First published in DM168

An injectable HIV prevention drug shows high promise, researchers from the HIV Prevention Trials Network (HPTN) announced this week. The trial, called HPTN 084, is focused on female trial participants. It follows a sibling study focused on men who have sex with men and trans women.

The research has been hailed a scientific leap forward and the long-acting cabotegravir (CAB) injection being tested has been so successful that independent monitors have given the instruction to stop the blind-testing phase of the trial.

This allows all trial participants to know the results and to have the option in the coming months to be on the injections, which are administered once every eight weeks, or to take the daily oral dose of pre-exposure prophylaxis treatment.

DM168 spoke to lead HPTN 084 researcher Professor Sinead Delaney-Moretlwe, who is also the director of research at the Wits Reproductive Health Institute.

The WHO recommended in 2016 that pre-exposure prophylaxis (PrEP) of a daily dose of an oral drug containing the antiretroviral medicine tenofovir/emtricitabine (TDF/FTC) be part of a comprehensive HIV-prevention strategy. Who will benefit from more PrEP options, like the CAB injection?

The WHO recommendation is based on mathematical modelling where HIV incidence is greater than 3%. In Southern and Eastern Africa, PrEP should be available for adolescent girls and young women who are at the highest risk for HIV. It’s not because of your behaviour, it’s about the fact that you live in a place where you know the prevalence of HIV is high and not all of those people are in treatment and your risk for exposure could be high.

In South Africa, our guideline for PrEP is anyone who identifies themselves at substantial risk for HIV infection. In our setting, the goal now is to work to provide PrEP in all its forms at all primary healthcare facilities for anyone who is at risk.

Professor Sinead Delany-Moretlwe heads up the team that’s been conducting trials into long-acting cabotegravir injections that are proving to be a breakthrough in HIV prevention options for women. (Photo: Wits University)

The HPTN 084 trials have been under way since 2017 in research sites in Botswana, Eswatini, Kenya, Malawi, Uganda, Zimbabwe and South Africa. But this field of preventative treatment has been going on for more than a decade already. What was the reaction of the scientific community when you made such game-changing trial results public?

What was really impressive for the scientific community was that overall in this trial of 3,223 women, we saw an incidence of 1%, proving that it is highly effective. It was a blind trial so all the participants received either the long-acting CAB injection and a placebo pill, or the oral pill of tenofovir/emtricitabine and a placebo injection. Participants didn’t know which group was receiving which treatment. Even among those receiving the tenofovir/ emtricitabine pill, the HIV incidence was under 2%.

The CAB injection marks the third form of PrEP to become part of a treatment menu that will be available in the future. A few months ago, the European Medicines Agency’s (EMA) recommended a topical form of PrEP – a vaginally inserted ring that contains dapivirine, another antiretroviral, and is replaced once a month.

PrEP is really working to prevent HIV. I think we recognise that we can’t treat our way out of this epidemic. A country like South Africa cannot afford to keep putting people on to treatment. There is real value in preventing infection because the cost of PrEP is not lifelong. We believe the more HIV prevention choices people have, the more we can fight stigma and the challenges of following a daily treatment regime. People will choose an option that suits their lifestyle and their life stage.

In a time of Covid-19, we have seen the importance of good data, good science and also good communication. But we have also seen an era of science bashing. What lessons can be learnt from this?

Especially in low- and middle-income countries and places such as sub-Saharan Africa, it’s important that we do depend on science to get good answers to good questions because we can’t afford to waste taxpayers’ money on things that are not going to work. With Covid-19 we’ve learnt that we can expedite the pathway to get treatment to people. HIV is another emergency and we should try to expedite this pathway for new PrEP options without cutting corners.

What is the journey from trial to making the CAB injection accessible and affordable?

We have to compile all this data and submit this to regulatory authorities for review, which will allow or expedite licensure. We have to take the lessons from the trial to see how we implement this in a real-world setting. Governments are going to have to negotiate the price of the CAB injections, which means all stakeholders – scientists, government officials, bilateral agencies, communities and civil society – need to keep focused on this.

ViiV Healthcare, which makes cabotegravir, plans to file with the United States’ Food and Drug Administration (FDA) early next year. If there’s an expedited review, we may have an answer by early 2022. DM168

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