[Preclinical studies for development of anti-cancer drugs: current and historical status and problems]

In this review, we present the current and historical status of preclinical studies for development of new anti-cancer drugs. In our company, especially focusing on the stage of drug screening, pharmacology, toxicology and pharmacokinetic studies. We have discovered numerous new compounds with anti-cancer potential mainly with microbial origins, from which some drugs have been developed to clinical trials. We hope that clinical trials of drugs with a new mode of action will be designed and conducted with a more rational basis, and followed by analysis of the pharmacokinetics and pharmacodynamics so as to predict the toxicity and efficacy of the drugs in humans.