** Shares of drug developer Rezolute RZLT.O rise 2.1% to $1.95 premarket

** Co says late-stage trial of ersodetug in congenital hyperinsulinism missed main goals but showed drug activity

** Congenital HI causes frequent severe drops in blood sugar; all 59 patients opted for extension study, RZLT says

** Some children stopped other treatments, relying only on ersodetug, co says

** Expanded access program in tumor-related HI saw 75% patients stop hospital glucose infusions, RZLT says

** Co plans FDA meeting early this year

** Ersodetug aims to block excess insulin effects; drug generally well-tolerated so far, co says

** As of last close, stock down ~19% over the past year

(Reporting by Sahil Pandey in Bengaluru)

((Sahil.Pandey@thomsonreuters.com))