This 100-page research note provides a comprehensive overview of the state of play of treatment for Alzheimer's disease. Its focus is on similarities in the mechanisms of action of five treatment candidates owned by four different biotech companies that have reported stabilization or improvement in cognition in Alzheimer's patients, their differences and the respective risks for each of the companies.The companies that are the focus of this research are BioVie, INmune Bio, Cassava Sciences and Coya Therapeutics. Their respective drug candidates are NE3107, XPro, simufilam and Coya 301 / Coya 302. Destined to investors and the wider public, the author believes this is the most comprehensive overview given so far on these four companies.