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Safety Study of Tasimelteon for Treating Non-24-Hour Sleep-Wake Disorder in Blind Individuals Without Light Perception

Verified siteRegistered drugNo placebo
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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 a condition known as , which affects individuals who are blind and have no perception of light. This disorder makes it difficult for people to synchronize their internal body clock with the 24-hour day-night cycle, leading to sleep problems. The treatment being tested in this study is a medication called , which is taken as a 20 mg hard capsule. The purpose of the study is to understand the safety of using tasimelteon over a one-year period.

Participants in the study will take tasimelteon daily for up to one year. The study will monitor any side effects or changes in health, including mood changes, vital signs like blood pressure, and results from lab tests and heart exams. The study will also look at how the medication affects sleep patterns, both at night and during daytime naps, as well as overall impressions of change in sleep quality.

This study is open-label, meaning that both the participants and the researchers know that tasimelteon is being administered. The goal is to gather information on how safe tasimelteon is for long-term use in treating Non-24-Hour Sleep-Wake Disorder in blind individuals. Participants will be regularly assessed to ensure their safety and to evaluate the effects of the medication on their sleep-wake cycles.

The research process

The trial runs in 4 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, you will be asked to provide informed consent. This means you agree to participate after understanding the study's purpose and procedures.

    You must be at least 18 years old and have a Body Mass Index (BMI) between 18 and 40 kg/m². BMI is a measure of body fat based on height and weight.

    If you are a female of child-bearing potential, you must use an acceptable method of birth control for 35 days before the first dose and have a negative pregnancy test at the screening and baseline visits.

  2. Step 2

    Medication administration

    You will take a medication called tasimelteon, which comes in the form of 20 mg hard capsules.

    The medication is taken orally, meaning you will swallow the capsule.

    You will take the medication once daily for a duration of one year.

  3. Step 3

    Monitoring and assessments

    Throughout the study, your safety will be monitored. This includes checking for any adverse events such as changes in mood, vital signs, or any unusual symptoms.

    Regular assessments will be conducted, including clinical laboratory evaluations, electrocardiograms (ECGs), and physical exams.

    You will be asked to provide feedback on your sleep patterns using the Patient Global Impression-Change (PGI-C) for nighttime sleep and daytime naps.

  4. Step 4

    Completion of the study

    At the end of the one-year period, you will complete the study.

    Final assessments will be conducted to evaluate your overall experience and any changes in your condition.

Who can join the trial?

8 criteria

  • Ability and acceptance to provide informed consent (agreeing to participate after understanding the study).
  • Men or women aged 18 years or older.
  • Body Mass Index (BMI) between 18 and 40 kg/m2. BMI is a measure of body fat based on height and weight.
  • Males, females who cannot have children, or females who can have children must use an acceptable method of birth control (like birth control pills, patch, intrauterine device [IUD], diaphragm, condom with spermicidal jelly or foam, abstinence, or cervical cap) for 35 days before the first dose and must have a negative pregnancy test at the screening and baseline visits.
  • Willing and able to follow study requirements and restrictions.
  • No perception of light (unable to see light).
  • History within the last 3 months of trouble sleeping at night (difficulty falling asleep or staying asleep), difficulty waking up in the morning, or feeling sleepy during the day, as determined by answering yes to at least one question in the Sleep Complaint Questionnaire.
  • Affiliated with or a beneficiary of a social security system.

Who cannot join the trial?

3 criteria

  • Patients who are not diagnosed with Non-24 Hour Sleep-Wake Disorder cannot participate.
  • Patients who are not within the specified age range for the study cannot participate.
  • Patients who are part of a vulnerable population, which means they might need special protection, cannot participate.
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Investigated drugs

Tasimelteon is a medication used in this clinical trial to help manage a condition called Non-24-Hour Sleep-Wake Disorder (N24HSWD), which affects people who are completely blind and cannot perceive light. This disorder can cause sleep problems because the body's internal clock is not in sync with the 24-hour day. Tasimelteon works by helping to regulate the sleep-wake cycle, making it easier for patients to fall asleep at night and stay awake during the day. The trial aims to assess the safety of using this medication over a one-year period.

What is already known about the treatment

Tasimelteon – Tasimelteon is administered orally in the form of capsules and is currently being studied for its safety in treating Non-24-Hour Sleep-Wake Disorder, particularly in blind individuals who have no light perception. This medication is recognized in medical literature as a treatment option for this specific sleep disorder. It works by targeting receptors in the brain that help regulate the sleep-wake cycle, essentially helping to reset the body's internal clock. Tasimelteon is classified pharmacologically as a melatonin receptor agonist, which means it mimics the action of melatonin, a natural hormone involved in sleep regulation.

Investigated diseases

Non-24-Hour Sleep-Wake Disorder – This disorder is characterized by a chronic pattern of sleep and wake times that are not aligned with the 24-hour day. It often occurs in individuals who are completely blind, as their internal body clock does not receive light cues to synchronize with the external environment. The sleep-wake cycle in affected individuals typically shifts later each day, leading to periods of insomnia and excessive daytime sleepiness. Over time, the cycle may temporarily align with the 24-hour day, but it eventually shifts again. This misalignment can disrupt daily activities and social obligations. The disorder is considered rare and can significantly impact the quality of life.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-516721-31-00Protocol codeVP-VEC-162-3202Estimated enrolment140 patientsSponsorVanda Pharmaceuticals Inc.

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