Responsibilities of clinical pharmacology in the early phase of drug development

Abstract

The path of a new drug from the idea to the product may be divided into 2 phases, namely drug discovery and drug development. Due to the scientific progress new and simple methods could be developed to determine the biological efficacy of a large number of compounds. During the first part of drug development necessary requirements for the first use in man are met by performing preclinical pharmacological, toxicological and pharmacokinetic investigations in the animal and in in-vitro testing. After a first clinical-pharmacological profile of the new substance has been established during phase I on the basis of which a decision for the continuation of the clinical trial is made, the aim of phases II and III is now to answer the important questions of the therapeutic efficacy and tolerability in a large number of patients with the target indication. Due to the continuously increasing time and costs of drug development, drug development should be streamlined combining preclinical and early clinical phases as an exploratory stage and later clinical development as a confirmatory stage. The development and appropriate use of surrogates and models may be helpful to determine drug actions in human and to assist in dose selection as the main requirement for a successful large clinical trial in the confirmatory stage. Identifying the genes responsible for the huge variations in how different patients respond to a drug, in terms of both the product's effectiveness and its side effects, and genotyping patients before including in large clinical trials may prevent selecting the wrong patient population and avoid expensive repetition of these studies. Taking responsibility as the link between research and development gives clinical pharmacology a major opportunity to assume a pivotal role in drug development. To reach this goal, clinical pharmacology must be fully integrated in the whole process of drug development from the candidate selection until the approval.