NCT07598708 · Centessa Pharmaceuticals (UK) Limited
A Study to Investigate the Effects of Cleminorexton Compared With Placebo in the Treatment of Participants With Central Disorders of Hypersomnolence
What this study is about
Narcolepsy Type 1 (NT1) and Narcolepsy Type 2 (NT2) 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) and Narcolepsy Type 2 (NT2) 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. 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. 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 is designed to mimic the action of orexin. The purpose of this study is to see how safe and tolerable cleminorexton is in NT1 and NT2 and learn about what the drug does to the body. Another goal of the study is to see if cleminorexton can help people with NT1 and NT2 feel less sleepy and make other symptoms better.
Interventions
DRUG
cleminorexton
Oral cleminorexton capsule
DRUG
Placebo
matching placebo capsule
Primary outcome measures
Change from baseline in mean sleep latency (average of the first 4 trials) on the Maintenance of Wakefulness Test (MWT)
Time frame: Baseline to week 12
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
- 18-70 years of age
- Body Mass Index (BMI) within the range ≥ 17.0 and ≤ 45 kg/m\^2 (inclusive)
- Meets the diagnostic criteria of Narcolepsy Type 1 (NT1) or Type 2 (NT2) according to International Classification of Sleep Disorders, 3rd edition, Text Revision edition (ICSD-3-TR) criteria
- Is willing and able to discontinue all medications used for the treatment of narcolepsy
- Is willing and able to adhere to additional protocol requirements Key
Exclusion criteria
- Medical disorder other than NT1 or NT2, that is associated with excessive daytime sleepiness (EDS)
- Presence of significant cardiovascular, pulmonary, gastrointestinal, hepatic, renal, hematological, malignancy, endocrine, neurological or psychiatric disease
Where
- Colorado Springs, Colorado
- Miami, Florida
- Miami Lakes, Florida
- Orlando, Florida
- Atlanta, Georgia
- Flowood, Mississippi
- Denver, North Carolina
- Huntersville, North Carolina
- Cincinnati, Ohio
- Dublin, Ohio
- Columbia, South Carolina
- Sugar Land, Texas
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 Aug 11, 2026 · Source of record for eligibility and locations