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Assessment of NBI-1065845 as an Additional Treatment for Adults with Major Depressive Disorder

Verified siteInvestigationalNo placebo
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What is this trial about?

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

This study focuses on Major Depressive Disorder (MDD), a mental health condition characterized by persistent feelings of sadness and loss of interest in activities. The research evaluates the medication NBI-1065845 when added to existing antidepressant treatment for adults whose depression has not adequately responded to their current medication.

The purpose of this study is to determine if NBI-1065845 is effective and safe compared to placebo when used as an additional treatment for people with moderate to severe depression. Participants in this study will continue taking their regular antidepressant medication while also receiving either the study drug or placebo.

The study will monitor changes in depression symptoms over an 8-week period. Participants will need to attend regular appointments for evaluations of their depression symptoms using standardized rating scales that measure the severity of depression and how it affects daily functioning.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Screening and Baseline Assessment

    You will attend an initial screening visit where doctors will confirm your diagnosis of Major Depressive Disorder (MDD) using a face-to-face evaluation called the Mini-International Neuropsychiatric Interview (MINI).

    Your current antidepressant treatment will be evaluated to confirm you have had an inadequate response to treatment for your current depressive episode.

    A questionnaire called the Massachusetts General Hospital - Antidepressant Treatment Response Questionnaire (MGH-ATRQ) will be used to assess your response to previous treatments.

    You will complete the Hamilton Depression Rating Scale (HAM-D17), and must score 22 or higher to qualify for the study.

  2. Step 2

    Randomization

    If you qualify for the study, you will be randomly assigned (like flipping a coin) to receive either NBI-1065845 tablets or identical-looking placebo tablets (tablets that contain no active medication).

    Neither you nor the study doctor will know which treatment you are receiving during the study.

  3. Step 3

    Treatment Period

    The treatment period will last 56 days (8 weeks).

    You will take the study medication (either NBI-1065845 or placebo) as an add-on treatment to your current antidepressant medication.

    You must continue taking your regular antidepressant medication throughout the study period.

    You will need to follow the dosing instructions provided by the study team for both your regular medication and the study medication.

  4. Step 4

    Study Assessments

    Throughout the 56-day study period, you will attend several clinic visits for assessments.

    At each visit, your depression symptoms will be evaluated using the Montgomery-Asberg Depression Rating Scale (MADRS), which measures changes in your depression symptoms.

    You will also complete other assessments including the Sheehan Disability Scale (SDS) to measure how your depression affects your daily functioning, and the Clinical Global Impression-Severity (CGI-S) scale to assess the overall severity of your depression.

    The study team will monitor you for any side effects or changes in your health during these visits.

  5. Step 5

    Final Assessment

    On Day 56 (the end of the treatment period), you will complete a final comprehensive assessment.

    The main outcome that researchers will be measuring is the change in your MADRS score from the beginning to the end of the study.

    Changes in your SDS total score and CGI-S score from baseline to Day 56 will also be measured.

    After completing the final assessment, the study team will provide instructions for follow-up care.

Who can join the trial?

7 criteria

  • You must complete the informed consent process.
  • You must be at least 18 years of age when you sign the informed consent.
  • You must have a primary diagnosis of recurrent Major Depressive Disorder (moderate or severe) or persistent depressive disorder. This diagnosis will be confirmed through a face-to-face interview using a structured psychiatric assessment tool called the Mini-International Neuropsychiatric Interview (MINI).
  • You must currently be taking oral antidepressant medication(s) as specified in the study protocol.
  • You must have had an inadequate response to oral antidepressant treatments that were given at appropriate doses and duration during your current episode of depression. This will be assessed using a questionnaire called the Massachusetts General Hospital - Antidepressant Treatment Response Questionnaire.
  • Your depression severity score must be at least 22 on the Hamilton Depression Rating Scale (a 17-item questionnaire that measures depression severity) both at screening and on the first day of the study.
  • You must be willing and able to follow all study procedures and restrictions according to the investigator's judgment.

Who cannot join the trial?

10 criteria

  • You have a history of other psychiatric disorders besides major depressive disorder, such as bipolar disorder (a condition with extreme mood swings), schizophrenia (a mental disorder with distorted thinking), or schizoaffective disorder (a condition with symptoms of both schizophrenia and mood disorders).
  • You have a substance use disorder (addiction to drugs or alcohol) in the past 6 months.
  • You have thoughts of suicide or have attempted suicide within the past 6 months.
  • You have a history of seizures or other neurological disorders (conditions affecting the brain and nervous system).
  • You are pregnant or breastfeeding.
  • You have significant medical conditions that are not well-controlled.
  • You are taking medications that might interact with the study drug.
  • You have participated in another clinical trial within the past 30 days.
  • You have previously had treatment with the study drug or similar drugs.
  • You are unable to follow the study procedures or attend all required visits.
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Investigated drugs

  • NBI-1065845

    is an investigational medication being studied as an additional treatment for Major Depressive Disorder (MDD). It is taken alongside a person's current depression medication to potentially improve depression symptoms. This medication is still in the research phase, and this trial aims to determine if it can help reduce depression symptoms better than a placebo when added to existing treatment.

  • Placebo

    is an inactive substance that looks like the study medication but contains no active ingredients. In this study, it's used as a comparison to determine if NBI-1065845 provides real benefits for depression symptoms.

What is already known about the treatment

NBI-1065845 – This is an investigational medication currently being studied as an adjunctive (add-on) treatment for Major Depressive Disorder (MDD) in clinical trials. It is administered alongside existing antidepressant treatments in patients who haven't responded adequately to standard therapy alone. While the exact molecular mechanism isn't fully disclosed in public literature, it likely targets novel neurochemical pathways involved in mood regulation that differ from conventional antidepressants. The medication is still in Phase 3 clinical trials (indicated by the "MDD3025" study identifier), which means it has shown promising results in earlier studies but is not yet approved by regulatory agencies for general use.

Investigated diseases

Major Depressive Disorder – A mental health condition characterized by persistent feelings of sadness, emptiness, and loss of interest or pleasure in activities once enjoyed. It affects a person's thoughts, feelings, behavior, and can lead to a variety of emotional and physical problems. Symptoms typically include changes in sleep, appetite, energy level, concentration, and self-esteem, along with feelings of hopelessness or worthlessness. Major Depressive Disorder can vary in severity and duration, with episodes potentially lasting weeks to months. The condition often interferes with daily functioning and normal activities.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-519420-25-00Protocol codeNBI-1065845-MDD3025Estimated enrolment200 patientsSponsorNeurocrine Biosciences Inc.

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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).