** Shares of Stoke Therapeutics Inc STOK.O slump ~27% to
$9.10 - set for worst daily pct fall on record
** Stock top loser on Nasdaq Biotechnology index .NBI
** Co says its experimental drug, STK-001, shows median
reductions in seizure frequency in an early- to mid-stage study
for treating Dravet syndrome, a severe and progressive genetic
epilepsy
** Brokerage BTIG cites safety issues with increased protein
in cerebrospinal fluid, a watery fluid that flows in and around
brain and spinal cord
** The finding could likely "slow development modestly" for
the drug, with STOK agreeing to limit dosing in two of its
extension trials - BTIG
** Including session's loss, stock down ~62% YTD
(Reporting by Raghav Mahobe)
((Raghav.Mahobe@thomsonreuters.com;))