Figure 3.

Example of a pharmacokinetics/pharmacodynamics model. Chemotherapy is given by bolus and is assumed to show one-compartment pharmacokinetics. Drug concentrations lead to tumor shrinkage either by inhibiting tumor proliferation or enhancing tumor death. Tumor cells upregulate biomarker synthesis. The tumor and/or biomarker can be predictors of the clinical endpoint (i.e., overall survival). Tumor picture modified from Servier Medical Art, http://www.servier.com, Creative Commons Attribution 3.0 Unported License.