ORX750 for narcolepsy and idiopathic hypersomnia, compared with placebo
Tests ORX750 against placebo in adults with narcolepsy or idiopathic hypersomnia.
Key facts
- Who runs it
- Centessa Pharmaceuticals (UK) Limited
- Where
- Atlanta, Auburn, Austin, Brandon, Chandler, Cincinnati, Cleveland, Columbia, Denver, Dublin, El Paso, Henderson, Huntersville, Long Beach, Miami, New Orleans, Newton, North Charleston, Orlando, Riverdale, San Antonio, Santa Ana, Scottsdale, Southfield, Sterling Heights, Willow Grove, and Winter Park, United StatesSee the 27 sitesAlso in 4 other countries, 9 sites
- Trial code
- Registry title
- A Study of ORX750 in Participants With Narcolepsy and Idiopathic Hypersomnia
- Status
- Recruiting
- Phase
- Phase 2
- People taking part
- 248 people, planned
- Started
- 23 Dec 2024
- Expected to end
- Dec 2026
- Type of study
- Interventional, 3 groups
- Treatments tested
- ORX750
- Placebo
- Record updated
- 27 April 2026
Who can take part
AI summary
From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.
The trial is looking for adults with narcolepsy type 1, narcolepsy type 2 or idiopathic hypersomnia. These conditions cause strong sleepiness during the day.
- Age
- 18-65 years
- Sex
- All sexes can join.
- Disease stage
- Diagnosis of narcolepsy type 1 (NT1), type 2 (NT2) or idiopathic hypersomnia (IH) by ICSD-3-TR criteria. BMI ≥17 and ≤37 kg/m2.
- Earlier treatment
- People must be willing and able to stop all medicines they take for narcolepsy or idiopathic hypersomnia.
Main reasons for not taking part
- Another medical condition, other than NT1, NT2 or IH, that causes strong daytime sleepiness
- Serious heart, lung, gut, liver, kidney or blood disease
- Cancer
- Serious hormone, nerve or mental health disease
The registry criteria, word for word
Show all 7 criteriaShow less
Who can take part
- 18-65 years of age
- BMI ≥17 and ≤37 kg/m2
- Meets the diagnostic criteria of Narcolepsy Type 1 (NT1), Type 2 (NT2) or Idiopathic Hypersomnia (IH) according to ICSD-3-TR criteria
- Is willing and able to discontinue all medications used for the treatment of narcolepsy or idiopathic hypersomnia
- Is willing and able to adhere to additional protocol requirements
Who cannot take part
- A medical disorder other than NT1, NT2, or IH that is associated with excessive daytime sleepiness (EDS)
- Presence of significant cardiovascular, pulmonary, gastrointestinal, hepatic, renal, hematological, malignancy, endocrine, neurological or psychiatric disease
Check if you might fit
Answer for yourself. This is not a decision: only the study team can say whether you can take part.
- Are you between 18 and 65 years old?
Where in United States
Also in 4 other countries, 9 sites
- Atlanta, GeorgiaAtlanta, United StatesContact: Centessa PharmaceuticalsTaking people
- Auburn, AlabamaAuburn, United StatesContact: Centessa PharmaceuticalsTaking people
- Austin, TexasAustin, United StatesContact: Centessa PharmaceuticalsTaking people
- Brandon, FloridaBrandon, United StatesContact: Centessa PharmaceuticalsTaking people
- Chandler, ArizonaChandler, United StatesContact: Centessa PharmaceuticalsTaking people
- Cincinnati, OhioCincinnati, United StatesContact: Centessa PharmaceuticalsTaking people
- Cleveland, OHCleveland, United StatesContact: Centessa PharmaceuticalsTaking people
- Columbia, South CarolinaColumbia, United StatesContact: Centessa PharmaceuticalsTaking people
- Denver, North CarolinaDenver, United StatesContact: Centessa PharmaceuticalsTaking people
- Dublin, OhioDublin, United StatesContact: Centessa PharmaceuticalsTaking people
- El Paso, TXEl Paso, United StatesContact: Centessa PharmaceuticalsTaking people
- Henderson, NevadaHenderson, United StatesContact: Centessa PharmaceuticalsTaking people
- Huntersville, North CarolinaHuntersville, United StatesContact: Centessa PharmaceuticalsTaking people
- Long beach, CaliforniaLong Beach, United StatesContact: Centessa PharmaceuticalsTaking people
- Miami, FloridaMiami, United StatesContact: Centessa PharmaceuticalsTaking people
- New Orleans, LouisianaNew Orleans, United StatesContact: Centessa PharmaceuticalsTaking people
- Newton, MassachusettsNewton, United StatesContact: Centessa PharmaceuticalsTaking people
- North Charleston, South CarolinaNorth Charleston, United StatesContact: Centessa PharmaceuticalsTaking people
- Orlando, FLOrlando, United StatesContact: Centessa PharmaceuticalsTaking people
- Riverdale, GeorgiaRiverdale, United StatesContact: Centessa PharmaceuticalsTaking people
- San Antonio, TexasSan Antonio, United StatesContact: Centessa PharmaceuticalsTaking people
- Santa Ana, CaliforniaSanta Ana, United StatesContact: Centessa PharmaceuticalsTaking people
- Scottsdale, ArizonaScottsdale, United StatesContact: Centessa PharmaceuticalsTaking people
- Southfield, MichiganSouthfield, United StatesContact: Centessa PharmaceuticalsTaking people
- Sterling Heights, MichiganSterling Heights, United StatesContact: Centessa PharmaceuticalsTaking people
- Willow Grove, PennsylvaniaWillow Grove, United StatesContact: Centessa PharmaceuticalsTaking people
- Winter Park, FloridaWinter Park, United StatesContact: Centessa PharmaceuticalsTaking people
About the trial
What the trial wants to find out
Narcolepsy Type 1 (NT1), Narcolepsy Type 2 (NT2), and Idiopathic Hypersomnia (IH) are rare conditions that make people feel very sleepy during the day (often referred to as excessive daytime sleepiness [EDS]). People living with these conditions might find it hard to stay alert and pay attention when they are at school, working, driving, or performing other daily activities.
Read full original descriptionShow less
While all conditions result in feeling sleepy, there are some differences in other common symptoms:
* NT1: People with NT1 often feel very tired during the day and experience cataplexy. Cataplexy is a sudden loss of muscle strength, which can cause someone to collapse or lose control of their muscles for a short time. This is often triggered by strong emotions, such as laughter or surprise. They may also have trouble sleeping well at night. * NT2: People with NT2 feel sleepy during the day, just like NT1, but they do not have cataplexy. * IH: People with IH feel tired during the day, even after sleeping a lot at night. They may sleep for long periods, take long naps, and find it hard to wake up.
Orexin is a protein in the brain that helps coordinate a system that plays an important role in helping people to stay awake during the daytime. Cleminorexton (also known as ORX750) is designed to mimic the action of orexin. The purpose of this study is to see how safe and tolerable ORX750 is in NT1, NT2, and IH, and learn about what the drug does to the body. Another goal of the study is to see if ORX750 can help people with NT1, NT2, and IH feel less sleepy and make other symptoms better.
The 3 groups in the trial
- Narcolepsy Type 1: ORX750 and PlaceboTreatment being tested
Treatment: ORX750 and Placebo
- Narcolepsy Type 2: ORX750 and PlaceboTreatment being tested
Treatment: ORX750 and Placebo
- Idiopathic Hypersomnia: ORX750 and PlaceboTreatment being tested
Treatment: ORX750 and Placebo
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Contact the study team: see the registry record → Contacts and Locations
Print a page for my doctorData and sources
- Registry record
- Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
- Official title
- A Phase 2a, Randomized, Double-blind, Placebo-controlled Study of the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ORX750 in Subjects With Narcolepsy and Idiopathic Hypersomnia (CRYSTAL-1)
- Plain-language title
- ORX750 for narcolepsy and idiopathic hypersomnia, compared with placeboGenerated from the registry record. The registry title is the official one.
- AI summary
- From the trial's eligibility criteria. Read by machine on 14 November 2026.
- Fit questions
- Built from NCT06752668, who can take part
- Record updated
- 27 April 2026