Safety, Tolerability, and Preliminary Efficacy of Psilocybin Oral Solution in Adults With Generalized Anxiety Disorder

Inclusion Criteria:

1. Must provide written informed consent prior to the initiation of anyprotocol-specific procedures.

2. Male and female adults, between 18 and 60 years of age, inclusive.

3. Meets DSM-V criteria for a primary diagnosis of GAD at Screening (duration ofdiagnosis ≥1 year, based on self-report), confirmed using the MINI.

4. Clinician-rated GAD-7 score ≥14 at Screening (Visit 1).

5. Clinician-rated HAM-A score ≥14 at Screening (Visit1).

6. Females must be non-pregnant and non-lactating and must fulfil at least one of thefollowing:

• Be surgically sterile for a minimum of 6 months (achieved through hysterectomy,oophorectomy, or bilateral salpingectomy; note that tubal ligation is notconsidered a method of permanent sterilization).

• Post-menopausal for a minimum of 1 year (confirmed by follicle-stimulatinghormone test).

• Agree to avoid pregnancy and use a medically acceptable method of contraceptionwith male sexual partners from at least 30 days prior to the study until 30days after the study has ended (last study procedure).

• Medically acceptable methods of contraception include any of the following:

• Double-barrier methods (e.g., male condom, spermicide with diaphragm orspermicide with cervical cap)

• Oral contraceptives; hormonal patch, implant or injection; or hormonal ornon-hormonal intrauterine device. The male partner should use, at all times, amale condom with spermicide, should the female Patient choose to use any ofthese methods

• Complete abstinence, should it be in line with the Patient's preferred andusual lifestyle.

7. Males who are able to father children must agree to use medically acceptable methodsof contraception during the study and for 30 days after the last study drugadministration. If a patient's partner should become pregnant during hisparticipation in the study and for 30 days after he has completed his last studydrug administration, the patient must inform study staff immediately. Medicallyacceptable methods of contraception include:

• Using a condom with a female partner of child-bearing potential who is usingoral contraceptives; hormonal patch, implant or injection; hormonal ornon-hormonal intrauterine device; or diaphragm or cervical cap with spermicide

• Complete abstinence, should it be in line with the patient's preferred andusual lifestyle.

8. Males must refrain from sperm donation from clinic admission to at least 30 daysafter the last dose of study drug.

9. Must be able to speak, read, and understand English sufficiently to allow completionof all study assessments.

10. Must be willing to comply with the requirements and restrictions of the study.

Exclusion Criteria:

1. Personal history of schizophrenia, bipolar affective disorder, delusional disorder,paranoid disorder, moderate or severe panic disorder, moderate or severe socialanxiety disorder, schizoaffective disorder, moderate or severe obsessive-compulsivedisorder, anorexia nervosa, bulimia nervosa, moderate or severe post-traumaticstress disorder (as assessed by the IES-R), moderate or severe personality disorder (Cluster B and Cluster C only), moderate or severe MDD (as assessed by the MINI andtotal scores on the MADRS > 19).

2. History or presence of any clinically significant cardiac, endocrine, hematologic,hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic,renal, or other disease at Screening, which, in the opinion of the investigator,would jeopardize the safety of the patient or the validity of the study results.

3. Recently initiated non-pharmacological treatment (e.g., Cognitive BehavioralTherapy, psychotherapy) with a psychologist or health care professional (i.e., <4weeks prior to Screening). Patients who began a stable non-pharmacological treatmentregimen >4 weeks prior to Screening will be permitted. Patients currently stable ontreatment will not be permitted to modify or introduce new elements to theirexisting treatment regimen while enrolled in the study.

4. Currently taking pharmacological treatment for GAD or depressive symptoms on a dailybasis as outlined in Table 2. Patients who discontinue pharmacological treatmentwithin a minimum of 4 weeks or more of baseline will be permitted to enroll in thestudy. Sporadic, prn use of anxiolytics will be permitted; however, patients will berequired to document all medication use prior to study enrollment (See Section 9.7).

5. Clinically significant abnormality on ECG, including a QT interval corrected forheart rate (Bazett; QTcB interval) of >440 milliseconds in males and >460milliseconds in females.

6. History of allergies to the investigational product or excipients.

7. History of seizures, family history of seizures, history of head trauma, history ofneurosurgery, or close family history of idiopathic generalized epilepsy or othercongenital epilepsies.

8. Positive for hepatitis B virus surface antigen, hepatitis C virus antibody, or humanimmunodeficiency virus (HIV) antibody.

9. Positive urine drug screen at Screening , inclusive of cannabis use at a rate above 0.5g/day or 3g/week;

• Abstinence commitment clause: Patients who use cannabis at below or up to thefrequency/amount listed above may be allowed to participate if they are willingand able to discontinue use for the duration of the study period withoutexperiencing withdrawal symptoms.

10. Current or history of moderate or severe drug or alcohol use disorder (excludingcaffeine and nicotine) within the past 2 years, or lifetime history of participationin a drug rehabilitation program (other than treatment for smoking cessation).

11. Has used CNS drugs with perception-altering properties (e.g., ketamine, lysergicacid diethylamide [LSD], phencyclidine [PCP], 3,4 methylenedioxymethamphetamine [MDMA], mescaline, psilocybin, tryptamine derivatives, or ring-substitutedamphetamines with perception-altering effects) on more than 1 occasion fortherapeutic or non-therapeutic purposes (i.e., for psychoactive effects) within thepast 6 months. History of single or episodic use will not be consideredexclusionary.

12. History of suicidal ideation in the past 12 months or active/current suicidality,based on C-SSRS results.

13. Is currently using an investigational drug or device or has used such in the 30 daysprior to receiving study drug.

14. Female patient is pregnant or breastfeeding.

15. Patient, in the investigator's opinion, is unsuitable for clinical studyparticipation.

Criteria for Randomization into the Double-Blind Treatment Phase

1. Minimum 50% reduction in GAD-7 score from Open-Label Baseline Visit (Visit 1) toDouble-Blind Baseline Visit