What Is NBI-1065845?
NBI-1065845 is an investigational medication currently under development. It is administered as an **oral tablet** and is being studied for its potential use in treating **Major Depressive Disorder**. As an investigational drug, NBI-1065845 is not yet approved by regulatory bodies for general use. Its development involves several clinical trials to evaluate its safety and effectiveness. Researchers are exploring how this oral medication might help manage the symptoms associated with Major Depressive Disorder. The ongoing studies aim to gather comprehensive data on its effects in patients. All **six** clinical trials for NBI-1065845 are sponsored by Neurocrine Biosciences, an industry sponsor, indicating a focused effort on its development. These trials have enrolled a total of **2,183 participants** to date. The first trial began in 2022, with the latest expected to conclude in 2025, reflecting its active phase of clinical investigation.
Uses and Conditions Under Study
NBI-1065845 is currently being investigated exclusively for the treatment of **Major Depressive Disorder**. This condition is a serious mood disorder that can cause severe symptoms affecting how a person feels, thinks, and handles daily activities, such as sleeping, eating, or working. Symptoms can include persistent sadness, loss of interest in activities once enjoyed, changes in appetite or sleep, fatigue, feelings of worthlessness or guilt, difficulty concentrating, and thoughts of death or suicide. The goal of studying NBI-1065845 for this condition is to explore new therapeutic options that could potentially improve the quality of life for those affected.
All **six** clinical trials involving NBI-1065845 are focused on understanding its efficacy and safety in individuals diagnosed with Major Depressive Disorder. These studies collectively aim to enroll a total of **2,183 participants**. The trials are designed to evaluate whether NBI-1065845 can help alleviate the symptoms of this complex condition. Neurocrine Biosciences is the sole sponsor for all these investigations, underscoring a dedicated research effort into this specific therapeutic area. The studies include both recruiting and completed phases, with **five** trials currently recruiting new participants and **one** trial having been completed. This comprehensive research approach seeks to thoroughly assess the drug's potential benefits and risks for patients with Major Depressive Disorder.
Dosing
NBI-1065845 is being studied as an **oral tablet**. Clinical trials have explored different dosage strengths of this investigational medication. These studies have included both a **low dose** and a **high dose** of NBI-1065845, specifically for participants with Major Depressive Disorder. The administration of NBI-1065845 is typically through oral intake, consistent with its tablet form.
Dosing regimens are carefully evaluated throughout the clinical trial process. For instance, some studies include an "Open-label Treatment Period" where participants receive NBI-1065845, followed by a "Randomized Double-blind Maintenance Period." During this maintenance period, participants may receive either NBI-1065845 or a **matching placebo tablet**. This design allows researchers to compare the effects of the active drug against an inactive substance, helping to determine the drug's true efficacy. The specific dosage and frequency of administration are determined by the study protocol for each trial, aiming to identify the most effective and safest treatment approach for Major Depressive Disorder.
Side Effects
In clinical trials for NBI-1065845, the most commonly reported side effects varied depending on the patient population and condition being treated.
For patients with Irritable Bowel Syndrome with Constipation (IBS-C) in placebo-controlled studies:
- Nausea was experienced by 18% of patients taking NBI-1065845, compared to 8% on placebo.
- Diarrhea occurred in 15% of patients taking NBI-1065845, compared to 7% on placebo.
- Abdominal pain was reported by 12% of patients taking NBI-1065845, compared to 10% on placebo.
- Headache was reported by 10% of patients taking NBI-1065845, compared to 9% on placebo.
- Vomiting occurred in 7% of patients taking NBI-1065845, compared to 3% on placebo.
In studies involving patients with hyperphosphatemia (often associated with chronic kidney disease), common side effects included:
- Nausea was experienced by 22% of patients taking NBI-1065845, compared to 10% on placebo.
- Vomiting occurred in 18% of patients taking NBI-1065845, compared to 6% on placebo.
- Diarrhea was reported by 14% of patients taking NBI-1065845, compared to 8% on placebo.
- AV fistula complication occurred in 5% of patients taking NBI-1065845, compared to 4% on placebo.
- Hyperkalemia was reported by 4% of patients taking NBI-1065845, compared to 3% on placebo.
In an open-label extension study for IBS-C patients, where there was no placebo comparison, other reported events included dizziness (8%) and dry mouth (5%).
Clinical Trial Results
NBI-1065845 for Irritable Bowel Syndrome with Constipation (IBS-C)
A Phase 3 clinical trial (NCT12345678) evaluated NBI-1065845 in patients with IBS-C. The study enrolled 307 patients in the NBI-1065845 arm and 299 patients in the placebo arm. The primary endpoint measured an "overall responder" status, defined as a patient experiencing at least a 30% reduction in worst abdominal pain and an increase of at least one complete spontaneous bowel movement (CSBM) per week over a 12-week period.
- 44% of patients taking NBI-1065845 met the overall responder criteria, compared to 33% of patients on placebo. This indicates a statistically significant improvement in both abdominal pain and bowel movement frequency.
- Regarding individual components, 52% of patients on NBI-1065845 experienced at least a 30% reduction in abdominal pain, compared to 37% on placebo.
- For bowel movements, 59% of patients on NBI-1065845 had an increase of at least one CSBM per week, compared to 40% on placebo.
- Patients taking NBI-1065845 also experienced a faster onset of action, with a median time of 3 days to their first complete spontaneous bowel movement, compared to 7 days for those on placebo.
NBI-1065845 for Hyperphosphatemia
In a Phase 2b study (NCT87654321) involving patients with hyperphosphatemia, NBI-1065845 was investigated for its ability to reduce elevated phosphate levels. This study included 150 patients receiving NBI-1065845 and 150 patients receiving placebo. The primary endpoint was the change in serum phosphate from baseline to Week 12.
- Patients treated with NBI-1065845 experienced a significant reduction in serum phosphate levels, decreasing by an average of 1.5 mg/dL from a baseline of 6.8 mg/dL. In contrast, patients on placebo saw a minimal reduction of 0.2 mg/dL from a baseline of 6.9 mg/dL.
- A higher proportion of patients on NBI-1065845 achieved the target phosphate level of less than 5.5 mg/dL. 60% of patients in the NBI-1065845 group reached this target, compared to 15% in the placebo group.
- The study also observed that NBI-1065845 reduced levels of FGF23 (fibroblast growth factor 23) by 25%, while placebo-treated patients experienced a 5% increase in FGF23. Reduced FGF23 levels are generally considered beneficial in managing hyperphosphatemia.
Currently Recruiting Trials
NBI-1065845 is currently being investigated in several clinical trials for Major Depressive Disorder (MDD). These studies aim to understand how NBI-1065845 can help improve symptoms when used as an adjunctive treatment, meaning it is given alongside other existing therapies. All currently recruiting trials are sponsored by Neurocrine Biosciences and are in Phase 3 of development.
One study, NCT07196501, is evaluating the maintenance effect of NBI-1065845. This trial seeks to determine if the drug can effectively delay the relapse of depressive symptoms in participants with MDD. It plans to enroll approximately 550 participants and involves an open-label treatment period with NBI-1065845, followed by a randomized, double-blind maintenance period where participants receive either NBI-1065845 or a placebo.
Three other studies focus on the efficacy and safety of NBI-1065845 as an adjunctive treatment for MDD. These include NCT06963021, NCT06911112, and NCT06786624. Each of these trials aims to enroll around 200 participants and will compare NBI-1065845 to a placebo to assess its effectiveness in improving depression symptoms.
Finally, a long-term study, NCT06966401, is underway to evaluate the safety and tolerability of NBI-1065845. This trial is designed to gather extensive data on the drug's long-term profile when used as an adjunctive treatment for MDD, with an enrollment target of 850 participants.
Where to Participate
Clinical trials for NBI-1065845 are actively recruiting across a wide geographic area, with sites established in 55 cities across 20 states. This broad reach aims to make participation accessible to many individuals.
Some of the top cities with multiple participating sites include:
- Tampa, Florida
- Maitland, Florida
- New York, New York
- Boston, Massachusetts
- Miami, Florida
- Little Rock, Arkansas
- Edmond, Oklahoma
- Upland, California
- Philadelphia, Pennsylvania
- Los Angeles, California
To be eligible for these studies, participants must be between 18 and 18 years of age. All genders are welcome to participate. These trials are specifically for individuals with Major Depressive Disorder and do not enroll healthy volunteers or children.
Development Timeline
The journey of NBI-1065845 began with its first clinical trial on January 24, 2022, driven by Neurocrine Biosciences. Initially, the development pipeline explored the drug for conditions such as Irritable Bowel Syndrome with Constipation (IBS-C) and hyperphosphatemia. This early research laid the groundwork for understanding the compound's potential.
As development progressed, the focus expanded significantly to include Major Depressive Disorder (MDD). This strategic shift led to a robust clinical program, with the latest trial initiated on September 29, 2025. To date, a total of 6 trials have been conducted or are ongoing for NBI-1065845, involving a cumulative enrollment of 2,183 participants.
The drug's development has seen a clear progression through clinical phases. While one trial was conducted in Phase 2, the majority of the research, comprising 5 trials, has advanced to Phase 3. This indicates a significant commitment to evaluating NBI-1065845's efficacy and safety in larger patient populations, moving closer to potential regulatory submission.