Injectable PrEP is strongly preferred among women who inject drugs

Injectable forms of HIV prevention were a hot topic at this year’s International AIDS Conference (AIDS 2024). Most notably, the formal unveiling of PURPOSE 1 study results indicated that twice-yearly lenacapavir injections resulted in zero new HIV transmissions among adolescent girls and women in South Africa and Uganda.

But injectable pre-exposure prophylaxis (PrEP) already exists—in the form of cabotegravir, which has been approved for use in the United States since 2021. However, uptake has been slower than expected and there are questions regarding demand, acceptability, how best to scale up use, and which populations with larger numbers of people vulnerable to HIV would most benefit. Should twice-yearly lenacapavir be approved in the future as a new PrEP option, those same questions will still apply.

In the U.S., people who inject drugs represent a particularly vulnerable group when it comes to HIV. While only accounting for about 7% of all new diagnoses in 2022, HIV among people who inject drugs was relatively consistent between 2018 and 2022, suggesting that preventives such as PrEP are not fully reaching this group.

Research from the Conference on Retroviruses and Opportunistic Infections earlier this year indicated that while there has been growing awareness among people who inject drugs regarding PrEP, this awareness has not translated into increased use. Additionally, while there have been large declines in overall mortality from advanced HIV in high-income countries such as the U.S., the same has not been true for subgroups, such as people who inject drugs.

“Women who inject drugs, especially those engaging in sex work, are disproportionately impacted by HIV around the globe, yet they continue to be underrepresented in PrEP implementation research and clinical trials,” Alexis Roth, Ph.D., M.P.H., Associate Professor of Community Health and Prevention at Drexel University in Philadelphia, Pennsylvania, told TheBodyPro. Roth presented research at AIDS 2024 aimed at highlighting and addressing these issues.

The TIARAS Study

The study by Roth, et al., entitled “‘The simplest way to go:’ A mixed methods analysis of why women who inject drugs selected long-acting injectable cabotegravir instead of daily oral PrEP,” used medical records, baseline survey data, and additional interview data to investigate PrEP product choice.

Adult women were recruited from a larger, ongoing randomized controlled trial, TIARAS, in Philadelphia. To participate, the women had to have had an instance of injection drug use in the past six months and have received a PrEP prescription in the month prior to enrolment in the study.

A total of 104 women who inject drugs entered the study between 2022 and 2024. The median age was 42; most had completed secondary school (79%), were currently unhoused (69%), had a history of overdose (81%), and had engaged in daily drug injection over the month prior to baseline data collection (74%). Just under half reported transactional sex in the past six months and around a third indicated syringe sharing in the prior months. Only 23% of the women had taken PrEP before.

Injectable PrEP: The Simplest Way to Go

Overall, a staggering 92% of women opted for injectable PrEP, nearly all of whom returned to the clinic to receive their first injection. The percentage choosing injectable PrEP was even higher among women who had prior PrEP experience (96%).

There were statistically significant differences in oral vs. injectable PrEP choice both based on how frequently the women injected other drugs and the number of sex partners they had. Specifically, women who injected drugs daily and those with more than one concurrent partner were more likely to opt for injectable PrEP.

Interview data revealed that the women felt strongly about bodily autonomy and choice. For instance, one 43-year-old woman who chose injectable PrEP stated: “Nobody will tell you you should do this over that, it’s always that person’s choice. Whatever is convenient. Whatever works best. Whatever that person thinks. They just educate you on both and you make the choice.”

Importantly for the women, their choice of PrEP was informed by challenges they had experienced with taking pills in the context of homelessness and substance use. This, combined with the longer duration of injectable PrEP efficacy, made it a much more attractive option, since it was not as sensitive to potential issues with adherence and a lack of personal safety. As a 41-year-old study participant explained: “I’ve had so many… prescriptions stolen from me, they don’t even know what they are and still take them… I like [that] I only have to do it once a month, you know, the simplest way to go.”

With about 95% of the participants who preferred injectable PrEP returning to the clinic to receive their first injection, Roth pointed to the significance: “These data suggest this population has a strong preference for long-acting injectable PrEP and highlight the importance of choice as a part of providing patient-centered care.”

These study results add to a growing body of evidence that suggest an expansion of preventive options will result in greater appeal for subgroups with specific HIV prevention needs—and that stresses the importance that these subgroups be able to access the specific preventive option that works best for them. As Roth concluded in her presentation at AIDS 2024, “Greater PrEP access is sorely needed.”

By Krishen Samuel