AuthorisedTherapeutic confirmatory (Phase III)Interventional

HELIOS: An Open-Label, Long-Term Study to Investigate the Safety, Tolerability, and Efficacy of DISC-1459 (Bitopertin) in Participants with Erythropoietic Protoporphyria (EPP) or X-Linked Protoporphyria (XLP).

The HELIOS study is a long-term research project for adults with either Erythropoietic Protoporphyria (EPP) or X-Linked Protoporphyria (XLP). These are rare conditions that make people very sensitive to sunlight. The study is investigating a new medication called Bitopertin. We want to find out if this medicine is safe to use and if people can take it without too many problems. We will also be looking at whether Bitopertin helps people with EPP or XLP spend more time in the sun without experiencing pain or other symptoms. This is an important step to see if Bitopertin could become a useful treatment for these conditions.

At a glance

Status

Authorised

Phase

Therapeutic confirmatory (Phase III)

Sponsor

Disc Medicine Inc.

Enrolment target

Start

12 Feb 2026

X-Linked Protoporphyria (XLP)Erythropoietic Protoporphyria (EPP)

What is this study about?

The HELIOS study is a clinical trial focusing on two rare conditions: Erythropoietic Protoporphyria (EPP) and X-Linked Protoporphyria (XLP). Both conditions cause severe sensitivity to sunlight, making everyday activities outdoors very challenging and painful for those affected. This can significantly impact a person's quality of life.

Researchers are investigating a new medicine called Bitopertin. The main goal of this study is to understand if Bitopertin is safe for people with EPP or XLP and if they can tolerate it without too many side effects. We'll be carefully monitoring participants through various health checks.

Beyond safety, the study also wants to see if Bitopertin can help people with EPP or XLP spend more time in sunlight without pain. This is a very important measure, as increased daylight tolerance could mean a much better quality of life for those living with these conditions. We will also check how the body processes the medicine.

Key takeaways

This study is testing a new medicine called Bitopertin for EPP and XLP.
It aims to check the safety and how well people tolerate the medicine.
Researchers want to see if Bitopertin helps people spend more time in sunlight without pain.
Participants must be 18 or older and have a confirmed diagnosis of EPP or XLP.
It's a long-term study with regular health checks and monitoring.

Who may be eligible?

To take part in this study, you must be 18 years old or older. There is no upper age limit, meaning older adults can also participate.

This study is open to both men and women.

Crucially, you must have a confirmed diagnosis of either Erythropoietic Protoporphyria (EPP) or X-Linked Protoporphyria (XLP). The study is specifically designed for people with these conditions.

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.

Are you 18 years old or older?
Do you have a diagnosis of Erythropoietic Protoporphyria (EPP)?
Or do you have a diagnosis of X-Linked Protoporphyria (XLP)?
Are you able to attend regular hospital visits for health checks?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you would be provided with the study medication, Bitopertin. You'll have regular hospital visits where the study team will monitor your health very closely. These visits will include checks like observing your vital signs (such as blood pressure and heart rate), carrying out physical examinations, and taking blood and urine samples to check your general health and how the medicine is affecting your body. We will also ask you to record how much time you can spend in sunlight and when you first feel discomfort. The total duration of your participation in this long-term study will be explained in detail by the study team.

Potential risks and benefits

Taking part in this study might offer potential benefits, such as access to a new experimental medicine that could improve your ability to tolerate sunlight, which might improve your quality of life. However, as with any medication, there are potential risks, including side effects from Bitopertin. The study team will explain all known and potential risks in detail. Remember, your participation is completely voluntary, and you have the right to withdraw from the study at any time without giving a reason, and this will not affect your usual medical care.

Locations (9)

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

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Unverified
Italy
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Unverified
France
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Unverified
Ireland
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Unverified
Belgium
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Unverified
Sweden
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Unverified
Germany
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Unverified
Netherlands
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Unverified
Norway
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Unverified
Spain

Common questions

What are EPP and XLP?

Erythropoietic Protoporphyria (EPP) and X-Linked Protoporphyria (XLP) are rare genetic conditions that make a person's skin extremely sensitive to sunlight, leading to pain and burning.

What is Bitopertin?

Bitopertin is the new experimental medicine being tested in this study. It's hoped it might help manage the symptoms of EPP and XLP.

Will I know if I'm taking the actual medicine or a placebo?

This is an 'open-label' study, which means both you and the study doctors will know that you are receiving the Bitopertin medicine, not a placebo (dummy medicine).

How long will the study last?

This is described as a 'long-term' study, meaning your involvement could be over an extended period. The exact duration for you will be discussed by the study team.

What kind of tests will I have?

You'll have regular health checks, including physical exams, blood tests, checks of your heart rate and blood pressure, and you'll log your sun exposure and symptoms.