A clinical trial of 5 mg psilocybin plus psychological support vs 25 mg psilocybin plus psychological support in adults with generalised anxiety disorder

Phase 2

• Conditions: Generalised anxiety disorder; Mental and Behavioural Disorders

• Registration Number: ISRCTN14487299
• Lead Sponsor: Incannex Healthcare Limited

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Results First Posted: 1900-01-01
• Study Start: 2024-09-25
• Last Update Posted: 30 September 2024
• Study Completion: 2025-10-31

Recruitment & Eligibility

• Status: Ongoing
• Sex: All
• Target Recruitment: 96

Inclusion Criteria

1. Aged 18 - 70 years 2. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)/International Classification of Diseases 11th Revision (ICD-11) defined GAD as the primary diagnosis, with severity indicated by a HAM-A score >25 3. Any sex or gender 4. Body Mass Index 18 - 35 kg/m²5. Medically suitable as determined by screening including a past medical history, family history, drug history, social history, physical examination and investigations, including an electrocardiogram (EEG) and blood tests. 6. Refrain from taking contraindicated or excluded medications, including herbal, complementary or over-the-counter medications, or have safely tapered and washed out from excluded medications in accordance with the washout period specified in the protocol.

Exclusion Criteria

1. Any clinically significant, untreated or unstable illness (e.g., hepatic, renal or cardiovascular functions) 2. Type 1 diabetes or insulin dependent type 2 diabetes 3. A diagnosis of epilepsy or at significant risk of seizures based on medical history 4. Positive urine drug test for psychoactive substances at in-clinic screening visit or dosing visits 5. Positive alcohol breathalyser test at the in-clinic screening visit or dosing visits 6. Female participants who are pregnant, breastfeeding or of childbearing potential who are unwilling or unable to use a highly effective method of contraception 7. Participation in another clinical trial of an investigational drug within 30 days or 5 half-lives of the drug (whichever is longest) prior to screening 8. Allergy, hypersensitivity or other Adverse Reaction (AR) to previous use of psilocybin, other hallucinogens, rescue medication and their excipients microcrystalline cellulose 9. Anyone with organic brain injury 10. Treatment with any other antidepressant medication other than a currently prescribed permitted SSRI which must be a stable dose (constant for at least 6 months with no plan to increase)11. Diagnosed with or having a first degree-relative family history of any of the following psychiatric disorders: schizophrenia or prodromal symptoms, any bipolar disorder, or other psychotic disorder as assessed during screening12. Any history of suicide attempts or behaviours as indicated by reporting yes on any item of the Suicide Behaviour Section of the Columbia Suicide Severity Rating Scale (C-SSRS) within the last 5 years13. History of suicidal ideation with some intent to act within the last 12 months prior to screening; the participant scores yes on item four or item five of the Suicidal Ideation section of the C-SSRS14. Judged to be of high suicide or self-harm risk following psychological assessment at screening or baseline15. Judged to be unfit for psilocybin-assisted therapy based on assessments made during psychological support sessions prior to first dosing session16. Current or recent treatment with prohibited medications 17. History of hallucinogen use disorder, or any use in the past 1 year, or >25 lifetime uses18. History of electroconvulsive treatment (ECT) or transcranial magnetic stimulation treatment, ketamine, or vagal nerve stimulation19. Current (within 12 months) alcohol or drug abuse identified as moderate or severe during screening through medical history and the Mini International Neuropsychiatric Interview (MINI) 7.0.2

Study & Design

• Study Type: Interventional
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
The efficacy of two doses of 25 mg psilocybin with psychological support versus two doses of 5 mg psilocybin with psychological support in the reduction of GAD symptoms in participants with severe GAD (who may or may not be taking concurrent selective serotonin reuptake inhibitor (SSRI) antidepressant). This will be calculated by assessing the change from baseline in Hamilton Anxiety Rating Scale (HAM-A) total score at week 8, irrespective of treatment discontinuation.