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Study on TAK-861 for Treating Narcolepsy with Cataplexy in Patients

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the condition known as Narcolepsy with Cataplexy, also referred to as Narcolepsy Type 1. Narcolepsy is a sleep disorder that causes excessive daytime sleepiness and sudden muscle weakness called cataplexy. The study will evaluate a new treatment called TAK-861, which is taken in tablet form. The purpose of the study is to assess how well TAK-861 can improve excessive daytime sleepiness in people with Narcolepsy Type 1.

Participants in the study will be randomly assigned to receive either the TAK-861 tablet or a placebo, which looks like the TAK-861 tablet but does not contain the active medication. The study will last for a period of 12 weeks, during which participants will take the assigned tablets and attend regular check-ups to monitor their condition and any changes in their symptoms.

The main goal is to see if TAK-861 can reduce sleepiness as measured by a tool called the Epworth Sleepiness Scale, which helps to assess how likely someone is to fall asleep in different situations. The study will also look at other aspects of narcolepsy, such as the frequency of cataplexy episodes and overall quality of life. Participants' health and safety will be closely monitored throughout the study to ensure their well-being.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, eligibility is confirmed based on specific criteria such as age, body mass index, and health status.

    A diagnosis of narcolepsy with cataplexy is required, along with certain genetic markers or specific test results.

  2. Step 2

    Initial assessment

    An initial assessment is conducted, including medical history review, physical examination, and laboratory tests.

    A 12-lead electrocardiogram (ECG) and vital sign measurements are performed to ensure health status.

  3. Step 3

    Medication administration

    Participants receive either the TAK-861 tablet or a placebo, which looks the same but does not contain the active substance.

    The medication is taken orally as per the study protocol.

  4. Step 4

    Treatment period

    The treatment period lasts for 12 weeks, during which the effect of the medication on excessive daytime sleepiness is monitored.

    Participants are required to follow the dosage and frequency as instructed by the study team.

  5. Step 5

    Evaluation and monitoring

    Throughout the study, various assessments are conducted to evaluate the impact of the medication.

    These include measuring sleep latency, cataplexy episodes, and other health-related quality of life scores.

  6. Step 6

    Final assessment

    At the end of the 12-week period, a final assessment is conducted to evaluate the overall effect of the treatment.

    This includes a review of any side effects experienced during the study.

Who can join the trial?

6 criteria

  • Participants must be men or women aged between 18 and 70 years old.
  • Participants should have a body mass index (BMI) between 18 and 40. BMI is a measure that uses your height and weight to work out if your weight is healthy.
  • Participants must have a diagnosis of **Narcolepsy Type 1 (NT1)**. This is a condition that affects sleep and causes sudden muscle weakness.
  • Participants should experience at least 4 episodes of **cataplexy** per week. Cataplexy is a sudden loss of muscle strength, often triggered by strong emotions.
  • Participants must test positive for a specific **human leukocyte antigen (HLA)** type, known as HLA-DQB1*06:02, or have a low level of a brain chemical called **hypocretin-1** in their spinal fluid. This is checked through a special test.
  • Participants must be considered healthy enough to join the study, based on various health checks like blood tests, medical history, physical exams, heart tests (ECG), and vital signs like blood pressure and heart rate.
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Investigated drugs

TAK-861 is a medication being studied for its potential to treat narcolepsy with cataplexy, also known as Narcolepsy Type 1. This condition is characterized by excessive daytime sleepiness (EDS) and sudden muscle weakness triggered by strong emotions. The trial aims to evaluate how well TAK-861 can reduce daytime sleepiness, as measured by a specific scale called the Epworth Sleepiness Scale (ESS). The study is designed to ensure that neither the participants nor the researchers know who is receiving the actual medication, which helps to provide unbiased results.

What is already known about the treatment

TAK-861 – TAK-861 is an investigational medication currently being studied for its potential to treat narcolepsy with cataplexy, also known as Narcolepsy Type 1. It is administered orally in the form of tablets. The medication is in the clinical trial phase, where its efficacy and safety are being evaluated. TAK-861 is designed to reduce excessive daytime sleepiness, a common symptom of narcolepsy, by influencing specific neurotransmitters in the brain. It falls under the pharmacological classification of central nervous system agents.

Investigated diseases

Narcolepsy with Cataplexy (Narcolepsy Type 1) – This is a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep. People with this condition often experience cataplexy, which is a sudden loss of muscle tone triggered by strong emotions such as laughter or surprise. The disorder disrupts the normal sleep-wake cycle, leading to fragmented nighttime sleep and excessive daytime sleepiness. Individuals may also experience sleep paralysis and hallucinations as they fall asleep or wake up. The progression of symptoms can vary, but they often begin in childhood or adolescence and persist throughout life. The condition is considered a rare disease and can significantly impact daily activities and quality of life.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-511998-30-00Protocol codeTAK-861-3002Estimated enrolment100 patientsSponsorTakeda Development Center Americas Inc.

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