20th International AIDS Conference - Melbourne, Australia


TUAC0105LB - Oral Abstract

Results of the iPrEx open-label extension (iPrEx OLE) in men and transgender women who have sex with men: PrEP uptake, sexual practices, and HIV incidence

Presented by Robert M Grant (United States).

R.M. Grant1,2,3, P.L. Anderson4, V. McMahan1, A. Liu2,5, K.R. Amico6, M. Mehrotra1, C. Mosquera7, M. Casapia8, O. Montoya9, S. Buchbinder2,5, V.G. Veloso10, K. Mayer11, S. Chariyalertsak12, L.G. Bekker13, S. Hosek14, E.G. Kallas15, M. Schechter16, D. Glidden2, for the iPrEx study team

1Gladstone Institutes, San Francisco, United States, 2University of California, San Francisco, United States, 3San Francisco AIDS Foundation, San Francisco, United States, 4University of Colorado, Denver, United States, 5San Francisco Department of Public Health, San Francisco, United States, 6University of Connecticut, Storr, United States, 7INMENSA, Lima, Peru, 8ACSA, Iquitos, Peru, 9Equidad, Guayaquil, Ecuador, 10FIOCRUZ, Rio de Janeiro, Brazil, 11Fenway Health, Boston, United States, 12Research Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand, 13Desmond Tutu Health Foundation, Cape Town, South Africa, 14Stroger Hospital of Cook County/The CORE Center, Chicago, United States, 15University of Sao Paulo, Sao Paulo, Brazil, 16Praca Onze, Rio de Janeiro, Brazil

Background: The impact of HIV PrEP depends on drug uptake, adherence, sexual practices, and interactions between these factors.
Methods: Participants in randomized placebo-controlled iPrEx, ATN 089, or US PrEP Safety trials were enrolled in a 72-week open label extension (iPrEx OLE). The study provided services regardless of choice to receive oral FTC/TDF PrEP. Tenofovir-diphosphate (TFV-DP) was quantified in dried blood spots (DBS) among seroconverters and a random sample of site and visit matched seronegatives.
Results: 1603 HIV-uninfected persons enrolled, of whom 76% opted to receive PrEP. Non-condom receptive anal intercourse (ncRAI) was associated with PrEP uptake (P=0.001). The reasons for not requesting PrEP included concern about side effects (49%), the inconvenience of a daily pill (24%), and preference for other prevention methods (14%). Among those starting PrEP, HIV incidence was 1.83/100PY which was 49% (95% CI: -1 to 74%) lower than among those who did not choose PrEP after adjusting for sexual behavior, 53% (95% CI: 26 to 70%) lower than in the placebo arm of the randomized phase (3.93/100PY), and 51% (95% CI: 23% to 69%) lower than during the gap between the randomized phase and OLE (3.81/100PY). Incidence was lower among those with higher drug exposure.

TFV-DP in DBS (fmol/punch)Est. dosing% of follow-upHIV incidence95% CI
<2.5None26%4.7/100 PY2.8 to 7.2
2.5 to < 350<2 tablets/wk27%2.2/100 PY1.1 to 4.1
>=350 to < 7002 to 3 tablets/wk12%0.6/100 PY0.0 to 2.5
>=700 to 12494 to 6 tablets/wk22%0 /100 PY0.0 to 0.6
>=1250Daily5%0 /100 PY0.0 to 1.1
[HIV Incidence According to TFV-DP in DBS]

Effective PrEP use (≥4 tablets/week) was associated with older age, more schooling, ncRAI, more sexual partners, and syphilis or herpes. The proportion reporting ncRAI decreased from 33% to 25% among PrEP recipients (P < 0.01) and from 27% to 20% among non-recipients (P< 0.01).
Conclusions: PrEP was preferentially requested by those reporting higher risk sexual practices; risk declined in the cohort, regardless of PrEP receipt. The impact of oral PrEP may be increased by these synergies and limited by non-adherence. DBS drug concentrations are convenient and strong correlates of PrEP protection.

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