Tenofovir/Emtricitabine With Doxycycline for Combination HIV and Syphilis Pre-exposure Prophylaxis in HIV-negative MSM

Summary

Men who have sex with men remain at high risk for HIV infection. Targeting prevention interventions to MSM at highest risk of seroconversion is an important goal of combination prevention interventions. Antecedent diagnosis of another sexually transmitted infection (STI), particularly syphilis, may serve as an entry point for biomedical prevention as these individuals are at highest risk for incident HIV. The use of the antiretroviral combination of tenofovir/emtricitabine has been shown to be associated with an overall 44% reduction in HIV acquisition in high-risk MSM when taken daily as PrEP. In those individuals with detectable drug levels, the benefit was as high as 90% risk reduction. In real-world evaluations of PrEP, high-risk sexual behaviour may continue as evidenced by high rates of intercurrent sexually transmitted infections. As such, biomedical interventions that may offer additional reduction in acquisition of common sexually transmitted infections should also be evaluated. Recently a small pilot study has demonstrated potential benefit from a similar strategy for syphilis prevention. In this study 30 MSM were randomized to receive either 100mg doxycycline once daily or contingency management strategies linked to remaining free of sexually transmitted diseases at progressive study visits. Overall, those receiving doxycycline were significantly less likely to be diagnosed with any STI during followup than those in the comparator arm. The investigators therefore propose to undertake a pilot study to evaluate the feasibility of using both tenofovir/emtricitabine and doxycycline (immediate or deferred use) for pre-exposure prophylaxis amongst HIV-negative MSM with recent history of syphilis infection in Vancouver, Canada.

Timeline

Start

2018-05-15

Primary completion

2020-05-28

Completion

2022-09-07

Publications

• Results Pathela P, Braunstein SL, Blank S, Shepard C, Schillinger JA. The high risk of an HIV diagnosis following a diagnosis of syphilis: a population-level analysis of New York City men. Clin Infect Dis. 2015 Jul 15;61(2):281-7. doi: 10.1093/cid/civ289. Epub 2015 Apr 13.
• Results Bolan RK, Beymer MR, Weiss RE, Flynn RP, Leibowitz AA, Klausner JD. Doxycycline prophylaxis to reduce incident syphilis among HIV-infected men who have sex with men who continue to engage in high-risk sex: a randomized, controlled pilot study. Sex Transm Dis. 2015 Feb;42(2):98-103. doi: 10.1097/OLQ.0000000000000216.

Drugs

Indications