** Shares of drug developer Altimmune ALT.O fall 6.7% to $4.91 premarket

** Co says Chairman Jerry Durso will take over as chief executive officer on January 1, 2026, succeeding Vipin Garg, who has led the company for seven years

** Co says Durso previously led Intercept Pharmaceuticals and spent over 20 years at Sanofi SASY.PA

** Co's lead drug pemvidutide is being developed for liver disease and weight loss - ALT

** ALT expects 48-week mid-stage trial data and FDA meeting on proposed late-stage study before year-end, co says

** Up to last close, stock down ~27% YTD

(Reporting by Sahil Pandey in Bengaluru)

((Sahil.Pandey@thomsonreuters.com))