The California HIV/AIDS Research Program (CHRP) recognized this need and provided funding for studies designed specifically for the transgender population to understand HIV prevention in general, uptake of PrEP, adherence to treatment, and other issues that may occur (such as hormone use and drug penetration in neo-vaginal tissue).  One of these new initiatives is about to start in Southern California and includes 5 sites: 2 in San Diego (Family Health Centers and at UCSD) and one site each at LA LGBT, USC, and Harbor-UCLA. Another similar study is opening in Northern California with multiple sites in the Bay area and Sacramento.

As part of this study, we are enrolling a cohort of 300 HIV-negative transgender men and women and will administer Truvada as PrEP for one year. We are using text messaging to improve adherence and assessing whether the addition of personalized counseling might help with adherence when added to text messaging. Our previous studies have shown benefits of text messaging to improve PrEP adherence, but this has not been done in a sufficient number of transgender individuals.

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Infectious Disease Advisor: Why is it important to study PrEP specifically in transgender people? Do you expect any differences in efficacy between transgender individuals and cisgender men and women? Or is it mostly a problem with outreach?

Dr Morris: The question of efficacy is still open, since we have very little experience with transgender individuals from previous studies. Even though Truvada is currently indicated for use broadly also in transgender populations, more studies are needed to tackle this question. Interestingly, for the iPrEx clinical trial ( identifier: NCT00458393),4 the original publication only indicated that 1% of the participants were transgender. However, on a subsequent re-analysis and after re-classifying participants (according to self-reported gender identity, reporting a different gender than at birth, or men taking feminizing hormones), the authors found that up to 14% of their subjects were possibly transgender, mostly within non-US sites.5

In this secondary analysis of IPrEx data, there was no difference in efficacy between the PrEP group and the placebo group for transgender people. The most important finding was that among active-arm participants, the drug was detected in only about 18% of the transgender participants. 

This was much less than that seen in the overall group and suggests that adherence to treatment might be a particularly challenging issue in this population. All of the transgender women who seroconverted in the PrEP arm of the study had no detectable TDF in their blood, suggesting that they did not take the medication as prescribed. 

On the other hand, there were no HIV infections among those transgender participants who had adequate drug concentrations in blood. More prospective studies are needed to confirm that the efficacy is the same and that drug levels are the same as what we would expect.  In fact, one of the main goals of our upcoming PrEP study is to assess adherence and to compare it with measured drug levels in blood.

Infectious Disease Advisor: Are there any unique challenges when studying the transgender population?  How do you address them as part of your study?

Dr Morris: There are some important issues, and they are strongly related to the overall lower socioeconomic status of this population and their history of discrimination. Transgender individuals have experienced discrimination in every aspect of their lives, including within the medical community. Studies across the United States have indicated that transgender people experience obstacles when attempting to access adequate primary health care.  Often they are isolated from family, religious groups, and healthcare providers. 

To overcome this situation, transgender people have fostered their own support networks to obtain peer advice and share safe places to get medical care and other essential services. Unfortunately, many transgender people still have bad experiences in the medical setting and do not get treated appropriately. Therefore, there is an overall apprehension associated with becoming part of research.

This article originally appeared on Infectious Disease Advisor