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ART containing vaginal microbicides in the clinical pipeline: A status of the studies Salim S. Abdool Karim Director: CAPRISA Pro Vice-Chancellor (Research): University of KwaZulu-Natal Professor in Clinical Epidemiology, Columbia University Executive Committee Member, Microbicide Trials Network
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Outline Is there still a need for microbicides? Past & current microbicide clinical trials ARV microbicides in clinical and pre- clinical development Challenges in ARV microbicides Conclusion
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Vaginal gel applicator Vaginal ringVaginal film A microbicide is a product that can be applied to the vaginal or rectal mucosa with the intention of preventing the transmission of sexually transmitted infections including HIV Microbicides containing antiretroviral drugs = Topical PrEP (Pre-exposure prophylaxis)
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Is there still a need for microbicides?
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Source: Abdool Karim Q, Abdool Karim SS, Singh B, Short R, Ngxongo S. AIDS 1992; 6: 1535-9 Age and gender distribution of HIV infection in South Africa 0 <910-14 Prevalence (%) 15-1920-2425-2930-3940-49 2 4 6 8 10 Female Male >49
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Source: Data from South African Department of Health Antenatal Surveys. www.doh.gov.za/ 0 5 10 15 20 25 30 35 1989199119931995199719992001200320052007 HIV Prevalence (%) The HIV epidemic in South Africa HIV prevalence in pregnant women attending public antenatal clinics in South Africa 1989-2006
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Past & Current Microbicide Clinical Trials Stopped for futility Safe but not effective Increased HIV infection Zena Stein publishes seminal article “HIV prevention: the need for methods women can use” Kenya N-9 sponge trial FHI N-9 film trial UNAIDS COL-1492 trial CONRAD CS trial FHI SAVVY trial PopCouncil Carraguard trial HPTN PRO2000 & BufferGel trial 1 st class: Surfactants eg. N9, SAVVY 2 nd class: Polymers eg. PRO2000, Carraguard, Cellulose Sulfate (CS) 3 rd class: ARVs eg. Tenofovir gel, Dapivirine gel/ring 4 th class: Co-receptor Blockers eg. CD4 blocker, CCR5 Blockers CAPRISA Tenofovir gel trial MTN Tenofovir gel & tablet trial MDP 0.5% PRO2000 trial ‘90 ‘92 ’98 ’00 ‘03 ‘04 ‘04 ’05 ’05 ’07 ’09 ‘10 IPM Dapivirine gel & ring trial FHI CS Trial 2% PRO2000
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ARV microbicides
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Tenofovir gel nRTI from Gilead Sciences, licensed to CONRAD & IPM Effective & licensed therapeutic agent Very good safety profile with long half life Shows protection in several animal challenge studies Multiple genetic changes needed for resistance
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Gel --Cervicovaginal Fluid Gel-- Vaginal Tissue Tablet-- Cervicovaginal Fluid Tablet --Blood Plasma Gel --Blood Plasma CONRAD PK Study Results Information courtesy of Jill Schwartz, CONRAD Tablet data: Dumond et. al AIDS 2007
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Tenofovir Clinical Development Pathway 1995 // 2006 2007 2008 2009 2010 1995 // 2006 2007 2008 2009 2010 HPTN Phase I safety & PK HPTN Phase IIa safety &PK CONRAD tenofovir gel male tolerance MTN Phase I gel and tablet PK MTN Phase I safety in pregnancy MTN VOICE Phase IIb trial CAPRISA Phase IIb Test of Concept trial 1 st Macaque challenge study 20 th Macaque challenge study CONRAD gel PK
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CAPRISA 004 Tenofovir gel trial: Status Phase IIb randomized, double-blind, ToC trial 845 of 1250 participants enrolled Overall 12 month retention rate: 91% Gel adherence: 88% & Condom use: 74% Pregnancy rate: 2.8 per 100 person-years Challenge: co-enrolled participants – 183 terminated Quarter of total HIV endpoints reached (on target) Estimated completion: 1 st quarter 2010
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V aginal and O ral I nterventions to C ontrol the E pidemic Five-arm, multi-site, randomized trial Status: Protocol approved – accrual to start in mid-2009 TOTAL SAMPLE (4200) ORAL (2520) Truvada (840) Viread (840) Placebo tablet (840) TOPICAL (1680) Tenofovir Gel (840) Placebo Gel (840) MTN-VOICE : Phase IIb Tenofovir gel Viread tablet & Truvada tablet trial Information courtesy of Jeanne Marrazzo, MTN
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Dapivirine (TMC120) NNRTI developed by Tibotec, licensed to IPM Developed originally as therapeutic - highly potent ARV Low toxicity Easily manufactured, stable & cheap Also as combination: Dapivirine + Maraviroc N C H 3 N C H 3 C 3 HC H NN H N Information courtesy of IPM
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Dapivirine Clinical Development Pathway 2007 2008 2009 2010 2011 IPM Dapivirine gel male tolerance IPM Dapivirine ring PK IPM Dapivirine ring safety & PK IPM Dapivirine gel PK IPM Dapivirine gel safety (mulitple studies) IPM Dapivirine gel & ring efficacy trial Information courtesy of IPM
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IPM: Phase III trial design Adaptive trial design with multiple arms Only the best in class moves forwardOnly the best in class moves forward Strong focus on safety (early looks for harm) Early stop for futility Powered for licensure Improved adherence Daily participant contactDaily participant contact Smart applicatorSmart applicator Longer-acting formulationsLonger-acting formulations Anticipated start date: mid 2010 Information courtesy of IPM
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UC-781 Licensed to CONRAD NNRTI with potent anti-HIV activity Low toxicity Also as combination: UC-781 + Tenofovir
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UC-781 Clinical Development Pathway 200620072008 Phase I Safety Phase 1 Safety (14 day) Male Tolerance Vaginal pK and safety Rectal Safety Information courtesy of Sharon Hillier, MTN
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MIV-150 NNRTI licensed to the Population Council Combination (PC-815): MIV-150 + Carraguard Trials starting in 2008/9: Phase 1 safety and PKPhase 1 safety and PK Male toleranceMale tolerance Information courtesy of Louise Pedneault, PopCouncil
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MaravirocMaraviroc Licensed to IPM Being developed as a gel and ring as combination product: Dapivirine + Maraviroc Currently in pre-clinical assessment: Animal vaginal dosing studies ongoing Animal vaginal dosing studies ongoing Information courtesy of IPM
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CompoundLicenseYearType/Stage Development Status M167, M872, M882 Merck2005CCR5 blockers Pre-clinical (on hold) BMS793BMS2005gp120 binder Early pre-clinical L’644 peptide Merck2008gp41 binderEarly pre-clinical IPM pipeline: other compounds Information courtesy of IPM
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Challenges in ARV microbicide trials Criteria for selection of candidates: No validated animal model - so multiple criteria usedNo validated animal model - so multiple criteria used Promising new approach: ex-vivo challenge modelPromising new approach: ex-vivo challenge model No surrogate markers of safety & protection HIV endpoint: only gold standard for safety & efficacyHIV endpoint: only gold standard for safety & efficacy Real world adherence to daily or coital use esp. over years (eg. daily acyclovir use at 12 months = 34.5%) # Potential for drug resistance - will this affect their subsequent care and choice of ARV treatment? Trial design challenges (IOM report): # Source: Watson-Jones, Weiss, Rusizoka, et al: NEJM 2008; 358: 1560-71
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Conclusion 3 RTI ARVs (Tenofovir, Dapivirine & UC-781) are well along in the clinical development pathway First ARV microbicide effectiveness trial underway Two large effectiveness trials (VOICE & IPM-009) to start within next 2 years New ring formulation – important advance Two other ARVs (MIV-150: NNRTI) and (Maraviroc: CCR5 inhibitor) are in advanced pre-clinical testing Combination microbicides are being developed
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Acknowledgement My appreciation to the following people who provided information for this presentation: My appreciation to the following people who provided information for this presentation: Sharon Hillier, Jeanne Marrazzo, Lisa Noguchi Pam Norick, Zeda Rosenberg Henry Gabelnick, Jill Schwartz, Chris Mauck Louise Pedneault Quarraisha Abdool Karim Leya Hassanally
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