Review ArticleAlzheimer Disease Clinical Trials Targeting Amyloid Lessons Learned From Success in Mice and Failure in HumansReiss, Allison B. MD*; Montufar, Natalie BA*; DeLeon, Joshua MD*; Pinkhasov, Aaron MD*; Gomolin, Irving H. MD*; Glass, Amy D. PhD*; Arain, Hirra A. BS*; Stecker, Mark M. MD, PhD†Author Information *Department of Medicine, NYU Long Island School of Medicine, Mineola, NY †Fresno Center for Medical Education and Research, Department of Medicine, University of California—San Francisco, Fresno, CA Supported by The Alzheimer’s Foundation of America and the following donor fund: The Herb and Evelyn Abrams Family Amyloid Research Fund (A.B.R.). The authors declare no conflict of interest. Correspondence to: Allison B. Reiss, MD, NYU Long Island School of Medicine, 101 Mineola Boulevard, Mineola, NY 11501. E-mail: [email protected]. The Neurologist: March 2021 - Volume 26 - Issue 2 - p 52-61 doi: 10.1097/NRL.0000000000000320 Buy Metrics Abstract Background: The goal of slowing or halting the development of Alzheimer disease (AD) has resulted in the huge allocation of resources by academic institutions and pharmaceutical companies to the development of new treatments. The etiology of AD is elusive, but the aggregation of amyloid-β and tau peptide and oxidative processes are considered critical pathologic mechanisms. The failure of drugs with multiple mechanisms to meet efficacy outcomes has caused several companies to decide not to pursue further AD studies and has left the field essentially where it has been for the past 15 years. Efforts are underway to develop biomarkers for detection and monitoring of AD using genetic, imaging, and biochemical technology, but this is of minimal use if no intervention can be offered. Review Summary: In this review, we consider the natural progression of AD and how it continues despite present attempts to modify the amyloid-related machinery to alter the disease trajectory. We describe the mechanisms and approaches to AD treatment targeting amyloid, including both passive and active immunotherapy as well as inhibitors of enzymes in the amyloidogenic pathway. Conclusion: Lessons learned from clinical trials of amyloid reduction strategies may prove crucial for the leap forward toward novel therapeutic targets to treat AD. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.