Alzheimer's Disease - Input of Vitamin D With mEmantine Assay (AD-IDEA)

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.

All participants start the treatment with memantine on the first day of the study and immediately start vitamin D supplementation.

Participants in this arm start the treatment with memantine in the same way as the 'Intervention' group. They also immediately start Vitamin D placebo administered at the same pace.

Memantine is administered to all participants according to the usual strategy, with upward titration of 5 mg per week during the first three weeks to reduce the risk of side effects. The final dosage is 20 mg per day, with no subsequent modification of dosage or specialty during the trial.

Subjects receive Vitamin D supplementation (cholecalciferol 100,000 IU, drinking solution, 2 mL vial) at a rate of 1 drinking vial of 100,000 IU cholecalciferol every month. In brief, the total dose is 600,000 IU over the duration of the study starting with one vial at the time of inclusion, then at week(W) 4, W8, W12, W16 and W20. The dose of vitamin D supplementation will not be adjusted except in case of an adverse event such as hypercalcemia. In this case, vitamin D supplementation is stopped and the participant is released prematurely from the study.

Subjects receive Vitamin D placebo (drinking solution, 2mL vial) at a rate of 1 drinking vial every month. In brief, the subjects start with one vial at the time of inclusion, then at week(W)4, W8, W12, W16 and W20. The placebo drinking solution contains all the excipients present in the Vitamin D vial.

Cognitive performance is measured with Alzheimer's Disease Assessment Scale-cognition score (ADAS-cog)

These outcomes are assessed together with the serum concentrations of 25OHD, calcium and parathyroid hormone.

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

Annweiler C, Beauchet O. Possibility of a new anti-alzheimer's disease pharmaceutical composition combining memantine and vitamin D. Drugs Aging. 2012 Feb 1;29(2):81-91. doi: 10.2165/11597550-000000000-00000.

Annweiler C, Fantino B, Parot-Schinkel E, Thiery S, Gautier J, Beauchet O. Alzheimer's disease--input of vitamin D with mEmantine assay (AD-IDEA trial): study protocol for a randomized controlled trial. Trials. 2011 Oct 20;12:230. doi: 10.1186/1745-6215-12-230.