All companies involved in developing therapeutics leverage the use of vendors to support their drug development needs -whether it is in planning and executing clinical trials or manufacturing drug substance or product, the use of vendors is core to their success.  Selecting the right vendor and then  effectively overseeing their activities is an important responsibility that falls to the sponsor. Demonstration of effective vendor oversight is a regulatory requirement - regulators expect to see processes and supporting documentation demonstrating how companies oversee their vendors.