NCT06752668 · Centessa Pharmaceuticals (UK) Limited
A Study of ORX750 in Participants With Narcolepsy and Idiopathic Hypersomnia
(CRYSTAL-1)
What this study is about
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.
View original scientific description
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.
Interventions
DRUG
ORX750
ORX750 capsule.
DRUG
Placebo
ORX750 matching placebo capsule.
Primary outcome measures
Number of Participants With Treatment Emergent Adverse Events (TEAEs) and Serious TEAEs
Time frame: Up to Day 35
Number of Participants With Abnormal Changes From Baseline in Laboratory Tests
Time frame: Up to Day 35
Number of Participants With Abnormal Change From Baseline in Vital Signs
Time frame: Up to Day 35
Number of Participants With Abnormal Change From Baseline in Electrocardiograms (ECG)
Time frame: Up to Day 35
Number of Participants With Suicidal Ideation or Suicidal Behavior as Measured Using Columbia-Suicide Severity Rating Scale (C-SSRS)
Time frame: Up to Day 35
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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
Exclusion criteria
- 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
Where
- Auburn, Alabama
- Chandler, Arizona
- Scottsdale, Arizona
- Long Beach, California
- Santa Ana, California
- Brandon, Florida
- Miami, Florida
- Orlando, Florida
- Winter Park, Florida
- Atlanta, Georgia
- Riverdale, Georgia
- New Orleans, Louisiana
And 15 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Apr 27, 2026 · Source of record for eligibility and locations