AuthorisedTherapeutic exploratory (Phase II)Interventional

Inducing durable immunological control of HIV-1 through administration of long-acting broadly neutralizing antibodies and low-dose anti-PD-1 – a randomized, double-blinded, placebo-controlled trial (the IDUNN trial)

Modern daily tablets for HIV, called antiretroviral therapy (ART), work brilliantly to keep the virus suppressed. However, researchers want to find long-lasting treatments that allow people to take breaks from daily pills. The IDUNN study is testing a new approach using laboratory-made proteins called broadly neutralising antibodies alongside a low dose of an immunotherapy drug called nivolumab. Together, these are designed to help the body's own immune system fight and control HIV. Participants receive these treatments and then temporarily pause their daily HIV medication under careful, frequent medical supervision. Doctors monitor their blood tests closely. If virus levels climb or protective immune cells fall below set safety limits, standard HIV tablets are restarted straight away. The main goal is to see how long participants can safely stay off daily medication while keeping the virus under control.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Region Midtjylland

Enrolment target

Start

13 Jul 2026

HIV-1 disease

What is this study about?

For most people living with HIV, taking daily antiretroviral therapy keeps the virus at undetectable levels, protecting their health and preventing transmission. Even so, the virus hides inside dormant cells, meaning medication must be taken every day for life. Researchers around the world are working to find ways to give people long-lasting control of the virus without relying on daily tablets.

The IDUNN trial is looking at whether the immune system can be trained to hold HIV in check. It combines two long-acting antibodies (proteins designed to neutralise HIV) with a low dose of an immunotherapy drug called nivolumab. Nivolumab is designed to help 'wake up' and energise the immune system so it can recognise and clear out virus particles more effectively.

To find out if this therapy works, volunteers will pause their regular HIV medication in what doctors call an 'analytical treatment interruption'. Because stopping treatment carries some risk, the study has strict safety guardrails. Doctors monitor participants with regular blood tests to check viral load and CD4 cell counts. If the virus begins to multiply or immune cell levels drop, standard HIV tablets are restarted immediately.

This research is an essential step towards finding an effective, long-term remission strategy for HIV. By taking part, volunteers help scientists understand how the immune system can be strengthened to fight HIV naturally, bringing us closer to future treatments that do not rely on daily pills.

Key takeaways

Tests whether new immune therapies can keep HIV suppressed without daily tablets.
Combines two long-acting antibodies with a low-dose immunotherapy drug.
Requires a carefully monitored temporary pause of regular HIV medication.
Regular tablets are restarted immediately if the virus rises above safety limits.
Open to adults aged 18 and older living with HIV-1 who are in stable health.

Who may be eligible?

This study is open to adults aged 18 and over who are living with HIV-1 and are currently taking regular antiretroviral therapy. Participants generally need to have well-controlled HIV, meaning their viral load is undetectable and their immune system (measured by CD4 cells) is healthy and stable.

Because the study involves temporarily pausing daily HIV medication, participants must be in good overall health. People with other serious medical conditions, active infections, or those who are pregnant or breastfeeding may not be able to join, as safety is the top priority.

The research team will review your full medical history and perform detailed health checks and blood tests to confirm whether this study is safe and suitable for you.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am aged 18 or older.
I have been diagnosed with HIV-1.
I am currently taking daily HIV medication and have an undetectable viral load.
I have a stable immune system with healthy CD4 cell counts.
I am willing to attend frequent hospital visits for blood tests and monitoring.
I am comfortable temporarily pausing my daily HIV medication under doctor supervision.

Answer every question to see your result.

What does participation involve?

Taking part in this trial lasts for over a year (up to around 60 weeks). You will visit a specialist hospital clinic to receive the study treatments through a slow drip into a vein (an intravenous infusion). Some participants receive the active study medications, while others receive a dummy treatment (placebo) alongside active antibodies, depending on the study group.

Once the study medications are given, you will pause your usual daily HIV tablets. During this break, you will have frequent clinic visits—often every week or two initially—for blood tests. These tests track your viral load and CD4 immune cells very carefully.

If your blood tests show that the virus is multiplying again, or if your CD4 count drops below 350, you will restart your regular HIV medication immediately. You can also choose to restart your medication at any point. Once you restart standard treatment, doctors will continue to check on you to ensure your viral load returns to undetectable levels.

Potential risks and benefits

A potential benefit of joining is receiving cutting-edge immune treatments and very close, expert health monitoring throughout the trial. However, there is no guarantee that the study therapy will keep your virus controlled without tablets. The main risk is that your HIV viral load could rebound while pausing your regular tablets, which can temporarily lower your CD4 count or cause mild flu-like symptoms. There is also a risk of side effects or allergic reactions from the infusions. Very strict safety rules are in place to restart standard medication quickly if needed, and you are free to stop participating and return to your usual care at any time.

Locations (4)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Sweden
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Unverified
Norway
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Unverified
Denmark
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Unverified
Iceland

Common questions

Why do I have to pause my usual HIV medication?

Pausing daily tablets is currently the only way scientists can find out if the new immune treatments are able to control the virus on their own.

Is pausing my HIV medication safe?

It is done under strict medical supervision. You will have frequent blood tests, and clear safety limits are set so your regular tablets are restarted immediately if the virus rebounds.

Could I pass HIV to my partner while taking a break from medication?

Yes. Because your viral load might rise during the treatment pause, the protection provided by 'Undetectable = Untransmittable' (U=U) may not apply. You will need to use barrier methods like condoms or ensure your partner takes PrEP.

What happens if the study treatments do not work for me?

If your viral load rises or your immune cells drop, you will restart your standard HIV medication right away, which typically brings the virus back under control quickly.

Can I leave the study early if I change my mind?

Yes. Participation is entirely voluntary. You can choose to stop at any time and return to your standard daily treatment without affecting your normal NHS care.