Study of ALTO-300 in MDD

July 21, 2025 updated by: Alto Neuroscience

A Randomized, Double-Blind, Placebo-Controlled Study of ALTO-300 With an Open-Label Extension in Adults With Major Depressive Disorder

The purpose of this study is to determine efficacy differences between ALTO-300 and placebo, used adjunctively to an antidepressant, related to patient characteristics.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
321

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85012
        • Recruiting
        • Site 200
      • Phoenix, Arizona, United States, 85021
        • Withdrawn
        • Site 189
      • Yuma, Arizona, United States, 85364
        • Recruiting
        • Site 187
    • Arkansas
      • Rogers, Arkansas, United States, 72758
        • Recruiting
        • Site 193
    • California
      • Bellflower, California, United States, 90706
        • Recruiting
        • Site 218
      • Glendale, California, United States, 91206
        • Recruiting
        • Site 217
      • Lafayette, California, United States, 94549
        • Recruiting
        • Site 335
      • Los Angeles, California, United States, 90064
        • Recruiting
        • Site 209
      • Mather, California, United States, 95655
        • Recruiting
        • Site 219
      • Mission Viejo, California, United States, 92691
        • Recruiting
        • Site 194
      • Temecula, California, United States, 92591
        • Recruiting
        • Site 197
    • Colorado
      • Colorado Springs, Colorado, United States, 80918
        • Recruiting
        • Site 203
      • Evergreen, Colorado, United States, 80439
        • Recruiting
        • Site 349
    • Connecticut
      • Norwalk, Connecticut, United States, 06851
        • Recruiting
        • Site 214
    • Florida
      • Clermont, Florida, United States, 34711
        • Recruiting
        • Site 159
      • Miami Gardens, Florida, United States, 33014
        • Recruiting
        • Site 225
      • Miami Lakes, Florida, United States, 33016
        • Recruiting
        • Site 190
      • Okeechobee, Florida, United States, 34972
        • Recruiting
        • Site 161
      • Tampa, Florida, United States, 33629
        • Recruiting
        • Site 221
      • West Palm Beach, Florida, United States, 33407
        • Recruiting
        • Site 220
    • Georgia
      • Savannah, Georgia, United States, 31405
        • Recruiting
        • Site 224
      • Snellville, Georgia, United States, 30078
        • Recruiting
        • Site 208
    • Idaho
      • Boise, Idaho, United States, 83702
        • Recruiting
        • Site 119
    • Illinois
      • Chicago, Illinois, United States, 60634
        • Recruiting
        • Site 310
    • Louisiana
      • Marrero, Louisiana, United States, 70072
        • Terminated
        • Site 201
      • Monroe, Louisiana, United States, 71201
        • Terminated
        • Site 198
    • Mississippi
      • Jackson, Mississippi, United States, 39216
        • Recruiting
        • Site 215
    • Nevada
      • Las Vegas, Nevada, United States, 89102
        • Recruiting
        • Site 344
    • New Mexico
      • Albuquerque, New Mexico, United States, 87108
        • Recruiting
        • Site 114
    • New York
      • Rochester, New York, United States, 14618
        • Terminated
        • Site 191
      • Staten Island, New York, United States, 10314
        • Recruiting
        • Site 192
    • North Carolina
      • Hickory, North Carolina, United States, 28601
        • Recruiting
        • Site 199
    • Ohio
      • Cincinnati, Ohio, United States, 45215
        • Recruiting
        • Site 202
    • Oklahoma
      • Oklahoma City, Oklahoma, United States, 73112
        • Recruiting
        • Site 195
    • Pennsylvania
      • Allentown, Pennsylvania, United States, 18104
        • Recruiting
        • Site 216
      • Media, Pennsylvania, United States, 19063
        • Recruiting
        • Site 350
      • Moosic, Pennsylvania, United States, 18507
        • Recruiting
        • Site 352
    • Texas
      • Dallas, Texas, United States, 75235
        • Withdrawn
        • Site 102
      • Fort Worth, Texas, United States, 76104
        • Recruiting
        • Site 347
      • Fort Worth, Texas, United States, 76244
        • Withdrawn
        • Site 148
      • Missouri City, Texas, United States, 77459
        • Withdrawn
        • Site 206
      • Plano, Texas, United States, 75093
        • Not yet recruiting
        • Site 353
      • Richmond, Texas, United States, 77407
        • Recruiting
        • Site 196
    • Utah
      • Clinton, Utah, United States, 84015
        • Recruiting
        • Site 207
    • Virginia
      • Roanoke, Virginia, United States, 24018
        • Recruiting
        • Site 211

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: ALTO-300
Participants will receive ALTO-300 capsule once daily in the evening, from Day 1 to Day 42 in double blind (DB) treatment period. Eligible participants who will enter the open-label (OL) treatment period will receive ALTO-300 capsule once daily in the evening from OL baseline until the end of OL period/early termination visit (Up to 8 weeks).
Drug: ALTO-300
ALTO-300 capsule QD
Placebo Comparator: Placebo
Participants will receive matching placebo capsule once daily in the evening, from Day 1 to Day 42 in double blind (DB) treatment period.
Drug: Placebo
Placebo capsule QD

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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.
Change over time for up to week 6

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
To assess efficacy of adjunctive ALTO-300 versus placebo on symptoms of MDD in all randomized 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.
Change over time for up to week 6
To assess efficacy of adjunctive ALTO-300 versus placebo for MDD as measured by the change over time up to week 6 in response (>50% improvement from baseline) rates based on the 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.
Change over time for up to week 6
To evaluate the safety of ALTO-300 during both the OL and DB periods of the study as measured by the assessment of the incidence, severity, and relatedness of Adverse Events.
Time Frame: Assessed from Day 1 to Week 14
Incidence, severity, and relatedness of Adverse Events
Assessed from Day 1 to Week 14
To evaluate the safety of ALTO-300 during both the OL and DB periods of the study as measured by the assessment of Heart Rate.
Time Frame: Assessed from Day 1 to Week 14
Assessment of Heart Rate
Assessed from Day 1 to Week 14
To evaluate the safety of ALTO-300 during both the OL and DB periods of the study as measured by the assessment of Weight.
Time Frame: Assessed from Day 1 to Week 14
Assessment of Weight
Assessed from Day 1 to Week 14
To evaluate the safety of ALTO-300 during both the OL and DB periods of the study as measured by the assessment of Blood Pressure.
Time Frame: Assessed from Day 1 to Week 14
Assessment of Blood Pressure
Assessed from Day 1 to Week 14
To evaluate the safety of ALTO-300 during both the OL and DB periods of the study as measured by the assessment of suicidality with the Concise Health Risk Tracking Self-Report,12 item scale (CHRT-SR12).
Time Frame: Assessed from Day 1 to Week 15
The CHRT is a brief, self-report measure that systematically assesses both suicidal thinking and associated thoughts that may indicate the propensity for suicidal acts. The CHRT-SR12 is a 12 item scale. The patient assigns a score of 0-4 for each item of the scale, allowing for a total score of 0 to 48, with the higher score signifying more severe symptoms.
Assessed from Day 1 to Week 15

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Alto Neuroscience

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Adam Savitz, MD, PhD, Alto Neuroscience

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 8, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 26, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 19, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 28, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 24, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 21, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ALTO-300-201

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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