# PrEP and dPEP: Doxycycline post-exposure prophylaxis for prevention of sexually transmitted infections among Kenyan women using HIV pre-exposure prophylaxis

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 2021 · $805,259

## Abstract

ABSTRACT
In the past decade, HIV pre-exposure prophylaxis (PrEP) has demonstrated high HIV protection among at-risk
groups, with the first indications that PrEP may be reducing population-level new HIV infections. At the same
time, rates of curable sexually transmitted infections (STIs) have increased markedly in populations worldwide,
and PrEP-taking populations, including in our preliminary data among African women, have been found to have
very high STI rates. Post-exposure prophylaxis (PEP) with the antibiotic doxycycline (dPEP) has been proposed
as a novel STI control strategy. A recent open-label clinical trial of dPEP among PrEP-taking men who have sex
with men (MSM) in France found a 47% relative reduction in new bacterial STIs (Chlamydia trachomatis,
Neisseria gonorrhoeae, or Treponema pallidum), with >70% protection for C. trachomatis and T. pallidum but
expectedly no protection for N. gonorrhoeae given high rates of tetracycline resistance in Europe; two new
studies of dPEP among MSM are planned for 2019. African women face disproportionate risk from overlapping
HIV-STI epidemics, with STI rates comparable to MSM in high-income countries and with consequences (pelvic
inflammatory disease, tubal infertility, complications of pregnancy) arguably more severe than those faced by
MSM. In contrast to other STI prevention strategies that rely on partner participation, on-demand dPEP would
be woman-controlled, and doxycycline has evidence of safety for use by women. We propose to conduct the
first study evaluating dPEP to prevent STIs in PrEP-taking African women, who are a priority population for STI
prevention, given high risk and engagement in longitudinal prevention services. STI PEP carries substantial
potential benefits but also important potential risks, and we have framed our work as capturing key data to inform
the risk-benefit calculus for this cutting-edge question. We hypothesize that dPEP will substantially reduce the
incidence of curable STIs, particularly C. trachomatis, the most common bacterial STI and the one responsible
for greatest morbidity. STI dPEP carries potential risk of antimicrobial resistance, which we have considered: C.
trachomatis resistance has never been seen worldwide, making new resistance from dPEP unlikely, but N.
gonorrhoeae tetracycline resistance is common in Kenya, and for that reason we hypothesize dPEP may provide
little protection for that pathogen but will also not generate new resistance. In addition to resistance risk, data
are needed to determine whether dPEP is safe, acceptable, adhered to, and affordable. Aim 1 will determine the
benefit of dPEP to reduce the incidence of curable STIs through an open-label 1:1 randomized trial of dPEP
versus standard of care among 446 women aged 18-30 taking PrEP. Aim 2 will assess associated risks of dPEP
by exploring a) safety, b) acceptability, c) adherence, and d) resistance, using novel and rigorous behavioral and
laboratory science methods. Aim 3 will mea...

## Key facts

- **NIH application ID:** 10223161
- **Project number:** 5R01AI145971-03
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Elizabeth Anne BUKUSI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $805,259
- **Award type:** 5
- **Project period:** 2019-08-01 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10223161

## Citation

> US National Institutes of Health, RePORTER application 10223161, PrEP and dPEP: Doxycycline post-exposure prophylaxis for prevention of sexually transmitted infections among Kenyan women using HIV pre-exposure prophylaxis (5R01AI145971-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10223161. Licensed CC0.

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