Doxycycline demonstrated greater efficacy compared with azithromycin among women with concurrent anorectal and urogenital Chlamydia trachomatis infection, according to findings published in The Lancet Infectious Diseases.
Between October 2018 and April 2020, researchers conducted a multicenter, open-label, randomized controlled superiority trial in France to compare the efficacy of doxycycline with azithromycin against C trachomatis infection in adult women. Patients were randomly assigned in a 1:1 fashion to receive either a single 1-g dose of azithromycin or a 7-day course of doxycycline 100 mg twice daily. The microbiologic anorectal cure rate was the primary outcome, defined as a negative result for C trachomatis infection observed via nucleic acid amplification testing (NAAT) of self-collected anorectal specimens 6 weeks after treatment initiation.
Among 357 patients included in the modified intention-to-treat analysis who were positive for concurrent anorectal and urogenital C trachomatis infection via NAAT, 52% received doxycycline and 48% received azithromycin. Patient demographics were similar in regard to age, nationality, marital status, education level, professional status, history of sexually transmitted infections, and sexual behavior.
At 6 weeks following treatment initiation, 28 patients in the doxycycline group and 31 in the azithromycin group were lost to follow-up. Among patients in the doxycycline (n=156) and azithromycin (n=142) groups for whom complete follow-up data were available, 94% and 85% were negative for C trachomatis infection via NAAT, respectively (adjusted odds ratio, 0.43; 95% CI, 0.21-0.91; P =.0274). Similar results were observed in both the secondary and sensitivity analyses.
Adverse events (AEs) potentially related to treatment were assessed among patients initially included in both groups at baseline (both n=228). The most commonly reported AEs were gastrointestinal related for patients in the doxycycline vs azithromycin groups (8% vs 11%).
Limitations of this study included the lack of blinding, the use of patient-collected anorectal specimens, and potentially limited generalizability for those at decreased risk for C trachomatis infection.
In women with C trachomatis infection, the researchers concluded that “doxycycline should be the recommended first-line treatment.”
Disclosure: One author declared receipt of funds from the French Ministry of Health.
Peuchant O, Lhomme E, Martinet P, et al. Doxycycline versus azithromycin for the treatment of anorectal Chlamydia trachomatis infection in women concurrent with vaginal infection (CHLAZIDOXY study): a multicentre, open-label, randomised, controlled, superiority trial. Lancet Infect Dis. Published online May 9, 2022. doi:10.1016/S1473-3099(22)00148-7