An urgent need exists to find effective treatments for Alzheimer's disease (AD) that can arrest or reverse the disease at its earliest stages. The emotional and financial burden of AD to patients, family members, and society is enormous, and is predicted to grow exponentially as the median population age increases. Current FDA-approved therapies are modestly effective at best. This study will examine a novel therapeutic approach using intranasal insulin (INI) that has shown promise in short-term clinical trials. If successful, information gained from the study has the potential to move INI forward rapidly as a therapy for AD. The study will also provide evidence for the mechanisms through which INI may produce benefits by examining key cerebral spinal fluid (CSF) biomarkers and hippocampal/entorhinal atrophy. These results will have considerable clinical and scientific significance, and provide therapeutically-relevant knowledge about insulin's effects on AD pathophysiology. Growing evidence has shown that insulin carries out multiple functions in the brain, and that insulin dysregulation may contribute to AD pathogenesis.

This study will examine the effects of intranasally-administered insulin on cognition, entorhinal cortex and hippocampal atrophy, and cerebrospinal fluid (CSF) biomarkers in amnestic mild cognitive impairment (aMCI) or mild AD. It is hypothesized that after 12 months of treatment with INI compared to placebo, subjects will improve performance on a global measure of cognition, on a memory composite and on daily function. In addition to the examination of CSF biomarkers and hippocampal and entorhinal atrophy, the study aims to examine whether baseline AD biomarker profile, gender, or Apolipoprotein epsilon 4 (APOE-ε4) allele carriage predict treatment response.

In this study, 240 people with aMCI or AD will be given either INI or placebo for 12 months, following an open-label period of 6 months where all participants will be given active drug. The study uses insulin as a therapeutic agent and intranasal administration focusing on nose to brain transport as a mode of delivery.

Inclusion Criteria:

• Fluent in English or Spanish
• Diagnosis of aMCI by Petersen criteria or probable AD by National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria
• Mini Mental State Examination (MMSE) score at screening is greater than or equal to 20
• Clinical Dementia Rating is 0.5-1 at screening
• Logical Memory is less than or equal to 8 for 16 or more years of education, less than or equal to 4 for 8-15 years of education, less than or equal to 2 for 0-7 years of education. Scores measured at screening on Delayed Paragraph Recall (Paragraph A only) from the Wechsler Memory Scale-Revised
• Able to complete baseline assessments
• Modified Hachinski score of less than or equal to 4
• A study partner able to accompany the participant to most visits and answer questions about the participant
• The study partner must have direct contact with the participant more than 2 days per week (minimum of 10 hours per week) and provide supervision of drug administration as needed
• Stable medical condition for 3 months prior to screening visit
• Stable medications for 4 weeks prior to the screening and baseline visits
• Stable use of permitted medications
• At least six years of education or work history
• Clinical laboratory values must be within normal limits or, if abnormal, must be judged to be clinically insignificant by the investigator
• Visual and auditory acuity adequate for neuropsychological testing

Exclusion Criteria:

• A diagnosis of dementia other than probable AD
• Probable AD with Down syndrome
• History of clinically significant stroke
• Current evidence or history in past two years of epilepsy, focal brain lesion, head injury with loss of consciousness or Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM IV) criteria for any major psychiatric disorder including psychosis, major depression, bipolar disorder, alcohol or substance abuse
• Sensory impairment that would preclude the participant from participating in or cooperating with the protocol
• Diabetes (type 1 or type II) requiring pharmacologic treatment (including both insulin dependent and non-insulin dependent diabetes mellitus)
• Current or past use of insulin or any other anti-diabetic medication
• Evidence of any significant clinical disorder or laboratory finding that renders the participant unsuitable for receiving investigational drug including clinically significant or unstable hematologic, hepatic, cardiovascular, pulmonary, endocrine, metabolic, renal or other systemic disease or laboratory abnormality.
• Active neoplastic disease, history of cancer five years prior to screening (history of skin melanoma or stable prostate cancer are not excluded)
• History of seizure within the past five years
• Pregnancy or possible pregnancy
• Contraindications to Lumbar Puncture (LP) procedure: prior lumbosacral spine surgery, severe degenerative joint disease or deformity of the spine, platelets is less than 100,000 or history of bleeding disorder
• Use of anticoagulants warfarin (Coumadin) and dabigatran (Pradaxa) due to LP requirement
• Contraindications for MRI (claustrophobia, craniofacial metal implants of any kind, pacemakers)
• Residence in a skilled nursing facility at screening
• Use of an investigational agent within two months or screening visit
• Regular use of narcotics, anticonvulsants, medications with significant anticholinergic activity, antiparkinsonian medications or any other exclusionary medications