Alzheimer's Disease - Input of Vitamin D With mEmantine Assay

Evaluation d'Une stratégie thérapeutique d'Association médicamenteuse Pour la Prise en Charge de la Maladie d'Alzheimer et Des Maladies apparentées au Stade modéré

The purpose of this study is to compare the effect after 24 weeks of the oral intake of vitamin D3 (cholecalciferol) with the effect of a placebo on the change of cognitive performance in patients suffering from moderate Alzheimer's disease or related disorders (ADRD) and receiving memantine.

Current treatments for Alzheimer's disease and related disorders (ADRD) are symptomatic and can only temporarily slow down ADRD. Future possibilities of care could rely on multi-target drugs therapies that address simultaneously several pathophysiological processes leading to neurodegeneration. We hypothesized that the combination of memantine with vitamin D could be neuroprotective in ADRD, thereby limiting neuronal loss and cognitive decline.

The primary objective of this trial is to compare the effect after 24 weeks of the oral intake of vitamin D3 with the effect of a placebo on the evolution of cognitive performance in patients suffering from moderate ADRD and receiving memantine.

The secondary objectives of the study are as follows:

• To compare the effect after 12 weeks of the oral intake of vitamin D3 with the effect of a placebo on the evolution of cognitive performance in patients suffering from moderate ADRD and receiving memantine.
• To compare the effect after 12 and 24 weeks of the oral intake of vitamin D3 with the effect of a placebo on the evolution of functional abilities in patients suffering from moderate ADRD and receiving memantine.
• To compare the effect after 12 and 24 weeks of the oral intake of vitamin D3 with the effect of a placebo on the evolution of postural and gait performance in patients suffering from moderate ADRD and receiving memantine.
• To determine the compliance to treatment and tolerance of the oral intake of vitamin D3 in patients suffering from moderate ADRD and receiving memantine.

Inclusion Criteria:

• Age ≥ 60 years
• Diagnosis of moderate Alzheimer's disease or related disorders (DSM-IV/NINCDSADRDA) with a score of Mini-Mental State Examination (MMSE) between 10 and 20 inclusively
• To have hypovitaminosis D (i.e., serum 25-hydroxyvitamin D [25OHD]concentration < 30 ng/mL)
• To have no hypercalcemia (defined as serum calcium concentration ≥ 2,65 mmol/L)
• To have given and signed an informed consent form to participate in the trial (or informed consent form obtained from the trusted person or legal representative, as appropriate)
• To be affiliated to French Social Security

Exclusion Criteria:

• The use of standard antidementia drugs (i.e., anticholinesterasics, memantine, or vasodilatators) in the past 60 days
• Severe hepatic or renal failure
• Severe, unstable or poorly controlled medical conditions at the time of the inclusion
• Other cognitive disorders (untreated dysthyroid, deficiency in vitamin B9 or B12, chronic ongoing ethylism, history of syphilis, stroke, delirium revealed with the Confusion Assessment Method (CAM), severe depressive symptomatology (Geriatric Depression score ≥ 10/15))
• Contra-indications to memantine or vitamin D
• Enrollment in another simultaneous clinical trial