Alexion Pharmaceuticals Inc. has announced its relocating its headquarters from New Haven to Boston.

In what it calls a plan to "re-align the global organization with its refocused corporate strategy," the company also announced today it is cutting 20-percent of its workforce.

According to the company, about 400 jobs will move to Boston by the middle of next year. The company will maintain a research and development center in New Haven with about 450 employees.

Alexion says the moves are expected to save about $270 million annually, and allow the reinvestment of about $100 million a year into research and development.

Chief Executive Officer Ludwig Hantson says the moves "will create a leaner organization with greater financial flexibility."

Alexion developed Soliris, a high-priced treatment for two rare genetic disorders.