ACP-211 Monotherapy for Major Depressive Disorder With Inadequate Antidepressant Response

NCT07284667 | Recruiting Phase 2 DMC FDA Drug

• 1 other identifier: ACP-211-002
• Study Type: interventional
• Target: 153
• Locations: 1 country
• Sites: 26

Brief Summary

The goal of this clinical trial is to learn if ACP-211 can help treat adults with major depressive disorder (MDD) who have not improved with antidepressant therapy (ADT), including those with treatment resistant depression (TRD). The main questions the study aims to answer are:

• Does ACP-211 work better than a placebo (a look-alike capsule with no medicine) to reduce symptoms of depression?
• What adverse events do participants have when taking ACP-211?

Conditions

Major Depressive Disorder (MDD); Depressive Disorder, Treatment-Resistant

Keywords

Major Depressive Disorder (MDD); Depressive Disorder, Treatment-Resistant; Antidepressive Agents; Randomized Controlled Trial; Double-Blind Method; Clinical Trial, Phase II; Psychiatric Status Rating Scales; Ketamine

Outcome Measures

Primary Outcomes (1)

• Change From Baseline in Montgomery-Åsberg Depression Rating Scale (MADRS) Total Score at Day 28

  The MADRS is a clinician-rated scale that assesses the severity of depressive symptoms. It consists of 10 items, each scored from 0 (no symptoms) to 6 (severe symptoms), resulting in a total score range of 0 to 60. Higher scores indicate greater depression severity.

  Baseline and Day 28

Secondary Outcomes (7)

• Change From Baseline in MADRS Total Score at Day 2

  Baseline and Day 2 (24 hours postdose)

• Change From Baseline in MADRS Total Score at Scheduled Postbaseline Visits

  Baseline through Day 28

• Change From Baseline in Clinical Global Impression-Severity (CGI-S) Score at Scheduled Postbaseline Visits

  Baseline through Day 28

• Proportion of Subjects in Remission at Scheduled Postbaseline Visits (MADRS ≤10)

  Up to Day 28

• Proportion of Subjects With Response at Scheduled Postbaseline Visits (≥50% Reduction From Baseline in MADRS Total Score)

  Up to Day 28

Study Arms (3)

ACP-211 600 mg

EXPERIMENTAL

ACP-211 600 mg, administered orally twice weekly

Drug: ACP-211

ACP-211 300 mg

EXPERIMENTAL

ACP-211 300 mg, administered orally twice weekly

Drug: ACP-211

Placebo

PLACEBO COMPARATOR

Matching placebo, administered orally twice weekly

Drug: Placebo

Interventions

Placebo DRUG

Placebo control

Placebo

ACP-211 DRUG

ACP-211 monotherapy

ACP-211 300 mg; ACP-211 600 mg

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults ≥18 and ≤65 years of age
• Provides written informed consent
• Clinical diagnosis of MDD
• History of inadequate response to at least two antidepressants, with at least one inadequate response documented during the current episode
• Currently treated with an approved antidepressant at a stable dose prior to Screening
• MADRS total score ≥28, CGI-S score ≥4 , and QIDS-SR16 score ≥16 at Screening and Baseline
• Females of childbearing potential must have a negative pregnancy test and agree to use acceptable contraception; males must agree to use barrier protection and refrain from sperm donation

You may not qualify if:

• Current diagnosis of certain personality disorders or persistent depressive disorder
• Recent substance use disorders, excluding caffeine or nicotine
• Active suicidal risk or recent suicidal attempt
• History of schizophrenia, psychotic disorders, bipolar disorder, or MDD with psychotic features
• Current treatment requirement for PTSD, acute stress disorder, panic disorder, or OCD
• History of neuroleptic malignant syndrome, serotonin syndrome, or epilepsy (except single febrile seizure in infancy)
• Allergy or sensitivity to ketamine or esketamine
• Significant cardiovascular disease
• Positive history of hepatitis B, hepatitis C, or HIV infection
• Unstable diabetes or uncontrolled medical conditions
• Positive urine drug test for an illicit drug or cannabis
• Received neuromodulation therapies (ECT, TMS, VNS, DBS) in the current depressive episode
• Recent initiation or change in psychotherapy

Sponsors & Collaborators

• ACADIA Pharmaceuticals Inc.: lead

Study Sites (26)

University of Alabama at Birmingham

Birmingham, Alabama, 35294, United States

WITHDRAWN

Inland Psychiatric Medical Group

Chino, California, 91710, United States

RECRUITING

Behavioral Research Specialists, LLC

Glendale, California, 91107, United States

RECRUITING

Kadima Neuropsychiatry Institute

La Jolla, California, 92037, United States

RECRUITING

PNS Clinical Research LLC dba ATP Clinical Research

Orange, California, 92866, United States

RECRUITING

Mountain View Clinical Research

Denver, Colorado, 80209, United States

RECRUITING

New Access Research and Medical Services, Inc.

Fort Myers, Florida, 33901, United States

RECRUITING

The Medici Medical Research

Hollywood, Florida, 33021, United States

RECRUITING

Sandhill Research, LLC/DBA Accel Research Sites

Largo, Florida, 33777, United States

WITHDRAWN

Clinical Neuroscience Solutions, Inc.

Orlando, Florida, 32801, United States

RECRUITING

IPTB Clinical Research

Tampa, Florida, 33629, United States

RECRUITING

Neuroscience Research Institute, Inc.

West Palm Beach, Florida, 33407, United States

RECRUITING

Adams Clinical, Inc.

Watertown, Massachusetts, 02472, United States

RECRUITING

Vitalix Clinical, Inc.

Worcester, Massachusetts, 01608, United States

RECRUITING

Precise Research Centers

Flowood, Mississippi, 39232, United States

RECRUITING

St. Charles Psychiatric Associates, Inc. dba Midwest Research Group

Saint Charles, Missouri, 63304, United States

RECRUITING

Alivation Research, LLC

Lincoln, Nebraska, 68526, United States

RECRUITING

Redbird Research LLC

Las Vegas, Nevada, 89134, United States

RECRUITING

CenExel Hassman Research Institute, LLC

Marlton, New Jersey, 08053, United States

WITHDRAWN

Integrative Clinical Trials LLC

Brooklyn, New York, 11229, United States

RECRUITING

Magnolia Clinical Research, LLC

Cary, North Carolina, 27511, United States

RECRUITING

Neuro-Behavioral Clinical Research

North Canton, Ohio, 44720, United States

RECRUITING

Baylor College of Medicine

Houston, Texas, 77030, United States

RECRUITING

Dynamed Clinical Research LP d/b/a DM Clinical Research

Houston, Texas, 77081, United States

WITHDRAWN

Olympus Clinical Research, LLC

Katy, Texas, 77450, United States

RECRUITING

Family Psychiatry of The Woodlands

The Woodlands, Texas, 77381, United States

RECRUITING

MeSH Terms

Conditions

Depressive Disorder, Major; Depressive Disorder, Treatment-Resistant

Condition Hierarchy (Ancestors)

Depressive Disorder; Mood Disorders; Mental Disorders

Central Study Contacts

Sandy Filosi

CONTACT

+1(609) 250-6920; sfilosi@ACADIA-Pharm.com

Lori Lykens

CONTACT

+1(609) 250-6917; lori.lykens@acadia-pharm.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 9, 2025
• First Posted: December 16, 2025
• Study Start: November 14, 2025
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: September 14, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

US (26)