Major Depressive DisorderPhase 2NCT06391593
PD, PK, and Safety of ALTO-203 in Patients With MDD
A Phase 2 study testing ALTO-203 25 μg and ALTO-203 75 μg in people with Major Depressive Disorder and Anhedonia, run by Alto Neuroscience at 15 sites in United States.
Trial summary
The goal of this clinical trial is to determine the pharmacodynamic effects of ALTO-203 in patients with MDD in a randomized, placebo-controlled, single-dose crossover treatment period. Read more about this study
- Who is it for?
- Ages 25 to 64 years
- Conditions the study is for
- Major Depressive Disorder, Anhedonia
- What is being tested?
- ALTO-203 25 μg and ALTO-203 75 μg
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 69 participants
- Where
- 15 sitesUnited States
- Study dates
- 25 Mar 2024to 21 Apr 2025
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 64 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Have a diagnosis of moderate major depressive disorder (MDD)
- Presence of anhedonia symptoms
- Not taking antidepressant at Screening Visit 2
- Willing to comply with all study assessments and procedures
Who cannot join
- Evidence of unstable medical condition
- Diagnosed bipolar disorder, psychotic disorder, or dementia
- Concurrent use of prohibited medications
- Current moderate or severe substance use disorder
- Concurrent or recent participation in another clinical trial for mental illness involving an investigational product or device
Trial locations and contacts
15 sites in 1 country.
15 sites in 1 country
United States15 sites
Site 4031
Atlanta, Georgia, 30030
Site 4040
Austin, Texas, 78737
Site 4033
Bellevue, Washington, 98007
Site 4059
Clermont, Florida, 34711
Site 4007
Clinton, Utah, 84015
Site 4072
Houston, Texas, 77081
Site 4036
Las Vegas, Nevada, 89121
Site 4022
Marlton, New Jersey, 08053
Site 4082
Oceanside, California, 92056
Site 4005
Orlando, Florida, 32801
Site 4054
Pikesville, Maryland, 21208
Site 4134
Princeton, New Jersey, 08540
Site 4023
Torrance, California, 90504
Site 4058
Tucson, Arizona, 85704
Site 4075
Westlake, Ohio, 44145
About this study
Official title: Double-Blind, Single and Multiple Dose Study to Determine Pharmacodynamic Markers, Pharmacokinetic Parameters, and Safety of ALTO-203 in Patients With Major Depressive Disorder
The goal of this clinical trial is to determine the pharmacodynamic effects of ALTO-203 in patients with MDD in a randomized, placebo-controlled, single-dose crossover treatment period. Additionally, safety, tolerability, and PK will be assessed in a subsequent randomized placebo-controlled multi-dose parallel-group treatment period of 28 days.
Participants will complete subjective response questionnaires and perform cognitive tasks during the single-dose period, in which participants will receive ALTO-203 25 μg and 75 μg, as well as placebo. During the multiple-dose period, participants will receive either ALTO-203 25 μg, 75 μg , or placebo. Safety will be assessed over the single dose and 28-day multiple dose periods.
- Conditions
- Major Depressive Disorder, Anhedonia
- Being tested
- ALTO-203 25 μg, ALTO-203 75 μg, Placebo
- Medical subject headings
- Depressive Disorder, Major, Anhedonia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ALTO-203 25 μgDrug
Active, ALTO-203 25 μg
ALTO-203 75 μgDrug
Active, ALTO-203 75 μg
PlaceboDrug
Comparator, Placebo-to-match
| Study group | Role | What they receive |
|---|---|---|
| ALTO-203 25 μg | Experimental | Drug: ALTO-203 25 μg
Single-Dose Treatment Period: Single Dose, ALTO-203 25 μg
Multi-Dose Treatment Period: ALTO-203 25 μg, administered orally, once daily for 28 days Receives: Drug: ALTO-203 25 μg |
| ALTO-203 75 μg | Experimental | Drug: ALTO-203 75 μg
Single-Dose Treatment Period: Single Dose, ALTO-203 75 μg
Multi-Dose Treatment Period: ALTO-203 75 μg, administered orally, once daily for 28 days Receives: Drug: ALTO-203 75 μg |
| Placebo | Placebo comparator | Drug: Placebo
Single-Dose Treatment Period: Single Dose, Placebo
Multi-Dose Treatment Period: Placebo, administered orally, once daily for 28 days Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Single Dose Period: To evaluate pharmacodynamic measures in patients with MDD after single doses of 25 μg ALTO-203, 75 μg ALTO-203, and placebo as measured by the alertness and mood components of the Bond-Lader Visual Analog Scale (BL-VAS).
The Bond-Lader Visual Analogue Scale (BL-VAS) is used to measure the effects of drugs on the participants' mood. It consists of 16 VAS measurements of different mood state. For each question, the participants will rate their feelings at the time of assessment by indicating the point on the 10 cm line which best represents their mood. Each item is scored by measuring the position relative to the left-hand end of the line. The combined domains of alertness and mood will be assessed for the primary endpoint.
Measured: Single-Dose Treatment Period - Pre-Dose, 1.5 hours, 3 hours, and 5 hours on Day 1 at Treatments 1, 2, and 3
Multi-Dose Period: To assess the incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] during the multi-dose treatment period for ALTO-203 25 μg and ALTO-203 75 μg as compared to placebo.
Incidence, severity, and relatedness of TEAEs, SAEs, discontinuation due to TEAEs.
Measured: Multi-Dose Treatment Period Day 1 to Day 35
Secondary outcomes (2)
Single Dose Period: To assess the incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] during the single-dose treatment period for ALTO-203 25 μg and ALTO-203 75 μg as compared to placebo.
Incidence, severity, and relatedness of TEAEs, SAEs, discontinuation due to TEAEs.
Measured: Single-Dose Treatment Period Day 1 to Day 21
Multi-Dose Period: To understand the pharmacokinetics (PK) of multi-doses of ALTO-203 in capsule formulation
Bioanalysis of plasma samples and observed plasma concentrations of ALTO-203 after multiple days of dosing.
Measured: Multi-Dose Treatment Period Day 1 to Day 35
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Apr 2024
- Study start25 Mar 2024
- Primary completion14 Apr 2025
- Study completion21 Apr 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Major Depressive DisorderStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- The study will consist of two treatment periods. The initial Single-Dose Treatment Period is a randomized, double-blind, placebo-controlled 3-way crossover design with oral administration of a single dose of ALTO-203 25 μg, ALTO-203 75 μg, and matching placebo. In the subsequent Multi-Dose Parallel-Group Treatment Period, participants will receive ALTO-203 25 μg, ALTO-203 75 μg, or matching placebo randomized 1:1:1 for a total of 28 days.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 69 participants (actual)
Sponsor and investigators
- Lead sponsor
- Alto Neuroscience
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06391593
- Sponsor's protocol ID
- ALTO-203-201
- Status last verified
- Apr 2026
- First submitted
- 8 Apr 2024
- Last updated
- 17 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Double-Blind, Single and Multiple Dose Study to Determine Pharmacodynamic Markers, Pharmacokinetic Parameters, and Safety of ALTO-203 in Patients With Major Depressive Disorder
- ClinicalTrials.gov ID
- NCT06391593
- Acronym / sponsor ID
- ALTO-203-201
- Conditions
- Major Depressive Disorder, Anhedonia
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 69 participants (actual)
- Lead sponsor
- Alto NeuroscienceIndustry (pharma, biotech, devices)
- Study start
- 25 Mar 2024 (actual)
- Primary completion
- 14 Apr 2025 (actual)
- Study completion
- 21 Apr 2025 (actual)
- First posted
- 30 Apr 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to determine the pharmacodynamic effects of ALTO-203 in patients with MDD in a randomized, placebo-controlled, single-dose crossover treatment period. Additionally, safety, tolerability, and PK will be assessed in a subsequent randomized placebo-controlled multi-dose parallel-group treatment period of 28 days.
Participants will complete subjective response questionnaires and perform cognitive tasks during the single-dose period, in which participants will receive ALTO-203 25 μg and 75 μg, as well as placebo. During the multiple-dose period, participants will receive either ALTO-203 25 μg, 75 μg , or placebo. Safety will be assessed over the single dose and 28-day multiple dose periods.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
- Model description
- The study will consist of two treatment periods. The initial Single-Dose Treatment Period is a randomized, double-blind, placebo-controlled 3-way crossover design with oral administration of a single dose of ALTO-203 25 μg, ALTO-203 75 μg, and matching placebo. In the subsequent Multi-Dose Parallel-Group Treatment Period, participants will receive ALTO-203 25 μg, ALTO-203 75 μg, or matching placebo randomized 1:1:1 for a total of 28 days.
| Arm | Type | Receives |
|---|---|---|
| ALTO-203 25 μg | Experimental | Drug: ALTO-203 25 μgDrug: ALTO-203 25 μg Single-Dose Treatment Period: Single Dose, ALTO-203 25 μg Multi-Dose Treatment Period: ALTO-203 25 μg, administered orally, once daily for 28 days |
| ALTO-203 75 μg | Experimental | Drug: ALTO-203 75 μgDrug: ALTO-203 75 μg Single-Dose Treatment Period: Single Dose, ALTO-203 75 μg Multi-Dose Treatment Period: ALTO-203 75 μg, administered orally, once daily for 28 days |
| Placebo | Placebo comparator | Drug: PlaceboDrug: Placebo Single-Dose Treatment Period: Single Dose, Placebo Multi-Dose Treatment Period: Placebo, administered orally, once daily for 28 days |
Who may qualify
- Ages
- 25 to 64 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Have a diagnosis of moderate major depressive disorder (MDD)
- Presence of anhedonia symptoms
- Not taking antidepressant at Screening Visit 2
- Willing to comply with all study assessments and procedures
Key exclusion criteria (5 listed)
- Evidence of unstable medical condition
- Diagnosed bipolar disorder, psychotic disorder, or dementia
- Concurrent use of prohibited medications
- Current moderate or severe substance use disorder
- Concurrent or recent participation in another clinical trial for mental illness involving an investigational product or device
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ALTO-203 25 μgActive, ALTO-203 25 μg | Drug | ALTO-203 25 μg |
| ALTO-203 75 μgActive, ALTO-203 75 μg | Drug | ALTO-203 75 μg |
| PlaceboComparator, Placebo-to-match | Drug | Placebo |
Primary outcome
Single Dose Period: To evaluate pharmacodynamic measures in patients with MDD after single doses of 25 μg ALTO-203, 75 μg ALTO-203, and placebo as measured by the alertness and mood components of the Bond-Lader Visual Analog Scale (BL-VAS).
Time frame: Single-Dose Treatment Period - Pre-Dose, 1.5 hours, 3 hours, and 5 hours on Day 1 at Treatments 1, 2, and 3
The Bond-Lader Visual Analogue Scale (BL-VAS) is used to measure the effects of drugs on the participants' mood. It consists of 16 VAS measurements of different mood state. For each question, the participants will rate their feelings at the time of assessment by indicating the point on the 10 cm line which best represents their mood. Each item is scored by measuring the position relative to the left-hand end of the line. The combined domains of alertness and mood will be assessed for the primary endpoint.
Multi-Dose Period: To assess the incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] during the multi-dose treatment period for ALTO-203 25 μg and ALTO-203 75 μg as compared to placebo.
Time frame: Multi-Dose Treatment Period Day 1 to Day 35
Incidence, severity, and relatedness of TEAEs, SAEs, discontinuation due to TEAEs.
2 secondary outcomes
Single Dose Period: To assess the incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] during the single-dose treatment period for ALTO-203 25 μg and ALTO-203 75 μg as compared to placebo.
Time frame: Single-Dose Treatment Period Day 1 to Day 21
Multi-Dose Period: To understand the pharmacokinetics (PK) of multi-doses of ALTO-203 in capsule formulation
Time frame: Multi-Dose Treatment Period Day 1 to Day 35
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Apr 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
15 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing ALTO-203 25 μg and ALTO-203 75 μg in people with Major Depressive Disorder and Anhedonia, run by Alto Neuroscience at 15 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 15 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Single Dose Period: To evaluate pharmacodynamic measures in patients with MDD after single doses of 25 μg ALTO-203, 75 μg ALTO-203, and placebo as measured by the alertness and mood components of the Bond-Lader Visual Analog Scale (BL-VAS). (time frame: Single-Dose Treatment Period - Pre-Dose, 1.5 hours, 3 hours, and 5 hours on Day 1 at Treatments 1, 2, and 3). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Apr 2026.