** Shares of drug developer Rezolute RZLT.O fall 91% to $1.04 premarket

** Rezolute says its experimental drug for a rare condition that causes dangerously low blood sugar failed to meet the main goal in a late-stage trial

** RZLT's drug, ersodetug, was being tested in patients with congenital hyperinsulinism, a rare disease in which beta cells in the pancreas secrete too much insulin

** Rezolute plans to meet with U.S. FDA to discuss further steps

** As of last close, stock had more than doubled YTD

(Reporting by Siddhi Mahatole)

((siddhi.mahatole@thomsonreuters.com))