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

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Centessa Pharmaceuticals UK Limited

Participant type

Patients

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Diseases [C] - Nervous System Diseases [C10]

Trial duration

13 Mar 2026 → ongoing

Decision date (initial)

2026-02-16

Transition trial

No

Low-intervention

No

Rare-disease indication

Yes

Vulnerable population

No

Funding sources

Centessa Pharmaceuticals (UK) Limited

External identifiers

EU CT number

2025-522987-34-00

ClinicalTrials.gov

NCT07096674

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Pharmacokinetic, Efficacy, Others, Safety, Pharmacogenomic, Therapy

To evaluate the long-term safety and tolerability of ORX750

Secondary objectives 1

1. To evaluate the PK of ORX750 and to evaluate the efficacy of ORX750 as assessed by the MWT and the ESS.

Conditions and MedDRA coding

Narcolepsy and Idiopathic Hypersomnia

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 3

1. All Participants: • Participants with narcolepsy (NT1 or NT2) or IH who have completed the full treatment period in Study ORX750-0201. • Participants must be able and willing to participate in all scheduled evaluations and procedures per protocol and must agree to be available to complete all study measurements and comply with study restrictions. • Male and female participants must comply with contraception requirements described in the protocol.
2. Returning Participants Only: o 18-65 years of age o BMI ≥17.0 and ≤37 kg/m2 o Estimated glomerular filtration rate ≥60 mL/min/1.73 m2 o Is willing and able to discontinue all medications used for the treatment of narcolepsy or idiopathic hypersomnia o Is willing and able to adhere to additional protocol requirements
3. Rollover Participants Only: o Each participant must provide written informed consent by the final treatment visit (Day 42) in Study ORX750-0201, before the performance of any study-related procedures in the LTE study

Exclusion criteria 2

1. Returning Participants Only: • Participant has a medical condition(s) other than NT1, NT2, or IH for which excluded medications should not be discontinued. • Participant has participated in a study with an investigational drug other than ORX750 within the previous 30 days or within 5 half-lives of the investigational drug administration, whichever is longer, calculated from the last dose of the investigational drug or any AE related to the prior study to the screening day. • Presence of significant cardiovascular, pulmonary, gastrointestinal, hepatic, renal, hematological, malignancy, endocrine, neurological or psychiatric disease.
2. Rollover Participants Only: o Development of any new disease/disorder that in the opinion of the investigator would make the participant unable to continue the study.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 5

1. Incidence, severity, and causal relationship of treatment emergent adverse events (TEAEs), including serious TEAEs
2. Changes from baseline in laboratory tests, including biochemistry, hematology, and urinalysis
3. Changes from baselinea in vital signs and weight
4. Changes from baseline in 12-lead electrocardiograms (ECGs)
5. Columbia-Suicide Severity Rating Scale (C-SSRS) scores

Secondary endpoints 2

1. PK: - Predose and post dose PK concentrations of ORX750 - Other PK parameters as appropriate
2. Efficacy: o Mean sleep latency (changes from baseline to Day 63) in the MWT (average of the first 4 trials) o Subjective daytime sleepiness (changes from baseline to specified post dose timepoints) using the ESS

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 4

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Centessa Pharmaceuticals UK Limited

Sponsor organisation

Centessa Pharmaceuticals UK Limited

Address

3rd Floor, 1 Ashley Road 1 Ashley Road

City

Altrincham

Postcode

WA14 2DT

Country

United Kingdom

Scientific contact point

Organisation

Centessa Pharmaceuticals UK Limited

Contact name

Senior Vice President, Clinical Development

Public contact point

Organisation

Centessa Pharmaceuticals UK Limited

Contact name

Senior Vice President, Clinical Development

Third parties 11

Locations

3 EU/EEA countries · 8 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 55 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

3 submissions — initial application plus substantial / non-substantial modifications