Slow subject enrollment

This study is designed to evaluate the safety, tolerability and pharmacokinetics of multiple doses of ABT-957 in subjects with mild to moderate Alzheimer's disease.

Inclusion Criteria:

• Meets the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria for probable Alzheimer's disease (AD);
• Has a Mini-Mental State Examination total score of 16 to 26;
• Has a Modified Hachinski Ischemia Scale score of ≤ 4;
• Is taking a stable dose of donepezil, galantamine or rivastigmine for at least 30 days;
• Has had a computerized tomography or magnetic resonance imaging. The scan must not show evidence for an alternative etiology for dementia;
• With the exception of a diagnosis of mild-to-moderate AD and the presence of stable medical conditions, is in general good health.

Exclusion Criteria:

• Positive screen for drugs of abuse, alcohol or cotinine;
• Females must not have positive results for pregnancy;
• Focal neurological signs on examination;
• Has a clinically significant abnormal value, in serum chemistry, hematology or urinalysis;
• History of any significant neurologic disease other than AD;
• History of head trauma, motor vehicle accident, concussion.