Clinical trials of twice-yearly PrEP injections for HIV prevention begin

Two clinical trials have begun in the USA to examine six-monthly PrEP injections using an antiretroviral drug called lenacapavir. Here’s all you need to know. 

What is this trial about? 

Whether twice-a-year PrEP injections are safe and effective.  

To test this, two mid-stage trials are beginning in the USA – one with cisgender women and one with people who inject drugs. Both will test the safety, acceptability, and pharmacokinetics (how a drug moves through the body) of an antiretroviral called lenacapavir.  

Why is it important? 

PrEP provides an effective and safe way for HIV-negative people to protect themselves from HIV. Where it is available, daily PrEP pills tend to be offered. But many people struggle to take pills every day. People have also reported issues with getting regular PrEP refills and being stigmatised for taking medication associated with HIV. 

PrEP injections offer an alternative that might address some of these issues. And a number of countries, including South Africa and Uganda, have approved PrEP injections and are running trials. PrEP injections are more discrete than daily PrEP pills and they are more convenient because they last for longer. Currently, the longest-acting PrEP injection available is cabotegravir, which can be given every other month. If the lenacapavir trials are successful, an even longer lasting form of PrEP could become available.  

What will this trial do? 

The first trial will include 250 cisgender women. Women who are Black or Latina will be prioritised. The second trial will include a diverse group of 250 people who inject drugs. Both studies are for people aged 18 and over. 

In both trials, participants will be randomly assigned to receive PrEP injections or daily PrEP pills. Participants’ health will be monitored closely throughout, including the HIV infection rate in each group. Participants will provide laboratory samples and give feedback on their experience of taking each form of PrEP. 

The two trials are part of the HIV Prevention Trails Network under the PURPOSE programme. Through PURPOSE, five clinical trials in total will test lenacapavir PrEP injections in different groups at risk of HIV.  

What does this mean for HIV services? 

This is another important step in PrEP research. One day, it may contribute to widening the HIV prevention options available to people at heightened risk of HIV. Both trials and the wider PURPOSE programme are driven by an understanding that HIV prevention must be person-centred. This means that people need HIV prevention methods that fit in their lives because they are easy to access and use.  

Both trials are not expected to end until 2027. This means it will be an number of years before six-monthly PrEP injections are likely to be approved, even in the USA. It will then take time for other countries to follow.  

Shobha Swaminathan MD, Professor of Medicine and Director of HIV Services at Rutgers New Jersey Medical School, who is the protocol chair for the PURPOSE trial involving cisgender women, said: “Ending the HIV epidemic means ending it for everyone—including and especially women, who are often underrepresented in HIV research and clinical trials and whose need for new HIV prevention options is critical.”