** Shares of Dyne Therapeutics DYN.O fall ~11.5% to $25
premarket
** Co says it is appointing John Cox as its new chief
executive officer
** Cox will succeed Joshua Brumm, who will serve as an
advisor to Dyne after stepping down - DYNE
** Dyne says Cox has served as CEO of Biogen's rare disease
spinoff Bioverativ and most recently was CEO of private co
Repertoire Immune Medicines
** The muscle disease specialist's shares had doubled in
January after its experimental therapy for a muscle-wasting
disorder showed promise in a small, early-stage trial
** Up to last close, stock has more than doubled in the last
12 months
(Reporting by Christy Santhosh)
((Christy.Santhosh@thomsonreuters.com))