# Oral Preexposure Prophylaxis Uptake and Discontinuation in the HIV Vaccine Trials Network 704/HIV Prevention Trials Network 085 Study: Implications for Biomedical Human Immunodeficiency Virus Prevention Trials

## TL;DR

This study analyzed how oral PrEP was used in an HIV prevention trial, finding that PrEP use varied by region and reduced HIV risk for users.

## Contribution

The study provides insights into real-world PrEP usage patterns and their impact on HIV prevention in a clinical trial setting.

## Key findings

- 31.8% of participants initiated PrEP, with the highest rates in Brazil and the US.
- PrEP initiators had a 58% lower risk of acquiring HIV compared to non-initiators.
- PrEP discontinuation rates varied by region, with Brazil showing significantly lower discontinuation than the US.

## Abstract

HIV Vaccine Trials Network (HVTN) 704/085, a placebo-controlled clinical trial assessing the efficacy of VRC01 broadly neutralizing antibody infusion for HIV prevention, offered oral preexposure prophylaxis (PrEP) as the standard of prevention at no cost to participants.

We characterized features of- identified factors associated with- PrEP initiation and discontinuation, and the effects of PrEP initiation on HIV incidence.

Of 2221 participants, 31.8% initiated oral PrEP during study follow-up, with the highest proportion of PrEP initiations in Brazil (83.2%) and the United States (US) (54.2%). Prior PrEP use was associated with PrEP initiation (hazard ratio [HR], 2.22 [95% confidence interval {CI}, 1.25–3.95]). Participants from Switzerland (HR, 0.5 [95% CI, .3–1.0]) and Peru (HR, 0.08 [95% CI, .06–.1]) had lower likelihood of PrEP initiation compared to the US, while participants from Brazil had higher likelihood (HR, 2.6 [95% CI, 2.0–3.3]). In the US, PrEP initiation was lower in areas with higher unmet need for PrEP (HR, 0.9 per 5 units [95% CI, 0.8–1.0]). PrEP initiators had 58% less risk of acquiring HIV than PrEP noninitiators. Among PrEP initiators, 34.4% discontinued PrEP during study follow-up. Brazil had 63% less likelihood of PrEP discontinuation than the US (HR, 0.37 [95% CI, .22–.60]).

When included as standard of prevention in HVTN 704/085, oral PrEP utilization patterns mirrored those observed in real-life settings. Variable effects of oral PrEP on HIV outcomes in clinical trials may be expected based on regional differences in oral PrEP use.

HVTN 704/085, a placebo-controlled HIV prevention study, offered oral preexposure prophylaxis (PrEP) as standard of prevention. Of all participants, 31.8% initiated PrEP and 34.5% of them discontinued PrEP during study participation. PrEP decreased the likelihood of HIV acquisition among PrEP initiators.