A long-acting treatment that only requires one injection every two months is highly effective at preventing HIV infection in women, according to a Phase 3 study by The HIV Prevention Trials Network (HPTN). The study found cabotegravir, an anti-retroviral injectable treatment, was 89 percent more effective than current daily therapies.
“This is a major, major advance,” said Dr Anthony Fauci, the top infectious disease doctor at the National Institutes of Health (NIH), reports AP news. “I don’t think we can overemphasize the importance of this study.”
HIV currently affects over 38 million people globally. The cabotegravir treatment is aimed at HIV prevention, called pre-exposure prophylaxis (PrEP), and must be taken prior to infection of HIV. Current PrEP treatments are taken daily (Truvada pills) and are effective at preventing HIV, but the daily regimen must be strictly adhered to and even short lapses in taking the treatment can reduce its protection. Cabotegravir, on the other hand, protects against HIV for 2 months per single injection and even provides more protection than the oral counterpart.
The study, called HPTN 084, was launched in late 2017 to test the effectiveness of cabotegravir at protecting sexually-active cisgender women from HIV across sub-Saharan Africa. The cohort consisted of 3,223 women aged 18-45 years old and involved one group taking oral treatments and one group taking the experimental treatment of cabotegravir. The new treatment was found to be 89 percent more effective than the alternative, with just four women contracting HIV in the trial group compared to 34 cases in the oral treatment group. Two of those four women in the cabotegravir group stopped taking the injections.
Urgent treatment alternatives are needed for at-risk women, as women have high incidences of HIV within affected countries and many struggle with the daily PrEP regime. Previous studies found cabotegravir to be both safe and effective at preventing HIV in cisgender men and transgender women.
“After years of evaluating HIV prevention strategies for women, I am thrilled that we have found CAB LA so effectively reduces HIV acquisition and provides women more choices in how to protect themselves,” said Dr Mina Hosseinipour, HPTN 084 protocol co-chair, professor of medicine at the University of North Carolina (UNC) at Chapel Hill School of Medicine, and scientific director of UNC Project-Malawi in Lilongwe, Malawi, in a statement.
The study was to finish in 2022, but an interim meeting on November 5, 2020, found compelling evidence that the drug was safe, highly effective, and had no notable side effects. The blind trial has now been ceased, but participants have the option to remain on the treatment until the original end date of 2022.
Despite the promising results, the study will have to be fully reviewed and further trials will be needed. For example, there are questions as to whether or not cabotegravir is safe for adolescents and pregnant women, which will need to be studied further before the treatment can be made widely available.
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