Does Psilocybin Change Synaptic Density in Amnestic Mild Cognitive Impairment

Study Overview
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Brief Summary
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The goal of this clinical trial is to investigate the effects of psilocybin on synaptic vesicular density (SVD) as measured by the positron emission tomography (PET) radiotracer, 18F-SynVesT-1, in participants with amnestic Mild Cognitive Impairment (aMCI) and healthy participants. The investigators hypothesize that SVD levels in the brain will be higher following the ingestion of psilocybin in comparison to placebo, and that increases in SVD will be associated with improvements in cognition. 60 participants (30 with aMCI, and 30 sex and age matched healthy volunteers) will: Be randomized to receive either: Two 25 mg macrodoses of psilocybin separated by 1 week. Two placebo doses separated by 1 week. Receive a baseline 18F-SynVesT-1 PET scan, clinical, and neuropsychological assessments. Receive a 18F-SynVesT-1 PET scan one week after the last dose of treatment. Receive a third PET scan at any time within 4 weeks of the screening visit to quantify tauopathy with the [18F]T807 radiotracer. Receive clinical and neuropsychological testing 1, 4, and 12 weeks after the last treatment. Researchers will compare placebo vs. experimental groups to see if psilocybin will increase SVD, and if increases in SVD are associated with cognitive improvements.

Detailed Description
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The proposed study will investigate the effects of on synaptic vesicular density (SVD) levels as measured by the positron emission tomography (PET) radiotracer, 18F-SynVesT-1, and cognition (i.e., global cognition, executive function, and memory domains) in amnestic Mild Cognitive Impairment (aMCI) and healthy participants. Participants will be randomized to receive either two 25mg doses of psilocybin separated by one week, or two placebo doses separated by one week. Brain scans, clinical, and cognitive assessments will be conducted one week before, and one week, four weeks, and 12 weeks post dosing.

Official Title
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Does Psilocybin Change Synaptic Density in the Brains of Patients With Amnestic Mild Cognitive Impairment

Conditions
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Amnestic Mild Cognitive Impairment

Intervention / Treatment
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* Drug: Psilocybin
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria The aMCI participant must meet all of the inclusion criteria to be eligible for this clinical trial: Male or female participants of any race or ethnicity Inpatients or outpatients 60 to 75 years of age (on day of randomization) Diagnosis of MCI based on DSM 5 diagnostic criteria of Minor Neurocognitive Disorder Categorization of episodic memory impairment based on scores ≥ 1.0 SD lower on any of the following measures in comparison to normative data i. Logical Memory Test (62), ii. California Verbal Learning Test (63), iii. Modified Rey-Osterrieth Complex Figure (64). Non-smoker/Non-nicotine user Montreal Cognitive Assessment (MoCA) score = < 26 and MMSE score > = 24 Capable of consenting to participate in the research study On a stable dose of medication for at least 2 months [see section 5.6], and unlikely to undergo changes in dose during the study Availability of a study partner who has regular contact with the participant Ability to read and communicate in English (with corrected vision and hearing, if needed) The Healthy Control participant must meet all of the inclusion criteria to be eligible for this clinical trial: Male or female participants of any race or ethnicity 60 to 75 years of age (on day of randomization) Does not meet SCID-5 criteria for Mild Neurocognitive Disorder, Alzheimer's disease, or other major neurocognitive disorder Non-smoker/Non-nicotine user Capable of consenting to participate in the research study On a stable dose of medication for at least 2 months [see section 5.6], and unlikely to undergo changes in dose during the study Availability of a study partner who has regular contact with the participant Ability to read and communicate in English (with corrected vision and hearing, if needed) Exclusion Criteria An individual who meets any of the following criteria will be excluded from participation in this clinical trial: Unwilling or incapable to consent to the study Unstable medical or any concomitant major medical or neurological illness, including presence of a relative or absolute contraindication to psilocybin, i.e. a drug allergy, recent stroke history, uncontrolled hypertension, low or labile blood pressure, recent myocardial infarction, cardiac arrhythmic, severe coronary artery disease, or moderate to severe renal or hepatic impairment. History of head trauma resulting in loss of consciousness > 30 minutes that required medical attention. DSM-5 diagnosis, with active symptoms in the last three months, of major depression; lifetime diagnosis of bipolar disorder; intellectual disability; Alzheimer's Disease; or a psychotic disorder DSM-5 substance dependence (except caffeine) within 12 months of entering the study Anticonvulsant, antidepressant, antipsychotic, mood stabilizer, opioid, or benzodiazepine use Lifetime use of serotonergic psychedelic drugs Positive urine drug screen at the screening visit Having taken a cognitive enhancer (acetylcholinesterase inhibitor or memantine) within the past 6 weeks Acute suicidal or homicidal ideation Receiving treatment with medications such as levetiracetam that blocks SV2a binding, and/or inability to discontinue the following medications before study drug dosing: inhibitors of uridine 5'-diphospho-glucuronosyltransferase (UGT)1A9 and (UGT)1A10, and ALDH inhibitors and alcohol dehydrogenase (ADH) inhibitors. Exceeding allowed annual radiation exposure levels (20 mSv), as outlined by our PET Centre guidelines Disorders of coagulation or taking anticoagulant medication Having completed multiple PET scans in the past, such that participation in this study would cause participant to exceed lifetime limit (8 PET scans) Metal implants or pacemaker precluding an MRI scan or other contraindications to MRI (e.g., claustrophobia) Female with childbearing potential*, pregnancy (as confirmed by a negative pregnancy test) or breastfeeding Active gender affirming hormonal treatment Any first-degree relative with a diagnosis of schizophrenia-spectrum disorder; psychotic disorder (unless substance-induced or due to a medical condition); or bipolar I or II disorder as determined by the family medical history form and discussions with the participant. Allergies to hydroxypropyl methylcellulose *A woman/female or person who is not of childbearing potential is considered to be postmenopausal after at least 12 months without menstruation. Postmenopausal is defined as 12 consecutive months with no menses without an alternative medical cause. Females/people of childbearing potential are those who have experienced menarche and do not meet the criteria for women not of childbearing potential.

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Amnestic Mild Cognitive Impairment Participants Receiving Psilocybin<br>Receiving 2 doses of 25mg of psilocybin separated by 1 week. | Drug: Psilocybin<br>* 2 macrodoses of 25mg separated by one week.<br>|
| Experimental: Healthy Participants Receiving Psilocybin<br>Receiving 2 doses of 25mg of psilocybin separated by 1 week. | Drug: Psilocybin<br>* 2 macrodoses of 25mg separated by one week.<br>|
| Placebo Comparator: Amnestic Mild Cognitive Impairment Participants Receiving Placebo<br>Receiving 2 doses of placebo separated by 1 week. | Drug: Placebo<br>* 2 doses of placebo separated by one week.<br>|
| Placebo Comparator: Healthy Participants Receiving Placebo<br>Receiving 2 doses of placebo separated by 1 week. | Drug: Placebo<br>* 2 doses of placebo separated by one week.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Synaptic Vesicular Density | Synaptic vesicular density will be assessed with PET imaging by measuring the volume of distribution (i.e., defined as the ratio of the radioligand concentration in tissue target region (CT, kBq·cm-3) to that in plasma (CP, kBq·mL-1) at equilibrium) of the [18F]SynVesT-1 radioligand in the cortical and subcortical gray matter regions in the whole brain and more specifically, the hippocampus and dorsolateral prefrontal cortex. | 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Global Cognition | The results of the neuropsychological battery will be combined to a global cognition composite score as a Z-score, the change of which will be a secondary outcome measure. Z-scores will be comprised of the Mini-Mental State Examination, Montreal Cognitive Assessment, Boston Naming Test, Category Fluency Test, Letter Fluency Test, Trail Making Test Parts A and B, Wisconsin Card Sorting Test, Stroop Neuropsychological Test, Executive Interview, Block Design Test, Clock Drawing Test, Grooved Pegboard, Digit Symbol Test, Logical Memory Test, California Verbal Learning Test, and Modified Rey-Osterrieth Complex Figure, and will be calculated based on the performance of the equated comparison group. Each domain will contribute equally to the global cognition composite score. | 3 years | 
| Memory | A memory composite Z-score will be generated using the performance on the following individual tests: Logical Memory Test, California Verbal Learning Test, and Modified Rey-Osterrieth Complex Figure. Z-scores will be calculated based on the performance of the equated comparison group, and each domain will contribute equally to the global cognition composite score. | 3 years | 
| Executive Function | An executive function composite Z-score will be generated using the performance on the following individual tests: Trail Making Test Part B, Wisconsin Card Sorting Test, Stroop Neuropsychological Screening, and the Executive Interview. Z-scores will be calculated based on the performance of the equated comparison group, and each domain will contribute equally to the global cognition composite score. | 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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psilocybin, amnestic mild cognitive impairment, SV2A, positron emission tomography, synaptic vesicular density