** Shares of drugmaker Rhythm Pharmaceuticals RYTM.O rise 15.14% to $75 premarket

** Co tested its experimental drug bivamelagon in a mid-stage trial of 28 patients aged 12 years or older

** The drug showed reductions in body mass index at 14 weeks of treatment in patients with acquired hypothalamic obesity

** Co plans to seek input from U.S. and EU regulatory authorities on a late-stage trial design

** Acquired hypothalamic obesity is a rare form of obesity that occurs following damage to the hypothalamic region of the brain

** Up to last close, stock up ~16% YTD

(Reporting by Sriparna Roy in Bengaluru)

((Sriparna.Roy@thomsonreuters.com;))