The pharmacology of therapeutic monoclonal antibodies (mAbs) is complex and dependant on both the structure of the antibody and the physiological system that it targets. Patient exposure and responses to mAbs are also related to the structure and activity of mAbs. Furthermore, the pharmacokinetics and pharmacodynamics of mAbs are often inter-related. Pharmacokinetic and pharmacodynamic modeling have been used to elucidate or support the mechanisms of antibodies in development and can be used to identify appropriate dose regimens. Consequently, pharmacokinetic and pharmacodynamic modeling often plays a larger role during the development of therapeutic mAbs than for small molecules.