Rationale and design of a multicenter study of selegiline and alpha-tocopherol in the treatment of Alzheimer disease using novel clinical outcomes. Alzheimer's Disease Cooperative Study

Abstract

This report describes the rationale and design of a clinical trial using selegiline (10 mg/day) and alpha-tocopherol (2,000 IU/day) to slow the progression of dementia in Alzheimer disease (AD). This study was developed by the Alzheimer's Disease Cooperative Study (ADCS), a consortium of clinical research centers actively involved in AD research. The major goal of the consortium is to design and conduct clinical investigations leading to the development of treatments for AD. This study uses a randomized double-blind, placebo-controlled, 2 x 2 factorial, parallel group design to test two drugs for the treatment of AD. The primary outcome of the study is the time to reach any one of the following four endpoints: death, institutionalization, loss of two of three basic activities of daily living, and progression of Clinical Dementia Rating (CDR) stage from 2 to 3. Patients with moderately severe disease (CDR = 2) were enrolled and evaluated 10 times over a period of 2 years to determine if these agents reduce the time to reach any endpoint. A database from the Consortium to Establish a Registry for Alzheimer's Disease indicated adequate power analyses to observe a treatment effect on this clinically meaningful outcome measure. Recruitment and baseline characteristics of the population are provided. The rationale for the choice of a factorial design, the use of a novel, clinically meaningful endpoint, and the selection of a cohort of patients with AD of moderate severity are discussed.