** Shares of drugmaker Biogen BIIB.O fall 5% to $170
** BIIB says it expects an acquisition-related charge of $222 million in Q4
** Co expects charge to impact Q4 net income by about $1.26 per share
** BIIB is set to report Q4 results on February 6
** Shares were up 15.1% in 2025
(Reporting by Gnaneshwar Rajan in Bengaluru)
((Gnaneshwar.Rajan@thomsonreuters.com))