** Shares of Avidity Biosciences RNA.O jump 43.6% to $70.60 premarket
** Stock set to open at a record high, if gains hold
** Swiss drugmaker Novartis NOVN.S to buy U.S. biotech firm for about $12 billion
** Avidity stockholders will receive $72 per share in cash, representing a premium of 46% to stock's closing price on Friday
** Prior to closing deal, Avidity will separate its early-stage precision cardiology programs into a new company, which is expected to be publicly traded
** All 17 brokerages rate RNA stock "buy" or higher; median price at $65, as per LSEG data
** RNA up 69% YTD vs NASDAQ Biotechnology index's .NBI 20.3% gain
(Reporting by Utkarsh Tushar Hathi in Bengaluru)
((utkarshtushar.hathi@thomsonreuters.com))