View original publication on BetaBlog.org
When I read results from clinical trials about PrEP—or other HIV prevention tools or strategies for that matter—I’m often left wondering: Where do I fit in?
There aren’t guidelines about Truvada-based PrEP use for transgender men who have sex with men because there haven’t been any studies specifically looking at how the drug works in our bodies. In fact, major PrEP clinical efficacy trials have not included transgender men in any of their study populations to date. Robert Grant, MD, MPH, the principal investigator of the first successful randomized controlled PrEP trial with human subjects, iPrEx, confirmed this, saying, “to my knowledge, no trans men have been included in PrEP research.”
Grant says that it’s challenging to get study protocols that include transgender men approved. “The study sponsors will often ask that trans women and men be excluded if there will not be sufficient recruitment for a separate analysis. We had to argue to include trans women in iPrEx. We wanted to include trans men too, but we did not have estimates of HIV incidence among trans men that were required for inclusion in an efficacy trial.”
Because the majority of transgender men have reported condomless anal or vaginal sex with cisgender (non-transgender) men, it makes sense from a public health standpoint to include us in studies in order to capture the role we play in HIV prevention and transmission as a part of the MSM population.
Studies that present their findings as applicable to all MSM but do not include transgender MSM in their data fall short of having representative samples. This gap in our research agenda, evidence-based recommendations, and knowledge of PrEP has important clinical, ethical, and practical implications. Not knowing how PrEP can, and will, work for transgender bodies means that we’re left to wonder—are we truly protected?
“The lack of information about PrEP in trans men is a real problem,” said Grant.
The PrEP CDC guidelines tell us that it may take different amounts of time for people to achieve full protection based on whether they’re exposed to HIV rectally or vaginally. Many PrEP providers tell male patients that they will be adequately protected against HIV after seven consecutive days of adherence, with the assumption that their patients will be exposed to HIV only during anal sex.
Providers may fail to note, however, that Truvada takes longer to accumulate in vaginal tissue—and that transgender men often do not engage exclusively in anal intercourse. The best available information suggests that transgender men who have receptive vaginal intercourse will be protected after 20 consecutive days of dosing, when Truvada reaches its maximum concentration in the body.
Everything known about how PrEP works during vaginal sexual exposure is based on studies of cisgender women—but transgender men have different biological and physiological considerations than cisgender women. Transgender men oftentimes experience vaginal atrophy as a result of testosterone use. Might this condition significantly change the effectiveness of Truvada as PrEP?
Many men are unable or unwilling to use condoms for receptive vaginal intercourse because of the tearing and bleeding that often occurs during sex with vaginal atrophy. Does PrEP provide better HIV protection in combination with condoms despite the damage caused, or counterintuitively, does PrEP provide better protection without condoms since they may exacerbate tissue damage?
PrEP providers may reassure male patients that it’s not a big deal to miss a single dose once in a rare while1, based on the iPrEx OLE study which found no seroconversions among MSM who took Truvada at least 4 times per week. Because no transgender men were included in the iPrEx study, however, we can’t say for sure if this also holds true for transgender men. Cisgender women need to have nearly perfect adherence in order for PrEP to provide full protection against HIV. Is this the case for transgender men who engage in receptive vaginal intercourse, too?
It will be some time before PrEP research is able to fill in the missing data for trans men and answer these questions, but it is critical that efforts begin immediately. Transgender men are currently experiencing a watershed moment of visibility in the larger gay community. Casual bath house sex, cruising, and hooking up using phone apps are increasingly commonplace.
“The field desperately needs HIV and STD prevalence and incidence data, as well as information on demographics, comorbidities, and risk behaviors. In concert with epidemiologic characterization, at-risk trans men should be included in HIV prevention studies based on the type of exposure being investigated—that is, trans men who engage in receptive rectal intercourse should be included with other populations who have receptive rectal intercourse, and trans men who engage in receptive vaginal intercourse should be included in studies of others who have the same sexual practices,” said Raphael J. Landovitz, Associate Professor of Medicine in the Division of Infectious Diseases at UCLA.
Despite the gaps in clinical knowledge of how PrEP works for transgender men, all evidence supports the idea that Truvada provides a high degree of protection in people who take the pill consistently as prescribed—with no reason to believe that it is ineffective for transgender people. Even if there is a slight reduction in effectiveness, which has not yet been tested and is thus unknown, PrEP isrecommended for anyone HIV-negative at substantial risk for HIV infection.
PrEP may well be a life saver for transgender people who are disproportionately affected by HIV risk factors like poverty, unstable housing, discrimination, survival sex work, and disconnection from health care. We can’t give up on including transgender people in medical research. The urgency with which this minority population needs evidence-based guidance on sexual health care recommendations is an opportunity to improve the humanity of science moving forward.