Deferiprone to Delay Dementia (The 3D Study)

1. Able to provide written informed consent in accordance with federal, local and institutional guidelines. For subjects unable to provide written consent, consent will be provided by the Person Responsible per local regulations.

2. Age ≥65 years, or ≥55 years if they have been diagnosed by a psychiatrist or neurologist with dementia, or if they have a validated previous positive amyloid PET scan.

3. Weight between 40 and 120 kg

4. Have an available caregiver

5. Have ≥ 6 years of education (any) and able to follow testing instructions.

6. Have visual and auditory acuity sufficient to perform neuropsychological testing.

7. Have prior evidence of AD pathology, by a positive amyloid assessment, or amyloid PET scan.

8. Demonstrate abnormal memory function in the last 6 months or at screening: International Shopping List Test (ISLT) >1.5 SD below the age adjusted mean

9. Subjective or clinical history of retrospective cognitive decline ≥6 months

10. Evidence of mild symptomatology, as defined by a screening MMSE score of ≥ 20 points

11. Meet National Institute on Ageing/Alzheimer's Association Diagnostic Guidelines for Alzheimer's Disease (NIAAA) research criteria for mAD or pAD

12. If receiving medication for symptomatic AD, have a stable dosing regimen for 3 months prior to screening.

13. Females of Child Bearing Potential (FCBP) must have confirmed negative serum pregnancy test within the 21 days prior to randomization.

14. FCBP and male subjects who are sexually active with FCBP must agree to use highly effective contraception during the study and until 90 days after the last dose of treatment (for sexually active male participants whose partners are FCBP) or until 30 days after the last dose of treatment (for women of childbearing potential participants)

1. Clinically significant haematological disorder, including moderate or severe anaemia (blood haemoglobin <110 g/L, WHO definition)

2. Iron deficiency (serum ferritin < 10 ng/mL)

3. Clinically significant abnormal haematological results (sufficiently outside the normal range to warrant further investigation). Mild anaemia (haemoglobin ≥110 g/L) is not an exclusion.

4. Clinically significant abnormal renal or liver function results (sufficiently outside the normal range to warrant further investigation)

5. Presence of non-AD condition that may affect cognition, such as but not limited to Parkinson's Disease (PD), normal pressure hydrocephalus, sleep apnoea requiring O2 treatment

6. Clinically evident vascular disease that could potentially affect the brain, such as but not limited to significant carotid or vertebral stenosis, aortic aneurysm, cerebral haemorrhage

7. History of any stroke in the past 2 years, or transient ischemic attack within the last 6 months

8. History of persistent neurologic deficit, intracranial tumour or structural brain damage

9. History of infection that could affect brain function (eg HIV and syphilis)

10. Autoimmune disorders that potentially cause progressive neurologic disease with associated cognitive deficits, such as but not limited to multiple sclerosis, lupus

11. Major psychiatric illness (depression is acceptable if patient has not had an episode within the past year or is considered in remission or controlled by treatment)

12. A history of relapsing neutropenia.

13. Presence of agranulocytosis or with a history of agranulocytosis

14. Known hypersensitivity to DFP or excipients.

15. Alcohol and/or substance abuse

16. MRI evidence of clinically-significant cerebrovascular pathology. Focal white matter lesions, ≤ 2 lacunar infarcts in non-critical sites and other minor pathology assessed by the investigator to not be causing the current cognitive impairment, will not lead to exclusion.

17. Active major medical illness

18. FCBP not using adequate method of contraception or who is pregnant or nursing

19. Inability to provide informed consent

20. Participation in another clinical trial within 3 months prior to inclusion in the study

21. Subjects for whom MRI is contraindicated (severe claustrophobia, pacemaker, incompatible surgical material, unmovable electronic pump implant)

22. Negative amyloid PET scan or CSF in the last 2 years.

23. Hospital Anxiety and Depression Scale (scores > 8/21 are disqualified).

24. Subject cannot commit to regular blood tests with the interval between tests not exceeding 10 days from the scheduled visit for the duration of the study.

25. Subject has planned surgery which does not permit regular blood tests with the interval between tests not exceeding 10 days from the scheduled visit.