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Daridorexant for Insomnia in Patients with Major Depressive Disorder and Moderate to Severe Insomnia

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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 studying major depressive disorder and insomnia, which means trouble falling asleep, staying asleep, or getting restful sleep. The treatment being tested is daridorexant, a medicine taken by mouth. It will be compared with placebo during the study.

The purpose of the study is to see whether daridorexant can help improve sleep in people with depression and insomnia, and to check its safety. The study is organized as a double-blind and randomized trial, which means the treatment is assigned by chance and neither the participants nor the study team know which treatment is given during the study. Treatment lasts about 3 months, and sleep and mood are checked during this time to see how the medicine works and whether any side effects occur.

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

    Start of the study

    After joining the study, you are assigned to one of two treatment groups in a double-blind, randomized, controlled trial. Randomized means that the treatment group is chosen by chance. Double-blind means that neither you nor the study team knows whether you receive the study medicine or the placebo during the treatment period.

    The study is designed for people with a major depressive episode and moderate to severe insomnia disorder. The main aim is to assess whether the study medicine improves insomnia after 3 months.

  2. Step 2

    Study treatment period

    You take the assigned treatment by mouth for 3 months.

    If you are assigned to the study medicine, you take daridorexant 50 mg orally once daily for 3 months.

    If you are assigned to the placebo group, you take placebo tablets by mouth for 3 months. The placebo contains microcrystalline cellulose 138300 µg, colloidal silicon dioxide 3000 µg, croscarmellose sodium 7500 µg, and magnesium stearate 1200 µg.

  3. Step 3

    Assessment of sleep after 3 months

    After 3 months of treatment, your insomnia is assessed using the Insomnia Severity Index (ISI). The ISI is a scale used to measure how severe insomnia is.

    Your sleep may also be checked with overnight polysomnography, which is a sleep study that records sleep during the night. This assessment looks at sleep latency (how long it takes to fall asleep), total sleep time (how long you sleep in total), and wake after sleep onset (how much time you are awake after first falling asleep).

  4. Step 4

    Assessment of depression and safety at 3 months

    After 3 months, your depressive symptoms are assessed with the Montgomery–Åsberg Depression Rating Scale (MADRS). This is a tool used to measure the severity of depression.

    Your safety is checked by looking for worsening of depressive symptoms and any suicidal thoughts using the mini suicide module, which is a set of questions about suicidal thoughts and related risk.

  5. Step 5

    Quality of life assessment after treatment

    After the insomnia treatment period at 3 months, your quality of life is measured with the EuroQol (EQ-5D). This is a questionnaire used to assess general health and quality of life.

  6. Step 6

    End of the trial period

    At the end of the 3-month treatment period, the study compares the effects of daridorexant and placebo on insomnia, depressive symptoms, safety, side effects, and quality of life.

    The overall trial is planned to run within the study period from 2026-01-15 to 2028-01-15.

Who can join the trial?

8 criteria

  • Be 18 to 99 years old.
  • Have a current major depressive episode, which means a period of significant depression, diagnosed according to DSM-5, the standard medical guide used to diagnose mental health conditions.
  • Be in a stable phase of depression, meaning there have been no major changes in antidepressant medicine for at least 4 weeks.
  • Have had no psychiatric hospitalizations in the previous 8 weeks. Psychiatric hospitalization means staying in a hospital for mental health care.
  • Have depression of at least moderate severity, shown by a score of 20 or higher on the MADRS scale, which is a questionnaire doctors use to measure depression symptoms.
  • Have insomnia disorder confirmed according to DSM-5, meaning a diagnosed sleep problem with trouble sleeping that meets standard medical criteria.
  • Be able and willing to give written informed consent, meaning permission to take part after understanding the study.
  • Agree to follow all study visits, treatment plans, and study procedures, meaning the patient must attend appointments and do what the study requires.

Who cannot join the trial?

16 criteria

  • Any current psychiatric disorder other than major depressive disorder, such as active psychotic disorders (loss of contact with reality), mania or hypomania (unusually high energy or mood), acute schizophrenia, or schizoaffective disorder.
  • Use of moderate or strong CYP3A4 inhibitors, which are medicines that can change how the study drug is broken down in the body and may cause a harmful drug interaction.
  • Moderate or severe liver problems, or any liver condition the investigator considers unsafe for daridorexant use.
  • Relapse or worsening of depression if the severity is high enough that the person cannot continue in the study, based on the investigator’s judgment.
  • A history of substance use disorder that has not been in sustained remission. A past problem with sedative medicines may be allowed only if the remission requirements are clearly met and the investigator agrees.
  • Daily caffeine intake above 400 mg, which is more than about 4 standard cups of coffee.
  • Alcohol use above the allowed risk limits, which means more than 4 standard drinks per day for men or more than 2 standard drinks per day for women.
  • Current use of sleep medicines not allowed by the protocol, such as melatonin, benzodiazepines, sedative antidepressants, or sedative antipsychotics, if the person is unwilling to follow the required slow dose reduction plan.
  • If there were no sleep medicines used for at least 30 days before the start of the study, but the person still has withdrawal symptoms (symptoms after stopping a medicine) and/or sleep problems measured by the BWSQ questionnaire before the study begins.
  • Any severe medical condition that is not under control and could affect study safety, study tests, or study results, such as unstable heart, lung, nerve, or hormone problems.
  • Pregnancy or breastfeeding.
  • Significant cognitive impairment, meaning thinking or memory problems that prevent the person from understanding or completing study forms or procedures.
  • A known allergy or hypersensitivity to daridorexant or any ingredient in the study medicine.
  • Sleep apnea or hypopnea with an index of 15 or more events per hour, or any breathing event during sleep that causes oxygen levels to drop below 80%, based on a sleep test called polysomnography.
  • A periodic limb movement index of 15 or more events per hour, based on a sleep test.
  • Restless legs syndrome, circadian rhythm sleep-wake disorders (problems with the body clock that controls sleep timing), REM behavior disorder (acting out dreams during sleep), or narcolepsy (a condition that causes extreme daytime sleepiness).
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Investigated drugs

Daridorexant is the study medicine being tested in this trial. It is taken by mouth and is being studied to see if it can help improve insomnia in people who have major depressive disorder. The trial is looking at whether it can make sleep better over time and whether it is safe to use in this patient group.

What is already known about the treatment

Daridorexant - Daridorexant is an oral tablet taken by mouth, usually once at bedtime, and it is used in studies and medical practice for insomnia. It is a fairly new sleep medicine in medical literature and is known for helping people fall asleep and stay asleep, especially when sleep problems are linked with mental health conditions. It works by blocking orexin, a natural brain signal that helps keep people awake, so it lowers wakefulness and supports sleep. Daridorexant belongs to the orexin receptor antagonist class, which means it reduces the brain’s “stay awake” drive.

Investigated diseases

  • Major depressive disorder

    A mental disorder marked by a persistent depressed mood and loss of interest or pleasure, often with changes in sleep, appetite, energy, thinking, and concentration. It usually develops in episodes that can last weeks or longer. Symptoms may come and go over time, and some people experience repeated episodes.

  • Insomnia disorder

    A sleep disorder in which a person has trouble falling asleep, staying asleep, or waking too early despite having enough opportunity to sleep. It can be short-term or long-lasting, and the sleep problem often continues through repeated nights. Over time, poor sleep may become more frequent and may be linked with daytime tiredness, low energy, and difficulty concentrating.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-524794-16-00Protocol codeSEDAEstimated enrolment134 patientsSponsorFundacio Institut D'Investigacio Biomedica De Bellvitge IDIBELL

sourced from the EU Clinical Trials Register and site verification

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