|The first step in the development of a medicinal product is finding an active substance which is then further investigated in preclinical trials. Clinical research refers to the part of the development process when clinical trials involving humans are being conducted. During each phase the risk benefit ratio is determined and reassessed, if necessary.
Phase I trials involve healthy subjects and aim at testing the tolerability of a new medicinal product. Phase II trials are dose-finding studies with patients suffering from the disease in question. Phase III trials shall confirm safety and efficacy of the investigational medicinal product among a large patient population. Only once those three phases have been successfully completed, i.e. the positive risk benefit ratio has been confirmed, the manufacturer may apply for a marketing license for the new medicinal product. Phase IV trials are conducted following the product’s market launch. These are long-term studies within the field of pharmacovigilance aiming at discovering rare side effects and interactions with other drugs.