ZymoGenetics, the area's largest independent biotech, named chief scientific officer Douglas Williams as its new president, the company said Monday.

Former president Bruce Carter will retain his role as chief executive and chairman of the board. Other executives were also promoted: James Johnson, chief financial officer and treasurer, has been named executive vice president, and Darren R. Hamby becomes senior vice president for human resources.

The changes come as ZymoGenetics "grows and gets bigger," Carter told The Seattle Times.

Carter will now "have the time to focus" on the commercialization of rThrombin, a product for surgical bleeding control expected to launch in October, and in the company's long-term strategy, he said.