ViiV Healthcare's trial assessing an investigational, long-acting injection for HIV prevention has been stopped early due to high levels of efficacy.

Interim analysis of the HIV Prevention Trials Network (HPTN) 083 study showed that ViiV's cabotegravir is 69% more effective at preventing HIV acquisition than daily oral PrEP with emtricitabine/tenofovir disoproxil (FTC/TDF).

Among the 50 people in the trial who acquired HIV, 12 were randomised to the long-acting cabotegravir arm and 38 were randomised to the daily, oral FTC/TDF arm, which translated HIV incidence rates of 0.38% versus 1.21%, respectively.

The firm said the study achieved its primary objective of non-inferiority with the difference approaching superiority in favour of cabotegravir, pending final analysis.

Also of note, safety was similar in the two groups, ViiV noted. Discontinuation due to injection site reactions or injection intolerance in the cabotegravir arm of the study was 2% and there were no discontinuations due to ISRs in the FTC/TDF arm.

“Each year, an estimated 1.7 million people are newly diagnosed with HIV. To lower that number, we believe more prevention options are needed in addition to currently available oral tablets for daily use,” said Myron S. Cohen, co-principal Investigator of the HPTN and the Yeargan-Bate Distinguished Professor of Medicine, Microbiology and Immunology and Epidemiology at the University of North Carolina (UNC).

“If approved, a new injectable agent, such as long-acting cabotegravir administered every two months, could play an important role in reducing HIV transmission and helping to end the HIV epidemic.”

“We are thrilled with the results not only because of the high efficacy of cabotegravir but also because we have demonstrated high efficacy in a study that adequately represents some of the populations most disproportionately impacted by HIV - black MSM in the US, young MSM globally and transgender women,” added Kimberly Smith, head of Research & Development at ViiV.

The HPTN 083 study, which included around 4,600 men who have sex with men (MSM) and transgender women who have sex with men across more than 40 sites in North and South America, Asia, and Africa, is one of the first clinical trials to directly compare two active prevention agents.