Xanamem™ in Healthy Elderly Subjects

Inclusion Criteria: 1. Volunteers aged 50 to 75 years. 2. Female subjects: 1. Post-menopausal women, defined as no menses for 12 months without an alternative medical cause. If there is any concern about the menopausal status of a prospective female subject, a follicle stimulating hormone test (FSH) should be requested to confirm post-menopausal status. Post-menopausal women confirmed by FSH level \> 40 mIU/mL, will be confirmed by the local laboratory. 2. Women of childbearing potential (WOCBP) must have a negative pregnancy test. 3. Male Subjects: 1. Who are sexually active, fertile men must use highly effective methods of contraception from Day 1 until 3 months after last dose of study drug if their partners are WOCBP 2. Who are permanently sterile or have had bilateral orchiectomy or bilateral vasectomy. 4. No disease which may cause a peripheral neuropathy. 5. No evidence of alcohol abuse (defined as greater than 21 standard units per week for males and greater than 14 standard units per week for females). 6. Must provide written informed consent to participate in the study and be willing and able to participate for the maximum of 12 weeks of treatment and 16 weeks of site visits. Exclusion Criteria: 1. Clinically significant abnormalities in vital signs (blood pressure, heart rate, respiration rate and oral temperature), as determined by the investigator. 2. Body Mass Index (BMI) \> 38 kg/m2 3. Clinically significant abnormal haematology, biochemistry and urine examination values, as determined by the investigator. 4. Participants who have a history of liver disease, including fatty liver, or LFT elevations requiring investigation will not be eligible. 5. Has had a significant systemic illness or infection within the past 4 weeks prior to randomisation, as determined by the investigator. 6. Documented diagnosis of Type I or Type II diabetes. 7. Has a history of disease directly related to the hypothalamus, the pituitary and/or the adrenal glands which affects the hypothalamic-pituitary-adrenal axis function. 8. Has any uncontrolled clinical condition relating to glucose or lipid metabolism. 9. Subjects with clinical evidence of peripheral neuropathy or historical evidence of clinically significant nerve conduction abnormalities. Clinical evidence of neuropathy. 10. Clinically significant electrocardiogram (ECG) abnormalities, including QTc interval \> 450 msec (male) and \> 470 msec (female), following ECG tracings at Screening. 11. Use of any prohibited medication. 12. Participation in another clinical study of a drug or device whereby the last investigational drug/device administration is within 60 days of Screening. 13. Inability to communicate well with the investigator (i.e. language problem, non-fluent English \[as questionnaires and study drug label will be provided in English only\], poor mental development or impaired cerebral function). 14. Subject will undergo the Columbia Suicide Severity Rating Scale (CSSRS), Toronto Clinical Neuropathy Score (TCNS), EuroQoL Health Related Quality of Life - 5 Dimensions - 5 Levels (EQ-5D-5L), and Cogstate Test Battery at the indicated time-points to avoid uncontrolled learning effects. Subjects who need to perform these tests externally to and in parallel with this study will be excluded. 15. For subjects that consent, and are subsequently accepted for enrolled into, the CSF optional sub-study, subjects must have no contraindications to the lumbar puncture procedure as assessed by the Principal Investigator. Such contraindications may include uncontrolled bleeding abnormalities or skin or spine abnormalities. 16. Positive testing for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), or hepatitis C antibodies (HCV). Subjects returning a positive result will be managed by the site in line with standard care.