In vivo Pharmacology in Drug Discovery and Development

Abstract

These Annotations and Reflections are based on a symposium held in September 2004 by the Danish Society of Pharmacology and Toxicology. The symposium took place in the historical auditorium from 1856 at The Royal Veterinary and Agricultural University, Copenhagen. The symposium was organised with the aim to highlight the status and essentials of in vivo pharmacology in the process of discovering and developing new therapeutic agents. This is a crucial area in the process of drug research and development. The importance can be substantiated by the high number of drug candidates that have failed in the clinical phase of drug development in the recent decade. Thus, US FDA Commissioner, Dr. Lester M. Crawford, has stated that historically 14% of tested products had gained regulatory approval and entered the market, but today the chance of a candidate drug entering Phase I trials is only 8%. In the past, a product failure rate in late stage Phase III trials of 20% was common; however, this figure is now close to 50% (Crawford 2004). The loss of invested efforts is tremendous such as intellectual properties, patient expectations and maybe most of all, financially. The most obvious reasons for the clinical failure of potential drug candidates are poor or inadequate preclinical prediction of clinical efficacy, safety pharmacology or potential toxicity. This means that the animal models used to predict these effects have been inadequate to the purpose and underline the urgent need for development of more reliable models. The failures cannot be taken as an indication that animal models are not useful, rather that the models need refinement for the purpose. Within different therapeutic areas new drug targets are constantly being developed as a consequence of basic research in the understanding of the disease pathogenesis and pathophysiology. The new targets are initially in the hands of molecular and cellular biologists who have deep insight