Background
Post-exposure prophylaxis (PEP) with doxycycline has been shown to prevent sexually transmitted infections (STIs) among cisgender men and transgender women, but data from trials with cisgender women are lacking.
Methods
We conducted a randomized, open-label trial comparing post-exposure prophylaxis (PEP) with doxycycline (doxycycline hyclate, 200 mg administered within 72 hours of condomless intercourse) with standard care among Kenyan women aged 18 to 30 years. age who were receiving pre-exposure prophylaxis against human immunodeficiency virus (HIV).
The primary endpoint was any incident infection with Chlamydia trachomatis, Neisseria gonorrhoeae, or Treponema pallidum. Hair samples were collected quarterly for objective assessment of doxycycline use.
Results
A total of 449 participants were randomized; 224 were assigned to the doxycycline-PEP group and 225 to the standard care group. Participants were followed quarterly for 12 months.
A total of 109 STI incidents occurred (50 in the doxycycline-PEP group [25.1 per 100 person-years] and 59 in the standard care group [29.0 per 100 person-years]), with no differences significant in the incidence between the groups. (relative risk, 0.88; 95% confidence interval [CI], 0.60 to 1.29; P = 0.51).
Among the 109 incident STIs, chlamydia accounted for 85 (78.0%) (35 in the doxycycline-PEP group and 50 in the standard care group; relative risk, 0.73; 95% CI, 0.47 to 1,13).
The trial investigators did not consider any serious adverse events to be related to doxycycline and there were no incidents of HIV infection.
Among 50 randomly selected participants in the doxycycline-PEP group, doxycycline was detected in 58 of 200 hair samples (29.0%).
All positive N. gonorrhoeae isolates were resistant to doxycycline.
Conclusions Among cisgender women, the incidence of STIs was not significantly lower with doxycycline PEP than with standard care. Based on analysis of hair samples, use of PEP with doxycycline among those assigned to receive it was low. |
(Funded by the National Institutes of Health; dPEP ClinicalTrials.gov number, NCT04050540. opens in new tab.)
