Many gay/bisexual men currently taking PrEP would switch to injectable forms of the therapy should it become available

Approximately a third of gay and bisexual men who are currently taking oral (tenofovir/emtricitabine) pre-exposure prophylaxis (PrEP) would prefer long-acting injectable PrEP should it become available, investigators report in AIDS and Behavior. Individuals were less likely to prefer injectable PrEP if they had concerns about the level of protection it provided against HIV and/or about its durability.

“About one-third of GBM [gay and bisexual men] currently taking oral PrEP would prefer LAI-PrEP [long-acting injectable PrEP], suggesting some men could change dosing forms after Phase 3 clinical trials are completed,” write the authors. “This research adds to a growing body of research supporting the acceptability and preference of LAI-PrEP dosing.”

Approximately two-thirds of new HIV infections in the US involve gay and bisexual men. Oral PrEP offers high levels of protection against infection with HIV. The treatment is now recommended by the US Centers for Disease Control and Prevention for gay and bisexual men at risk of HIV.

Long-acting injectable PrEP is currently in Phase 2a clinical trials. It has a number of potential advantages, removing the requirement to take daily treatment and the need to maintain high levels of treatment adherence.

Research involving gay men who are not currently taking PrEP has shown that they would find injectable PrEP acceptable.

Investigators in New York City wanted to assess knowable and acceptability of long-acting injectable PrEP among gay/bisexual men who are currently taking oral PrEP.

“This research fills a critical gap in the literature about the potential of GBM transitioning from oral to LAI-PrEP once commercially available,” write the authors.

Participants were recruited between November 2015 and November 2016. All were born male, identified as gay/bisexual and had been taking oral PrEP for at least 30 days. Recruitment was designed to ensure that 50% of the sample used club drugs such as ecstasy, GHB, cocaine and methamphetamine. Knowledge of and attitudes towards injectable PrEP were assessed using computerised questionnaires.

The investigators gathered data on the participants' demographics, income, and level of education to see if any factors were associated with knowledge of an acceptability of long-acting injectable PrEP.

Half of the 104 participants were white. Approximately three-quarters had a bachelors degree or higher and 42% had an annual income of at least $50,000. The mean age was 35 years and 64% had been taking PrEP for less than a year.

Just over half (52%) had heard of long-acting injectable PrEP. About a third (30%) said they’d prefer this therapy should it become available. Another third had a pragmatic approach, stating they’d prefer whichever therapy was shown to be the more effective.

The majority (62%) had no concerns about the use of needles to administer injectable PrEP. Just over half (55%) expressed no real concerns about the need to attend quarterly medical check-ups to receive the injectable therapy. (Studies of injectable PrEP using the integrase inhibitor cabotegravir are now using an 8-weekly dosing schedule.)

Most men (88%) had at least some reservations about the possible long-term health effects of injectable PrEP, and 93% said they had concerns about potential side-effects.

There was widespread concern (88%) that the protective effects of injectable treatment might wear off between doses, and 93% said they had some concerns about the level of protection provided by injectable treatment.

Men with lower levels of education were more likely to express a preference for injectable PrEP compared to those with a college degree. Concerns about incomplete protection against HIV and the possibility of protection wearing off were both associated with lower odds of expressing a preference for injectable PrEP.

Individuals who had been on PrEP for a year were ten times more likely to have heard of injectable PrEP than men who had started PrEP more recently. Longer duration of therapy was also associated with a preference for injectable treatment, though this did not reach statistical significance.

“Nearly half of the PrEP-using GBM in this sample had not heard of LAI-PrEP previously, but many men currently on oral PrEP appeared interested in transitioning to LAI-PrEP should it become available,” conclude the investigators. “Findings about HIV protection and longevity of HIV protection from ongoing clinical trials will likely influence whether oral PrEP users consider LAI-PrEP.”