A Phase 2A Trial of DT402 for Autism Spectrum Disorder

August 31, 2026 updated by: Definium Therapeutics US, Inc.

An Open-label Study Evaluating DT402 in Adults With Autism Spectrum Disorder

A Phase 2A Trial of DT402 Open-Label Study in Adults with Autism Spectrum Disorder

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.

Detailed Description

This study will enroll approximately twenty adults with Autism Spectrum Disorder (ASD) aged 18 to 65 years of age.

This is a multi-center, open-label study to evaluate the effects after a single administration of DT402 to adults with ASD.

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.
20

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

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:

  1. Diagnosis of ASD per records as confirmed by standard semi-structured interview for Autism diagnosis (eg, Autism Diagnostic Observation Schedule-Second Edition)
  2. Male or Female aged 18 to 65
  3. Presents with clinically significant deficits in socialization and communication as determined by Social Responsiveness Scales (SRS-2) ≥66

Exclusion Criteria:

  1. Has uncorrected abnormalities in eye movement, alignment, or acuity or atypical eye features that could interfere with eye tracking
  2. First degree relative with or lifetime history of a psychotic disorder or bipolar disorder
  3. Current diagnosis of alcohol or substance use disorder (excluding nicotine and caffeine)
  4. Any clinically significant unstable illness

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

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: 200 mg DT402
A psychoactive substance that mediates effects mainly through a release of the monoaminergic neurotransmitters, with the greatest effect on 5-HT, followed by NE and DA
Drug: DT402 (R-enantiomer of 3,4-methylenedioxymethamphetamine (MDMA))
A psychoactive substance that mediates effects mainly through a release of the monoaminergic neurotransmitters, with the greatest effect on 5-HT, followed by NE and DA
Other Names:
  • MDMA
  • R-MDMA
  • MM402

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
Change from Baseline in 11-point Numerical Rating Scale (NRS) scores
Time Frame: Baseline, pre-dose and 2, 4, 6, 8, and 24 hours post-dose and day 15
The NRS is an 11-point PRO scale used to measure the severity or intensity of effects from 0 (no effect) to 10 (high severity or intensity of effect). It consists of various items related to both positive and negative effects in the autism patient population.
Baseline, pre-dose and 2, 4, 6, 8, and 24 hours post-dose and day 15

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
Subjective 5-question Drug Effects Questionnaire (DEQ) scores
Time Frame: 1, 2, 4, 6, 8, and 24 hours post-dose
The Drug Effects Questionnaire is used in studies to assess the participant's acute subjective effects after ingesting substances. It consists of 5 PRO items. The analog scale of responses ranges from "not at all" to "extremely." The score is determined by the distance between the left anchor point and the participant's mark on the line. Each item is scored separately.
1, 2, 4, 6, 8, and 24 hours post-dose
Pharmacokinetic Parameters (Cmax)
Time Frame: pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Maximum concentration (Cmax).
pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Pharmacokinetic Parameters (Tmax)
Time Frame: pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Time to maximum concentration (Tmax).
pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Pharmacokinetic Parameters (t1/2)
Time Frame: pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Time to maximum concentration half-life (t1/2).
pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Pharmacokinetic Parameters (AUC0-inf)
Time Frame: pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Area under the concentration curve from time 0 to infinity (AUC0-inf).
pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Pharmacokinetic Parameters (AUC0-24h)
Time Frame: pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Area under the concentration curve from time 0 to 24 hour (AUC0-24h).
pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Pharmacokinetic Plasma concentrations
Time Frame: pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose
Maximum Plasma Concentration [Cmax] of DT402 in the blood.
pre-dose and 1, 2, 4, 6, 8, and 24 hours post-dose

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.
Definium Therapeutics US, Inc.

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.
December 3, 2025

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.
August 1, 2027

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.
August 1, 2027

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).
December 22, 2025

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.
December 23, 2025

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.
December 26, 2025

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.
September 2, 2026

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.
August 31, 2026

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.
March 1, 2026

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.
  • MM402-105

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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings