** Drug developer's shares ATHX.O slump 48% to 39 cents
premarket, set to open at their lowest level since 2009
** Co says a study by Japan-based partner Healios KK
4593.T of ATHX's MultiStem cell therapy failed to meet the
main goal of a trial testing it in patients with ischemic
stroke, the most common type of stroke urn:newsml:reuters.com:*:nBw3071MQa
** Athersys and Healios plan to further analyze the data;
say data suggests the therapy has long-term impact on quality of
life
** Stock set to wipe out this week's gains of ~29% if losses
hold during regular trading; down ~16% YTD
(Reporting by Manas Mishra)
((Manas.Mishra@thomsonreuters.com;
www.twitter.com/Manaswrites15))