WASHINGTON, Dec 23 (Reuters) - An indictment unsealed on

Monday charged the former chief scientific officer of

biopharmaceutical company Humanigen with engaging in

an insider trading scheme involving the firm's stock, the U.S.

Justice Department said.

Between June and August of 2021, Dale Chappell, 54, avoided

more than $38 million in losses by selling millions of shares of

Humanigen stock while in possession of material non-public

information about Humanigen's application to the Food and Drug

Administration for approval of a drug to treat COVID-19 called

Lenzilumab, the Justice Department said.