[Drug clinical trials and their importance for diabetology]

The system of drug clinical trials has gradually become the basic pillar of pharmacotherapy principles denoted as evidence-based medicine. It serves, in particular, to ensure the efficacy and safety of newly introduced drugs. The first institute dealing with drugs in the territory of the current Czech Republic was founded as early as in 1918. The then drug research institute became one of the predecessors of the modern State Institute for Drug Control. The definition of drug clinical trials covers several basic factors, such as pharmacodynamics, pharmacokinetics, adverse effects, drug safety and efficacy and, in particular, testing systematicness. The clinical trial itself is carried out in four basic stages. Each of them consists of a set of studies which rationally follow up one another. In stage I, the first administration of the drug to the patient, the basic evaluated factor is the drug's safety. In stage II, pilot studies are carried out in patients, which serve to verify safety and to monitor efficacy. Before a new drug is registered, extensive clinical studies in large cohorts of patients are carried out in stage III, covering many pharmacological characteristics of the drug. The statistical evaluation of the extensive set of data thus obtained determines the quality of interpretation of the study results. The significance of negative effects (bias) can thus be reduced. The planning of a control group, randomization and clinical study blinding serves this purpose. When applying the drug clinical trial data in practical pharmacotherapy, certain limits ofclinical studies need to be taken into consideration as well. The entire system ofdrug trials will change based on certain modern methods (biotechnology, pharmacogenetics).