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).
Aidsmap reports that 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.
Dr Raphael Landovitz of the University of California-Los Angeles, and principal investigator of the HPTN083 study, is now 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.
23rd International HIV Conference (AIDS 2020: Virtual), abstract OAXLB0101, 2020.
“It’s great to see such a high level of efficacy in a potential additional HIV prevention option, and to see the high level of efficacy for an already available option, daily oral PrEP,” said Mitchell Warren, AVAC executive director in a report in The Times.
“As we celebrate this exciting new data, we also must ensure that the companion HPTN 084 study of the same product in cisgender women finishes as quickly as possible, and simultaneously work to ensure broader access and support for daily oral PrEP in communities where it is needed now. We need options that will work in people’s lives, we need existing daily PrEP delivered at scale now, and we need multiple additional PrEP options to address diverse needs. CAB-LA, the dapivirine vaginal ring, and future products that show efficacy must be brought to market as quickly as possible,” said Warren.
In 2016, women aged 15 to 24 accounted for 37% of new infections, about four times greater than men their age. To tackle this problem, in 2017 South Africa became the first African country to offer young women and adolescent girls an antiretroviral, Truvada, after research showed it was safe and effective to prevent HIV. However, stigma and name-calling, including women labelled as “sluts”, has resulted in many not using this pill.
Professor Linda-Gail Bekker, deputy director of the Desmond Tutu HIV Centre, said in the report in The Times that the HIV community is very keen to see the injectable PrEP made as widely available as possible. “We are keen to see it made available for all men having sex with men and transgender people worldwide, but cost will be a big factor.”Full Aidsmap report
HIV Prevention Trials Network (HPTN) material
Full report The Times