Effect of GET73 on MRS Measures of Central Glutamate and GABA in Individuals With Alcohol Use Disorder

This study is aimed at examining whether GET73 modulates the indices of central glutamate and
γ-aminobutyric acid (GABA) levels in recently abstinent subjects that meet Alcohol Use
Disorder (AUD) criteria, as measured by proton nuclear magnetic resonance spectroscopy
(¹H-MRS), in order to provide a human translation of the findings demonstrated in different
preclinical models, both in vitro and in vivo. In addition, the study will examine the
effects of GET73 on alcohol cue induced brain activation by using a well-established
blood-oxygen-level-dependent (BOLD) functional magnetic resonance (fMRI) paradigm in the same
individuals. In summary, the study should provide important information on (i) the potential
mechanism of action of GET73, (ii) on the brain mechanisms that would support its potential
use for reduction in craving and drinking in AUD patients, and (iii) expand data on its safe
use as a medication in heavy drinking individuals.

The enrolment period will last approximately 9 to 12 months. For each subject the study will
last 25 to 45 days.

The primary objective of the study is to evaluate whether GET73 modulates central glutamate
levels in recently abstinent individuals with AUD, using proton nuclear magnetic resonance
spectroscopy (¹H-MRS).

The secondary objectives of the study are:

1. To evaluate whether GET73 modulates central GABA levels in recently abstinent
individuals with AUD, using proton nuclear magnetic resonance spectroscopy (¹H-MRS)

2. To evaluate whether GET73 affects alcohol cue induced brain activity in reward areas of
brain.

3. To explore whether the effects of GET73 on glutamate and GABA levels are related to its
effects on alcohol cue induced brain activity.

Safety Objective To evaluate the safety profile of GET73 in individuals with AUD, comparing
Adverse Events (AEs) occurrence during GET73 treatment period vs placebo treatment period.

This is a within-subject cross-over, randomized, double-blind, placebo-controlled study.

Being a double blinded study, GET73 and placebo will be packaged identically. Both the
Investigator and the study participant will be unaware of the treatment administered.

The investigational product will be supplied to the Center packaged in "patient kits". Each
"patient kit" will be made of 2 bottles (bottle A and bottle B) each containing 20 capsules
of either GET73 or placebo.

Being a cross-over design, all participants will receive both placebo and active treatment.
The sequential order in which they will be administered to each participant will be defined
by the randomization list. The participant will always receive bottle A in the phase A of the
study and bottle B in phase B, but the content of the two bottles varies according to the
randomization list. Research personnel will be blind to the content of the bottles, i.e. what
study medication the subject is taking.

Inclusion Criteria:

1. Male participants, or females who are post-menopausal or surgically sterile.

2. Age between 21 and 40 years old (inclusive).

3. Meets Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5)
criteria for current Alcohol Use Disorder, moderate severity (4 or more criteria met)
as indicated by the Structured Clinical Interview for DSM‑5 (SCID-5-RV).

4. Reports drinking, on average, > 20 standard drinks per week in the 90 days prior to
screening evaluation, and in the last week prior to screening.

5. Must report drinking within the 48 hours prior to the first dose of medication in each
study medication period.

6. Positive for Ethyl Glucuronide (EtG) in urine (> 100 ng/ml) at screening and prior to
the first dose of medication in each study medication period.

7. Currently not engaged in, and does not want treatment for, alcohol related problems.

8. Able to read and understand questionnaires and informed consent.

Exclusion Criteria:

1. Current DSM-5 diagnosis of any other substance use disorder except Nicotine Use
Disorder.

2. Any psychoactive substance use (except marijuana and nicotine) within the last 30 days
before the screening visit, as indicated by self-report and/or urine drug screen.

3. No marijuana use within the last seven days before the screening visit, by verbal
report and negative urine drug test (< 50 ng/mL); if positive at screening, must be
negative or decreasing urine Delta9-Tetrahydrocannabinol (THC) levels (corrected for
urine creatinine level) at the second test (Day1 A-1).

4. Current DSM-5 Axis I diagnosis, including major depression, panic disorder,
obsessive-compulsive disorder, post-traumatic stress disorder, bipolar affective
disorder, schizophrenia, dissociative disorders, eating disorders, or any other
psychotic or organic mental disorder.

5. Current suicidal or homicidal ideation.

6. Need for maintenance or acute treatment with any psychoactive medication, including
antiepileptic medications.

7. Current use, or use in the past 30 days, of any medication known to affect alcohol
intake (e.g., disulfiram, naltrexone, acamprosate, topiramate).

8. History of severe alcohol withdrawal (e.g., seizure, delirium tremens), as evidenced
by self-report or a Clinical Institute Withdrawal Assessment for Alcohol-Revised
(CIWA-Ar) score > 10.

9. Clinically significant medical problems (e.g., unstable hypertension, neurological,
cardiovascular, renal, gastrointestinal, or endocrine problems) that would impair
participation or limit medication ingestion.

10. Current or past hepatocellular disease, as indicated by verbal report or elevations of
alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 300% the upper
limit of the normal range, or bilirubin > 150% the upper limit of the normal range.

11. Lack of a stable living situation.

12. Presence of ferrous metal in the body, as evidenced by metal screening and
self-report.

13. Severe claustrophobia or weight > 300 pounds that preclude placement in the MRI
scanner.

14. History of head injury with > 2 minutes of unconsciousness.

15. Participation in any behavioral and/or pharmacological study within the past 30 days;

16. Concomitant use of CYP2C19 substrates; use of CYP2C19 and CYP3A4 inhibitors or
inducers in the 14 days before dosing.