Shares of Cassava Sciences Inc. plunged 24.2% in premarket trading on Wednesday after Reuters reported that the Justice Department is investigating whether the company manipulated clinical data for a still-investigational Alzheimer’s disease drug, citing people familiar with the matter. Cassava put out a news release in December that said a scientific journal did not find evidence of manipulated data in a 2005 paper authored by the company’s scientists after short sellers alleged data manipulation in some previously published research. Cassava’s Alzheimer’s drug candidate is currently in Phase 3 clinical trials. The company did not immediately respond to a request for comment. Cassava’s stock has tumbled 50.3% this year, while the S&P 500 has declined 16.7%.

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