** ASX-listed shares of medical device-maker ResMed RMD.AX fall as much as 7.3% to A$36.02, their lowest level since April 24
** Stock of co, which is involved in treating sleep apnea, COPD and other chronic diseases, marks biggest intraday pct loss since March 12
** RMD is the top pct loser on the ASX 200 benchmark
** Rival Apnimed, which is unlisted, announced positive topline results in first phase 3 clinical trial of AD109, an oral pill for obstructive sleep apnea
** Stock up 0.6% YTD
(Reporting by Sneha Kumar in Bengaluru)
((Sneha.kumar@thomsonreuters.com;))