Merck & Co has announced that its current president, Kenneth Frazier, will succeed Richard Clark, as chief executive of the US drugs giant, effective January 1.

The company said the announcement is the result of "a long-term, thoughtful succession planning process" led by Mr Clark, who  is stepping down as CEO having reached the mandatory company retirement age of 65, though he will continue as chairman. Mr Frazier has been at Merck since 1992 and lead director of the board, William Harrison, said he is "a proven executive who has played a key role in shaping Merck’s business strategy".

Mr Harrison added that thanks to the close partnership Mr Frazier and Mr Clark have developed over the last decade, "we expect this leadership transition to proceed smoothly". The new boss said that in "a period of dramatic industry change", Merck needs to focus on sustainable growth for the future. He added that "we must continue to adjust our operating model and achieve a level of transformation never before seen in our industry".