by Thomas Grillo, Real Estate Editor

Vertex is leasing space at One Marina Park Drive in advance of moving its headquarters to Fan Pier in 2013.

Vertex Pharmaceuticals is wasting no time moving to Boston’s Seaport District.

The Cambridge. Mass., firm that has a pair of buildings under construction at Fan Pier is leasing two floors at One Marina Park Drive, Joseph Fallon’s first waterfront building on what is expected to be a $3 billion neighborhood spanning nine city blocks. Vertex is temporarily leasing 56,000 square feet on the 12th and 13th floors as it builds new headquarters nearby.

“We moved a couple of our functions over there because we needed the space now as opposed to a year and a half from now,” said Zachry Barber, a Vertex spokesman. “It’s not labs, but information systems and accounting support that didn’t need to be here in Cambridge.”

Vertex (VRTX) broke ground on the two buildings in June that will total 1.1 million square feet, and will be the new home to 1,800 workers on Northern Avenue and Fan Pier Boulevard. The buildings are slated to be completed by the close of 2013.

The 18-story glass tower at One Marina Park Drive is the first of Fallon’s buildings along the waterfront. Following construction of the Vertex lab and office space, Fallon will proceed with plans for 150 condominiums, a five-star hotel and a six-acre marina and park.