Vertex may be closer to Boston move

Vertex Pharmaceuticals Inc. has taken another step toward moving its Cambridge headquarters to Boston.

The fast-growing biotechnology company signed a nonbinding letter of intent to lease at least 500,000 square feet of office and laboratory space in Boston's Fan Pier neighborhood on the South Boston waterfront, the Boston Business Journal reported on its Website.

The buildings are being developed by Joe Fallon, and the letter of intent could make it easier for him to line up financing for the project. A Fallon spokesman could not be reached for comment. But Vertex hasn't signed a lease and could still go elsewhere. "It is way too early to say Vertex is coming to Boston,'' said Dorothy Joyce, a spokeswoman for Boston Mayor Thomas M. Menino.

Vertex spokesman Zachry Barber said the company couldn't comment on the letter of intent. "We remain engaged in a process to determine how best to accommodate our real estate needs and are not commenting on that process," he said.

The company has previously said it was looking at various options as it expands, including staying in Cambridge, moving to a nearby city or even moving out of state.

A Patrick administration spokeswoman couldn't immediately be reached for comment. But Governor Deval Patrick has personally urged Vertex on numerous occasions to remain in Massachusetts.

Vertex, which is developing a highly anticipated drug to treat hepatitis C, has more than 1,200 employees, including 950 in Massachusetts. The company is planning to report its second-quarter earnings this afternoon. (By Todd Wallack, Globe staff)