Experimental PrEP drug injected once every two months to begin global trial

21 December 2016

Adherence challenges with pre-exposure prophylaxis (PrEP) could be overcome if experimental long-acting HIV drug is found to be effective and acceptable.

Injectable medications

An experimental HIV drug, cabotegravir, is starting global phase III clinical trials to assess the safety and efficacy of its use as a long-acting injectable pre-exposure prophylaxis (PrEP) among people at a high risk of HIV.

The trial will compare cabotegravir, injected once every four weeks for the first two months and every eight weeks thereafter, with oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) –  more commonly know under its brand name of Truvada – taken daily.

The trial, called HPTN 083, is the first large-scale trial of a long-acting injectable for HIV prevention. 4,500 high-risk, HIV-negative men who have sex with men and transgender women who have sex with men will be enrolled in the study from North and South America, Asia and Africa. The trial is due to last for four and a half years with primary results released in 2020.  

Truvada is currently the only drug licensed for use as PrEP. It is a proven HIV prevention tool and endorsed by the World Health Organization (WHO) in their HIV treatment guidelines. However, ensuring people adhere to the drug as prescribed is vital for its effectiveness. If cabotegravir is found to be effective, the long-acting injectable drug could provide another way in which PrEP can be taken which may be more acceptable among some populations.

Anthony S. Fauci, M.D., director of the USA National Institute of Allergy and Infectious Diseases (NIAID), said: "We urgently need more HIV prevention tools that fit easily into people's lives […] Although daily oral Truvada clearly works for HIV prevention, taking a daily pill while feeling healthy can be difficult for some people. If proven effective, injectable cabotegravir has the potential to become an acceptable, discreet and convenient alternative for HIV prevention."

A similar trial, HPTN 084, will also look at the efficacy and acceptability of the long-acting injectable cabotegravir for HIV prevention among young women in sub-Saharan Africa – one the groups most affected by HIV globally. As there are limited discreet HIV prevention methods that women can control, cabotegravir is an exciting development. This trial is expected to begin in early 2017.

Cabotegravir is an experimental, non-FDA approved integrase inhibitor, a class of HIV drug that blocks the integration of HIV DNA into the CD4 cell. It is also being assessed as an HIV drug for people living with HIV.

The trial is being run as a collaboration between ViiV Healthcare, the HIV Prevention Trials Network (HPTN), the US National Institute of Allergy and Infectious Disease (NIAID) and Gilead Sciences.

Photo credit:
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Written by Caitlin Mahon

Content Specialist - HIV & Sexual Health