Use of Long-Acting Injectable PrEP May Be Hindered by Health Care Provider Visits, Efficacy Concerns

Two studies examine whether users of daily oral PrEP would switch to a long-acting injection with interesting results.

Kathrine Meyers, DrPH, MPP

A long-acting, injectable form of pre-exposure prophylaxis (PrEP) is being developed as an alternative to the currently available daily oral treatment regimen; however, investigators on 2 studies found that the burden of having to visit a health care provider regularly to receive the injections as well as concerns about the injection’s efficacy may be a deterrent for some individuals.

Kathrine Meyers, DrPH, MPP, Instructor of Clinical Investigation, The Rockefeller University, and director, China AIDS Initiative, Aaron Diamond AIDS Research Center, New York, NY, and colleagues describe their National Institutes of Health-funded study as the first to directly ask current oral PrEP users whether they would switch to a long-acting injectable PrEP (LAI-PrEP) product were it to become available, "and probe the product-level and psychosocial aspects of their switch intentions."

LAI-PrEP, which would serve as an alternative to daily oral emtricitabine and tenofovir disoproxil fumarate (Truvada, Gilead), is a combination of the investigational agent, cabotegravir (ViiV Healthcare), an integrase strand transfer inhibitor, with rilpivirine (Edurant, Janssen Sciences), a non-nucleoside reverse transcriptase inhibitor. The long-acting combination injection has been tested in phase 3 trials with 4- and 8-week dosing intervals.

"For this new biomedical prevention strategy to be effective," Meyers and colleagues indicate, "it is important to understand not only interest in [LAI-PrEP] during clinical development, but also its likelihood of being adopted by real users and the factors that might underlie decisions about uptake."

The investigators identified 105 subjects from participants of a PrEP demonstration project in New York City which began in October 2014 and included individuals who were assigned male sex at birth. The subjects were between the ages of 19 and 63, and 46.7% were men of color. A total of 89.5% of subjects identified as gay.

Each of the subjects had been taking PrEP for at least 12 months before participating in the study. After reading a brief description of LAI-PrEP, the subjects responded to a series of open- and close-ended questions developed to elucidate product-related attitudes and concerns, as well as psychosocial factors that could affect their choice of switching to the product.

The results of the survey indicated that two-thirds (66.7%) of the current PrEP users would switch to LAI-PrEP.

Logistics of obtaining the product were pertinent to the likelihood of its adoption. The odds an individual would switch were lower (odds ratio = 0.37) if they viewed the dosing schedule as complicated (ie, having to visit a health care provider every 8 to 12 weeks to receive the injection). For example, 1 Black 29-year-old male is quoted as saying, “Biggest drawback is that it’s a shot and that I have to actually visit a health care provider to receive the dosage.”

Those subjects who self-identified as not being averse to receiving shots were more likely to switch to LAI-PrEP than those concerned with post-injection pain.

Several of the psychological aspects, such as having anxiety about missing oral doses, were not found to significantly influence the likelihood of switching to the injectable. Among the psychosocial factors associated with switching were having a sense of responsibility for PrEP use, and self-identifying as an early adopter of treatments.

Another study, conducted by Christian Grov, PhD, MPH, chair, department of Community Health and Social Service, City University of New York (CUNY) Graduate School of Public Health and Health Policy, New York, NY, and colleagues, examined the awareness of, and preference for, using the injectable product. For this study, Grov and colleagues administered a computer-based survey to a similar number (n = 104) of current PrEP users, drawn from the PrEP & Me demonstration study in New York City which recruited participants between November 2015 and November 2016.

The investigators reported that about half of the subjects had heard of LAI-PrEP and that 30.8% indicated they would prefer that dosage form. Only a few of the subjects expressed fear or dislike of needles or shots, and most leaned toward little to no concern about the prospect of quarterly medical check-ups and injections.

Grov and colleagues also noted that those subjects who had been taking PrEP for a longer period were more likely to prefer switching, "indicating the potential maintenance burden of daily oral PrEP and need for long-acting dosing alternatives.”

In this study, rather than being deterred by visits to the health care provider for LAI-PrEP, the subjects who were less likely to switch expressed concern about whether the injection would provide the same level and longevity of HIV protection as the daily oral dosing. Almost all (93.3%) expressed some level of concern about incomplete protection with the new dosage form.

The study of intentions to switch to injectable PrEP conducted by Meyers and colleagues was published July 19 in PLOSone.