Stopped: A safety signal has emerged in Phase 2 studies of TAK-994. As an immediate precautionary measure, Takeda has suspended dosing of patients and has decided to stop Phase 2 studies early.
The main aims of the study are: * To check for side effects from TAK-994 and check what dose of TAK-994 participants can tolerate. * To check what dose range provides adequate relief of narcolepsy symptoms. * To check how much TAK-994 stays in the blood of participants, over time. The study will have 4 parts. Participants can only join 1 of the parts. A. Participants with type 1 narcolepsy will take either TAK-994 or placebo tablets for 28 days. A placebo looks just like TAK-994 but will not have any medicine in it. B. Participants with type 1 narcolepsy will take 1 of 3 doses of TAK-994 or placebo tablets for 56 days. C. Participants with type 1 narcolepsy in China only will take TAK-994 or placebo tablets for 56 days. D. Participants with type 2 narcolepsy will take either TAK-994 or placebo tablets for 28 days.
Age range
18 Years – 65 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Part A: Number of Participants Who Experience at Least One Treatment Emergent Adverse Event (TEAE) During the Study
Timeframe: First dose of study treatment to end of study follow-up (up to Day 35) in Part A
Part A: Number of Participants Who Meet the Markedly Abnormal Value Criteria for Safety Laboratory Tests at Least Once Postdose During the Study
Timeframe: First dose of study treatment to end of study follow-up (up to Day 35) in Part A
Part A: Number of Participants Who Meet the Markedly Abnormal Value Criteria for Vital Sign Measurements at Least Once Postdose During the Study
Timeframe: First dose of study treatment to end of study follow-up (up to Day 35) in Part A
Part A: Number of Participants Who Meet the Markedly Abnormal Value Criteria for Safety Electrocardiogram (ECG) Parameters at Least Once Postdose During the Study
Timeframe: First dose of study treatment to end of study follow-up (up to Day 35) in Part A
Parts B and C: Change From Baseline in Average Sleep Latency as Assessed by the Maintenance of Wakefulness Test (MWT)
Timeframe: Baseline and Week 8 (Day 56) in Parts B and C