Cassava Sciences said that its drug did not significantly reduce cognitive decline in 1,900 people with mild to moderate Alzheimer’s disease.

(Reuters) -Cassava Sciences said on Monday it will stop all trials of its Alzheimer's disease drug after it failed a late-stage study, sending shares of the drug developer plummeting more than 80% before the bell.

Cassava Sciences’ phase 3 Alzheimer’s disease trial has missed its co-primary endpoints. With the study also missing secondary and exploratory biomarker endpoints, the biotech has pulled the plug on another phase 3 trial and an open-label extension.