ALTO-207 in Adults With Treatment-resistant Depression (TRD)

April 23, 2026 updated by: Alto Neuroscience

A Randomized, Double-blind, Placebo-controlled Trial of ALTO-207 in Adults With Treatment-resistant Depression

The purpose of this trial is to measure depressive symptoms following treatment with ALTO-207 compared with placebo in participants with TRD.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

178

Phase

  • 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 Locations

  • United Kingdom
      • Antrim, United Kingdom
        • Not yet recruiting
        • Site 7419
      • Birmingham, United Kingdom
        • Not yet recruiting
        • Site 7411
      • Bristol, United Kingdom
        • Not yet recruiting
        • Site 7414
      • Cardiff, United Kingdom
        • Not yet recruiting
        • Site 7412
      • Exeter, United Kingdom
        • Not yet recruiting
        • Site 7418
      • London, United Kingdom
        • Not yet recruiting
        • Site 7415
      • Nottingham, United Kingdom
        • Not yet recruiting
        • Site 7413
      • Oxford, United Kingdom
        • Not yet recruiting
        • Site 7410
      • Prescot, United Kingdom
        • Not yet recruiting
        • Site 7402
      • Sheffield, United Kingdom
        • Not yet recruiting
        • Site 7416
  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35294
        • Not yet recruiting
        • Site 7074
      • Dothan, Alabama, United States, 36345
        • Not yet recruiting
        • Site 7173
    • Arizona
      • Phoenix, Arizona, United States, 85012
        • Recruiting
        • Site 7000
    • California
      • Chino, California, United States, 91710
        • Not yet recruiting
        • Site 7153
      • Oakland, California, United States, 94610
        • Not yet recruiting
        • Site 7156
      • Oceanside, California, United States, 92056
        • Recruiting
        • Site 7082
      • Palo Alto, California, United States, 94304
        • Not yet recruiting
        • Site 7159
      • Sacramento, California, United States, 95655
        • Not yet recruiting
        • Site 7016
      • San Diego, California, United States, 92123
        • Recruiting
        • Site 7144
      • Valley Village, California, United States, 91607
        • Not yet recruiting
        • Site 7171
    • Florida
      • Saint Augustine, Florida, United States, 32086
        • Recruiting
        • Site 7152
    • Georgia
      • Albany, Georgia, United States, 31707
        • Recruiting
        • Site 7148
      • Atlanta, Georgia, United States, 30060
        • Not yet recruiting
        • Site 7146
      • Peachtree Corners, Georgia, United States, 30078
        • Not yet recruiting
        • Site 7064
      • Savannah, Georgia, United States, 31406
        • Recruiting
        • Site 7141
    • Indiana
      • Indianapolis, Indiana, United States, 46202
        • Not yet recruiting
        • Site 7169
    • Maryland
      • Annapolis, Maryland, United States, 21401
        • Recruiting
        • Site 7151
      • Pikesville, Maryland, United States, 21208
        • Not yet recruiting
        • Site 7054
    • Massachusetts
      • Worcester, Massachusetts, United States, 01606
        • Not yet recruiting
        • Site 7166
    • Michigan
      • Ann Arbor, Michigan, United States, 48109
        • Not yet recruiting
        • Site 7155
      • Bloomfield Hills, Michigan, United States, 48302
        • Recruiting
        • Site 7154
    • New York
      • Amherst, New York, United States, 14226
        • Not yet recruiting
        • Site 7170
      • Cedarhurst, New York, United States, 11516
        • Not yet recruiting
        • Site 7055
      • Lewiston, New York, United States, 14214
        • Not yet recruiting
        • Site 7162
      • Syracuse, New York, United States, 13210
        • Not yet recruiting
        • Site 7157
    • North Carolina
      • Charlotte, North Carolina, United States, 28287
        • Recruiting
        • Site 7143
    • Ohio
      • Cincinnati, Ohio, United States, 45215
        • Recruiting
        • Site 7029
      • Garfield Heights, Ohio, United States, 44125
        • Not yet recruiting
        • Site 7158
    • Rhode Island
      • East Providence, Rhode Island, United States, 02914
        • Not yet recruiting
        • Site 7172
    • Texas
      • Dallas, Texas, United States, 75243
        • Not yet recruiting
        • Site 7176
      • Fort Worth, Texas, United States, 76104
        • Not yet recruiting
        • Site 7160
      • Galveston, Texas, United States, 77555
        • Not yet recruiting
        • Site 7150
      • Houston, Texas, United States, 77007
        • Not yet recruiting
        • Site 7175
      • Houston, Texas, United States, 77030
        • Recruiting
        • Site 7145
      • Irving, Texas, United States, 75062
        • Recruiting
        • Site 7161
    • Virginia
      • Fairfax, Virginia, United States, 22030
        • Not yet recruiting
        • Site 7177
    • Washington
      • Seattle, Washington, United States, 98004
        • Not yet recruiting
        • Site 7128
    • West Virginia
      • South Charleston, West Virginia, United States, 25303
        • Not yet recruiting
        • Site 7163

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male and female participants, ages 18 to 75 years, inclusive, at the time of signing the ICF.
  • Prior diagnosis of MDD without psychotic symptoms (in the current episode) and have confirmatory diagnosis of current MDD (moderate to severe).
  • Failure to respond (<50% improvement) to at least 2-5 antidepressant treatments (including the current treatment)
  • Currently taking a stable dose of at least 1 but no more than 2 oral antidepressants at baseline

Exclusion Criteria:

  • Evidence of unstable medical condition
  • Concurrent use of any prohibited medications or substance use disorder
  • Diagnosed bipolar disorder or a psychotic disorder or symptoms
  • Significant current PTSD symptoms or history of PTSD
  • Clinically significant current impulse control difficulties
  • Has a history of hypersensitivity or allergic reaction to ALTO-207 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
Intervention / Treatment
Placebo Comparator: Placebo
Drug: Placebo
Matching Placebo
Experimental: ALTO-207
Drug: ALTO-207
ALTO-207 BID

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in the MADRS total score
Time Frame: Change from baseline up to 8 weeks
Montgomery Asberg Depression Rating Scale (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 from baseline up to 8 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in response (≥50% improvement) raters based on MADRS
Time Frame: Change from baseline up to 8 weeks
Montgomery Asberg Depression Rating Scale (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 from baseline up to 8 weeks
Change in the Clinician-administered CGI-S score over time from Baseline to Week 8
Time Frame: Change from baseline up to 8 weeks
The Clinician Global Impression-Severity scale (CGI-S) is a 7-point global assessment scale that measures the clinician's impression of the severity of illness exhibited by a participant, rating according to: 1=normal (not at all ill); 2=borderline ill; 3=mildly ill; 4=moderately ill; 5=markedly ill; 6=severely ill; and 7=among the most extremely ill participants. Higher scores represent a more severe condition.
Change from baseline up to 8 weeks

Collaborators and Investigators

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

Sponsor

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 (Estimated)

May 1, 2026

Primary Completion (Estimated)

November 1, 2027

Study Completion (Estimated)

December 1, 2027

Study Registration Dates

First Submitted

March 31, 2026

First Submitted That Met QC Criteria

April 23, 2026

First Posted (Actual)

April 28, 2026

Study Record Updates

Last Update Posted (Actual)

April 28, 2026

Last Update Submitted That Met QC Criteria

April 23, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ALTO-207-201

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

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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