Global biopharmaceutical company AstraZeneca has announced that CEO and board member David Brennan has decided to retire, effective June 1, 2012.

Following Brennan's decision, the board has asked executive director and CFO Simon Lowth to act as interim CEO from June 1, 2012, until a permanent successor is in place. Julie Brown, vice president of group finance, will become interim CFO on the same date.

"After more than six years as chief executive officer of this great company I have decided that now is the right time to step down and allow a new leader to take the reins,” said Brennan. “The board's decision to appoint Simon Lowth as interim chief executive officer has my full support and I am confident that AstraZeneca will continue to have a positive impact on the lives of patients around the world and by doing so will deliver real value to our shareholders."

Brennan was appointed to his current role in January 2006 and is one of the longest serving chief executives in the pharmaceutical sector.