Elenbecestat,also known as E2609 is a BACE1 inhibitor. By inhibiting BACE, a key enzyme in the production of Aβ peptides, E2609 decreases the formation of these peptides which can aggregate into toxic oligomers and protofibrils and eventually form amyloid plaques in the brain. Elenbecestat has been shown to reduce Aβ levels in cerebrospinal fluid, was investigated in two global phase 3 studies in early AD.