The pharmaceutical giant will split in two, with a new company set up with Pfizer.
It’s currently based in Brentford, with some employees moved to a temporary facility in Weybridge while the new headquarters are built.
The rest of the employees will stay on in Brentford while new, smaller offices are looked for nearby.
Brentford MP Ruth Cadbury and Hounslow Council leader Steve Curran say they’re speaking to the company to find out the impact on the area.