Biogen Idec to move its main offices to Weston

Biogen Idec Inc., one of Massachusetts' largest biotech companies, will move its headquarters from Cambridge to an office building being built in Weston adjacent to routes 20 and 128.

The 350,000-square-foot building, which the company plans to move into in 2010, marks the largest lease deal in Boston's suburbs this year, according to several real estate brokers. The construction project will be managed by Boston Properties Inc.

Biogen Idec said it will save money by moving management and administrative functions to the suburbs. The company is likely to pay an annual lease rate of close to $45 a square foot, according to several brokers, while space in Cambridge can cost more than $60 a square foot.