A Phase 2 interventional study of VLS-01-203 BU and VLS-01-BU Placebo in Treatment Resistant Depression, sponsored by atai Therapeutics, Inc.. Completed at 48 sites in 4 countries. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-10-30.
Sponsored by atai Therapeutics, Inc. · Phase 2, Interventional, and Treatment
This Phase 2 study (protocol number VLS-01-203) will determine the efficacy, safety, and tolerability of short-term treatment with a VLS-01 transmucosal buccal film (VLS-01-BU) in patients with treatment resistant Major Depressive disorder (TRD) and will characterize the onset and durability of antidepressant effects of VLS-01-BU versus placebo.
This Phase 2, multicenter, double-blind, randomized, placebo-controlled trial will enroll approximately 142 participants with TRD, randomized 1:1 to receive a total of 2 double-blind administrations of VLS- 01-BU (buccal film containing VLS-01) or placebo, administered via the buccal transmucosal route, with a 2-week interval between each administration, during the placebo-controlled treatment period. All participants will have their symptoms monitored for 12 weeks in the placebo- controlled follow-up period, following the second administration of VLS-01-BU or placebo. After the placebo-controlled treatment and observation period all participants will be re-randomized 1:1 to receive one double-blinded administration of VLS-01-BU (dose strength 1 or dose strength 2) during a non-placebo-controlled treatment period. Final safety and efficacy assessment will be conducted two weeks after administration of the third dose.
448 studies on the registry are indexed under Depressive Disorder, Treatment-Resistant; 147 are open to participants now.
This study's enrollment of 142 is above the median of 59 across 372 interventional studies indexed under Depressive Disorder, Treatment-Resistant.
Browse Depressive Disorder, Treatment-Resistant studies →atai Therapeutics, Inc. is the lead sponsor of 3 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: VLS-01-203 BU
Drug: VLS-01-BU Placebo
VLS-01 buccal transmucosal administration
Placebo buccal transmucosal administration
Change from Baseline in Montgomery-Åsberg Depression Rating Scale (MADRS) total score
Time frame: Baseline to Day 29
Change from Baseline in MADRS total score
Time frame: Baseline to Day 43
Incidence and severity of adverse events, adverse events of special interest and serious adverse events
Time frame: Baseline to Day 113
Incidence of clinically significant abnormalities in physical examinations, vital signs, electrocardiogram parameters, and safety laboratory results
Time frame: Baseline to Day 113
Columbia-Suicide Severity Rating Scale (C- SSRS) scores
Time frame: Baseline to Day 113
Plan to share: No
No publications or documents are linked to this record.
Ran from Dec 2024 to primary completion in Jul 2026, 19 months.
Of 50 phase 2 interventional studies under Depressive Disorder, Treatment-Resistant, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 17 and three quarters within 41. This study's 19 months is below that.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 30, 2026: primary completion Aug 2026 → Jul 2026 and completion Aug 2026 → Oct 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Depressive Disorder, Treatment-Resistant →
atai Therapeutics, Inc.