(Bloomberg) -- AstraZeneca Plc’s chief medical officer is leaving, adding to a wave of high-level defections amid a reorganization of the U.K. drugmaker.

Sean Bohen, who’s also executive vice president for global medicines development, will part ways with the Cambridge, England-based company after it completes the transition to a new structure unveiled last week, according to an email from a spokesman.

AstraZeneca’s research and development arm has been among Big Pharma’s most efficient and prolific, with the company gaining approvals for numerous new drugs while selling off rights to aging products. Bohen will follow Bahija Jallal, former head of the Medimmune unit, and ex-product and portfolio strategy chief Mark Mallon, who left in the last few weeks.

Bohen’s future has recently been a subject of speculation, with Tim Anderson, an analyst with Wolfe Research, saying in a note to clients Friday that he was likely to leave. While the spate of departures doesn’t appear to foretell an R&D crisis or imminent bad news at Astra, “the optics of having respected leaders leave a company are never good,” the analyst said.

The company wouldn’t answer questions about the impact of the defections or say whether more were imminent.

Chief Executive Officer Pascal Soriot said in an interview last week that Astra will reorganize its drug R&D into two major units that will shepherd products from discovery all the way through human trials. Veteran research head Mene Pangalos will head cardiovascular and respiratory drugs, while new hire Jose Baselga, who left his previous position as physician-in-chief of the Memorial Sloan Kettering Cancer Center under a cloud, will oversee oncology.

Two years ago, Soriot himself was reported to be considering a move to Teva Pharmaceutical Industries Ltd. The CEO said last week that he remains committed to AstraZeneca and that the move to restructure the company demonstrates it.

Cancer Focus

“I would not reorganize the company if I thought in the next 12 to 18 months I was going to leave,” he said. “I would give this to my successor to do.”

The reorganization is aimed at increasing the company’s speed and focus in oncology, which is rapidly becoming the most lucrative area in the industry. Global cancer drug sales likely exceeded $100 billion in 2017, according to Bloomberg Intelligence.

The importance of cancer drugs has increased the value of executives like Bohen who have experience in the area. Gilead Sciences Inc. signaled its push into the field by poaching veteran Daniel O’Day from Roche Holding AG, the world’s biggest maker of oncology drugs, to become CEO and chairman of the biotechnology company.

Astra’s track record of bringing new drugs to market -- led by Tagrisso and Lynparza for cancer -- has given the company solid growth prospects after patent expirations on blockbusters such as Seroquel. Its executives have been targeted for picking off since U.K. rival GlaxoSmithKline Plc hired away Luke Miels to become president of global pharmaceuticals in 2017.

Other Astra executives are leaving for plum biotech jobs: Jallal became CEO of Immunocore Ltd., while Mallon is now chief of Ironwood Pharmaceuticals Inc.

Ludovic Helfgott, who headed diabetes and kidney treatments at Astra, left in October and is going to drugmaker Novo Nordisk A/S, where he’ll be executive vice president of the biopharm unit.

To contact the reporter on this story: John Lauerman in London at jlauerman@bloomberg.net

To contact the editor responsible for this story: Eric Pfanner at epfanner1@bloomberg.net

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