** Shares of drugmaker Biogen rise 3.6% to $190.01 premarket
** Co reports Q1 adj. profit of $3.57/shr vs analysts' average estimate of $2.77/shr - LSEG data
** BIIB's quarterly revenue of $2.48 billion beats analysts' average expectation of $2.26 billion, helped by better-than-expected sales of its multiple sclerosis drugs
** Co lowers annual adjusted profit forecast to between $14.25 and $15.25 per share from a range of $15.25 to $16.25, on acquisition-related costs
** Up to last close, stock up 4.2% YTD
(Reporting by Christy Santhosh)
((Christy.Santhosh@thomsonreuters.com))