Mr Tulstrup takes over as CEO from Keith McCullagh, who is retiring but will remain a member of the board of directors of the company.
Prior to joining Merck, Mr Tulstrup held management positions with Sandoz (now Novartis) in Basel, Switzerland and Abbott Laboratories in Copenhagen, Denmark.
Flemming Ornskov, chairman of the board at Santaris Pharma, said: “I am delighted to welcome Soren Tulstrup as our new CEO. We are very pleased to have an executive of Soren’s calibre joining Santaris Pharma to lead the company through the next important stages of growth.”