AstraZeneca’s chief executive officer David Brennan will step down on June 1st after serving in the position for six years. Chief financial officer Simon Lowth will replace Mr. Brennan on an interim basis while a permanent successor is found. Also, Leif Johansson will succeed Louis Schweitzer as non-executive chairman on June 1st, and will head the search for Mr. Brennan’s replacement.   The news follows first quarter revenue decline of 11% and a 43% drop in earnings. The company ha...