Herrera C, Serwanga J, Else L, Limakatso L, Opoka D, Ssemata AS, Pillay AD, Namubiru P, Seiphetlo TB, Odoch G, Mugaba S, Seatlholo P, Alieu A, Penchala SD, Muhumuza R, Alinde B, Petkov S, O'Hagan K, Callebaut C, Seeley J, Weiss H, Khoo S, Chiodi F, Gray CM, Kaleebu P, Webb EL, Martinson N, and Fox J
Background: The efficacy of on-demand HIV pre-exposure prophylaxis (PrEP) for men in sub-Saharan Africa has not been evaluated, and the on-demand PrEP dosing requirement for insertive sex remains unknown., Methods: HIV-negative males 13-24 years, requesting voluntary medical male circumcision (VMMC), were enrolled into an open-label randomised controlled trial (NCT03986970), and randomised 1:1:1:1:1:1:1:1:1 to control arm or one of eight arms receiving emtricitabine-tenofovir disoproxil fumarate (F/TDF) or emtricitabine-tenofovir alafenamide (F/TAF) over one or two days, and circumcised 5 or 21 h thereafter. The primary outcome was foreskin p24 concentrations following ex vivo HIV-1 BaL challenge. Secondary outcomes included peripheral blood mononuclear cell (PBMC) p24 concentration, and drug concentrations in foreskin tissue, PBMCs, plasma and foreskin CD4+/CD4-cells. In the control arm, post-exposure prophylaxis (PEP) activity of non-formulated tenofovir-emtricitabine (TFV-FTC) or TAF-FTC was assessed with ex vivo dosing 1, 24, 48 or 72 h post-HIV-1 challenge., Findings: 144 participants were analysed. PrEP with F/TDF or F/TAF prevented ex vivo infection of foreskins and PBMCs both 5 and 21 h after PrEP dosing. There was no difference between F/TDF and F/TAF (p24 day15 geometric mean ratio 1.06, 95% confidence interval: 0.65-1.74). Additional ex vivo dosing did not further increase inhibition. In the control arm, PEP ex vivo dosing was effective up to 48 post-exposure diminishing thereafter, with TAF-FTC showing prolonged protection compared to TFV-FTC. Participants receiving F/TAF had higher TFV-DP concentrations in foreskin tissue and PBMCs compared with F/TDF, irrespective of dose and sampling interval; but F/TAF did not confer preferential TFV-DP distribution into foreskin HIV target cells. FTC-TP concentrations with both drug regimens were equivalent and ∼1 log higher than TFV-DP in foreskin., Interpretation: A double dose of either F/TDF or F/TAF given once either 5 or 21 h before ex vivo HIV-challenge provided protection across foreskin tissue. Further clinical evaluation of pre-coital PrEP for insertive sex is warranted., Funding: EDCTP2, Gilead Sciences, Vetenskapsrådet., Competing Interests: Declaration of interests CH has received research grants from EDCTP, Vetenskapsrådet and Gilead Sciences. LE has received research grants from EDCTP, and Gilead Sciences. LL has received research grants from EDCTP, Gilead Sciences, Roche Diagnostic, DO has received research grants from EDCTP, AS has received research grants from EDCTP, AP has received research grants from EDCTP, PN has received research grants from EDCTP, PS has received research grants from EDCTP, DS has received research grants from EDCTP, RM has received research grants from EDCTP, BA has received research grants from EDCTP, SP has received research grants from EDCTP, CC is an employee of Gilead Sciences, JS has received research grants from EDCTP, HW has received research grants from EDCTP, SK has received research funding, speaker honoraria and consulting fees from EDCTP, Gilead Sciences, ViiV, Merck, GSK, and Ridgeback. FC has received research grants from EDCTP and Vetenskapsrådet. ELW has received grants from EDCTP, MRC, and NIH. CG has received research grants from EDCTP. PK has received research grants from EDCTP. EW has received research grants from EDCTP, NIH and MRC. NM has received research grants from EDCTP, and Gilead Sciences and provided unpaid advice and leadership in the DSMB and Setshaba boards. CC is a full-time employee of Gilead Sciences. All other authors declare no competing interests aside from the research grant received for this study by EDCTP., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)