Alzheimer's disease (AD) is an age-related degenerative disorder of the brain, characterized by progressive decline in cognitive function and ability to perform activities of daily living, and ultimately can lead to death due to complications of the disease. AD is thought to be caused by an excess of A-Beta amyloid, a sticky protein in the brain that forms amyloid plaques. Treatments that slow the synthesis or deposition of A-Beta amyloid, or that increase clearance, might be expected to slow the progression of AD.

LY2062430 (solanezumab) is a humanized anti-A Beta peptide immunoglobulin G-1 (IgG1) monoclonal antibody being developed for the treatment of AD. The primary hypothesis being tested is that LY2062430 will slow cognitive and functional decline in AD as compared with placebo. Each patient's participation will last approximately 19 months. Patients taking approved AD medications may participate in this study and continue taking these medications during the study.

Inclusion Criteria:

• Meets criteria for mild to moderate Alzheimer's Disease (AD) with Mini-Mental State Examination score of 16 through 26 at screening
• Modified Hachinski Ischemia Scale score of less than or equal to 4
• Geriatric Depression Scale score of less than or equal to 6
• A magnetic resonance imaging (MRI) or computerized tomography (CT) scan in the last 2 years with no findings inconsistent with a diagnosis of AD
• If receiving concurrent AD treatment, must be on the medication for at least 4 months at a stable dose for at least 2 months prior to randomization

Exclusion Criteria:

• Has serious or unstable illness(es)
• Does not have a reliable caregiver who is in frequent contact with patient (at least 10 hours per week)
• Meets National Institute of Neurological Disorders and Stroke/Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS/AIREN) criteria for vascular dementia
• Does not have good venous access, such that intravenous (IV) drug delivery would be difficult
• Has had multiple episodes of head trauma or history within the last 5 years of a serious infectious disease affecting the brain
• Has allergies to humanized monoclonal antibodies
• Chronic alcohol and/or drug abuse within the past 5 years
• Has any contraindications for MRI studies
• Requires treatment with another monoclonal antibody