A study suggests that a new medication – taken as an injection every two months – could be more effective at preventing HIV transmissions than Truvada.
Truvada was the first medication approved by the FDA for pre-exposure prophylaxis (PrEP). But data from a clinical trial shows that the integrase inhibitor Cabotegravir may be just as effective at stopping the spread of HIV.
The study included 4500 participants in several countries who were transgender women or cisgender men who have sex with men and were determined to be at high risk of HIV transmission. With enrollment starting in late 2016, participants were given Truvada, Cabotegravir, or one of two placebos – either a pill or an injection.
An early look at the data – which has not yet been peer-reviewed – showed that 12 of the people who were given Cabotegravir got HIV, while 38 of the people who were given Truvada got HIV, so the Cabotegravir group had 69% fewer new infections than the Truvada group.
The results support the idea that Cabotegravir is at least as effective at stopping HIV infections as Truvada, and Truvada has previously been shown to stop 99% of HIV transmissions if taken as directed. Studies have shown that people who got HIV while on the drug have mostly had trouble taking it every day.
Cabotegravir has the benefit of being administered as an injection every eight weeks instead of as a daily pill, which experts believe could make adherence easier for many people. Two percent of the people who were given Cabotegravir left the study early due to pain from the injection.
“It’s really exciting,” University of Washington epidemiologist Jared Baeten told Science. Baeten was not involved with the clinical trial but has studied PrEP in the past. “It gives another option for people who can’t or don’t want to take daily pills.”
Baeten compared PrEP to birth control in that having more options available could result in more people using it.
Having options may get more people to use PrEP, Baeten says, like how there are many forms of birth control for people to choose from.
UCLA researcher Raphael Landovitz, who was the protocol chair of the study, said that researchers were operating at 43 sites in the U.S., South Africa, Argentina, Brazil, Peru, Vietnam, and Thailand, but that 11 of the sites had to close because of the coronavirus pandemic and other sites struggled to maintain participation.
The researchers asked their supervising board to change the endpoint of the study April so that they could work with an “undisrupted data set.” Instead of trying to show that Cabotegravir is better than Truvada, they decided just to show “noninferiority” – that it’s just as safe and effective.
Cabotegravir is produced ViiV Healthcare, a joint venture of GlaxoSmithKline, Pfizer, and Shionogi. Truvada is produced by Gilead Sciences.