Around 78% of people who are living with HIV take a daily pill to manage their infection. These drugs work by preventing the HIV virus from multiplying.

Although these drugs are very effective, some people struggle to stick with the daily regimen. There are many reasons for this – including pill fatigue, stigma and accidentally missing a dose.

But our recent research has shown that a once-weekly pill is as effective as daily pills in treating HIV.

The global study included 607 participants with well-controlled HIV from 11 countries. The trial was designed to reduce bias and was a double-blind placebo-controlled study. This means that the participants did not know if they were taking the weekly oral pill or daily pills.

The study found that the weekly oral pill worked for 93% of participants, while the daily pill was 92% effective. Importantly, nobody developed resistance to either of the medications.

It’s impressive that the once-weekly pill worked as well as the daily pill, as the daily treatment we used in our study is recommended as one of the best HIV treatments currently available.

Side-effects were comparable between the two drugs. The most common side-effects for both the daily pill and weekly pill were headache and nausea. Only two out of 304 people stopped taking the weekly pill due to the side-effects they experienced.

The once-weekly pill contains two compounds (lenacapavir and islatravir) that have been combined into a single tablet. These compounds work together by blocking HIV from replicating at two different points in the HIV virus’s life cycle.

The weekly pill requires two “loading doses” to be given for the first two days before it can be given weekly. This is so that the correct drug levels can be reached before starting weekly dosing. If a dose is missed, it will only last in the body for a further week – so taking it weekly is very important.

Treatment options

The once-weekly pill is now in its final phase of testing before we apply for regulatory approval. If it is approved for use, it would give people living with HIV more choice over their treatment.

There are many advantages to having multiple safe and effective treatment choices for people who need to take medication for a long time. We have seen this with contraception, where offering a choice of methods – such as pills, injections, implants or patches – has been transformative in giving people greater reproductive autonomy and choice over the option that works best for their lives.

Weekly pills used to manage other chronic conditions have also been shown to better help people adhere to treatment. For instance, one study into people with osteoporosis found that around 57% of weekly users were still taking their medication a year later compared to 39% of daily users.

Although injectable HIV treatments – which are delivered every two months – are available in high-income countries, implementing these therapies has proven very challenging for strained healthcare systems because people must go to a hospital or clinic every two months for an injection, which is time-consuming for both patients and staff.

As such, a weekly pill option is a welcome innovation which could help many more people to persist on HIV tablets.

However, some potential disadvantages of the weekly pill could be that the weekly pill stops working if missed for more than seven days. People would need to take another loading dose in order for the treatment to be effective again.

For daily pills, people who have missed a pill can restart without requiring another loading dose – but there is also less leeway than there is with the weekly pill if a person has missed a dose.

People who have well-established habits of taking daily pills may find it harder to adjust to taking weekly pills. There is also the risk of forgetfulness as they get used to the new schedule.

Still, having an additional tool in the HIV treatment toolkit could bring us a step closer to reaching global targets for HIV elimination, which would need everyone living with HIV to be taking a treatment that works for them. It will now be up to regulators and health technology agencies to approve the weekly pill for use.

But it will also be key for health agencies to put more work into tackling HIV stigma if they want to achieve this goal.

Stigma still affects most people living with HIV. Research has even found it affects a person’s relationship with treatment – with one survey finding that around 60% of people have hidden their pills from others to avoid revealing their status. Stigma and discrimination can also affect treatment outcomes and adherence.

A once-weekly pill may be a welcome innovation for many people living with HIV. It may allow them to feel less stigma about taking their treatment, which may better help them adhere in the long run.