To compare the effect of different PrEP drugs (FTC-TDF and FTC-TAF), doses and timing of doses on p24 antigen level in resected foreskin tissue following HIV exposure ex vivo challenge.
1. Investigate the timing and dose of FTC-TDF and FTC-TAF as oral PrEP and in vitro PEP (applied directly to removed foreskin tissue) required to prevent ex vivo HIV infection in foreskin tissue and blood using the explant model 2. Determine blood, rectal fluid and foreskin tissue concentrations of FTC, TFV, TAF and their active metabolites that are required for ex vivo HIV protection 3. Evaluate inflammation, cellular activation, foreskin mucosal integrity, gene expression and microbiome in foreskin tissue following oral in vivo PrEP and in vitro PEP 4. Evaluate the efficacy of in vitro post exposure dosing with PrEP in protection against ex vivo HIV infection using the explant model 5. To investigate sexual behaviour, PrEP acceptability and feedback on HIV prevention trials implementation
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
72
Pre-exposure prophylaxis
The Perinatal HIV Research Unit
Johannesburg, Gauteng, South Africa
HIV Infection free
We will ascertain the proportion of patients' foreskin tissue that is not infected with HIV 15 days following our ex-vivo HIV challenge. We will use the concentration of p24 antigen (pg/mL) at day15 and also report the slope of the p24 curves from day 3 to 15 (pg/mL per day) and also the AUC day 3 to 15 (pg/mL days).
Time frame: 15 days
Timing
The delay between the timing of last dose of FTC-TDF and FTC-TAF as oral PrEP and the timing of circumcision.
Time frame: 1 year
Dose
The efficacy of preventing in-vitro HIV infection by dose of FTC-TDF and FTC-TAF as oral PrEP compared to no intervention
Time frame: 1 year
Blood PrEP Concentrations
Plasma concentrations (ng/mL) of FTC, TFV, TAF and their active metabolites that are required for ex vivo HIV protection.
Time frame: 1 year
Rectal Fluid PrEP concentrations
Rectal fluid concentrations (ng/mL) of FTC, TFV, TAF and their active metabolites that are required for ex vivo HIV protection.
Time frame: 1 year
Foreskin tissue PrEP concentration
Foreskin tissue concentrations (ng/mL) of FTC, TFV, TAF and their active metabolites that are required for ex vivo HIV protection
Time frame: 1 year
Efficacy of post-exposure PrEP
The proportion of participants' foreskin tissue that remains HIV infection free in the ex-vivo challenge model when additional doses of PrEP are added to that model.
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Time frame: 1 year