• ADAS-Cog
  
• ADCS-CGIC
  

• 3MS
  
• ADCS-ADL
  
• NPI
  
• GDS
  
• QOL
  
• ADCS Pharmacoeconomic Assessment
  
• Plasma and CSF anti-amyloid antibody titers
  
• Plasma and CSF beta amyloid levels
  
• FDG Cerebral Glucose Utilization
  
• PIB Cerebral Amyloid Distribution (PET)
  
• PK11195 Microglial Activation (PET)
  
• Adverse Event Frequency and Severity
  

Abnormal processing of the beta-amyloid protein is thought to be an early and causative event in the pathogenesis of Alzheimer's disease (AD). Immunotherapy targeting beta amyloid (Aβ) has demonstrated a remarkable capacity to arrest and even reverse elements of AD brain pathology. Intravenous Immunoglobulin (IVIg) is a medication obtained from the pooled plasma of healthy human blood donors that contains natural anti-amyloid antibodies and exhibits potent central nervous system anti-inflammatory properties. IVIg has been FDA-approved and used for more than 25 years in patients with a variety of immune deficiency and autoimmune diseases and has an established safety record, but is not FDA-approved for the treatment of AD.

A total of 24 patients, males and females 50 years of age and older, with mild to moderate Alzheimer's disease (AD) will be enrolled in this research study. To be eligible, patients must meet the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for probable AD. After written informed consent is obtained, subjects will go through a screening process to determine if he or she meets the inclusion criteria. Screening procedures include medical history, blood and urine tests, neurologic exam, chest x-ray and MRI. Women who want to take part in this study must either be post-menopausal, surgically sterilized or agree to avoid becoming pregnant during the entire period of their participation in this study.

To be eligible for this research study, patients must be taking a stable dose of an approved AD medication for at least 3 months prior to entering this study or be unable to take these medications. The design of this protocol is that of an add-on study and we will recommend patients continue to take any FDA-approved AD medications they are taking at study entry.

Subjects' participation in the study will last approximately 13 months, including screening and baseline procedures, treatment with study drug and a follow-up visit 1 ½ months after finishing treatment, plus a visit for blood tests 6 months after the last infusion in the study. This research study requires that the patient have another person, (such as a spouse, child, other relative, close friend, aide or other professional caregiver), who will accompany the patient to each clinic visit.

Subjects will be randomized to a treatment group for 6 months of infusions of IVIg or placebo followed by a six-week "washout" period during which they will not receive study drug. The treatment groups compare different doses and frequencies of treatment. Patients will have a 33% chance of receiving placebo.

Blood will be obtained from subjects every two weeks and examined in our research laboratories to obtain more information about IVIg's biological effects. Cerebrospinal fluid will be obtained by lumbar puncture twice over the course of the study for the same purpose. Patients will be asked to allow a portion of a blood sample to be used for Apolipoprotein E (APOE) testing and banked for genetic research testing related to AD and aging, but do not have to participate in the testing or allow their blood sample to be stored in order to take part in the study.

Cognitive testing will be carried out at baseline and every three months oer a period of one year. A 4-6 week washout period is anticipate at the end of the study, followed by reeat cognitive testing. Results of cognitive testing will constitute the primary endpoint of this study. Positron Emission Tomography (PET) imaging substudies will be performed at two time points during the study. Safety laboratories and assessments will be carried out at regular intervals. Subjects will not be responsible for any research study-related costs but will be responsible for the costs of evaluations required to establish diagnosis.