Nearly Half of Daily PrEP Users Interested in Switching to On-Demand Dosing

HIV pre-exposure prophylaxis (PrEP) has proven effective in preventing HIV, but the once-daily pill most commonly recommended has drawbacks. Alternative dosing may be a solution for some with infrequent risk of exposure, with benefits including lower pill burden, costs, and adverse effects.

Nearly half of men who have sex with men in Australia reported an interest in switching to on-demand PrEP, according to a recent survey.

The study, published in Open Forum Infectious Diseases, included men who had participated in a previous study of PrEP and were users of daily PrEP.

The 15-question survey, administered by investigators at Central Clinical School, Monash University, asked participants whether they would be interested in participating in a study of on-demand PrEP, and 48% indicated an interest in making the switch.

“The interest in on-demand PrEP was higher than we expected, and higher than has been found in other international studies, except in France, where on-demand PrEP is the norm,” first author Vincent Cornelisse, PhD, Department of Infectious Diseases, Alfred Health, and Monash University, told Contagion^®. “This was surprising, as PrEP is licenced in Australia only as a continuous once-daily regimen, and Australian PrEP roll-out projects have all promoted this method. It goes to show that we need more options so that gay and bisexual men can tailor HIV prevention strategies to their needs.”

On-demand PrEP has been recommended for MSM with infrequent sexual exposures but high-risk behavior. The Intervention Préventive de l’Exposition aux Risques avec et pour les Gays (IPERGAY) trial in France involved taking 2 pills of tenofovir disoproxil fumarate and emtricitabine 2 to 24 hours before sex, followed by 2 single doses at 24 and 48 hours after exposure.

The Australia survey was approved by the Alfred Health Ethics Committee, and about 1000 responses were analyzed. Nearly all of the respondents were men who have sex with men (MSM), and the average age was 39. Among the respondents, 86% used daily PrEP and 14% had stopped using PrEP, with a perception of low risk being the most common reason cited for stopping the treatment. About a third (37%) of respondents had prior knowledge of on-demand PrEP.

About 12% of respondents reported being dissatisfied with PrEP, with reasons including concerns about toxicity (27%), infrequent need (27%), dislike of taking pills (20%), difficulty remembering to take pills (16%), renal problems (5%), and ongoing adverse effects (4%).

Those who weren’t interested in on-demand PrEP cited reasons including concerns about its effectiveness (67%), feeling anxious (38%), and fears about remembering to take PrEP at least 2 hours before sex (58%). Some cited a low risk of contracting HIV (4%), and others noted the need to take a daily pill because of frequent sex (2%).

Previous studies have shown that those with a lower number of sexual partners were more likely to express interest in switching to on-demand PrEP.

The study called concerns about the efficacy of on-demand PrEP reasonable given the current emphasis on daily PrEP, limited data about on-demand PrEP and concerns about adherence to the more complex schedule of treatment and spontaneous nature of some sexual encounters. The study noted a need for specific adherence support for on-demand PrEP such as smartphone reminders.

“Our findings suggest that clinicians should discuss PrEP toxicity with their patients noting that there is little evidence for toxicity at least during the first few years of adults using PrEP,” senior author Edwina Wright, FRACP, PhD, Department of Infectious Diseases, Alfred Health, Monash University, told Contagion^®. “For people who have infrequent sex other options include condom use and on-demand PrEP. However, for people using on-demand PrEP very occasionally, we know that there have not been any seroconversions, but we are still waiting for more data to see if infrequent use of on-demand PrEP is just as protective as weekly use of on-demand PrEP.”

On-demand PrEP has been looked at as a possible solution to suboptimal retention in daily PrEP treatment. A previous survey of MSM and transgender women in the San Francisco Bay area found that 84% of individuals who had never used PrEP and 73% of those who had discontinued PrEP indicated they would consider starting or restarting treatment if they were offered on-demand PrEP.