Can postexposure prophylaxis with doxycycline reduce the risk of sexually transmitted infections in men who have sex with men?

In high-risk men who have sex with men, postexposure prophylaxis (PEP) with doxycycline reduces the risk of new sexually transmitted infections (STIs), including chlamydia and syphilis. No benefit occurred in reducing the risk of gonorrhea infection. (LOE = 1b)

Molina JM, Charreau I, Chidiac C, et al, for the ANRS IPERGAY Study Group. Post-exposure prophylaxis with doxycycline to prevent sexually transmitted infections in men who have sex with men: An open-label randomised substudy of the ANRS IPERGAY trial. Lancet Infect Dis 2018;18(3):308-317.  [PMID:29229440]

Randomized controlled trial (nonblinded)

Government

Concealed

Outpatient (any)

Higher rates of STIs are being reported among individuals using pre-exposure prophylaxis (PrEP) against HIV acquisition, most likely due to reduced condom use, These investigators initiated an open-label study extension of the ANRS IPERGAY trial, which showed the efficacy of PrEP in reducing HIV incidence. Eligible participants—232 HIV-negative men or transgendered women having sex with men—randomly received (concealed allocation assignment) either doxycycline PEP or no prophylaxis in addition to PrEP. Patients in the PEP group were instructed to take doxycycline (200 mg) after each high-risk sexual intercourse event (ie, condomless anal or oral sex) within 24 to 72 hours, but no more than 600 mg total per week. Participants underwent standard testing for STIs at baseline and every 2 months for a median of 8.7 months. Individuals who assessed outcomes remained masked to treatment group assignment. Complete follow-up occurred for 91% of participants. Using intention-to-treat analysis, significantly fewer STIs occurred in the PEP group than in the control group (22% vs 42%; number needed to treat = 6.8; 95% CI 3.8 - 37.0). In subgroup analyses, the occurrences of chlamydia and syphilis infections were significantly lower with PEP than without, but there was no significant group difference in the occurrence of gonorrhea infections.