Clinical development of a novel drug has traditionally been seen as a series of four phases, each having its own objectives in establishing the efficacy and safety of the drug. Increasingly individualized medicine and the changing mechanisms of drug action are also changing the designs of clinical drug testing. The borders of development phases become blurred and the traditional large, controlled multicenter studies may in part be replaced by individual and risk-based approaches. The indications for drugs are more precisely targeted from biological starting points, and a target-oriented development may guide the designs of clinical testing at all stages of development. Utilization of data from registries along with modeling will become more common in clinical drug testing.