Incorporating Pharmacokinetic/Pharmacodynamic Modeling in Drug Development—Are We Ready?

There is a growing awareness that simply saying that a drug is effective (ie, the p value is less than 0.05) is not adequate information for the optimal treatment of patients. It is increasingly appreciated that drugs act differently in different populations, for example the elderly, and at different doses or serum concentrations. These relationships should be defined to optimize use of drugs in different populations. Techniques are discussed that allow investigators to better describe the pharmacokinetic and pharmacodynamics response for individual patients. The term population pharmacokinetic/pharmacodynamic analysis (population PK/PD) has been applied to a collection of these techniques. The role of population PK/PD in the drug development process remains to be defined, but should be expanded.