Drug research: from the idea to the product

Abstract

The path of a new drug from the idea to product may be divided into 2 phases, namely drug discovery and drug development. In drug discovery a dramatic change is taking place. Due to a remarkable progress in understanding and explaining the underlying cause of many diseases by identifying and sequencing the genes encoded within DNA, it has become possible with new methods, like molecular biology or gene technology, to develop simple test assays by which a large number of compounds may be tested in regard to their biological efficacy. Automation of these test systems utilizing computer-controlled robotic systems has made it possible to evaluate up to 1 million substances per robot per year on their biological effect. While the classical medicinal chemistry cannot produce such a large number of new compounds, combinatorial chemistry may offer the opportunity to screen large numbers of novel compounds rapidly and to reduce the time taken to identify drug candidates substantially. Overall, it is estimated that combinatorial chemistry techniques have resulted in a reduction in the time taken to identify drug candidates of between 18-24 months. In drug development 2 partly overlapping phases can be differentiated, namely the preclinical and clinical phase. During the first part of drug development necessary requirements for first use in man are met by performing preclinical pharmacological, toxicological, and pharmacokinetic investigations in the animal and in in vitro testing. These investigations are playing a central part for the benefit/risk evaluation of new drugs. Only if the risks connected to the clinical study are medically justifiable in relation to the likely therapeutic benefit of the compound, the clinical trial may basically take place under consideration of the legal requirements of the country in which the study is carried out. In drug research clinical pharmacology is the connecting link between preclinical and clinical research. Clinical pharmacology produces the necessary basis for the clinical trial of a new substance in the patient with the target indication. 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 and the probable effective dose range and dosing interval is made, the aim of phase II-IV is now to answer the important questions of the therapeutic efficacy and tolerability in a large number of patients with the target indication. Only with a very careful drug investigation during phase I-IV it is really possible to register the therapeutic risk and benefit of a new drug and to control resulting serious problems. An analysis of registered drugs during the last years shows that despite enhanced efforts and dramatically rising development costs the innovation potential of the classical approach is steadily decreasing. Therefore, it is absolutely necessary to develop new innovative drugs with the help of new technologies like molecular and cell biology, gene technology, or immunology as well as combinatorial chemistry and robot supported substance screening.