** Drug developer Sage Therapeutics' shares fall 4.3% to $4.70 premarket ** Company says it will stop further development of its experimental drug, dalzanemdor, after it did not meet main goal in a mid-stage trial
** Sage was testing the drug to treat cognitive impairment associated with Huntington's disease, which causes nerve cells in the brain to decay over time
** 2 of 20 brokerages rate the stock "buy", 16 "hold" and 2 "sell"; median PT $9 - LSEG
** As of last close, stock down 77.3% YTD
(Reporting by Kamal Choudhury in Bengaluru) ((Kamal.Choudhury@thomsonreuters.com))