The first ever injectable drug that can prevent HIV has been approved for use in England and Wales.
Authors
- Rosalie Hayes
Research Assistant, Centre for Public Health & Policy, Queen Mary University of London
- Sara Paparini
Senior Lecturer in Public Health and Equity, Queen Mary University of London
- Sophie Strachan
Honorary Research Associate,, Queen Mary University of London
The drug, cabotegravir, would benefit an estimated 1,000 people at risk of HIV in England and Wales. It offers a long-acting alternative to other existing preventive HIV drugs, which are only available as pills and usually must be taken on a daily basis.
The jab belongs to a group of drugs called antiretrovirals , which were originally developed to treat HIV. It's now well established that antiretrovirals can also be used by HIV-negative people to dramatically reduce their risk of acquiring HIV .
The jab stops HIV from replicating within a person's cells, meaning infection cannot take hold. This approach is called pre-exposure prophylaxis, or Prep.
Injectable cabotegravir for Prep is administered by a single, intramuscular injection into the buttocks every two months. It must be administered by a trained health professional to ensure that the drug is delivered correctly into the muscle.
It is important to understand that cabotegravir is not a vaccine. Vaccines work by training the immune system to fight infections - whereas cabotegravir works by ensuring there are adequate levels of the antiretroviral drug in the bloodstream to prevent the HIV virus from replicating.
That's why people using cabotegravir as Prep need to make sure they get their injections every two months for as long as they're at risk of HIV.
Oral vs injectable Prep
Oral Prep is around 99% effective at preventing HIV when taken as prescribed - but this is reliant on people adhering to their pill regimen. Real-world effectiveness declines depending on adherence.
In contrast, injectable cabotegravir requires only six injections per year. Largely because it is easier to adhere to, cabotegravir has been found to reduce the risk of acquiring HIV by 66% in gay men, bisexual men and transgender women, and by 88% in cisgender women , compared to daily oral Prep.
There are other differences between injectable Prep and oral Prep beyond effectiveness.
People using cabotegravir for Prep will need to attend the clinic every two months to receive their injections. In comparison, people taking oral Prep will only need to get their prescription filled every three to six months.
Both injectable and oral Prep are very safe and well-tolerated medications, but possible side-effects differ between the two types. The most common side-effect of cabotegravir is swelling or tenderness around the injection site. Oral Prep's possible side-effects can include nausea, vomiting and headaches.
At the moment, current guidelines recommend cabotegravir is offered to people in need of Prep but who cannot use oral Prep effectively. This includes the small number of people with health conditions (such as severe liver or kidney problems) which may make oral Prep unsuitable for them and those with difficulty swallowing tablets.
It also includes those who are unable to adhere to oral Prep for social or personal reasons. For example, people who are homeless or in unstable housing who may easily lose medication or have it stolen, people experiencing intimate partner violence who may worry about their partner finding their pills and people who use drugs and find regular pill-taking challenging.
A significant milestone
Cabotegravir was already approved for use in England and Wales as part of a combination treatment for people living with HIV. Now, the drug will be available to those who are HIV-negative and looking to protect themselves from acquiring HIV. This is the first time an alternative to oral Prep has been made available on the NHS.
It offers access to highly effective HIV prevention for those who previously could not use Prep. Research shows that there is a strong preference for injectable Prep among people at risk of HIV, due to its convenience and the reduced pill burden.
This approval may also pave the way for other forms of injectable Prep that have an even longer duration. For instance, lenacapavir , which is already available in the United States, only needs to be administered every six months.
Currently, there are issues around inequitable access to Prep . For example, women make up only 3% of current Prep users but 35% of new HIV diagnoses . Recent research indicates that current Prep provision does not align with women's needs .
Giving patients more choice in the type of Prep they can access is an important step forward in addressing this inequality. But it will be crucial that sexual health services are adequately funded so they can deliver injectable Prep services.
Ongoing research also shows that delivering Prep outside of traditional sexual health settings, such as in community pharmacies and GP practices , could also make an important contribution to equitable access. Considering how injectables could be incorporated into these services will be a vital next step.
By increasing the numbers of people who can use Prep, injectables offer a critical new tool for achieving the government's goal of eliminating new HIV infections by 2030 .
Sara Paparini has received funding from ViiV Healthcare and Gilead Sciences.
Sophie Strachan receives funding from ViiV and Gilead and MSD she is affiliated with Sophia Forum
Rosalie Hayes does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
