Following completion of the acquisition, the combined company will operate under the name Chiltern and will gain global reach mostly in China and Japan.
It will also provide new service offerings for medical devices and diagnostics, clinical analytics and clinical supplies.
Chiltern CEO Dr Jim Esinhart said: "This is a direct response to client demand for a clinical research partner that can provide scientific and operating strengths globally, in a responsive and flexible way.
"This transaction will bring together more than 3,700 people in more than 45 countries dedicated to the philosophy of "Designed Around You."
The transaction, which is subject to customary regulatory and closing conditions, is expected to be completed within the next several weeks.
The two organizations will follow antitrust guidelines and continue to function as separate and independent entities until the acquisition is approved.