The study group ImPrEP CAB Brasil, an achievement of Fiocruz with the Ministry of Health, in collaboration with researchers from other institutions, gained prominence at the 32nd Conference on Retroviruses and Opportunistic Infections (CROI) – one of the main scientific events in the area. The study presented by the group, in San Francisco, in the United States, evaluated the coverage of daily oral HIV Pre-Exposure Prophylaxis (PrEP) and long-term injectable PrEP among young people from populations most affected by HIV in Brazil. According to the authors, the long-term injectable modality has been shown to significantly improve coverage and, consequently, HIV protection.
The results are especially promising to overcome the adherence challenges faced mainly by young people and vulnerable populations. In addition, the attendance of the participants in the appointments for injections application was high and consistent, an important data for the construction of the strategy for the implementation of this technology in the Unified Health System (SUS).
The study included 1,447 participants – gay, bisexual and other men who have sex with cisgender men (MSM), transgender and non-binary people – aged 18 to 30 who had never used PrEP. They were able to choose between daily oral PrEP or long-term injectable and started use as early as the first study visit. The research was conducted in six Brazilian cities (São Paulo, Rio de Janeiro, Florianópolis, Salvador, Manaus and Campinas). Participants were included between October 2023 and September 2024, with a minimum follow-up of 48 weeks.
For comparison, the researchers formed a comparison group with 2,411 people with similar demographic characteristics, who started daily oral PrEP in SUS units in the same study period. PrEP coverage was measured by the proportion of days that participants were protected with PrEP, either oral or long-acting injectable.
The results showed coverage rates of 95% for those who used long-term injectable PrEP and 58% for those who opted for daily oral PrEP, within the ImPrEP cab Brasil study. In the comparison group, the coverage was 48% . Paired coverage comparisons indicate significant differences between those who chose the long-term injectable regimen and the other groups.
The preference for the injectable regimen was expressive: 83% of the participants opted for long-term PrEP with Cabotegravir. Among them, 94% received the injections within the correct period and only 6% lost the study follow-up – only 0.8% underwent only the first application.
The study protocol allowed the change of modality. About 9% of participants switched from the daily oral regimen to the injectable one, while 4% went the other way. During follow-up, nine HIV infections were recorded among participants in the comparison groups who used daily oral PrEP, and no seroconversion among users of injectable PrEP in ImPrEP CAB Brasil.
According to infectologist Beatriz Grinsztejn, from Instituto Nacional de Infectologia Evandro Chagas (INI/Fiocruz) and main researcher at ImPrEP CAB Brasil, "the importance of the study is to show that the implementation of injectable Cabotegravir for people of sexual and gender minorities, including the most vulnerable, is feasible and very effective. Coverage was very high compared to oral PrEP, which is corroborated by the fact that we have not recorded HIV infections among people who used injectable PrEP".
Beatriz recalls that medications for daily use usually present greater difficulty in adherence, while Cabotegravir, applied every two months, provides much better coverage. She also points out that the drug remains in the muscle, ensuring protection for about two months.
"Eventually it is expected that the drug will be incorporated into the SUS, benefiting those who have more difficulty adhering to oral PrEP. Long-term injectable PrEP can increase both the number and diversity of people protected against HIV, contributing to the scale-up and reach of PrEP. This study provides important subsidies for the Ministry of Health to evaluate the feasibility of implementation", says the researcher. The presentation was very well received at CROI and the group was invited to participate in the press conference of the event, reflecting the relevance and repercussion of the results.
PrEP
In the field of HIV/AIDS technologies, long-term medications have been playing a prominent role, both as new treatments and as prevention alternatives. In the case of prevention, they offer new options to face the challenge of daily adherence required by oral PrEP. Many users are unable to maintain daily regularity in tablet intake, which may compromise the effectiveness of prophylaxis.
ImPrEP CAB Brasil is, to date, the largest long-acting PrEP implementation study in Latin America, generating evidence to support public health policies in Brazil and other countries in similar contexts. In addition to INI/Fiocruz, the STI/AIDS Training Reference Center in São Paulo, the STI/AIDS Reference Center in Campinas, Fundação de Medicina Tropical Heitor Vieira Dourado in Manaus, and the University of California participate in the study.
"The next stage of ImPrEP will be the study of Lenacapavir, another injectable medication that treats and prevents HIV," says Beatriz. "It will be a study conducted in the same six centers and in another unit in São Paulo. We will evaluate the use of Lenacapavir applied every six months as PrEP for sexual and gender minorities, this time covering people aged 15 to 30 years”.
CROI
Created in 1993, CROI has consolidated itself as one of the main scientific sources on retroviruses and opportunistic infections. The conference brings together scientists and clinical researchers to discuss advances in epidemiology, biology and treatments of HIV/AIDS, hepatitis, Sars-CoV-2 (including Long Covid) and mpox, promoting the exchange of knowledge between basic and clinical research and contributing to the development of new prevention, diagnosis and treatment strategies.