Anticancer drug pharmacodynamics.

A considerable amount of information is available on the pharmacokinetics of anticancer drugs, but much less is known of their pharmacodynamics, that is of the relationship between therapeutic or toxic response and drug concentration. Drug dosage regimens which are to achieve defined therapeutic objectives can only be designed when both the pharmacokinetic and the pharmacodynamic characteristics of a drug are known. There are a few reports in the literature of relationships in man between toxic response and pharmacokinetic parameters of anticancer drugs, and an even smaller number of reports of relationships between therapeutic response and pharmacokinetic parameters. It is suggested that the lack of pharmacodynamic information is currently limiting the application of pharmacokinetic information to cancer therapy. Ways of improving knowledge of the pharmacodynamics of anticancer drugs are suggested.