Results from PrEP Efficacy Trials

Clinical trials have demonstrated the safety and efficacy of pre-exposure prophylaxis (PrEP) for preventing HIV

Trial (Reference) Population Location PrEP
Regimen
Efficacy PrEP
Adherence
Notes
iPrEX (Grant RM; N Engl J Med 2010;363:2587-2599)

Phase III trial that evaluated the safety and efficacy of once-daily oral TDF/FTC to prevent HIV infection in men who have sex with men and transgender women who have sex with men. For more information: www.avac.org/trial/iprex

2,499 men and transgender women who have sex with men USA, Peru, Ecuador, Brazil, Thailand, South Africa TDF/FTC 44% reduction in HIV incidence compared to placebo 51% In participants with >90% adherence, efficacy was 77%
FEM-PrEP (Van Damme L;. N Engl J Med 2012;367:411-422)

Phase III trial that evaluated the safety and effectiveness of once-daily oral TDF/FTC for HIV prevention in women. For more information: www.avac.org/trial/fem-prep

2,120 women Kenya, South Africa, Tanzania TDF/FTC N/A 21–37% Adherence was too low to evaluate efficacy
TDF-2 (Thigpen MC; N Engl J Med 2012;367:423-434)

Phase II/III trial that evaluated the safety of once-daily oral TDF/FTC in heterosexual men and women. For more information: www.avac.org/trial/tdf2

1,219 women and men Botswana TDF/FTC 62% reduction in HIV incidence compared to placebo 84% Efficacy was 78% when restricting the analyses to seroconverters within 30 days of last dose
Partners PrEP (Baeten JM;. N Engl J Med 2012;367:399-410)

Phase III trial that evaluated the safety and efficacy of two different strategies to prevent HIV transmission in HIV-serodiscordant couples: once-daily oral TDF and once-daily oral TDF/FTC. For more information: www.avac.org/trial/partners-prep

4,758 serodiscordant, heterosexual couples Kenya, Uganda TDF/FTC 75% reduction in HIV incidence compared to placebo 82% No significant differences in efficacy by gender
TDF 67% reduction in HIV incidence compared to placebo
VOICE (Marrazzo JM;. N Engl J Med 2015;372:509-518)

Phase IIb trial that evaluated the safety and effectiveness of three different strategies to prevent HIV in women: once-daily oral TDF, oral TDF/FTC, and vaginal tenofovir gel. For more information: www.avac.org/trial/mtn-003-voice

5,029 women Uganda, South Africa, Zimbabwe TDF/FTC N/A 29% Inefficacy was attributed to poor adherence
TDF N/A 30%
PROUD (McCormack S; Lancet 2016;387:53-60)

Phase IV trial that evaluated the efficacy and uptake of once-daily oral TDF/FTC among men who have sex with men. For more information: www.avac.org/trial/mtn-003-voice

544 men who have sex with men UK TDF/FTC 86% reduction in HIV incidence among immediate PrEP users compared to deferred PrEP users ~100% Trial stopped due to early demonstration of efficacy
Bangkok Tenofovir Study (Choopanya K; Lancet 2013;381:2083-90)

Phase II/III trial to assess the safety and efficacy of daily TDF to prevent HIV among people who inject drugs. For more information: www.avac.org/trial/cdc-4370-bangkok-tenofovir-study

2,413 people who inject drugs Thailand TDF 49% reduction in HIV incidence compared to placebo 61-71% Among those with detectable TDF, efficacy was 70%
DISCOVER (Mayer K; Lancet 2020; 396(10246):239-254) TAF/FTC vs TDF/FTC

Phase III trial to compare the efficacy of Discovy daily tenofovir alafenamide/emtricitabine (TAF/FTC) and tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) among men who have sex with men and transgender women who have sex with men. For more information:www.avac.org/trial/discover

5,387 men and transgender women who have sex with men Austria, Denmark, France, Germany, Ireland, Italy, Netherlands, Spain, UK, Canada and USA TDF/FTC 99.4% remained HIV negative 84–96%
  • TAF/FTC was noninferior to TDF/FTC
  • PrEP medicines worked best when taken every day
TAF/FTC 99.7% remained HIV negative
Long-acting PrEP (Landovitz R; N Engl J Med; 2021 385:595-608)

Phase IIb/III trial to evaluate the safety and efficacy of injectable drug cabotegravir (CAB-LA) among men who have sex with men and transgender women who have sex with men. For more information: www.avac.org/trial/hptn-083

4,566 men and transgender women who have sex with men Argentina, Brazil, Peru, South Africa, Thailand, the U.S., and Vietnam CAB-LA 99.6% remained HIV negative -
  • CAB-LA was superior (66% efficacy) compared to TDF/FTC
  • Both CAB-LA and TDF/FTC were efficacious among trial participants
  • Trial stopped due to early demonstration of efficacy
TDF/FTC 98.8% remained HIV negative

Reference: PrEP Efficacy Trial Results: Pacific AIDS Education & Training Center (Pacific AETC);

[Available from: http://paetc.org/wp-content/uploads/2018/02/PAETC_PrEPEfficacy.pdf.]