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Potential role of PEP, PrEP and ART for HIV Prevention among Men who have Sex with Men

Potential role of PEP, PrEP and ART for HIV Prevention among Men who have Sex with Men . Frits van Griensven, PhD, MPH Division of HIV/AIDS Prevention US Centers for Disease Control and Prevention and Thailand MOPH - US CDC Collaboration .

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Potential role of PEP, PrEP and ART for HIV Prevention among Men who have Sex with Men

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  1. Potential role of PEP, PrEP and ART for HIV Prevention among Men who have Sex with Men Frits van Griensven, PhD, MPH Division of HIV/AIDS Prevention US Centers for Disease Control and Prevention and Thailand MOPH - US CDC Collaboration Disclaimer: The views expressed herein are solely the responsibility of the author and do not necessarily represent the official views of the CDC

  2. In this presentation 1) Non-occupational (or sexual) post exposure prophylaxis (NPEP) 2) Pre-post exposure prophylaxis or PrEP Oral Topical 3) Antiretroviral treatment for prevention

  3. Non-occupational post exposure prophylaxis (NPEP) for MSM Efficacy concerns • No solid data supporting efficacy in MSM; controlled studies are not available • Observational studies in MSM show no clear effect on transmission (Kahn et al, 2001; Schechter et al, 2004; Poynten et al, 2009) • Animal data show no protection against rectal SHIV challenge if started too late (+24 hrs) but some protection if started timely (+2hrs) (Garcia-Lerma et al, 2010) • Men fail to timely recognize high risk exposure, even in the presence of direct access to ARVs (Schechter et al, 2004) • Public health impact of NPEP is considered limited and only cost-effective in very specific situations (MMWR, 2005; Poynten et al, 2007)

  4. Non-occupational post exposure prophylaxis (NPEP) In conclusion • NPEP not feasible for programmatic scale-up in MSM • Can be offered as an individual service on a case-by-case basis

  5. Non-occupational post exposure prophylaxis (NPEP) • BUT eventually PEP led to PrEP • If you need to take so soon after, why not take it before? • Series of animal studies looking at the timing of drug intake versus exposure, 2 hrs before, 24 hrs after etc, etc. • Particularly relevant are the rectal challenge models • The results of these experiments are driving the PrEP research agenda for MSM today

  6. Controls (n = 21) FTC/TFV daily (n=6) Efficacy of daily and pre- and post-exposure oral Truvada in preventing SHIV infection following rectal challenge in macaques 100 (HR>20, p<0.0001) FTC/TFV -2h/+22h (n=6) (HR>20, p<0.0001) 75 50 % Uninfected macaques 25 0 0 2 4 6 8 10 12 Number of weekly rectal exposures Garcia-Lerma et al, PLOS, 2008

  7. iPrEx: PrEP Initiative Sponsored by NIH/NIAID/DAIDS With co-funding from the Bill and Melinda Gates Foundation And drug donated by Gilead Sciences Slides, courtesy of Dr Robert Grant

  8. Men who have sex with men • MSM with a heavy burden • In the Americas • In Asia • In Africa • Different from HXY, IDU • Differing penetration of virus or drug into rectal tissue • iPrEx is the only study of PrEP efficacy in MSM Lima, Peru

  9. PrEP Initiative (iPrEx) • Men who have sex with men • Randomized 1:1 FTC/TDF vs Placebo • Daily oral • Followed for: • HIV seroconversion • Adverse Effects • Metabolic Effects • HBV exacerbations • Risk behavior and STIs (including HSV) • Adherence • If infected • Drug resistance • Viral load • Immunological responses and CD4 counts

  10. Intermittent PrEP (iPrep) • May be more in line with sexual life style • Reduce pill burden • Reduce drug burden • Reduce side-effects • Decrease costs • May increase adherence and coverage • And may be increase safer sex behavior • And is supported by animal models

  11. Efficacy of intermittent PrEP with Truvada in the repeat low-dose macaque model: design Garcia-Lerma et al, 2010

  12. -22h/+2h HR = 16.7, p = 0.006 -3 days/+2h HR = 15.4, p = 0.008 -7 days/+2h HR = 9.3, p = 0.003 +2h/+26h (PEP) HR = 4, p = 0.03 -2h/+22h HR = 4.1, p = 0.02 Risk reduction by iPrEP with oral Truvada 100 75 % Uninfected macaques 50 25 Untreated controls (n=32) (9 real time and 23 historical) 0 0 2 4 6 8 10 12 14 Number of rectal exposures Garcia-Lerma et al, 2010

  13. Figure 2 Sex frequency among 823 HIV negative MSM in Bangkok Thailand (“On how many days in the past week did you have sex?”) % reporting sex Number of days van Griensven F, et al. 2010

  14. Figure 4 Sex planning among 823 HIV negative MSM in Bangkok Thailand (“On the last day you had sex, was the first sex on that day planned?”) % reporting planned sex Day of the week van Griensven F, et al. 2010

  15. Multivariate analysis of sex planning among 823 HIV negative MSM in Bangkok, Thailand (first sex on last sex day was planned) Multivariate van Griensven F, et al. 2010

  16. Intermitent PrEP (iPrep) • Post IPREX generation of studies will be comparing continuous versus intermittent PrEP • Non-inferiority or equivalency studies (costly, large N) • Daily vs pre-post exposure • Daily vs standing doses plus post exposure dose • Daily vs standing doses • HPTN 067: the “ADAPT Study” • “Alternative Dosing to Augment Pill Taking Study” • Phase II, Randomized, Open-Label, Pharmacokinetic and Behavioral Study of the Use of Intermittent Truvada • 3-armed study: daily, vs pre-post, vs bi-weekly standing plus post exposure dose • N=360, MSM n=180 Bangkok; HW n=180, Capetown • Adherence, coverage, PK and risk behavior • Start January 2011

  17. Safety and adherence to intermittent Emtricitabine/Tenofovir for HIV pre-exposure prophylaxis (PrEP) in Kenya and Uganda. Mutua et al. IAC 2010, MOPE0369

  18. In the shadow of Caprisa Strong push for evaluation of rectal microbicides, e.g., TDF gel, possibly in combination with oral formulations Figure: Courtesy of Dr Ian McGowan

  19. Rectal Specific Products • CHARM Program • Combination HIV Antiretroviral Rectal Microbicide Program • DAIDS IPCP Program • Tenofovir, UC781, tenofovir + UC781 • Consortium • University of Pittsburgh • UCLA • Johns Hopkins • CONRAD PI: Ian McGowan MD PhD Courtesy of Dr Ian McGowan

  20. In the shadow of Caprisa

  21. Where Would We Conduct Phase 2/3 Studies? • Phase 2 studies • RAI sexually active men and women • Higher risk populations • Phase 2B studies • 3% sero-incidence MSM populations • North America • Latin America (Peru, Brazil) • Asia Pacific (Thailand) • Africa (South Africa) Courtesy of Dr Ian McGowan

  22. MTN 017 • Phase II, multi-site, randomized, six sequence, three period, open label crossover study of adherence and pharmacokinetics of oral and rectal formulations of tenofovir • 120 MSM • Bangkok, Thailand; Lima, Peru; 2 US Sites • Possibly roll-over into Phase IIB, III efficacy trial

  23. Rectal Microbicide Timeline* *An approximation based on 1% tenofovir Courtesy of Dr Ian McGowan

  24. ART as prevention • Test and link • Test and treat

  25. HPTN 065 – Wash DC and Bronx: Test-Link-Care-Plus Study Test HIV Positive Adopt safer behaviors Enroll in Care Treat Maintain viral suppression Initiation of ART Testing Adherence to ART Positive Prevention Linkage to care sites Decrease in HIV Transmission

  26. Treatment as Prevention for MSM • Rationale: lower viral load reduces transmission; ART reduces viral load, thus ART reduces transmission • Dr Myron Cohen will give an excellent review and summary on this • However: • No transmission studies in discordant MSM couples • No information about the reduction in transmission probability in discordant MSM couples in the presence of ART • We need scientific evidence to support this intervention in MSM • Study of 350 discordant couples is being prepared in Sydney, Australia (Prof Andrew Grulich); behavior, transmission events, phylogenetic analysis

  27. Treatment as Prevention for MSM • In the mean time: • April 2010 - San Francisco guidelines issued: offer treatment to all HIV positives, regardless of CD4 and VL • Strong association between mean community viral load, total community viral load and reduction in newly identified HIV cases from 798 in 2008 to 434 in 2008 • Very special situation with good surveillance data on HIV infection and viral load, almost universal access to ART

  28. Mean community viral load in San Francisco, by neighborhood, 2005-8 Das, et al, 2010

  29. Total community viral load in San Francisco, by neighborhood, 2005-8 Das, et al, 2010

  30. Reductions in VL, newly diagnosed and reported cases and estimated HIV incidence in San Francisco 2004-8 Das, et al, 2010

  31. Challenges for ARV prevention in MSM • Adherance • Risk compensation and behavioral disinhibition, individually and at the community level • Targeting and duration of programs • Programming outside the Western world • Implementation and programming in low HIV prevalence communities • Costs and competition with curation • Pill burden, drug burden, side-effects, toxicity, resistance • How to monitor impact

  32. In conclusion • PEP not ready for programmatic scale up, but good as an individual service on a case by case basis • Daily PrEP results expected soon; if efficacious, studies will try to identify non-inferior alternative regimens • Many implementation issues • Rectal PrEP – promising, but still long way to go • ART for prevention, seems reasonable, ecological evidence available, MSM transmission studies are urgently needed

  33. Acknowledgements Ian McGowan University of Pittsburgh Lynn Paxton US CDC Peter Kilmarx US CDC Tim Mastro Family Health International Bob Grant University of California, San Francisco Eduard Sanders University of Oxford/KEMRI/IAVI Susan Buchbinder SFDPH/UCSF Anchalee Varangrat Thailand MOPH–US CDC Collaboration Kathie McCarthy ASPH/CDC Global Public Health Fellow Disclaimer: the results and conclusions presented in this presentation are those of the author, and do not necessarily represent those of the US Centers for Disease Control and Prevention

  34. fav1@cdc.gov

  35. Status of Completed, Ongoing and Planned Advanced Stage Clinical Trials of Antiretrovirals for Prevention (Oral and Topical), 2010

  36. Non-occupational post exposure prophylaxis (NPEP) • Concern about negative behavioral side-effects • In some studies NPEP recipients were at higher subsequent risk for HIV seroconversion due to continued exposure or re-exposure (Poynten et al, 2009) • No increases in high risk behavior after NPEP were observed (Schechter et al, 2004; Martin et al, 2004), but no decreases were observed either (Poynten et al, 2007)

  37. Non-occupational post exposure prophylaxis (NPEP) • Drug side-effects • uncommon with current generation of ARVs available for NPEP • ARV resistance • unlikely, because HIV infection after NPEP is uncommon • current ARV’s less likely to cause resistance • Public health impact of NPEP is considered limited and only cost-effective in very specific situations (MMWR, 2005; Poynten et al, 2007) In conclusion • NPEP not feasible for programmatic scale-up in MSM • Can be offered as an individual service on a case-by-case basis

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