Cassava Sciences’ stock has dropped by more than 80% after the company revealed its lead and only investigational product simufilam did not meet the primary endpoints in a Phase III Alzheimer’s disease trial.

The Phase III ReThink-ALZ study (NCT04994483) of simufilam in mild-to-moderate Alzheimer’s disease did not meet each of the pre-specified co-primary, secondary, and exploratory biomarker endpoints. The co-primary endpoints were the change in cognition and function after one year, assessed by the Alzheimer’s Disease Assessment Scale – Cognitive Subscale (ADAS-COG12) and Alzheimer’s Disease Cooperative Study – Activities of Daily Living (ADCS-ADL) scales.

The company has also been conducting the ReFocus-ALZ trial (NCT05026177) but stated that due to the ReThink-ALZ data, it will drop the ReFocus-ALZ study and the open-label study (NCT05575076) – effectively ending all development of the drug.

The company’s stock crashed by 85% following the announcement, from a market close of $26.48 on Friday (22 November) to an open of $3.96 today (25 November)

Cassava did say that simufilam continued to demonstrate an overall favourable safety profile.

CEO Rick Barry said: “The results are disappointing for patients and their families who are living with this disease and physicians who have been looking for novel treatment options. We took careful measures to enrol patients with mild-to-moderate Alzheimer’s disease. Despite that, the loss of cognition in the placebo group was less pronounced than was previously reported in other placebo-controlled studies in Alzheimer’s disease. We are working to understand this better.”

Earlier this year, Cassava Sciences had to pay $40m to settle a US Securities and Exchange Commission (SEC) case alleging misleading data from its Phase IIb trial of simufilam. The SEC’s case was set out against the Texas-based company and two former executives, founder and former CEO, Remi Barbier, and the former Senior Vice President of Neuroscience, Dr. Lindsay Burns.

A separate SEC case was set out against Dr. Hoau-Yan Wang, an associate medical professor at the City University of New York’s (CUNY) Medical School and the therapeutic’s co-developer, for manipulating the reported clinical trial results. The SEC alleges that Wang violated antifraud provisions of the federal securities laws and that he aided and abetted Cassava’s violations of the reporting provisions.

The SEC charges are not the only difficulties faced by Cassava Sciences during its investigation of simufilam, having also launched a defamation lawsuit against ‘short sellers’ and faced a citizen petition to the US Food and Drugs Administration (FDA) to halt clinical trials of the drug.