Drug giant AstraZeneca (AZN) has poached Roche executive Pascal Soriot as chief executive, ending a months-long period of uncertainty after former CEO David Brennan suddenly retired at the age of 58 in April.

AstraZeneca said on Tuesday that he will take the helm and become executive director of the company’s board on Oct. 1, replacing interim CEO Simon Lowth.

Lowth, who was also among the candidates considered for the permanent position, will resume his responsibilities as chief financial officer and continue to serve as an executive director of the board.

Having first entered the pharmaceutical industry in 1986, Soriot has served as chief operating officer of Roche since 2010 where the 53-year old French national was responsible for the development, manufacturing, commercial operations and administration for the pharmaceutical business, which has 44,000 employees and recorded 2011 sales of $34 billion.

Earlier, Soriot served as CEO of Genentech where he was credited with leading the merger between the San Francisco-based biologics business and Roche.

"This is a key appointment at an important time for AstraZeneca and we are certain that Pascal's leadership qualities combined with his strategic thinking and relevant experience make him the right person to drive the company to success over the coming years,” the drug company’s chairman Leif Johansson said in a statement.

The management shake up comes months after Brennan quit at the end of May following investor anxiety over lackluster performance. The No. 2 drug maker in the U.K. by sales has been slow to bring blockbuster drugs to market as some of its biggest drugs face generic competition.

Buoyed for a while by cost-cutting initiatives, investors have become worried about its growth prospects. In July, AstraZeneca reported a 24% decline in quarter profit.

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