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Enrolling by invitationNCT06605105EXTENDUpdated Sep 25, 2026

Phase III Long-term Extension Trial to Assess Safety and Efficacy of CYB003 in MDD (EXTEND)

A Phase 3 interventional study of CYB003 in Major Depressive Disorder, sponsored by Cybin IRL Limited. Enrolling by invitation at 49 sites in 5 countries. Open to participants aged 18 Years to 85 Years. Per ClinicalTrials.gov, last updated 2026-09-25.

Sponsored by Cybin IRL Limited · Phase 3, Interventional, and Treatment

Updated Sep 25, 2026Primary completion movedStudy completion movedGo to Updates ↓
Phase
Phase 3
Study type
Interventional
Enrollment
468
Allocation
Not applicable
Ages
18 Years to 85 Years
Sex
All
01

Study summary

This is a long- term extension of the double-blind trials APPROACH (CYB003-002) and EMBRACE (CYB003-003). Its aim is to examine the safety and long-term efficacy of CYB003 in participants with MDD.

02

Conditions studied

  • Major Depressive Disorder

Keywords

  • Major Depressive Disorder
  • MDD
  • Psilocybin
  • Psychedelic
  • CYB003
  • Depression
  • CYB003-002
  • Long-Term Extension
  • CYB003-003
03

In context

Depressive Disorder, Major

3,041 studies on the registry are indexed under Depressive Disorder, Major; 588 are open to participants now.

This study's planned enrollment of 468 is above the median of 79 across 2,530 interventional studies indexed under Depressive Disorder, Major.

Browse Depressive Disorder, Major studies →

Lead sponsor

Cybin IRL Limited is the lead sponsor of 5 studies on the registry; 2 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 85 Years
Sexes eligible
All
Accepts healthy volunteers
No

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.

Inclusion criteria

  • Has successfully completed either CYB003-002 APPROACH or CYB003-003 EMBRACE and received both dose administrations of trial medication
  • Has continued the same antidepressant medication at the stable dose/day throughout CYB003-002 APPROACH or CYB003-003 EMBRACE
  • Has provided written , which includes compliance with the requirements and restrictions listed in the informed consent form
  • Participants capable of producing sperm must use a condom plus spermicide (where publicly available) during the trial and for 12 weeks after their final dose of IP, if their partner is a person of . In addition, their partner of childbearing potential must continue to use a highly effective method of (i.e., failure rate less than 1% when used consistently and correctly) throughout the trial until 12 weeks after the participant's final dose of IP
  • Participants of childbearing potential (POCBP) who have a partner capable of producing sperm must agree to continue to use a highly effective method of contraception (i.e., failure rate of less than 1% when used consistently and correctly) in combination with the use of a condom plus spermicide (where publicly available) during the trial and for 12 weeks after their final dose of IP
  • Female participants must have a negative pregnancy test at Baseline (the end of trial [EOT] Visit in the APPROACH or EMBRACE trial), and prior to dose administration on the dosing day

Exclusion criteria

Exclusion Criteria:

  • newly developed symptoms of schizophrenia spectrum or other psychotic disorders that manifested in the APPROACH or EMBRACE trial
  • Significant suicide risk as defined by suicidal ideation as endorsed on items 4 or 5 on the C-SSRS at Baseline OR has experienced an adverse event (AE) of suicide ideation/attempt or self-harm in CYB003-002 APPROACH OR has had a >1 point change in item 1 or 2 of the C-SSRS from Screening in CYB003-002 APPROACH
  • arrhythmia or vital sign changes noted during any of the dosing sessions in the APPROACH or EMBRACE trial
  • Presence of clinically significant abnormalities noted during the APPROACH or EMBRACE trials or at the Baseline of EXTEND
  • Sensitivity or suspected sensitivity to CYB003 noted in the APPROACH or EMBRACE trial
  • Positive urine test for drugs of abuse, or alcohol breath test prior to dosing.
  • Unwilling to consent to audio and video recording of psychological support and dosing sessions
Terms in these criteria, in plain language(5)

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.

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.

Childbearing potential

Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).

Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

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.

ECG (electrocardiogram)

A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.

05

Study design

Phase
Phase 3
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
468 participants (estimated)

Study arms

  • Experimental
    CYB003

    Initial non-responders in CYB003-002 APPROACH and CYB003-003 EMBRACE, or initial responders who later relapse will be eligible to receive 16 mg of CYB003 in 2 of 2 medicine sessions, approximately three weeks apart. If a participant relapses again, the participant may receive an additional single 16mg of CYB003 (maximum of 3 16mg doses in CYB003-004 EXTEND). Participants will continue on their current antidepressants and receive psychological support throughout the study.

    Drug: CYB003

Interventions

  • DrugCYB003

    CYB003 is a deuterated psilocin analog

06

What researchers measure

Primary outcomes

  1. Montgomery-Asberg Depression Rating Scale (MADRS)

    The MADRS is a 10-item scale with ratings based on a clinical interview which moves from broadly phrased questions about symptoms to more detailed ones allowing a precise rating of severity. The scale consists of ten items rated on a scale from 0 to 6, resulting in a total score ranging from 0 (normal / symptom absent) to 60 (severe depression).

    Time frame: Baseline, Day 28, Day 56, Day 84, Day 112, Day 140, Day 168, Day 196, Day 244, Day 252, Day 280, Day 301; additional assessments at Day -15, Day -1, Day 2, Day 10, Day 17, Day 21, Day 23, Day 31, Day 42 if non-response or relapse criteria met

07

Study locations

49 sites
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

1 registry update since Sep 25, 2026
Primary completion
Mar 15, 2028→Jun 6, 2028
Sep 25, 2026
Study completion
Mar 15, 2028→Jun 6, 2028
Sep 25, 2026
Show all 1 update
  1. Sep 25, 2026
    Primary completion Mar 15, 2028→Jun 6, 2028
    Study completion Mar 15, 2028→Jun 6, 2028

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 ↗

10

Registry details

Key details

Study ID
NCT06605105
Lead sponsor
Cybin IRL Limited
Collaborators
Worldwide Clinical Trials
Responsible party
Sponsor
First posted
Sep 20, 2024
Start date
Jul 18, 2025
Primary completion
Jun 6, 2028 (estimated)
Completion
Jun 6, 2028 (estimated)
Last update
Sep 25, 2026

Study contacts

Clinical Development
study chair · Cybin IRL Limited

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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Studies of the drug tested here: Deupsilocin

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