Doxycycline remains promising for preventing STIs, but not in cisgender women

SEATTLE — Studies continue to show that taking doxycycline after having unprotected sex can prevent sexually transmitted infections in transgender women and men who have sex with men. whether or not

On Monday, researchers at the Conference on Retroviruses and Opportunistic Infections presented the first major evidence that this may not be the case.

Specifically, in a randomized trial conducted in Kenya, a doxycycline post-exposure prophylaxis intervention (called doxy-PEP) significantly reduced sexually transmitted infections among cisgender women compared with testing and treatment alone. did not decrease to Jenelle Stewart, DO, MPH, Infectious disease physician and researcher at Hennepin Healthcare in Minneapolis.

At a press conference, Stewart suggested three possible reasons why this study failed to show significant benefits of doxy-PEP in cisgender women: “compliance, anatomy, and resistance.”

According to Stewart and colleagues, the women in the study reported taking doxycycline “at least as many days as they had sex” 78% of the time.

“They told us that they had a high adherence rate in their weekly text message survey. [to] I was on doxycycline PEP and was also told it was incomplete,” Stewart said.

Stewart says it’s unclear “how complete adherence is needed to prevent sexually transmitted infections of the cervix and opening of the uterus”. said all the gonorrhea samples they tested showed high levels of resistance to tetracyclines, the class of antibiotics to which doxycycline belongs.

The researchers enrolled approximately 450 women in the study, with an equal number of women receiving a single dose of 200 mg doxycycline within 72 hours of having unprotected sex and a quarterly screening and STI. They were randomly assigned to receive standard care, including treatment, but not doxy-PEP. More than one-third of her women reported transactional sex.

At follow-up, Stewart and colleagues diagnosed 50 STIs in the doxy-PEP arm and 59 STIs in the standard-of-care arm (RR = 0.88; 95% CI, 0.60-1.29). Results were similar when each STI was analyzed separately and participants were grouped by age, contraceptive use, traded sex, and whether she had STIs at baseline.

MSM, transgender women still benefit

Another randomized trial presented at the conference found that Jean-Michel Molina, MD, PhD, A professor of infectious diseases at the University of Paris and colleagues found that MSM were 84% less likely to contract chlamydia or syphilis and less likely to contract gonorrhea if they received doxy-PEP within three days after having sex without a condom. I found it to be about half Study participants who did not.

The study, which enrolled over 500 MSM who were already taking PrEP for HIV prophylaxis and who had had at least one STI in the past year, had good data and safety data because of how effective the intervention was. It was discontinued early on the advice of the Sexuality and Oversight Committee.

Molina and colleagues have previously reported that doxy-PEP Incidence halved Number of STIs in MSM tracked as part of another study on HIV PrEP.

In a new trial, Molina and colleagues also tested the meningococcal B vaccine Bexsero (GSK) in half of the participants for protection against gonorrhea, reducing the incidence of gonorrhea by about 50%. discovered.

In 2017, New Zealand researchers report first Meningitis B vaccine may prevent adult gonorrhea increasingly resistant Antibiotics in recent years. Bexsero’s potential as a gonorrhea vaccine is being tested in his $10 million NIH study conducted at the University of Alabama at Birmingham.

For now, Molina said a reduction in gonorrhea would be an “additional benefit” to the vaccine. was given.

“It would be nice if we could reduce the overall burden of gonorrhea infections. [and to] We’ll review these data, but at this point it’s probably going to be an individual decision to see if they get this vaccine,” Molina said. This is the period in which you are protected. [and] Whether booster injections are required. “

Moderate impact on resistance

Since last summer Annie F. Luetkemeyer, MD, A professor of medicine at the University of California, San Francisco presented findings pointing to doxy-PEP at the International AIDS Conference. Over 60% reduction in sexually transmitted infections Among transgender women and MSM, CDC has published interim clinical “considerations” for the use of doxy-PEP as an STI prevention tool in transgender women and MSM. Guidance has not yet been developed, nor does it address the use of doxy-PEP in other populations.

One open question was whether on-demand doxycycline use promotes resistance to STIs, particularly gonorrhea, or other common bacteria found in humans. Staphylococcus aureus.

On Monday, Luetkemeyer got the answer in the form of 12-month findings from a trial she published last summer: The effects of doxy-PEP on tolerance were modest and potentially clinically relevant. is low and must be considered in the context of how effective it is in reducing STIs.

However, the findings suggested that doxy-PEP may be less effective in preventing infection with tetracycline-resistant gonorrhea.

“I don’t think this means that doxy-PEP promoted tetracycline resistance,” Luetkemeyer said in the study.

most efficient strategy

In a fourth study presented at CROI on Monday, Michael Traeger PhD, Masters, Researchers at Harvard Medical School evaluated 10 different strategies for prescribing doxy-PEP for sexually transmitted infections and found that the most efficient strategy was based on the patient’s sexually transmitted infection status, rather than the patient’s HIV status or PrEP use. I have found that prescribing is based on the history of the disease.

The study included more than 10,000 MSM assigned male at birth between 2015 and 2020, transgender women, and nonbinary women who underwent at least two STD tests at an LGBTQ health clinic in Boston. people were registered.

For each of the 10 potential prescribing strategies, Traeger and colleagues determined the proportion of patients prescribed doxy-PEP, the number of STIs averted, and the number of STIs averted and one STI required to be treated annually to prevent it. We estimated the number of patients.

Researchers found that prescribing doxy-PEP to all patients prevented 70% of STIs, but only 3.7 patients needed treatment to prevent one infection. .

Prescribing only after a sexually transmitted infection diagnosis reduced the proportion of patients receiving antibiotics from 100% to 41% and prevented 42% of sexually transmitted infections, but the most efficient strategy is at least It was to be prescribed only to patients with two simultaneous infections. According to Traeger and his colleagues, using this strategy he only needs to treat her 1.2 patients to prevent one infection.

Providing an Outside Perspective, CROI Vice-Chair Landon Meyer medical doctor, “It really has the potential to change public health practices in the near future,” said Doxie PEP, Dean of Public Health and Family Medicine at the University of Cape Town, South Africa.

“It’s not for everyone,” Luetkemeyer added, noting that the Kenya study’s findings mean there are still no interventions for cisgender women. Including MSM with recent STIs and people with recurrent STIs who engage in condomless sex.

“That’s the population you really want to focus on. I don’t think this has to be the case for all MSM. You really want to focus on past STDs or risk factors for multiple STDs,” she said. said. “If someone is having condomless sex with multiple partners, I would discuss it with them.”

References:

• CDC. STD Treatment Guidelines, 2021. Doxycycline as an STI PEP: Considerations for Gay or Bisexual Men or Transgender Women Individuals and Health Care Providers. https://www.cdc.gov/std/Treatment-guidelines/clinical-primary.htm#CautionsForDoxyPEPLast confirmed date November 28, 2022. Accessed 20 February 2023.
• Luetkemeyer AF, et al. Summary 120. Place of Presentation: Conference on Retroviruses and Opportunistic Infections. February 19-22, 2023. Seattle.
• Molina JM et al. Abstract 119. Place of presentation: Conference on Retroviruses and Opportunistic Infections. February 19-22, 2023. Seattle.
• An NIH study investigating a vaccine to prevent gonorrhea. https://www.uab.edu/news/health/item/10852-nih-study-to-explore-vaccine-for-gonorrhea-preventionPublished October 23, 2019. Accessed 20 February 2023.
• Petousis-Harris H and others lancet2017; doi:10.1016/S0140-6736(17)31449-6.
• Stewart J, et al. Summary 121. Place of Presentation: Conference on Retroviruses and Opportunistic Infections. February 19-22, 2023. Seattle.
• Trager MW et al. Abstract 122. Place of presentation: Conference on Retroviruses and Opportunistic Infections. February 19-22, 2023. Seattle.

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