ANRS 174 DOXYVAC (doxycycline PEP)
Trial question
What is the role of doxycycline post-exposure prophylaxis in MSM?
Study design
Multi-center
Open label
RCT
Population
545 male patients.
Inclusion criteria: adult MSM, HIV-negative, with a history of bacterial STIs within the past 12 months.
Key exclusion criteria: previous meningococcal group B vaccination; current treatment with doxycycline; doxycycline allergy or other contraindication for use.
Interventions
N=362 doxycycline PEP (two tablets of 100 mg each PO within 72 hours after condomless sex, with no more than 3 doses of 200 mg/week).
N=183 no PEP (no doxycycline post-exposure prophylaxis).
Primary outcome
Incidence of first episode of chlamydia or syphilis, or both
8.8
53.2
53.2/100 py
39.9/100 py
26.6/100 py
13.3/100 py
0.0/100 py
Doxycycline
PEP
No
PEP
Significant
decrease ▼
Significant decrease in the incidence of first episode of chlamydia or syphilis, or both (8.8/100 py vs. 53.2/100 py; HR 0.17, 95% CI 0.12 to 0.26).
Secondary outcomes
Significant decrease in the incidence of first episode of gonorrhea (45.5/100 py vs. 68.4/100 py; HR 0.67, 95% CI 0.52 to 0.87).
Significant decrease in the incidence of first episode of syphilis (2.9/100 py vs. 14.5/100 py; HR 0.21, 95% CI 0.11 to 0.41).
Significant decrease in the incidence of cumulative incidence of chlamydia or syphilis (or both) (8.5/100 py vs. 56/100 py; IRR 0.15, 95% CI 0.1 to 0.22).
Safety outcomes
No significant difference in serious adverse events.
Conclusion
In adult MSM, HIV-negative, with a history of bacterial STIs within the past 12 months, doxycycline PEP was superior to no PEP with respect to the incidence of first episode of chlamydia or syphilis, or both.
Reference
Jean-Michel Molina, Beatrice Bercot, Lambert Assoumou et al. Doxycycline prophylaxis and meningococcal group B vaccine to prevent bacterial sexually transmitted infections in France (ANRS 174 DOXYVAC): a multicentre, open-label, randomised trial with a 2 × 2 factorial design. Lancet Infect Dis. 2024 Oct;24(10):1093-1104.
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