RecruitingPHASE2INTERVENTIONAL

A Long-term Extension Study of ORX750 in Participants With Narcolepsy and Idiopathic Hypersomnia

This study is a long-term look at a new medicine called ORX750. It’s for adults aged 18 to 65 who have narcolepsy (Type 1 or Type 2) or idiopathic hypersomnia and have already taken part in an earlier study for the same medicine. The main goals are to see if ORX750 is safe over a longer period, if people can tolerate it without too many side effects, and if it continues to help with their symptoms like extreme sleepiness. This is an extension of a previous study, meaning it follows on to gather more information about how the medication works over time for these specific sleep conditions.

At a glance

Status

Recruiting

Phase

PHASE2

Sponsor

Centessa Pharmaceuticals (UK) Limited

Enrolment target

Start

12 Aug 2025

Estimated completion

30 Apr 2026

Narcolepsy Type 1 Narcolepsy Type 2 Idiopathic Hypersomnia

What is this study about?

This study is a continuation of an earlier research project looking into a new medication called ORX750. It's designed for people who have already been taking ORX750 as part of a previous study and focuses on three sleep conditions: narcolepsy type 1, narcolepsy type 2, and idiopathic hypersomnia. These conditions all cause excessive daytime sleepiness, which can be very disruptive to daily life.

The main purpose of this follow-up study is to understand the effects of ORX750 over a longer period. Researchers want to ensure it remains safe and that people continue to feel well while taking it. They also want to see if the medication keeps helping participants manage their symptoms, like feeling overly sleepy during the day. By extending the study, they can gather more comprehensive information about its long-term benefits and any potential challenges.

This kind of long-term study is really important because some effects of medications, both positive and negative, only become clear after someone has been taking them for a while. The findings from this study will help doctors and patients understand better if ORX750 could be a good long-term treatment option for conditions that cause constant sleepiness.

Key takeaways

This study is for people already taking part in an ORX750 trial for narcolepsy or idiopathic hypersomnia.
It aims to check the long-term safety and effectiveness of ORX750.
Participants must be aged 18-65 and have completed a previous study.
You will continue to receive the study medicine, ORX750.
It's a chance to contribute to research on severe sleep conditions.

Who may be eligible?

This study is specifically for adults aged 18 to 65 years old. To join, you must have been diagnosed with narcolepsy (either Type 1 or Type 2) or idiopathic hypersomnia.

Crucially, you must have already taken part in and successfully finished the full treatment period of a previous study called ORX750-0201 (also known as CRYSTAL-1). This means this study is only an option if you are continuing from that earlier research.

There are also a few reasons why you might not be able to join. For example, if you've developed a new health problem that the study doctors feel would make it unsafe for you to continue. Also, you need to be able to avoid taking certain other medications, including those currently used to treat narcolepsy or idiopathic hypersomnia, as these could interfere with the study medicine.

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 between 18 and 65 years old?
Do you have a diagnosis of Narcolepsy (Type 1 or Type 2) or Idiopathic Hypersomnia?
Have you already completed the full treatment part of the CRYSTAL-1 (ORX750-0201) study?
Are you able to avoid taking other specific medications for your sleep condition?
Are you willing and able to follow all study instructions?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you'll continue to receive the study medication, ORX750. The specific details of how often you'll visit the clinic, what tests you'll have, and for how long the study will last usually depend on the specific study plan, but expect regular check-ups with the study team. These visits will help doctors monitor your health, how you're feeling, and if the medication is working for you. They will also keep track of any side effects you might experience. You will likely have physical exams, blood tests, and answer questions about your sleep and overall well-being. The total duration of your involvement could be several months or even longer, as this is a long-term study designed to gather information over an extended period.

Potential risks and benefits

Taking part in this study might offer the benefit of continuing access to a potential treatment for your condition, which could help manage your excessive sleepiness. However, as with all medications, there's a possibility of side effects, which the study team will monitor closely. There might also be inconvenience due to regular clinic visits. Remember, you can choose to leave the study at any time, for any reason, without it affecting your usual medical care.

Locations (24)

Auburn, alabama
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Auburn, United States· Recruiting
Santa Ana, California
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Santa Ana, United States· Recruiting
Miami, Florida
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Miami, United States· Recruiting
Orlando, Florida
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Orlando, United States· Recruiting
Winter Park, FL
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Winter Park, United States· Recruiting
Stockbridge, GA
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Atlanta, United States· Recruiting
Atlanta, Georgia
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Atlanta, United States· Recruiting
Sterling Heights, Michigan
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Sterling Heights, United States· Recruiting
Hendersen, Navada
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Henderson, United States· Recruiting
Henderson, Nevada
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Henderson, United States· Recruiting
Denver, North Carolina
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Denver, United States· Recruiting
Huntersville, North Carolina
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Huntersville, United States· Recruiting

Common questions

What is narcolepsy and idiopathic hypersomnia?

Both are long-term conditions that cause extreme daytime sleepiness, even after a full night's sleep. Narcolepsy often includes sudden attacks of sleep and sometimes muscle weakness when strong emotions occur. Idiopathic hypersomnia mainly causes a constant, overwhelming urge to sleep.

What is ORX750?

ORX750 is the name of the new medicine being investigated in this clinical trial. It's hoped to help people with narcolepsy and idiopathic hypersomnia feel less sleepy, but it's still being studied to understand its full effects.

Why is this called an 'extension study'?

An extension study means it's a follow-on from an earlier, shorter study. It allows researchers to gather more information on how the medicine works over a longer time, focusing on its safety and effectiveness for long-term use.

Will I receive the study drug ORX750 if I join?

Yes, if you meet all the requirements and are accepted into this extension study, you will continue to receive ORX750, as you would have done in the previous study.

How long will I be in the study?

This is a long-term study, so your involvement could last for many months. The exact duration will be explained by the study team if you are eligible.

How to find out more

Orexin Centessa Program Lead

orx750-lte@centessa.com 617-468-5770 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.