Changes in CSF parameters (Abeta40, Abeta42, T-tau, P-tau, NFL, YKL-40, neurogranin, BACE1 concentration) characteristic for AD pathophysiology from baseline and compared to placebo at

+48 weekstreatment differences within subgroups will be performed

Inclusion Criteria:

• Patients aged 60 to 85 years, inclusive, with a NIA-AA diagnosis of mild cognitive impairment (MCI) due to AD or early stage mild dementia due to AD. AD diagnosis should be made by an appropriately qualified medical specialist and AD pathology should be confirmed by either:
  1. Historical records of amyloid CSF assessment or
  2. Historical records of amyloid PET scan or
  3. If neither historical records are available, then AD pathological diagnosis confirmation should be offered at screening:

  i. CSF collection or ii. Amyloid PET iii. Past medical records of MRI or CT are optional.

• Mini Mental State Examination (MMSE) score between 20-28, inclusive.
• Free Recall score ≤17 or Total Recall score <40 on the Free and Cued Selective Reminding Test (FCSRT).
• Participants are either outpatients, or residents of an assisted-living facility. Participant has a designated study partner, who spends at least 10hrs per week with the participant, in order that assessments e.g. carer burden instruments are completed with true knowledge of the participant.
• No suicidal ideation of type 4 or 5 in the Columbia Suicide Severity Rating Scale (C-SSRS) in the past 3 months (i.e. active suicidal thought(s) with intent but without specific plan, or active suicidal thought(s) with plan and intent) OR suicidal behavior in the past 2 years (i.e. actual attempt, interrupted attempt, aborted attempt, or preparatory acts or behavior).
• Confirmation from the participant that, if of childbearing potential is not pregnant through urine pregnancy testing.

Exclusion Criteria:

• Patients who have a progressive medical or neurological condition that in the opinion of the investigator would interfere with the conduct of the study. Exception: If diagnosed with seizures, must be on stable anti-seizure medication for at least 3 months prior to screening.
• Current clinically significant systemic illness that is likely to result in deterioration of the patient's condition or affect the patient's safety during the study.
• History or clinically evident stroke or clinically significant carotid or vertebrobasilar stenosis or plaque.
• History of neurologic (e.g. stroke, traumatic brain injury) or psychiatric condition that the investigator deems may interfere with interpretability of data.
• History of untreated thyroid disorder, Type 1 diabetes, and insulin dependent or uncontrolled Type II diabetes, as determined by the investigator (e.g. non-insulin-controlled Type II diabetes, whose HbA1c value is higher than 8.0%).
• Body Mass Index (BMI) > 30.
• History of clinical hepatic dysfunction.
• Current symptomatic and unstable/uncontrolled gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological, hematological or hormonal disorders.
• Indication of liver disease, defined by serum levels of ALT (SGPT), AST (SGOT), or alkaline phosphatase above 3x upper limit of normal (ULN) as determined during screening.
• Significant history of drug addiction (with the exception of nicotine dependence) or abuse (including alcohol, as defined in DSM-V or in the opinion of the investigator) within the last two years prior to informed consent, or a positive urine drug screen for cocaine, opioid, phencyclidine (PCP), amphetamine or marijuana at screening. Prescription medication yielding a positive drug screen are acceptable except for tricyclic antidepressants (e.g. Amitriptyline, Amoxapine, Desipramine, (Norpramin) Doxepin, Imipramine (Tofranil), Nortriptyline (Pamelor), Protriptyline (Vivactil), Trimipramine (Surmontil)).
• Clinically significant infection within the last 30 days prior screening (e.g., chronic persistent or acute infection, urinary tract infections (UTI)).
• Treatment with immunosuppressive medications (e.g., systemic corticosteroids) within the last 90 days (topical and nasal corticosteroids and inhaled corticosteroids for asthma are permitted) or chemotherapeutic agents for malignancy within the last 3 years.
• Myocardial infarction within the last year.
• History of cancer within the last 3 years, with the exception of basal cell carcinoma and non-metastatic squamous cell carcinoma of the skin and prostate cancer with currently normal PSA.
• Other clinically significant abnormality on physical, neurological, laboratory, or electrocardiogram (ECG) examination (e.g., atrial fibrillation) that could compromise the study or be detrimental to the participant.
• Hemoglobin < 11 g/dL.
• Have any contraindication to MRI scanning, including cardiac pacemaker/defibrillator, ferromagnetic metal implants (e.g., in skull and cardiac devices or severe claustrophobia).
• Smoking > 1 pack of cigarettes per day (as assessed for the 30 days prior to screening).
• Alcohol use of more than 2 drinks per day.
• Current use of over-the-counter (OTC) supplements or nutraceuticals unless they are on stable dose for at least 3 months prior to screening and are documented in the eCRF.
• Use of over the counter (OTC) or prescription medication for sleep on 2 or more occasions per week.
• Being treated with psychoactive medications on a stable dose for less than 3 month.
• Any prior exposure to ANAVEX2-73.
• Individuals enrolled in previous AD clinical trial involving an investigational drug treatment less than 3 months ago (longer than 3 month ago allowed).
• Any known hypersensitivity to any of the excipients contained in the study drug formulation.
• Any other criteria (such as a clinically significant screening blood test result), which in the opinion of the Investigator causes the participant not to qualify for the study.
• Evidence of cerebrovascular dementia with a Hachinski score of 4 or more.