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Long-term ORX750 treatment for people with narcolepsy or idiopathic hypersomnia

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

Phase 2 Interventional Centessa Pharmaceuticals (UK) Limited · NCT07096674

This open-label extension will try continued ORX750 treatment in people with narcolepsy or idiopathic hypersomnia who completed the earlier ORX750 parent study.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment90 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorCentessa Pharmaceuticals (UK) Limited Industry-sponsored
Locations24 sites (Auburn, Alabama and 23 other locations)
Trial IDNCT07096674 on ClinicalTrials.gov

What this trial studies

This long-term extension enrolls participants who completed the parent ORX750-0201 (CRYSTAL-1) study to receive open-label ORX750 with ongoing monitoring. The main focus is collecting long-term safety and tolerability data, with additional measures of symptomatic benefit over time. Participants will attend regular clinic visits for examinations, adverse event monitoring, and efficacy assessments. New medical conditions or use of excluded medications may disqualify continued participation.

Who should consider this trial

Good fit: Ideal candidates are people with narcolepsy type 1 or 2 or idiopathic hypersomnia who completed the full treatment period of the parent ORX750-0201 (CRYSTAL-1) study and can follow the protocol.

Not a fit: People who did not finish the parent study, who develop new medical conditions that prevent continued participation, or who cannot stop excluded medications are unlikely to join or benefit.

Why it matters

Potential benefit: If successful, long-term ORX750 could offer a well-tolerated treatment option that reduces daytime sleepiness and other symptoms for people with narcolepsy or idiopathic hypersomnia.

How similar studies have performed: Earlier-phase studies of ORX750 and other orexin-targeting drugs have shown promising short-term effects on wakefulness, but long-term outcomes remain limited.

Eligibility criteria

Show full inclusion / exclusion criteria 
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

Where this trial is running

Auburn, Alabama and 23 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Narcolepsy Type 1Narcolepsy Type 2Idiopathic HypersomniaNT1NT2IHNarcolepsyExcessive Daytime Sleepiness
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.