The chief executive and a lead scientist stepped down weeks after a federal grand jury filed fraud charges against a research collaborator.
Two top officials at Cassava Sciences — a small pharmaceutical company in Austin, Texas, embroiled in years of controversy over a proposed Alzheimer’s drug — have resigned.
Remi Barbier, the chairman and chief executive, stepped down on Wednesday but will remain at Cassava “without duties or responsibilities” until September, according to a company statement.
Lindsay Burns, Cassava’s chief scientist, who is married to Mr. Barbier, will also leave the company.
In June, a neuroscientist at the City College of New York, Hoau-Yan Wang, was charged with fraud by a federal grand jury for allegedly falsifying data to obtain research grants from the National Institutes of Health.
In collaboration with Dr. Burns, Dr. Wang published research studies in support of Cassava’s drug candidate for Alzheimer’s, called simufilam. It is currently in advanced trials, although more than five of Dr. Wang’s studies have been retracted or questioned by scientific journals.
Mr. Barbier, Dr. Burns and Dr. Wang could not immediately be reached for comment.
In a leaked report last fall, a City University of New York committee investigating the research faulted Dr. Burns for some of the errors discovered in the papers. Its members accused Dr. Wang of “longstanding and egregious misconduct in data management and record keeping.”
In a regulatory filing earlier this month, Cassava reported that the Securities and Exchange Commission was investigating the company and two senior employees, who were not identified.
Scientists have long criticized the methodological “oddities” in Cassava’s experiments with simufilam, citing suspicious figures in its published papers and questioning the underlying hypotheses about the drug’s mode of action.
Dr. William Hu, an Alzheimer’s disease expert at Rutgers University and early critic of Cassava’s studies, said he hoped the resignations were the first of many steps the company would take to make its research rigorous and transparent.
Still, significant work needs to be done to “undo the harms from research misconduct,” he wrote in an email.
Richard Barry, who has served on Cassava’s board of directors since 2021, has replaced Mr. Barbier as chairman of the board. The company is in the process of finding a new chief executive.
Mr. Barry said in the statement that the board was committed to testing simufilam in Alzheimer’s patients with “transparency, accountability and highest ethical business practices.”
A spokeswoman at the Food and Drug Administration said it did not discuss ongoing clinical trials or products in development.