Every two-month injections show higher efficacy than oral PrEP

Today, Monday 18th May 2020, the HIV Prevention Trials Network (HPTN) announced the interim analysis of their study HPTN 083 which was evaluating the efficacy and safety of long-acting injectable cabotegravir for the prevention of HIV.

In the study cabotegravir was found to be 69% more effective (95% CI 41%-84%) in preventing HIV acquisition amongst men who have sex with men (MSM) and transgender women who have sex with men – when compared to the current standard of care, which is daily oral TDF/FTC tablets. This is one of the first ever trials to compare two active prevention agents.

The HPTN 083 study enrolled approximately 4,600 participants form across more than 40 sites in North & South America, Asia and Africa. Two-thirds of the study participants were under 30 years of age, 12% were transgender women and half of the participants in the United States identified as black or African American.

Of the almost 4,600 participants 50 acquired HIV during the study, and of those 12 were in the cabotegravir arm and 38 were in the daily oral TDF/FTC arm. This translates to a HIV incidence rate of 0.38% (95% CI – 0.20%-0.66%) in the cabotegravir arm and 1.21% (95% CI 0.86%-1.66%) in the TDF/FTC arm.

Safety data from the Data and Safety Monitoring Board (DSMB) found that the data clearly indicated that the long-acting injectable cabotegravir was highly effective at preventing HIV in the populations studied.

Myron S. Cohen, M.D., 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) at Chapel Hill, said: “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. 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.”

Following review of these findings, the DSMB recommended the blinded, randomised portion of the study be stopped early and results released.

Participants who were in the FTC/TDF arm will be offered long-acting injectable cabotegravir and participants in the cabotegravir arm will continue to receive it.

Participants who do not want to receive cabotegravir will be offered FTC/TDF until the end of the originally planned blinded component of the study.

The DSMB decision was approved by the U.S. National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), the study sponsor.

Kimberly Smith, M.D., Head of Research & Development at ViiV Healthcare said: “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,

“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.

“We are also committed to studying the effectiveness of cabotegravir in women and continue to be focused on the completion of HPTN 084, which will give us the companion study of 083 that will give us important information about the effectiveness of cabotegravir in women.

“New options are needed for HIV prevention that offer an effective alternative to daily oral PrEP. 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.”