** Shares of Prothena Corp PRTA.O soar 19.8% to $52.80 on
a report that the biotech firm is preparing for a potential sale
** Stock on track for biggest single-day percentage gain in
over five months, if gains hold
** Co is exploring options that may include a sale or
partnership; could attract interest from larger drugmakers -
Bloomberg News report
** The drugmaker's experimental treatment for Alzheimers's
disease is in early-stage trials; results expected by end of
year
** Report says deliberations are in early-stage
** Co has a market cap of $2.36 bln as of Monday - LSEG data
** Prothena said it does not comment on market speculation,
when contacted by Reuters
** Including session's gains, stock down 12.2% YTD
(Reporting by Purvi Agarwal in Bengaluru)
((Purvi.Agarwal@thomsonreuters.com))