PRWeek understands that Hanover, which has held the brief for the past four years, has been invited to pitch for the account.
Lilly UK is keen to look at more than just specialist pharmaceutical agencies for the brief, which will include government affairs, public policy, corporate and crisis comms.
A spokeswoman for Lilly said: "After four successful years with one agency Lilly has decided to go back to the market, in line with good sourcing practice.
"The process will be conducted by Corinna Peachey, head of government affairs, with pitches anticipated to take place during April."
Lilly UK is part of the world’s tenth largest pharmaceutical group. It currently operates across four sites in the UK, including Lilly’s second largest global research site in Surrey, which is home to much of the company’s research into Alzheimer’s disease.