A multicenter, double-blind, randomized study to evaluate the effects of tasimelteon vs. placebo in participants with Delayed Sleep-Wake Phase Disorder (DSWPD)
Delayed Sleep-Wake Phase Disorder (DSWPD) is a condition where your internal body clock runs much later than normal. People with this condition often find it hard to drift off until the early hours of the morning, making it tough to wake up for work or school. This Phase III clinical trial tests a medication called tasimelteon (also known as Hetlioz). Researchers want to see if taking a 20 mg capsule every day helps people fall asleep earlier over a 28-day period. Half of the participants will take the study medicine, and half will take a dummy pill (placebo) that looks identical. Neither you nor the study team will know which one you get. Participants will track their sleep using a daily diary and a wearable wrist monitor to see if the treatment helps improve sleep patterns and daytime tiredness.
At a glance
What is this study about?
Delayed Sleep-Wake Phase Disorder (DSWPD) is more than just being a 'night owl'. It is a real medical condition where your internal body clock is delayed by two or more hours. This means your body does not feel ready for bed until the early hours of the morning. For many people, this makes everyday life very difficult, as waking up for work, study, or family duties can lead to severe tiredness, brain fog, and low mood.
This clinical trial is testing a medicine called tasimelteon to see if it can help reset this internal clock. Tasimelteon works by copying the action of melatonin, a natural hormone your brain makes to signal that it is time for rest. By taking this capsule once a day, researchers hope to see whether people can start falling asleep at an earlier, more practical time.
Finding new treatments for DSWPD is important because standard sleep medicines often do not fix the root cause, which is a shifted body clock. If tasimelteon proves effective and safe, it could provide doctors with a new, targeted way to help people build healthier sleep habits and feel more awake during the day.
Key takeaways
- Tests whether tasimelteon helps people with delayed sleep patterns fall asleep earlier.
- Lasts for 28 days of daily treatment with a single oral capsule.
- Involves a 50/50 chance of receiving the active drug or a dummy pill (placebo).
- Uses sleep diaries and a wrist monitor to track your sleep habits.
- Open to adults aged 18 and over who struggle with a delayed body clock.
Who may be eligible?
This trial is open to adults aged 18 and older of any gender who have been diagnosed with Delayed Sleep-Wake Phase Disorder, or whose sleep patterns naturally run much later than usual.
Because this is a clinical trial, the research team will check your general health before you join. They will need to make sure that your late sleeping pattern is not caused by shift work, another medical illness, or certain prescription medicines.
If you take other sleep aids or medications that affect your nervous system, the study team will discuss whether it is safe for you to take part. You will also need to be willing to track your sleep and take a capsule once daily for about a month.
Could this study suit you?
Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.
- I am aged 18 or older.
- I regularly struggle to fall asleep until very late at night or early morning.
- My late sleep schedule causes problems with daytime work, study, or life.
- I am able and willing to complete a daily sleep diary for four weeks.
- I do not work night shifts that disrupt a set sleeping routine.
What does participation involve?
Taking part in this study lasts for around four weeks of active treatment. During this time, you will take one capsule each day by mouth shortly before bedtime. You will receive either the study medicine (tasimelteon 20 mg) or a dummy pill (placebo) that looks and tastes the same.
You will be asked to keep a daily sleep diary to record what time you go to bed, how long it takes you to fall asleep, and when you wake up. You may also wear a comfortable wrist device (called an actigraphy watch) that tracks your body movement day and night.
Throughout the study, you will have check-ups with the trial team. These visits may include short questionnaires about your energy and mood, as well as simple saliva tests to check your natural evening melatonin levels. The research team will guide you through every step.
Potential risks and benefits
Locations (2)
- —UnverifiedAustria
- —UnverifiedGermany
Common questions
What is Delayed Sleep-Wake Phase Disorder?
It is a body clock condition where your natural sleep time is delayed by several hours, making it hard to fall asleep before late night or early morning.
What is a placebo and why is it used?
A placebo is a dummy pill with no active medicine. It is used so researchers can compare the real medicine against doing nothing, ensuring results are genuine.
Will I know if I am taking the real medicine?
No. This is a 'double-blind' trial, which means neither you nor the study doctors will know which capsule you have until the study ends.
What is an actigraphy monitor?
It is a small, lightweight watch you wear on your wrist that tracks your movement to show when you are active and when you are asleep.
Can I leave the study early if I change my mind?
Yes. Taking part is completely voluntary. You can stop at any time without giving a reason, and your normal healthcare will not be affected.
How to find out more
Always speak to your GP or specialist before deciding to take part in a study.
Interested in taking part?
Discussion
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