Skip to main content
OpenTrials
Recruiting

NCT Number: NCT07096674

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

This study is a long-term extension (LTE) of the parent Study ORX750 0201, and will provide long-term open-label safety, tolerability, and efficacy of ORX750 in participants with narcolepsy type 1 (NT1), narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH).

Recruiting

Interested in participating?

Request Info

Key information

Conditions

Narcolepsy Type 1 Disorders of Excessive Somnolence Dyssomnias Idiopathic Hypersomnia Mental Disorders Narcolepsy Narcolepsy Type 2 Nervous System Diseases Sleep Disorders, Intrinsic Sleep Wake Disorders

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Toronto, Ontario, Canada

Loading trial locations.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of narcolepsy (NT1 or NT2) or IH who was eligible for and completed the full treatment period in the eligible parent study ORX750-0201 (CRYSTAL-1)
  • Is willing and able to adhere to additional protocol requirements

Exclusion criteria

  • Development of any new disease/disorder that in the opinion of the investigator would make the participant unable to continue the study
  • Unable to refrain from excluded medications, including those used for treatment of narcolepsy or idiopathic hypersomnia

Treatment and study plan

ORX750

Drug

Oral ORX750

Primary outcomes

  1. Treatment Emergent Adverse Events (TEAEs) and Serious TEAEs

    Time frame: Up to day 70

    Number of Participants With Treatment Emergent Adverse Events (TEAEs) and Serious TEAEs

  2. Abnormal Laboratory Tests

    Time frame: Up to day 70

    Number of Participants With Abnormal Changes From Baseline in Laboratory Tests

  3. Abnormal Vital Signs

    Time frame: Up to day 70

    Number of Participants With Abnormal Change From Baseline in Vital Signs

  4. Abnormal ECG

    Time frame: Up to day 70

    Number of Participants With Abnormal Change From Baseline in Electrocardiograms (ECG)

  5. Suicidal Ideation or Behavior

    Time frame: Up to day 70

    Number of Participants With Suicidal Ideation or Suicidal Behavior as Measured Using Columbia-Suicide Severity Rating Scale (C-SSRS)

Secondary outcomes

  1. Cmax

    Time frame: Up to day 63

    Cmax: Maximum Observed Plasma Concentration for ORX750

  2. Tmax

    Time frame: Up to day 63

    Tmax: Time of Maximum Concentration for ORX750

  3. AUClast

    Time frame: Up to day 63

    AUClast: Area Under the Plasma Concentration-time Curve From Time 0 to the Time of the Last Quantifiable Concentration for ORX750

  4. Cmax,ss

    Time frame: Up to day 63

    Cmax,ss: Maximum Observed Concentration at Steady State for ORX750

  5. AUCτ

    Time frame: Up to day 63

    AUCτ: Area Under the Concentration-time Curve During a Dosing Interval at Steady State for ORX750

  6. Maintenance of Wakefulness Test

    Time frame: Up to day 63

    Change From Baseline in Mean sleep latency (average of the first 4 trials) in the Maintenance of Wakefulness Test (MWT)

  7. Epworth Sleepiness Scale

    Time frame: Up to day 63

    Change From Baseline in Epworth Sleepiness Scale (ESS)

Study contacts

Contact information is provided by the study sponsor or research team.

Orexin Centessa Program Lead

CONTACT

[email protected]

617-468-5770

Sponsors and collaborators

Lead sponsor

Centessa Pharmaceuticals (UK) Limited

Industry

Registry information

Official study title

A Phase 2, Long-term Extension Study of the Safety and Efficacy of ORX750 in Participants With Narcolepsy and Idiopathic Hypersomnia Who Completed a Sponsored ORX750 Clinical Trial

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Jul 31, 2025
Registry last updated
Apr 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.