by Gus Cairns

PrEP administered as an injection every eight weeks was more effective in preventing HIV than oral PrEP in gay and bisexual men and transgender women, researchers confirmed at the 23rd International AIDS Conference (AIDS 2020: Virtual) today.

The headline findings were originally announced two months ago when the HPTN083 study was terminated early, because there were clearly fewer infections in people offered injectable PrEP than in people offered oral PrEP. At the time, the number of data points collected only allowed the researchers to say that the injectable drug was “non-inferior” to the oral drug – in other words, that, while it did seem to perform better, it had not passed a predetermined threshold enabling researchers to say it was clearly superior. The purpose of this threshold is to avert the possibility of random effects.

Today, Dr Raphael Landovitz of the University of California, Los Angeles, and principal investigator of the HPTN083 study, was able to say that bi-monthly injections of the drug cabotegravir were superior, in terms of preventing HIV infection, to oral doses of a combination pill of tenofovir disoproxil fumarate plus emtricitabine (the well-known blue pill whose brand name is Truvada.)

A companion study, HPTN084, is currently underway in 3200 cisgender women in seven countries in sub-Saharan Africa. Unless that is also stopped early, its results aren't likely to appear till mid-2021 (see this graphic). Read more via AIDSmap

Landovitz RJ et al. HPTN083 interim results: Pre-exposure prophylaxis (PrEP) containing long-acting injectable cabotegravir (CAB-LA) is safe and highly effective for cisgender men and transgender women who have sex with men (MSM,TGW). 23rd International HIV Conference (AIDS 2020: Virtual), abstract OAXLB0101, 2020.