** Stem cell therapy developer's shares ATHX.O up 21.51
pct at $3.40, third among top advancers in premarket across U.S.
exchanges
** Shares set to open at their highest since March 2015, if
gains hold
** Athersys expands existing collaboration with Japanese
cell therapy products developer Healios KK 4593.T into
additional therapeutic areas urn:newsml:reuters.com:*:nGNXL17Wh
** Healios gets rights to develop and commercialize ATHX's
stem cell therapy MultiStem for treatment of acute respiratory
distress syndrome, and also for additional indications; ATHX
gets $20 mln in fees
** ATHX may also get up to $360 mln in aggregate development
and commercialization milestones
** Healios had previously made ~$21 million equity
investment in ATHX, mid-March, for the development and
commercialization of MultiStem urn:newsml:reuters.com:*:nL3N1QV3XO
** As of Wednesday's close, ATHX shares scaled 54 pct this
year
(Reporting by Shreyashi Sanyal in Bengaluru)
((RM: Shreyashi.Sanyal.thomsonreuters.com@reuters.net))