** Shares of Neuren Pharmaceuticals NEU.AX up 16% at A$10.7, their biggest intraday percentage gain since December 18, 2023

** Stock is top gainer in the ASX 200 benchmark index .AXJO, which is up 0.6%

** The drugmaker says primary endpoints for its Phase 3 trial of NNZ-2591 in Phelan-McDermid syndrome (PMS), a genetic disorder, confirmed at a meeting with the U.S. Food and Drug Administration

** Stock down 26.5% this year, as of last close

(Reporting by Sherin Sunny in Bengaluru)

((Sherin.Sunny@thomsonreuters.com;))