The purpose of this guidance is to assist sponsors in the clinical development of drugs for the treatment of the stages of sporadic Alzheimer’s disease (AD) that occur before the onset of overt dementia (collectively referred to as early AD in this guidance, though it is recognized that patients with later stage early AD and patients with AD in the earliest stages of dementia may not differ significantly). This guidance is intended to serve as a focus for continued discussions among representatives of the Division of Neurology Products in the Center for Drug Evaluation and Research or the Office of Tissues and Advanced Therapies (OTAT) in the Center for Biologics Evaluation and Research, as appropriate, pharmaceutical sponsors, the scientific community, and the public. The design of clinical trials that are specifically focused on the treatment of patients with AD who have developed overt dementia, or any of the autosomal dominant forms of AD, is not discussed, although some of the principles in this guidance may be pertinent.