Doxycycline post-exposure prophylaxis for prevention of sexually transmitted infections among Kenyan women using HIV pre-exposure prophylaxis: study protocol for an open-label randomized trial

BACKGROUND: Women in Africa face disproportionate risk of human immunodeficiency virus (HIV) acquisition, accounting for more than half of new infections in Africa and similarly face a disproportionate burden of sexually transmitted infections (STIs). Very high STI prevalence is being observed globally, especially among people taking pre-exposure prophylaxis (PrEP) for HIV prevention. Doxycycline post-exposure prophylaxis (dPEP) has been proposed as an STI prevention strategy to reduce chlamydia, syphilis, and possibly gonorrhea, and trials are ongoing among cisgender men who have sex with men (MSM) and transgender women who are taking PrEP in high-income settings. We designed and describe here the first open-label trial to determine the effectiveness of dPEP to reduce STI incidence among cisgender women. METHODS: We are conducting an open-label 1:1 randomized trial of dPEP versus standard of care (STI screening and treatment and risk-reduction counseling without dPEP) among 446 Kenyan women aged ≥ 18 and ≤ 30 years old women taking PrEP. Women are followed for 12 months, with quarterly STI testing, treatment, and adherence counseling. The primary trial outcome will be the combined incidence of Chlamydia trachomatis, Neisseria gonorrhoeae, and Treponema pallidum, compared between the randomized groups. We will also assess dPEP acceptability, tolerability, safety, impact on sexual behavior, adherence, and occurrence of antimicrobial resistance (AMR) in N. gonorrhoeae and C. trachomatis isolates. Finally, we will estimate cost per incident STI case and complications averted accounting for nonadherence and benefits relative AMR or side effects. DISCUSSION: The results of this trial may have immediate implications for the global epidemic of STIs and sexual health. If effective, dPEP could put STI prevention into women’s hands. While dPEP may be able to prevent STIs, it carries important risks that could counter its benefits; global debate about the balance of these potential risks and benefits requires data to inform policy and implementation and our study aims to fill this gap. TRIAL REGISTRATION: ClinicalTrials.gov NCT04050540.