Dataset from A Multi-Center, Randomized, Double-Blind, Parallel Group Study With 3 Groups Receiving Placebo, 5 mg of E2020 and 10 mg of E2020

To evaluate the dose-response efficacy of E2020 (5 mg/day and 10 mg/day) versus placebo and verify superiority of E2020 to placebo in patients with severe AD using CIBIC-plus* and SIB** as the primary efficacy measures. Safety of E2020 will also be evaluated. (*for overall evalution of clinical symtoms) (**for cognitive function test)