A recent clinical trial found that injections of cabotegravir every eight weeks were 69% more effective at preventing HIV infection in men and transgender women who have sex with men than daily oral Truvada.
“These study results demonstrate that long-acting injectable cabotegravir dosed every two months can successfully reduce HIV acquisition in at-risk MSM and transgender women,” said ViiV Healthcare’s Kimberly Smith.
Phase III trials such as this one are rarely stopped in the middle of the trial because a drug proves so effective. However, that’s exactly what happened in this trial. Researchers stopped the trial early because the results were so positive.
The University of North Carolina’s Professor Myron Cohen said the researching team burst into tears of joy when told of the success of the trial.
“Every six months we meet with the oversight board and every one of those meetings is incredibly dramatic. You know, they can go either way. So it was a really tearful moment when they requested the study be stopped because of a positive result,” Cohen said. “We have 4,500 study subjects at 44 sites around the world. They have been wonderful and willing to let themselves participate in this study. So, it was a very moving moment. Everyone on the call just jumped out of their chairs and were like: ‘yeah!'”
Cabotegravir’s 69% advantage fell just short of statistical significance, meaning, from a technical standpoint, the study found that cabotegravir was equally as effective as Truvada. However, these results are still important because receiving one injection every eight weeks is a much easier medication regimen to adhere to than taking pills every day.
“If approved, this long-acting injectable has the potential to be a game-changer for HIV prevention by reducing the frequency of dosing from 365 days to six times per year,” said Smith.
The study involved approximately 4,600 men and transgender women who have sex with men. 12 people (0.38%) in the cabotegravir arm of the study were infected with HIV compared to 50 people (1.21%) in the Truvada arm. Adherence to the medication regimen in the Truvada was high: Truvada was detected in 87% of all Truvada arm samples tested.
Participants in the cabotegravir arm had cabotegravir injected into the muscle every eight weeks and were given placebo pills to take daily. Participants in the Truvada arm took Truvada orally every day and were given placebo injections every eight weeks.