** Shares of drug developer Akero Therapeutics AKRO.O rise 19.5% to $55.55 in premarket trading
** Novo Nordisk NOVOb.CO says it will buy AKRO for $4.7 billion in cash, along with $500 million contingent upon meeting certain milestones
** U.S.-listed shares of Danish drugmaker Novo NVO.N down 1.7% premarket
** AKRO is developing a drug for fatty liver disease called metabolic dysfunction-associated steatohepatitis (MASH), which effects more than 5% of the U.S. population
** Up to last close, AKRO shares up 67% YTD
(Reporting by Puyaan Singh)
((Puyaan.Singh@thomsonreuters.com;))