** Shares of biotech Moderna MRNA.O fall 3% to $46.70 in morning trading

** The U.S. FDA says it will hold a meeting of outside experts to review MRNA's experimental flu shot

** Advisory committee meeting is scheduled for June 18

** FDA had reversed course to review co's amended application for the mRNA-based seasonal flu vaccine after initially rejecting the submission

** Agency's decision is expected by August 5

** Including session's move, stock up 58.2% YTD