Pharmacokinetics and Pharmacodynamics of Biologics: Analyzing the Unique Characteristics of Biologics in Terms of Their Absorption, Distribution, Metabolism, and Excretion

Biologics, such as monoclonal antibodies, fusion proteins or recombinant cytokines, have changed the landscape in the treatment of many diseases. On the other hand, due to their large molecule size, advanced structure, and being native like endogeneous substances, the pharmacokinetics (PK) and pharmacodynamics (PD) of these drugs are fundamentally different from those of small molecule drugs. PD of biologics are generally target driven; however, they are closely related to its PK through TMDD and immunogenicity. This review highlights that the intricate relationship of the biologic structure, its target and the patients’ immune system determines the clinical exposure, efficacy and safety of a therapeutic. Appreciation for these distinct ADME characteristics is vital for rational design, preclinical development, and clinical dosing of biologic therapeutics.