Daniel O’Day has been appointed chairman and chief executive officer, Gilead Sciences, effective March 1, 2019. Mr. O’Day is currently chief executive officer of Roche Pharmaceuticals. He has held the position since 2012, and prior to that led Roche Diagnostics. He succeeds John F. Milligan, PhD, who will step down from his role as president and chief executive officer at the end of 2018. Also, Gregg Alton has been named interim chief executive officer from January 1, 2019 until March 1, 2019...