The purpose of this study is to determine in a 12-week treatment study if MEM 1003 is a safe and effective treatment for patients with mild to moderate Alzheimer's disease.

Alzheimer's disease is the leading cause of dementia and one of the most common diseases of the aging population. It is a chronic brain disease that involves gradual memory loss, decline in the ability to perform routine tasks, disorientation, difficulty in learning, loss of language skills, impairment of judgment, and personality changes in affected individuals. The neurodegenerative nature of the disease eventually leads to the failure of other organ systems and death.

Perturbations in calcium homeostasis in the central nervous system, such as those associated with Alzheimer's disease and aging as well as stroke and head trauma can result in an increase in intracellular levels of calcium (Ca2+). Increased levels of Ca2+ may lead to cellular dysregulation and cell death. The role of calcium in these neurodegenerative processes led to the hypothesis that controlling calcium levels may be beneficial, particularly where progressive neuronal damage results in cognitive dysfunction and memory loss.

MEM 1003 is the (+)-enantiomer of a dihydropyridine that has been optimized for central nervous system activity. It inhibits L-type Ca2+ channels and within the anticipated human dosing range has more benign cardiovascular effects than other DHP L-Type calcium channel modulators.

Inclusion Criteria:

• standardized MMSE Score of 10 to 24 points
• diagnosis of probable Alzheimer's disease
• magnetic resonance imaging or computed tomography examination compatible with AD
• modified Hachinski Ischemia Score of less than or equal to 4
• currently receiving no AD therapy or currently receiving donepezil, rivastigmine, or galantamine

Exclusion criteria:

• head injury associated with cognitive impairment
• history of vascular dementia stroke, transient cerebral ischemic episodes, major depression, major psychotic disorder, or symptomatic postural hypotension
• treatment for Alzheimer's disease other than donepezil, rivastigmine, or galantamine; tacrine is not permitted in the last 30 days or memantine in the last 90 days
• treatment with calcium channel blockers or any investigational medications within the prior 30 days