Understanding mucosal immunity and HIV transmission: the way to new prevention technologies Robin Shattock Centre for Infection, Division of Cellular & Molecular Medicine, St George’s University of London, UK AIDS 2010, Vienna

Mechanisms of transmission Infection of macaques after vaginal exposure to cell-associated simian immunodeficiency virus. Sallé B, Le Grand R.J et al. Infect Dis ;202(3):

For any prevention technology, success will depend on maintaining protective inhibitor concentrations at the mucosal portals of entry. Drug penetration

First generation concepts (successfully tested) but lacked potency Drive for more potent products (Anti-Retroviral ARV) products Systematic testing of the biological plausibility of different targets in primate models Drug distribution and tissue activity studies in NHP and human studies (PK/PD) Proof of concept for first ARV candidate (TFV gel) Current need to better understand dosing relationship (coital/non coital) Prioritization of new formulations that maximize adherence Development of combination products will increase in importance Prioritize (product/dosing) and acceleration of additional clinical trials State of the pipeline for microbicides.

Hours Days Weeks Haase T., Ashley, 11 March 2010, Nature, v. 464, p Time Viral binders CCR5 antagonists Inhibit entry PrEP Microbicide Inhibit reverse transcription NRTI (TDF) NNRTI (DPV/UC781) Inhibit Integrase & protease Integrase inhibitors Protease inhibitors

Nonnucleoside RTIs (NNRTIs) Delavirdine (DLV) Efavirenz (EFV), MIV-150* Nevirapine (NVP), Dapivirine (TMC-120) * Building on the ART of HIV-1 therapy – and success of CAPRISA 004 Protease Inhibitors (PIs) Amprenavir (APV) Atazanavir (ATV) Darunavir (DRV) * Fosamprenavir (FPV) Indinavir (IDV) Lopinavir/ritonavir (LPV/r) * Nelfinavir (NFV) Ritonavir (RTV) * Saquinavir (SQVhgc) * Tipranavir (TPV) Abacavir (ABC) Didanosine (ddI) Emtricitabine (FTC) * Lamivudine (3TC) * Stavudine (d4T) Tenofovir (TDF) * Nucleos(t)ide Reverse Transcriptase Inhibitors (NRTIs) Fusion Inhibitors (FIs) Enfuvirtide (ENF) Chemokine Receptor 5 (CCR5) Inhibitors Maraviroc (MVC)* Zalcitabine (ddC) Zidovudine (ZDV) 3TC/ABC 3TC/ABC/ZDV 3TC/ZDV FTC/TDF * Multiple Class Combinations Integrase Inhibitors EFV/FTC/TDF Raltegravir* * current candidates for PrEP and/or microbicides

Compounds protective in monkey models R5 virus challenges b12: MAb, SHIV-162P4, vaginal. PSC-, 6P4-, 5P12-RANTES: Modified chemokine, SHIV-162P3, vaginal. BMS-806: Small molecule to gp120, SHIV-162P3, vaginal. C52L: Peptide to gp41, SHIV-162P3, vaginal. T1249: Peptide to gp41, SHIV-162P3, SIVmac251, vaginal. CMPD 167: Small molecule to CCR5, SHIV-162P3, vaginal. Maraviroc: Small molecule to CCR5, SHIV-162P3, vaginal. TDF (tenofovir gel): NRTI, SIVmac251, vaginal + rectal (up to 3 days post application) *. L , Integrase inhibitor, SHIV-162p3, vaginal. NCp7 Nucleocapsid protein inhibitors (ZFI), SHIV-162P3+SHIV89.6, vaginal Griffithsin: Protein lectin, SHIV, SIVmac, vaginal PC-815: Carrageenan/MIV-150 (NNRTI), RT-SHIV, vaginal PC-1005: Carrageenan/MIV-150/ZInc, SHIV-RT, vaginal X4 virus challenges CAP: Polyanion, SHIV-33A, vaginal. Cyanovirin-N: Protein lectin, SHIV-89.6P, vaginal + rectal. SPL7013: Polyanion, SHIV-89.6P, vaginal PRO-2000: Polyanion, SHIV-89.6PD, vaginal. AMD3465: Small molecule to CXCR4, SHIV-189.6P, vaginal. >20 studies demonstrating biological plausibility TFV gel now becomes the bench mark. PK now needs to be related to protection

Non human primate studies are now being configured to relate drug distribution (Systemic, tissue, topical) to protection, providing a bridge to human studies (pharmacokinetics (PK)) – how much drug is needed and where is it need to provide protection? Parallel human studies are being performed to determine drug distribution following application Most importantly, studies to determine tissue drug activity are being developed as potential surrogate markers of protection (pharmacodynamics (PD)) – is the drug active at the site were it should work Drug distribution and tissue activity studies seen as critical (PK/PD) These are now seen as critical tools for product development Application of the tools to TFV gel may be critical in determining dosing regimes (coital/daily) and providing a bench mark for other candidates

Vaccines Pre-exposure prophylaxis STI treatment Male and female Condoms and lube Cervical barriers? Anti-retroviral therapies Opportunistic infection therapies Basic care Rights driven behavior change Prior to ExposurePoint of Transmission Prevention Time of Exposure Prior to Exposure Treatment and Care Male circumcision Microbicides Prevention for positives Education and behavioral change VCT Prioritization of new formulations that maximize adherence

1% gadolinium 1:100 in a sterile system with Dextrin sulphate gel, 2hrs post application (C. Lacey, Imperial College) Target cells must be protected at the time of viral exposure Critical parameters – turnover of target cells entering and exiting mucosal tissue in steady state and inflammation - Potential entry of infected donor cells

Coitally dependent, daily and sustained delivery Adapted from Karl Malcolm - Queen’s University Belfast Sex acts, A, B, C Semi-solid formulation, coitally independent Vaginal ring reservoir Gel formulation, coitally dependent

Biological questions raised by CAPRISA % protection in those with >80% compliance. Why not higher? – if measured compliance = real compliance Concentration of drug – would more be better (more TDF, or additional drug combinations) Spacing of dosing (BAT 24 – pre and post) Better adherence – alternative dosage forms/regimes Target cell turnover (inflammation, co-infection) Potential differences in efficacy against cell free vs cell associated virus?

Facing the problem of resistance to microbicides: when and how? Risks of resistance for topical ARV microbicdes are hypothetical. Risks may differ between products Topically applied drug may prevent transmission of resistant isolates Resistant virus may have reduced fitness for transmission In a clinical trial the risk/benefit ratio is likely to be low No resistance seen in CAPRISA 004 trial – but too early to asses impact on treatment ARV approach likely be initially implemented as a prescription only Resistance continued to be monitored with wider introduction If identified, enhanced emphasis would be placed on combinations

Product prioritization Mechanism of action: NRTI, NNRTI, CCR5 PI, II etc Stage of development – human data, manufacture Appropriateness for combinations Pharmacokinetics/pharmacodynamics (PK/PD) - NHP/human – TFV comparison Ability to be delivered in multiple dosage forms

Sustaining Accelerating progress in a changing prevention landscape Vaccine - Prime/Boost Thailand Oral TDF - IDU Thailand Oral Truvada – Heterosexual Botswana Oral TDF -MSM US (Ph II) Oral Truvada - MSM (iPrEx) Oral TDF, Truvada - Partners PrEP Oral Truvada - FemPrEP Microbicide - BufferGel, PRO2000 Microbicide - Tenofovir Gel CAPRISA 004 Microbicide - PRO2000 Oral TDF & Truvada & Tenofovir gel - VOICE Microbicide - Dapivirine gel & ring Index Partner Treatment HSV-2 Treatment - Infectiousness New Vaccine concept(s) Microbicides PrEP Vaccines Treatment Vaccine - DNA Prime/Ad5 Boost US TMC UK (Ph I/II)

Immunological protection Can they be combined? ARV protection

How might new prevention options work together? Combining microbicides or PreP with vaccines may deliver even better protection – the window for placebo controlled trials my be closing Provides protection during the immunization period Reduces infectious challenge. Boosts local immunity (virus/antigen) Broadening localized immunity through protected exposure to prevalent virus. Converting high risk challenge to low risk challenge (RV144) Vaccine induced immunity may cover intermittent compliance, break through virus and prevent resistance evolution

Pathways to reversing the epidemic A comprehensive approach to prevention ARV Prep ARV microbicide Partially effective vaccine highly effective vaccine Time HIV incidence

Thank you for your attention NIH U19 award AI060614–01