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Study on the Safety and Effectiveness of Aticaprant with Antidepressants for Adults and Elderly with Major Depressive Disorder

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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 effects of a medication called aticaprant on individuals with Major Depressive Disorder (MDD). The study aims to evaluate if adding aticaprant to a current antidepressant treatment is safe and can help improve symptoms of depression. Participants in the study will continue taking their existing antidepressant, which could be a type known as an SSRI or SNRI, while also taking aticaprant.

The purpose of the study is to assess the long-term safety and tolerability of aticaprant when used alongside a current antidepressant. The study will involve taking aticaprant in the form of a tablet by mouth. Participants will be monitored over a period of up to one year to observe any changes in their condition and to ensure the treatment is safe. The study will also look at various health indicators, such as vital signs, weight, and any side effects that may occur.

Throughout the study, participants will undergo regular health checks, including physical examinations and heart tests known as ECGs, to ensure they remain in good health. The study will also assess any changes in mood or behavior, including any thoughts of self-harm, using a specific rating scale. This trial is designed to provide valuable information on whether aticaprant can be a beneficial addition to existing depression treatments.

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

    Participants must have completed a previous study phase or meet specific medical criteria, including being medically stable and having a history of major depressive disorder (MDD).

    Participants should be aged between 18 and 74 years and have an inadequate response to at least one oral antidepressant treatment in the current episode of depression.

  2. Step 2

    Baseline assessments

    Participants undergo a physical examination, medical history review, vital signs check, and a 12-lead ECG to ensure medical stability.

    Clinical laboratory tests are performed to confirm eligibility.

  3. Step 3

    Medication administration

    Participants receive aticaprant in the form of a tablet for oral use.

    Aticaprant is administered as an adjunctive therapy to a current antidepressant, which is either a selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI).

  4. Step 4

    Ongoing assessments

    Regular monitoring of adverse events (AEs), including those of special interest, is conducted.

    Changes in vital signs, weight, and body mass index (BMI) are tracked.

    Suicidality is assessed using the Columbia Suicidality Severity Rating Scale (C-SSRS).

    Laboratory parameters and 12-lead ECGs are regularly evaluated.

  5. Step 5

    Withdrawal and sexual dysfunction assessments

    Withdrawal symptoms are assessed using the Physician Withdrawal Checklist, 20-item (PWC-20).

    The proportion of participants with clinically relevant sexual dysfunction is monitored over time using the Arizona Sexual Experiences Scale (ASEX) score.

  6. Step 6

    Study duration

    The study is designed to last up to one year, with an estimated end date of December 1, 2025.

Who can join the trial?

9 criteria

  • Participants must have completed the Double Blind Treatment Phase of Study 67953964MDD3001 or Study 67953964MDD3002.
  • Participants must be medically stable based on a physical exam, medical history, vital signs (like blood pressure), and a heart test called a 12-lead ECG, done at the start and before beginning the Open Label treatment.
  • Participants can be male or female, aged 18 to 74 years old.
  • Participants must be medically stable based on a physical exam, medical history, vital signs, and a 12-lead ECG done at screening and baseline.
  • Participants must be medically stable based on clinical lab tests done at screening.
  • Participants must meet the DSM-5 diagnostic criteria for Major Depressive Disorder (MDD), which means having repeated or single episodes of depression without psychotic features. If participants are 65 years or older, their first depression episode must have occurred before they were 55 years old.
  • Participants must have had an inadequate response to at least one oral antidepressant treatment, given at a proper dose and for a sufficient time during the current depression episode.
  • Participants must be taking and tolerating well a type of antidepressant called SSRI or SNRI for depressive symptoms at screening, and the dose must have been stable for at least 6 weeks.
  • Participants must have a HDRS-17 total score of 20 or higher at the first and second screening interviews and must not show a significant improvement between these two assessments. HDRS-17 is a scale used to measure the severity of depression symptoms.

Who cannot join the trial?

6 criteria

  • Patients who are not diagnosed with Major Depressive Disorder cannot participate. This is a condition where a person feels very sad, hopeless, and loses interest in activities for a long time.
  • Patients who are not taking a current antidepressant medication, specifically an SSRI or SNRI, cannot participate. SSRIs and SNRIs are types of medications that help improve mood by affecting certain chemicals in the brain.
  • Patients who are not within the specified age range cannot participate. The study is open to certain age groups only.
  • Patients who are not part of the specified clinical trial group cannot participate. This means the study is looking for specific types of participants.
  • Both male and female patients are eligible, so gender is not a reason for exclusion.
  • Patients who are considered part of a vulnerable population may not be eligible. This refers to groups of people who might need special protection or care.
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Investigated drugs

  • Aticaprant

    is being studied as an additional treatment for adults and elderly people with Major Depressive Disorder (MDD). It is used alongside a current antidepressant to see if it can help improve symptoms of depression over a long period. The study aims to understand how safe and tolerable this medication is when used with other antidepressants.

  • SSRI (Selective Serotonin Reuptake Inhibitor)

    is a type of antidepressant that is commonly used to treat depression. It works by increasing the level of serotonin, a chemical in the brain that helps improve mood.

  • SNRI (Serotonin-Norepinephrine Reuptake Inhibitor)

    is another type of antidepressant used to treat depression. It works by increasing the levels of serotonin and norepinephrine, chemicals in the brain that help regulate mood and may help relieve symptoms of depression.

What is already known about the treatment

Aticaprant – Aticaprant is administered orally and is currently being studied in clinical trials as an adjunctive therapy for Major Depressive Disorder (MDD). It is not yet widely recognized in medical literature as a standard treatment, as it is still under investigation for its long-term safety and efficacy. The main therapeutic indication for aticaprant is to enhance the effects of existing antidepressants, specifically SSRIs or SNRIs, in individuals with MDD. At the molecular level, aticaprant works by modulating specific receptors in the brain that are believed to influence mood and emotional regulation. It is classified pharmacologically as a receptor modulator, aiming to improve depressive symptoms when used alongside traditional antidepressant medications.

Investigated diseases

Major Depressive Disorder – This is a mental health condition characterized by persistent feelings of sadness, hopelessness, and a lack of interest or pleasure in activities. It can affect how a person thinks, feels, and handles daily activities, such as sleeping, eating, or working. The disorder often involves changes in appetite and sleep patterns, decreased energy, and difficulty concentrating. Individuals may experience feelings of worthlessness or excessive guilt. The symptoms can vary in intensity and may occur in episodes that last for weeks or longer.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-508163-74-00Protocol code67953964MDD3003Estimated enrolment1 067 patientsSponsorJanssen Cilag International

sourced from the EU Clinical Trials Register and site verification

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).