NCT05922878 · Alto Neuroscience
Study of ALTO-300 in MDD
What this study is about
The purpose of this study is to determine effectiveness differences between ALTO-300 and placebo, used adjunctively to an antidepressant, related to patient characteristics.
View original scientific description
The purpose of this study is to determine efficacy differences between ALTO-300 and placebo, used adjunctively to an antidepressant, related to patient characteristics.
Interventions
DRUG
ALTO-300
ALTO-300 capsule QD
DRUG
Placebo
Placebo capsule QD
Primary outcome measures
To assess efficacy of adjunctive ALTO-300 versus placebo on symptoms of MDD in a pre-defined subgroup of participants as measured by the change over time up to week 6 in the Montgomery-Åsberg Depression Rating Scale (MADRS).
Time frame: Change over time for up to week 6
MADRS is a clinician-administered scale designed to measure depression severity and detects changes due to antidepressant treatment. The MADRS evaluates the following 10 items: apparent sadness, reported sadness, inner tension, reduced sleep, reduced appetite, concentration difficulties, lassitude, inability to feel, pessimistic thoughts, and suicidal thoughts. Each item is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score of 60. Higher scores represent a more severe condition.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Have a diagnosis of moderate to severe major depressive disorder (MDD)
- At Visit 1, currently taking a single SSRI, SNRI, or bupropion for at least 6 weeks with no dose modifications in the past 2 weeks by Visit 2
- Willing to comply with all study assessments and procedures
- Must not be pregnant or breastfeeding at time of enrollment or throughout study
Exclusion criteria
- Evidence of unstable medical condition
- Nightly use of sleep medication
- Diagnosed bipolar disorder, psychotic disorder, or dementia
- Current moderate or severe substance use disorder
- Has a history of hypersensitivity or allergic reaction to ALTO-300 or any of its components/excipients
- Concurrent or recent participation in another clinical trial for mental illness involving an investigational product or device
Where
- Phoenix, Arizona
- Yuma, Arizona
- Rogers, Arkansas
- Bellflower, California
- Glendale, California
- Lafayette, California
- Los Angeles, California
- Mather, California
- Mission Viejo, California
- Temecula, California
- Colorado Springs, Colorado
- Evergreen, Colorado
And 31 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 24, 2025 · Source of record for eligibility and locations