ViiV's investigational, long-acting injectable cabotegravir was found to be 66% more effective than daily pills in preventing HIV-1 acquisition, according to final analysis of data from the HPTN 083 study.

The Phase Iib/III study compared cabotegravir administered every two months to daily oral emtricitabine/tenofovir disoproxil fumarate 200mg and 300mg (FTC/TDF) tablets for HIV pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) and transgender women who have sex with men.

The blinded phase of the study was stopped early in May 2020 following a pre-planned independent Data and Safety Monitoring Board review, which showed that long-acting cabotegravir was highly effective at preventing HIV in the target population.

Final analysis has now confirmed the superiority of long-acting cabotegravir, which was 66% more effective at preventing HIV when compared to daily oral FTC/TDF tablets, ViiV said.

In the final data analysis, 52 documented cases of HIV were recorded in the trial, with 13 cases occurring in the long-acting cabotegravir arm and 39 cases occurring in the daily, oral FTC/TDF arm, translating to HIV incidence rates of 0.41% and 1.22%, respectively.

Also of note, both therapies were well tolerated throughout the study, with most adverse events being mild or moderate in nature and balanced between both treatment arms, ViiV noted.

“These data are truly ground-breaking, demonstrating that long-acting injectable cabotegravir dosed every two months is superior to daily oral FTC/TDF at preventing HIV in at-risk men and transgender women who have sex with men,” commented Kimberly Smith, ViiV's head of R&D.

“This advancement has the potential to be a game-changer for HIV prevention, offering an option with very high rates of effectiveness and the convenience of reduced dosing from daily to just six times per year.

“We are thrilled with the results not only because of the high effectiveness of cabotegravir but also because this study adequately represents some of the populations most disproportionately impacted by HIV - black MSM in the US, young MSM globally and transgender women.”

The company said it plans to use the data from HPTN 083 for future regulatory submissions.