Dosage and Efficacy of Probucol-induced apoE to Negate Cognitive Deterioration (DEPEND)
Dementia of the Alzheimer Type, Age-related Cognitive Decline, Mild Cognitive Impairment Due to Alzheimer Disease
About this trial
This is an interventional prevention trial for Dementia of the Alzheimer Type focused on measuring apolipoprotein E, Alzheimer, pre-clinical, pre-symptomatic, dose-finding, prevention
Eligibility Criteria
Inclusion Criteria:
- Family history of one or more parents or multiple siblings who developed Alzheimer-like dementia, as established by review of history and/or medical records, and by responses to a brief questionnaire describing characteristics of the relatives' condition
- Aged 60+. May be aged 55-59 only if at least one parent or sibling experienced onset of Alzheimer's dementia at an age no more than 15 years beyond the prospective participant's current age
- At least six years of formal education
- Sufficient fluency in spoken and written English and/or French to participate in study visits and in psychometric testing
- A collateral respondent available to provide information on the cognitive and health status of the participant, and to assist with monitoring of study interventions, if needed
- Willingness to undergo four lumbar punctures for collection of CSF
- Affirmation of prior informed consent to undergo genetic testing for APOE and other known or suspected AD risk factors
- Ability and intention to participate in study visits per protocol, in the opinion of a study physician
- Willingness to limit use of over-the-counter or prescription medicines (e.g., tricyclic antidepressants, anti-histamines) known to prolong QTc interval, or to potentiate the tendency of probucol to prolong this interval, in the opinion of a study physician
- If on a statin or other lipid lowering drug that, in the opinion of a study physician, can safely be co-administered with probucol, willingness to remain on a stable dose of this medication during the entire trial period.
- Provision of informed consent for this trial.
Exclusion Criteria:
- Known or identified cognitive disorder diagnosed previously by a physician, psychologist, nurse-clinician, or other health care provider, or by StoP-AD staff
- Past or present use of a commercially available acetyl-cholinesterase inhibitor including tacrine, donepezil, rivastigmine, or galantamine
- Past or present use of memantine or other approved cognitive enhancement prescription agent
- History of heart disease, myocardial infarction or documented acute coronary syndrome, or arrhythmia (including atrial fibrillation)
- Corrected QT interval using Bazett's formula (QTcB) interval > 450 msec for males or 470 msec for females as detected by EKG and confirmed by consultant cardiologist
- Clinically significant hypertension, anemia, liver disease, or kidney disease, in opinion of a study physician (participants with treated hypertension who are normotensive as a result of intervention may be enrolled.)
- Concurrent use of over-the-counter or prescription medicines (e.g., tricyclic antidepressants, anti-histamines) known to prolong QTc interval, or to potentiate the tendency of probucol to prolong this interval, in the opinion of a study physician
- Any inflammatory or chronic pain condition that necessitates regular use of opiates (e.g., oxycodone, hydrocodone, tramadol, meperidine, hydromorphone), or NSAIDs (more than 4 doses / week)
- Current plasma creatinine > 132 mmol/l (1.5 mg/dl)
- Current alcohol, barbiturate or benzodiazepine abuse or dependence (in opinion of study physician)
- Any other medical condition that, in the opinion of a study physician, makes it inadvisable for the participant to be assigned to regular dosage of probucol
- Enrolment in any trial or experimental protocol that, in the opinion of a study physician, is likely to interfere with PREVENT-AD or any of its derivative protocols including this one
- Any other condition that, in the opinion of a study physician, makes it medically inappropriate for the participant to enroll in the program
Sites / Locations
- Douglas Hospital Research Centre
Arms of the Study
Arm 1
Experimental
Single arm
All subjects will receive probucol, starting with a fixed dose of 600 mg daily following the evening meal. The variable plasma concentrations achieved and the resulting modification in concentration of CSF apoE will suggest an ideal range of plasma concentrations for use of the drug as an inducer of increased availability of apoE in the CSF. The known dose-proportionality of the drug in plasma will then be used to estimate an ideal individualized dose for each participant. The effects of such individualized dosage will be tested over 1 year of follow-up observations, searching for treatment effects on CSF apoE and for evidence of other treatment effects, particularly including adverse effects.