Trial results
AI generated results summary. Written by an AI model from the official source data and checked on a sample basis. It can contain mistakes, so confirm anything important against the original source. How we use AI
According to the results reported on ClinicalTrials.gov, this trial enrolled 112 people across five groups to study a drug called TAK-861 in different doses for narcolepsy (a condition causing extreme daytime sleepiness and sudden muscle weakness). The five groups were: a placebo (dummy pill) group of 22 people, and four TAK-861 dose groups of 21–23 people each. The trial ran for 8 weeks and measured how long participants could stay awake during a formal test, how sleepy they felt on a standard questionnaire, how often they experienced cataplexy (sudden episodes of muscle weakness), and how many people experienced any unwanted medical events after starting the study drug. The reported data shows the following at the 8-week mark. For the main outcome — a supervised "stay awake" test measured in minutes — the placebo group's average score changed by −1.16 minutes from the start, while the four TAK-861 dose groups showed changes of +12.49, +23.50, +25.42, and +14.96 minutes respectively. On the sleepiness questionnaire (scored 0–24, where higher means sleepier), the placebo group's score changed by −2.50 points, while the TAK-861 groups changed by −8.92, −13.79, −12.81, and −11.29 points. For weekly cataplexy attacks, the placebo group reported an average of 8.76 attacks per week at week 8, compared with 4.24, 3.14, 2.48, and 5.89 in the four TAK-861 groups. Regarding unwanted medical events after starting the study drug, 7 out of 22 placebo participants experienced at least one such event, compared with 13, 15, 21, and 21 out of roughly 23 participants in the TAK-861 groups. These are the results as reported to ClinicalTrials.gov. They are not medical advice — always discuss what they mean for you with your doctor.
View full results on ClinicalTrials.gov ↗ · Read the linked publication on PubMed (PMID 41359331) ↗
These are the results as reported to ClinicalTrials.gov, not medical advice. Verify independently with the trial site and discuss what they mean for you with your doctor.
Phase 2 Narcolepsy Trial, Completed
Who may be able to join
AI generated eligibility summary. Written by an AI model from the official source data and checked on a sample basis. It can contain mistakes, so confirm anything important against the original source. How we use AI
Who might be able to join this trial:
- You are between 18 and 70 years old when you sign up (in Japan, ages 16 to 70 may also be eligible).
- Your Body Mass Index (BMI) — a measure of body weight relative to height — is between 18 and 40.
- You have been officially diagnosed with Narcolepsy Type 1 based on specific sleep tests (an overnight sleep study and a daytime nap test) carried out within the last 10 years.
- You have tested positive for a specific gene marker (HLA-DQB1*06:02), OR a spinal fluid test has shown very low levels of a brain chemical called orexin/hypocretin-1 (confirm with trial site).
Who may not be able to join:
- You have another medical condition (besides narcolepsy with cataplexy) that causes excessive daytime sleepiness.
- You have a significant liver or thyroid condition.
- You have been diagnosed with cancer in the past 5 years (some exceptions may apply for certain very early-stage or resolved cancers — confirm with trial site).
- You have significant heart problems, such as coronary artery disease, a history of heart attack, serious chest pain, serious heart rhythm problems, or heart failure.
- You have a significant history of head injury or head trauma.
- You have a history of epilepsy, seizures, or convulsions, or a family history of inherited conditions involving seizures (having had a single fever-related seizure as a child may be an exception — confirm with trial site).
- You currently have an unstable mental health condition, or have a history of certain psychiatric conditions such as bipolar disorder, schizophrenia or other psychotic disorders, obsessive compulsive disorder, intellectual disability, or severe depression with psychosis.
- You currently have, or have had in the past 6 months, a major depressive episode.
- You currently have or have a history of a substance use disorder.
- You have a history of stroke, a mini-stroke within the past 5 years, a brain aneurysm, or an abnormal tangle of blood vessels in the brain.
- You have tested positive for hepatitis B, hepatitis C, or HIV.
- Your kidneys are not filtering blood well enough (confirmed through a blood test — confirm with trial site).
- Your liver enzyme levels (measured by a blood test) are more than 1.5 times above the normal range.
- You are considered by the medical team to be at immediate risk of harming yourself or others, or you have attempted suicide in the past year.
Important: Always verify eligibility with the trial site directly before applying.
Based on publicly available eligibility criteria from ClinicalTrials.gov. Verify directly with the trial site before acting. This is not medical advice.
Contact this trial
Principal Investigator: Study Director, Takeda
Australian sites
Contact details sourced from ClinicalTrials.gov. Verify directly with the trial site before attending.
GP referral letter
Print a one-page summary to share with your doctor.
Trial details
Where this trial is recruiting
1 site(s) in Australia. Confirm current status and contact details directly with the trial site.
Primary endpoints
Change From Baseline in the Average Sleep Latency as Determined From the MWT at Week 8
Can't join this trial?
Data last synced from ClinicalTrials.gov: 28 July 2026. Trial status can change. Always verify current status directly with the trial site before making any decision.