Avagacestat (BMS-708163) is an investigational compound developed primarily for the treatment of Alzheimer's disease. It functions as a selective gamma-secretase inhibitor, which plays a role in reducing the production of amyloid-beta peptides. These peptides are known to accumulate in the brains of Alzheimer's patients, forming plaques that disrupt neuronal function and contribute to disease progression. By targeting gamma-secretase, avagacestat aims to lower levels of amyloid-beta, particularly the more toxic Aβ42 form, thereby potentially slowing cognitive decline. The compound was evaluated in clinical trials to assess its safety, tolerability, and efficacy in early and mild-to-moderate Alzheimer’s disease. However, development was discontinued due to lack of significant clinical benefit and concerns over side effects, including skin cancer and gastrointestinal toxicity. Despite this, avagacestat contributed valuable insights into the challenges of targeting amyloid pathways and informed the design of future Alzheimer's therapies. It remains a reference compound in preclinical research related to gamma-secretase modulation and amyloid pathology.