A Phase I, Randomized, Double-Blind, Placebo-Controlled, Two-Part, Multiple Ascending Dose Study to Assess the Safety, Tolerability, Pharmacokinetics and Effect on Biomarkers of AZD3293 in Plasma and Cerebrospinal Fluid in Healthy Male and Non-Fertile Female Elderly Volunteers and in Mild-to-Moderate Alzheimer Disease Patients