The course of a clinical trial is subject to strict international standardization. Before the start of the study, the objectives of the study are formulated in a study protocol and the exact procedure is determined. In addition, safeguards for possible risks for trapped patients are developed. The study design must then be approved by the responsible ethics committee.
High demands are also placed on the scientific procedure. For example, in comparative therapy studies it is very important that sufficient and comparable patients participate. The exact number of participants required must be calculated by a mathematician. In order to avoid distortions, the participating patients are usually randomly divided into different groups (randomisation). Before participating in a study, patients must be fully informed and sign a consent form.
Clinical trials are classified as follows: In Phase I, a therapy is applied to humans for the first time and its tolerability is investigated. In the next step, phase II, the findings will be tested on a larger group of patients with the aim of determining the optimal dosage for the new treatment. In the Phase III study, a large group of patients is then tested to determine whether the new active substance or the new procedure is actually superior to the established treatment.