus DC (LPS-IFN)-HIV lipo 5 vaccine

19 pts

Interrupt HAART

weeks 24

Primary endpointSafety

16 22

Vaccinations

48

Secondaryendpoint

Immunogenicity*

Follow up

Immune statusViral status

END OF STUDY

DALIA 1 trial: outline

HIV+, CD4>500 cells/mlNadir > 300 cells/mlHIV RNA < 50 cp/mlc-ART > 12 months

Y. Lévy, R. Thiébaut, G. Chène, J. Banchereau, K.PaluckaCROI 2012, Seattle, # G-109

* Elispot IFN-g,ICS, Luminex, transcriptomic (blood, cells)

Changes in plasma HIV RNA viral loads

Weeks

CD4

CD8

PRE-VACCINATION POST-VACCINATION

IL-2

IFNg

Vaccination with DCs leads to expansionof LIPO-5 mix-specific T cells in the blood

D1-11 Y. Levy et al CROI 2012

Luminex responses (IFN-g)Luminex responses (IFN-g)

G17 G253 N66 N116 POL C-

20

10

MF

I (x

10

3)

PRE-VACCINATION

G17 G253 N66 N116 POL C-

20

10

POST-VACCINATION

D1-1D1-2D1-3D1-4D1-5D1-6D1-7D1-8D1-9D1-10D1-11D1-14D1-15D1-17D1-18D1-19

Y. Levy et al CROI 2012

DALIA (Laura Richert)DALIA (Laura Richert)

L. Richert et al, IAS 2012 Abs THPE097

APHR-I L21

0

50

100

150

200

250

GAG PEPTIDE #

pg

/m

l

8

29

1

7538

87

6h-IFNg, IL-10 ICS

CD3, CD8

HIV+ Apher

PBMC

IL-2 (day 2)

day 7 Restim

Supernatant for

LUMINEX

48h IL-2IL-17IL-21TNFaIP10IL-13Il-1bIL-10

Aphr1 Profile of Cytokine Induced by HIV Gag Peptides by Luminex

+ Monica Montes, Sandy Zurawski (BIIR)

+ Sophie Hue (MIC)

DALIADALIA

J. Skinner, Y.Levy, R. Thiébaut, J. Banchereau, D. ChaussabelAIDS Vaccine 2011, Bangkok

An inverse correlation was found between the maximum observed VL and:% of polyfunctional CD4+ (r=-0.63, FDR=.007); production of IL-2 (r=-0.67, FDR=.006);

IFN-γ (r=-0.58, FDR=.01); IL-21 (r=-0.66, FDR=0.006) and IL-13 (r=-0.78, FDR=.001).

Principal Component Analysis: Correlation immunogenicity and Virological markers

Principal Component Analysis: Correlation immunogenicity and Virological markers

L. Richert et al, IAS 2012 Abs THPE097

Collaboration for HIV/AIDS Immunological Therapy (CHAIT)

Partners: Swiss Vaccine Research Institute/Lausanne University HospitalVaccine Research Institute, FranceBoheringer IngelheimFIT BiotechGSK BiologicalsSanofi PasteurViiV Healthcare

Scope and Objectives of the CHAIT Initiative

Establishment of a task force for the development of immunological therapeutic interventions to achieve ‘Functional HIV Cure’ and with the ultimate objective of HIV eradication.

Engagement of multidisciplinary expertise from academia and industry. A public-private partnership initiative is necessary for developing an innovative scientific roadmap for the clinical development of combined immunological therapeutic interventions to complement ART.

Added value and objectives: to identify scientific priorities to develop new concepts to bring into clinical development to engage a dialogue with Regulatory Agencies to define new criteria of response to

therapy to advocate for ear-marked funding at the level of international funding agencies and to

seek secured funding for long-term clinical studies.

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