Bayer AG kicked off a global review of its $1bn (£609m) ad and media accounts in July last year.
It has consolidated the agency roster of its Bayer HealthCare business in a bid to cut costs and improve efficiencies.
The agencies won the account in a competitive bid against undisclosed agencies including incumbents including JWT, BBDO and Initiative.
Bayer AG, known as Bayer in the UK and Ireland, has almost 109,000 employees worldwide and a yearly turnover of more than €33bn (£29bn) across its three main business areas of healthcare, material science and crop science.
In Europe, where 44% of the company’s turnover resides, the UK and Ireland region is placed fifth with close to one billion euros (£860m) in sales, 1,380 employees.