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Safety and Tolerability Study of NBI-1065845 as Additional Treatment for Adults 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 study focuses on people with Major Depressive Disorder (MDD), a serious mental health condition characterized by persistent feelings of sadness and loss of interest in daily activities. The research evaluates a new medication called NBI-1065845 when used together with existing antidepressant treatments in adults who have not responded well enough to current antidepressant medications alone.

The purpose of this research is to assess how safe and well-tolerated NBI-1065845 is when taken as an additional treatment alongside regular antidepressant medication. The study medication comes in the form of oral tablets that participants take along with their current antidepressant treatment.

This is a long-term study that lasts for approximately 52 weeks (one year). During this time, all participants receive the study medication NBI-1065845 while continuing their current antidepressant treatment at the same dose they were taking before joining the study. The study team monitors participants' health and any side effects that may occur throughout the treatment period.

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

    Initial screening and eligibility confirmation

    Your diagnosis of Major Depressive Disorder (MDD) will be confirmed

    A medical assessment will verify that you have been taking oral antidepressants for at least 8 weeks

    Your MADRS score (a depression severity scale) will be checked to ensure it is 18 or higher

  2. Step 2

    Starting the medication

    You will receive the study medication NBI-1065845 in tablet form to take by mouth

    You will continue taking your current antidepressant medication at the same dose throughout the study

    The study medication will be taken as an additional treatment alongside your regular antidepressant

  3. Step 3

    Long-term treatment period

    The treatment period will last for 52 weeks (one year)

    Regular medical check-ups will monitor your health and any side effects

    Your current antidepressant medication will remain unchanged during this period

  4. Step 4

    Safety monitoring

    Any side effects or health changes will be recorded throughout the 52-week period

    Regular assessments will track your response to the medication

    Medical staff will monitor your overall health and well-being during the study

  5. Step 5

    Study completion

    The study will conclude after 52 weeks of treatment

    A final medical assessment will be conducted

    Your participation will end after completing all required evaluations

Who can join the trial?

7 criteria

  • You must have been diagnosed with recurrent Major Depressive Disorder (MDD) that is moderate or severe, or have persistent depressive disorder (long-lasting depression)
  • Your current depression treatment with oral antidepressants has not worked well enough to improve your symptoms
  • You must have been taking oral antidepressant medications for at least 8 weeks and be willing to continue taking the same medication at the same dose throughout the study
  • Your depression severity score on the MADRS (Montgomery-Åsberg Depression Rating Scale - a tool that measures depression symptoms) must be 18 or higher when you are first evaluated
  • You must be able and willing to follow all study procedures and restrictions that the study doctor explains to you
  • You can be either male or female
  • You must be an adult (age 18-64)

Who cannot join the trial?

15 criteria

  • Current diagnosis of bipolar disorder (a mental health condition that causes extreme mood swings)
  • History of psychotic disorders (conditions that affect how your brain processes information)
  • Current substance use disorder within the past 6 months (problems with alcohol or drug use)
  • Significant risk of self-harm or suicide
  • Unstable medical conditions that could affect your safety during the study
  • Taking medications that could interact with the study drug
  • Pregnant or breastfeeding women
  • Previous participation in a clinical trial within the past 30 days
  • Known allergies or sensitivity to similar medications
  • Severe liver or kidney problems
  • History of seizures or epilepsy
  • Uncontrolled high blood pressure
  • Any condition that could interfere with the absorption of oral medication
  • Current use of certain antidepressant medications that cannot be safely stopped
  • Unable to follow study procedures or attend required visits
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Investigated drugs

NBI-1065845 is an investigational medication being studied as an add-on treatment for major depressive disorder (MDD). It is being tested in combination with patients' existing antidepressant medications to potentially improve treatment outcomes for depression. This is a long-term study focusing on understanding how safe the medication is and how well patients tolerate it when used over an extended period.

What is already known about the treatment

NBI-1065845 - An investigational medication being studied as an adjunctive treatment for Major Depressive Disorder (MDD) in clinical trials. This drug is currently undergoing long-term safety and tolerability evaluations when used alongside existing depression treatments. While the specific mechanism of action is still under investigation as part of ongoing clinical research, it represents a novel approach in the therapeutic area of mental health. As this is an experimental compound still in clinical trials, it is not yet available for general medical use and its complete safety profile and effectiveness are being determined through controlled studies. Note: Given the limited clinical trial data provided, this description focuses on the known aspects of the investigational medication while acknowledging its experimental status. The specific form of administration and detailed pharmacological classification are not included as this information was not provided in the source data.

Investigated diseases

Major Depressive Disorder - A mental health condition characterized by persistent feelings of sadness, loss of interest in activities, and decreased energy that lasts for at least two weeks. The condition affects how a person thinks, feels, and manages daily activities, often causing changes in sleep, appetite, and concentration. People with this disorder may experience feelings of worthlessness, difficulty making decisions, and reduced physical activity. The condition can develop gradually and may be triggered by life events or occur without an obvious cause. It affects emotional and physical well-being, influencing both personal and professional aspects of life. The disorder can vary in intensity from mild to severe, with symptoms fluctuating over time.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-519423-24-00Protocol codeNBI-1065845-MDD3028Estimated enrolment864 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).