** Shares of Traws Pharma TRAW.O down 20.81% at $1.58 premarket

** Co says the U.S. FDA placed on clinical hold its investigational new drug application for tivoxavir marboxil, a single oral tablet for prevention of seasonal influenza

** Adds that FDA flagged concerns "with the mutagenicity data package" for drug in application

** Also says it filed the application to allow the government's biomedical research unit to fully review its bid for inclusion in the strategic stockpile for avian‑flu treatment

** Clinical hold does not directly impact ongoing and planned studies outside of the United States; working to mitigate issue in clinical development plan - TRAW

** TRAW shares up 74.3% YTD

(Reporting by Gnaneshwar Rajan in Bengaluru)

((Gnaneshwar.Rajan@thomsonreuters.com;))