AIDS 2024: Studies show strong user preference for long-acting, injectable PrEP

Nearly two years after the World Health Organization released guidelines for the use of long-acting injectable cabotegravir (CAB-LA) as pre-exposure prophylaxis to prevent HIV, several demonstration studies looking at uptake and adherence to CAB-LA are underway in countries with high HIV burden, researchers said this week at AIDS 2024, the 25th International AIDS Conference. Nearly all of them have found similar results: When offered a choice between different forms of PrEP, the majority of clients choose CAB-LA.

In Zimbabwe — the first country in Africa to approve CAB-LA — the CATALYST demonstration study added CAB-LA as an HIV prevention method offered to study participants in April, in addition to offering oral PrEP and the dapivirine ring in the study’s cadre of PrEP options, Gertrude Ncube with the Zimbabwe Ministry of Health said. Since then, 72% of users on oral PrEP switched over to CAB-LA, with many participants indicating they made the switch to ease the pill burden of daily oral PrEP, Ncube said.

Participants also indicated that the CAB-LA injection, taken once every two months, is more convenient than oral PrEP and allows for more privacy as participants no longer need to hide their daily oral pill use from others, Ncube said. Men who have sex with men and female sex workers — both populations at high risk for becoming infected with HIV — show a particular preference for CAB-LA, Ncube said, most likely due to privacy concerns.

More than 90% of participants who made the switch to CAB-LA returned on schedule for their second injection, Ncube said, indicating high levels of adherence to the new PrEP method and engagement in care.

Malawi is one of the countries that participated in the groundbreaking HPTN 082 study, which found that CAB-LA use resulted in an 89% reduction in new HIV infections, compared to oral PrEP. Researchers there found similar key themes: patients preferred injectable CAB-LA over daily oral PrEP due to convenience, no pill burden and the ability to use PrEP without partner knowledge. Participants noted that although they remained uninfected with HIV, there is still stigma associated with taking a daily PrEP pill because others may assume HIV infection or promiscuity, Rose Nyirenda with the Malawi Ministry of Health said.

Study participants did indicate some concerns, however, Nyirenda noted, including potential side effects like injection site pain, headache and weight gain, as well as confusion around what CAB-LA is. Some participants mistakenly assumed the product is an HIV vaccine. Participants also noted concerns about the continuous availability of CAB-LA, Nyirenda said.

PrEP counseling and ongoing mentorship is key when initiating CAB-LA, Nyirenda noted, especially during the early stages of implementation. She noted that CAB-LA may overcome the adherence challenges associated with oral PrEP.

Adherence to oral PrEP is a challenge, Maryam Shahmanesh with the Africa Health Research Institute said, noting that due to the size of the pill and concerns around privacy, there is often a substantial drop off in adherence after oral PrEP initiation.

In a similar study looking at acceptability of oral PrEP vs. CAB-LA in South Africa, initial results show that 72% of study participants chose CAB-LA, researchers with the AXIS study said. The AXIS study is also looking at the acceptability of PrEP administration at private pharmacies in South Africa, researchers noted, with many study participants being familiar with receiving services at pharmacies, including routine immunizations, COVID-19 vaccination and injectable contraceptives.

Another study looking at the uptake of different PrEP methods through decentralized sexual and reproductive health services for adolescents and young women in South Africa — the LAPIS study — found that 77% of participants selected CAB-LA as their preferred choice for PrEP when given the option between CAB-LA, oral daily PrEP, the dapivirine ring or post-exposure prophylaxis. However, of those who selected CAB-LA, 16% switched to oral PrEP, stopped use or were lost to follow up. About 70% of CAB-LA users returned for their second injection, Shahmanesh said.

One population that didn’t primarily choose CAB-LA as their preferred PrEP method, however, was men who have sex with men, nonbinary and trans individuals aged 15-19 in Brazil, Ines Dourado with the Federal University of Bahia said. Among the 183 adolescents enrolled in the PrEP 1519 study across three sites in Brazil, 47% of participants chose CAB-LA and the rest chose daily oral PrEP, highlighting that different populations need diverse prevention methods that meet unique needs, Dourado said. Fear of needles was often cited as a reason for preference for daily pills over injections among this young population.

Having choices for PrEP is critical for increasing PrEP uptake and adherence, especially for adolescent girls and young women who are often at high risk for HIV in sub-Saharan Africa, panelists said. During the opening ceremony here, UNAIDS Executive Director Winnie Byanyima said three out of every four new HIV infections in high-burden countries in sub-Saharan Africa happen among adolescent girls and young women.

“Having multiple options gives us power and control over our sexual health,” Sanale Ngulube with Pangea Zimbabwe said, adding that having only one option is demotivating and deters young women from initiating PrEP. “Young people have different preferences and needs, and needs can change over time,” she said. Offering young people options will motivate them to seek health services and enable adherence to the choices they’ve made, Ngulube said. “Choice improves adherence.”