It makes no difference to Alexandria Real Estate Equities, the owner and developer of the building. Pfizer CEO Joel Marcus told analysts last week that Pfizer signed a 15-year lease that provides no "outs" until year 10. "They are looking to sublease and we understand they may be very close to achieving their goal, but we still have Pfizer cash and Pfizer credit on the lease for a 10 year period," Marcus said.

Pfizer's Biotherapeutics and Bioinnovation Center was scheduled to occupy the upper west-wing floors of 455 Mission Bay in early 2010, which is when it is scheduled for completion. The company reportedly held an option to lease an additional 50,000-square-foot in the east wing. Those plans changed abruptly after it acquired Madison, NJ-based Wyeth Pharmaceuticals earlier this year

A Pfizer spokeswoman told GlobeSt.com in July that the global real estate portfolio that comes with Wyeth played into the company's decision not to relocate its biotheraputics research operation to Mission Bay. Also taken into account were overall occupancy costs and the disruption to science caused by the relocation of a research operation, she said.

As a result, Pfizer's existing biotheraputics research operation will remain in South San Francisco at 259 East Grand Ave., the home of Rinat Neuroscience, a company it acquired in 2006, and the man slated to head the new center, Bay Area biotech entrepreneur Corey Goodman, is no longer with the company.

Pfizer leasehold is in 455 Mission Bay. Pfizer's Biotherapeutics and Bioinnovation Center was scheduled to occupy the upper west-wing floors of 455 Mission Bay in early 2010, which is when it is scheduled for completion. Pfizer's potential subtenant is "something arguably much better than Pfizer," Newsom said at the conference center, declining to elaborate.