Doxycycline Cuts STI Risk in Men, Trans Women Having Sex with Men


MONTREAL — One dose of doxycycline 200mg given as post-exposure prophylaxis (PEP) reduced the incidence of three sexually transmitted infections (STIs) by 65% ​​in men who have sex with men (MSM) and transgender women (TGW) living with HIV. or take pre-exposure prophylaxis (PrEP). The results of the open trial of DoxyPEP were presented at a press conference here at the 24th International AIDS Conference.

“It’s time to take action on the data we have and really think about putting it in the guidelines and implementing it in a safe and thoughtful way,” said study co-lead Annie Lutkemeyer, MD, of Zuckerberg General Hospital. in San Francisco. and professor of medicine at the University of California, San Francisco (UCSF).

An open-label study conducted in Seattle and San Francisco in randomized MSM/TGW living with HIV or on PrEP with a history of N. gonorrhoeae (GC), C. trachomatis (CT), or early syphilis in the past year, or doxycycline, or not to take it within 72 hours after intercourse without a condom. It was halted in early May when a scheduled interim analysis found that those randomized to doxycycline had significantly fewer STIs than participants assigned to the control group.


The intention-to-treat analysis included 501 patients in at least a quarter of the follow-up: 327 taking PrEP and 174 living with HIV. Among those taking PrEP, a new STI (GC, CT, or syphilis) occurred in 31.9% of control participants compared to 10.7% of participants on doxycycline, a decrease of 66% quarterly (P < 0.001). Among participants living with HIV, 30.5% of the control group developed new STIs compared to 11.8% of those taking doxycycline, resulting in a 62% quarterly reduction in STIs (P < 0.0001).

“Participants reported taking doxycycline 87% of the time after having sex without a condom, about half of the participants were taking less than 10 doses per month, 30% were taking 10-20 doses per month, and 16% were taking more than 20 doses of doxycycline per month. “Lutkemeyer said, adding that there were no serious side effects of Grade 2 or higher, and “most participants reported that doxy was acceptable or very acceptable.”

When asked by Medscape Medical News how widely doxycycline prophylaxis could be used in other populations, Lutkemeyer was cautious. “Our study participants had a very high rate of new STIs of 30% per quarter, and the use of doxyPE was well tolerated and very effective in reducing the number of new STIs. However, this is a rather limited group,” she said. “Additional data will be needed from ongoing studies to decide whether doxyAED should be considered for other groups, such as women taking PrEP or those at increased risk of STIs.”

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Lutkemeyer said her group is looking at three possible risks of antibiotic resistance with a doxy-PEP regimen: the risk to extraneous bacteria such as Staphylococcus aureus or commensal neisseria; impact on the intestines; and the risk of resistance to antibiotic therapy for STIs.

Regarding the latter, “we don’t really think it would be a problem in chlamydia and syphilis, and we are looking into gonorrhea closely,” she said, adding that it would be difficult to get definitive data from this particular study. because of its short sequel.

“Available culture data of those who had gonorrhea during the study showed a relatively low level of resistance to tetracycline, which is an indicator of resistance to doxycycline, at the level of 20% … However, larger studies and population-based surveillance of those who take doxycycline as PKP. to understand whether the use of doxycycline could induce an element of tetracycline resistance in gonorrhea,” she said, emphasizing that doxycycline is not used to treat active gonorrhea infections.


Calling the doxy-PEP regimen a “game-changing strategy,” Sharon Levine, AO, MD, president-elect of the International AIDS Society, said that many physicians are already prescribing it off-label based on the IPERGAY study (N Engl J Med 2015; 373:2237-2246), “but there is a clear need for further evidence to guide the use of this intervention.”

“This research has huge implications for clinical care,” said Monica Gandy, MD, MPH, infectious disease physician, professor of medicine, and associate director of the Division of HIV, Infectious Diseases, and Global Medicine at the University of California, San Francisco. “While drug resistance data is very important to evaluate, we certainly should consider using doxycycline PEP within 72 hours of bareback intercourse for our patients to prevent STIs,” she told Medscape.

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“In our practice, we are very excited about the possibility of a simple one-tablet post-exposure prophylaxis (doxycycline 200 mg) to reduce the risk of a number of STIs. We have used PEP for HIV infection for a number of years. and are very familiar with the concept of preventing post-infection infections,” said Gandhi, who is also director of the UC San Francisco Center for AIDS Research and medical director of the HIV Clinic (“Ward 86”) at San Francisco General Hospital. “We plan to introduce doxycycline as a PEP in my clinic after the publication of these results and will follow the rest of the study closely.”


The study was funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, through grant R01AI143439. The study was conducted at the San Francisco Zuckerberg General Hospital HIV Clinic and San Francisco City Clinic, which are part of the San Francisco Department of Public Health, as well as the Madison Clinic and Harborview Medical Center Sexual Health Clinic, both at the University of New York. Washington. Drugs were provided by Mayne Pharmaceuticals and laboratory support was provided by Hologic & Cepheid.

Levin discloses the following: Research-initiated and industry-funded studies for Gilead, Viiv, Merck; scientific advisory board (fee paid to her personally) for Gilead, Merck, Viiv, Esfam, Immunocore, Vaxxinity; collaborative research (unfunded) for AbbVie, Genentech, BMS. Lütkemeyer and Gandhi did not report their respective financial relationships.

24th International AIDS Conference (AIDS 2022): Abstract 13231: Submitted July 27, 2022 (media event)


Keith Johnson is a Montreal-based freelance medical journalist who has been writing in all areas of medicine for over 30 years.

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