This is the final phase III trial, before FDA approval, of the first injectable PrEP.

ViiV Healthcare has announced that it is recruiting participants for Phase III trials of a long-acting HIV prevention medication using cabotegravir, which will be given every two months by injection.

ViiV previously proved the effectiveness of cabotegravir as an injectable PrEP. However, the earlier study, which gave participants injections every three months, showed that the cabotegravir was absorbed more quickly than expected, which meant the timing of the injections would probably need to be dropped from every 12 weeks to every eight.

This study will now put that theory to the test and will compare its effectiveness with the daily dose of Truvada currently used as PrEP.

In the previous study participants reported they preferred the injectable over the daily pill, and many health experts believe that adherence will be much greater with an injectible form of PrEP.

The global Phase III study, HPTN 083, plans to enroll 4,500 HIV-negative men and transgender women who have sex with men, at more than 40 sites in North and South America, Asia, and Africa. A second Phase III study, which will evaluate the long-acting cabotegravir as HIV prevention among young cisgender women, will launch later in 2017. A Phase III trial is the last major hurdle before review (and hopefully approval) by the Food and Drug Administration.

“Twenty years ago we couldn’t have imagined a future with so many effective medicines to treat HIV," said John C Pottage, Jr, MD, chief scientific and medical officer at ViiV Healthcare, in a press statement. "However, there remains a need to provide more options for preventing HIV infection, such as long-acting regimens that don’t require daily dosing."

ViiV Healthcare is pursuing this study through their public-private collaboration with the HIV Prevention Trials Network, the U.S. National Institute of Allergy and Infectious Disease, and Gilead Sciences.

Anyone seeking to volunteer for the HPTN 083 trial, see "contacts and locations" here on ClinicalTrials.gov.