Biogen shares dropped as much as 4.6% on news of his appointment Monday.
Biogen, the U.S. drug maker focused on neurological, autoimmune and rare diseases, said on Monday it had appointed its chief commercial officer, Michel Vounatsos, as chief executive officer, ending a five-month search.
Biogen shares fell on the news of his appointment, which is effective as of Jan. 6. Vounatsos succeeds CEO George Scangos, who announced last July he would retire after leading the company since 2010.
