** Shares of Neurotech International NTI.AX rise as much as 10.6% to A$0.073, posting their biggest intraday percentage gain since Aug. 14

** Stock hits its highest level since Sept. 9

** Biopharmaceutical co says the U.S. Food and Drug Administration granted the orphan drug status to its NTI164 drug, aimed at treating Rett Syndrome

** FDA grants orphan drug status to promote drug development for rare diseases affecting fewer than 200,000 people in the U.S.

** About 1.6 mln shares change hands, compared with the 30-day average volume of around 601,000

** Stock up 1.5% YTD, including session's move

(Reporting by Aaditya Govind Rao in Bengaluru)

((Aaditya.govindrao@thomsonreuters.com))