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Safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and effects of intravenous (IV) and intramuscular (IM) dosing of SPL028 (deuterated DMT fumarate [a serotonergic psychedelic]) in healthy volunteers and participants with major depressive disorder (MDD)

A phase 1, double-blind study investigating the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of intravenous (IV) and intramuscular (IM) dosing of SPL028 (deuterated DMT fumarate [a serotonergic psychedelic]) in healthy participants (Part A); followed by an open-label study investigating the safety, tolerability, pharmacokinetics, pharmacodynamics and exploratory efficacy of SPL028 in participants with major depressive disorder (Part B)

Status
Active, not recruiting
Phases
Phase 1
Study type
Interventional
Source
ISRCTN
Registry ID
ISRCTN42293056
Enrollment
40
Registered
2024-08-13
Start date
2023-01-16
Completion date
Unknown
Last updated
2025-01-06

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Healthy participants Not Applicable

Interventions

Part A: Part A of this study is a Phase 1, double-blind study to determine the safety, tolerability, PK profile and PD of IV and IM dosing of SPL028 in healthy participants. It is planned to enrol up
they will not be given placebo in both Treatment Periods. In each of Cohorts 3-5, 6 participants will receive the study drug and 2 participants will receive placebo. Part B: This was an optional part

Sponsors

Cybin UK Ltd
Lead Sponsor

Eligibility

Sex/Gender
All

Inclusion criteria

Inclusion criteria: 1. Participant has a body mass index (BMI) of 18 to 33.9 kg/m², inclusive. 2. Participant has not been administered any Monoamine Oxidase (MAO) inhibitor class antidepressants for at least 3 months prior to Screening. 3. Registered with a GP in the UK. 4. Sufficient intelligence to understand the nature of the trial and any hazards of participation in it. Ability to communicate satisfactorily with the Investigator and therapist team to participate in, and comply with the requirements of, the entire trial. 5. Healthy as determined by a responsible physician, based on no clinically significant findings from medical evaluation including medical history, a physical examination, concomitant medication, vital signs, 12-lead ECG and clinical laboratory evaluations (including haematology, coagulation, biochemistry and urinalysis) at the Screening visit and admission. 6. Agree to follow the contraception requirements of the trial. 7. Willing to be contacted by email and telephone and video call. 8. Proficient in reading and writing English sufficient to complete questionnaires. 9. Willing to give written consent to have data entered into The Over-volunteering Prevention System. 10. Provision of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form, after having the opportunity to discuss the trial with the Investigator or their delegate. Part A – Cohorts 1 and 2 Only 1. Healthy participants aged 25 to 65 years, inclusive. 2. Healthy psychedelic-experienced participants (psychedelic-experienced is defined as having at least two previous experiences, with breakthrough [see Section 3.3.1 for definition], of serotonergic psychedelic drugs, including but not limited to: DMT, ayahausca, LSD, LSA [morning glory seeds], 2,5-Dimethoxy-4-iodoamphetamine [DOI], dimethoxybromoamphetamine [DOB], 2,5-Dimethoxy-4 chloroamphetamine [DOC], 2-(4-bromo-2,5-dimethoxyphenyl)ethanamine [2CB], 1-(2,5-Dimethoxy-4-ethylphenyl)-2-aminoethane [2CE], mescaline, peyote, san pedro, ibogaine and psilocybin [including mushroom species containing psilocybin]). 3. No psychedelic drug use 6 weeks prior to dosing (excluding the study drug) until the end of the study. Part A – Cohorts 3, 4 and 5 Only 1. Healthy participants aged 25 to 65 years, inclusive. 2. Healthy participants with little to no psychedelic experience (defined as a maximum of two previous experiences that weren’t breakthrough, including but not limited to: DMT, ayahausca, LSD, LSA, DOI, DOB, DOC, 2CB, 2CE, mescaline, peyote, san pedro, ibogaine and psilocybin [including mushroom species containing psilocybin]). 3. No psychedelic drug use 6 months prior to dosing (excluding the study drug) until the end of the study.

Exclusion criteria

Exclusion criteria: Psychiatric Exclusion Criteria Participants with any of the following will be excluded from study participation: 1. Participant meets the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) criteria for substance abuse disorder, as assessed by the Mini International Neuropsychiatric Interview (MINI) Version 7.0.2 at Screening, or a positive urine drugs of abuse result at Screening or Day -1 (excluding cannabis which is permitted to be taken up to 24 hours before each trial visit, but which may be detected in urine). Repeat tests may be considered by the Investigator with justification. 2. Current or clinically relevant history of a psychotic disorder, including schizophrenia, psychosis, bipolar disorder, delusional disorder, paranoid personality disorder, schizoaffective disorder, borderline personality disorder, emotionally unstable personality disorder or panic disorder, as assessed by a structured clinical interview (including the MINI Version 7.0.2). 3. In first-degree relatives, a clinically relevant history of a psychotic disorder, including schizophrenia, psychosis, bipolar disorder, delusional disorder, paranoid personality disorder or schizoaffective disorder. Significant history of mania (as determined by the Investigator and medical records, in agreement with the Sponsor’s Medical Monitor). 4. Significant history of mania (as determined by the Investigator and medical records, in agreement with the Sponsor’s Medical Monitor). 5. Psychiatric condition judged to be incompatible with establishment of rapport with the therapy team and/or safe exposure to DMT, based on the Investigator’s clinical evaluation (e.g., borderline personality disorder). 6. Significant suicide risk, as defined by: 6.1. Suicidal ideation as endorsed on the BSS within 1 year prior to Screening or on Day -1, or 6.2. Suicidal behaviours within 1 year prior to Screening, or 6.3. History of serious suicide attempts in lifetime (i.e., those that require hospitalisation), or 6.4. Clinical assessment of significant suicide risk during Participant interview General Medical Exclusion Criteria Participants with any of the following will be excluded from study participation: 1. Clinically relevant history of abnormal physical or mental health interfering with the study as determined by medical history and physical examinations obtained during Screening, as judged by the Investigator (including [but not limited to]: neurological, psychiatric, endocrine, thyroid, cardiovascular, respiratory, GI, hepatic, haematological, musculoskeletal, immunological, renal, connective tissue diseases or disorders or any other medically relevant condition as judged by the Investigator). 2. Clinically relevant abnormal laboratory results (including hepatic and renal panels, complete blood count, chemistry panel and urinalysis), 12-lead ECG and vital signs, or physical findings at Screening and/or Day -1 as judged by the Investigator, that in the Investigator’s opinion may constitute a risk for an individual who is exposed to DMT. In case of uncertain or questionable results, tests performed during Screening may be repeated to confirm eligibility or judged to be clinically irrelevant for healthy participants. 3. Any acute condition or infection, or history of chronic illness or condition, that could interfere with, or for which the treatment might interfere with, the conduct of the study as outlined in this Protocol, or that would, in the opinion of the Investi

Design outcomes

Primary

MeasureTime frame
Safety and tolerability of SPL028 with support therapy following intravenous (IV) and intramuscular (IM) administration: 1. Safety will be evaluated by monitoring of adverse events (AEs), vital signs (blood pressure [BP], heart rate [HR] and temperature), 12-lead electrocardiogram (ECG) evaluations cannulation and injection site reactions, clinical laboratory assessments (haematology, clinical chemistry, coagulation and urinalysis) and physical examination findings. Baseline to Day 29 2. Suicidal ideation and behaviour will be evaluated using the Beck Scale for Suicidal Ideation (BSS). Baseline to Day 15 3. Tolerability will be evaluated by reviewing the therapist’s notes that document the subjective psychedelic effects and a tolerability assessment. At Day 1

Secondary

MeasureTime frame
1. PK IV using frequent blood sampling from pre-dose to 2 hours post-dose 2. PK IM using frequent blood sampling from pre-dose to 4 hours post-dose 3. PD – Wellbeing using The Warwick-Edinburgh Mental Well-being Scale (WEMWBS) on day -1 and at Day 15 4. PD – Anxiety using Spielberger’s State-Trait Anxiety Inventory Trait Subscale (STAI-T) on day -1 and at Day 15 5. PD – Post-treatment changes using Post-Treatment Changes Scale (PTCS) and The Psychedelic Predictor Scale at Day 15 6. PD – Subjective experience using Mystical Experience Questionnaire (MEQ), The Ego Dissolution Inventory (EDI), Emotional Breakthrough Inventory (EBI), Challenging Experience Questionnaire (CEQ) at Day 1 post-dose (before the first post-dose integration session) and using Intensity Rating Visual Analogue Scale (IRVAS) at Day 1 post-dose (after the first post-dose integration session) 7. PD – arrythmia measured using continuous 12-lead Holter electrocardiogram (ECG) on Day -1, pre-dose, during-dosing, until at least 10 min after the 4 h (IV) and 5h (IM) post-dose PK blood sample, and at Day 2. 8. The degree of blinding measured using a Blinding Integrity Questionnaire (BIQ) at Day 1 post-dose, prior to the Integrations session

Countries

England, United Kingdom

Contacts

Public ContactEzanul Wahab
info@macplc.com+44 800 633 5507

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 4, 2026