By Ben Hirschler

LONDON, April 25 (Reuters) - AstraZeneca's move to the English university city of Cambridge will cost more and take longer than initially expected, following increased expenditure on new technology and equipment.

Investment in Cambridge, where AstraZeneca is building a strategic R&D centre and global corporate headquarters, is now expected to be more than 500 million pounds ($640 million), the drugmaker said on Tuesday.

Staff are set to start moving into the new building from 2018, with the site fully operational in 2019. Back in 2013, when the scheme was first unveiled, the cost was put at 330 million pounds and the aim was to establish the centre by 2016.

For Chief Executive Pascal Soriot, the new site on the Cambridge Biomedical Campus symbolizes his desire to create a science-led company with uniquely close ties to academia. The University of Cambridge has a global reputation for life sciences and the town is a hub for biotech start-ups.

More than 2,000 AstraZeneca staff are already located in the Cambridge area.

Speaking at a "topping out" ceremony to mark completion of the new building's concrete frame, Soriot said the site "embodies AstraZeneca's innovation-led transformation".

The premises will feature open laboratories with transparent glass walls and will also house a joint research centre with the state-backed Medical Research Council, where partnering scientists will work side-by-side with AstraZeneca researchers.

The centre will be AstraZeneca's largest site globally for oncology research, as well as housing scientists focused on respiratory, cardiovascular and metabolic diseases.

The shift to Cambridge coincides with an overhaul of the group's drug pipeline, where investor attention is focused on forthcoming data from a pivotal lung cancer trial. Initial results from the so-called MYSTIC immunotherapy study are expected mid-year.

Three years after spurning a takeover bid from Pfizer , AstraZeneca is going through the biggest "cliff" of patent expiries the drug industry has ever seen, wiping off more than half of its sales - or $17 billion - in 2011-2017.

Soriot is mapping a new route to profits by focusing on specialty drugs such as cancer treatments. ($1 = 0.7806 pounds) (Editing by Louise Heavens)