Clinical research includes all research carried out on humans. It aims at improving knowledge of diseases, developing novel diagnostic methods and new treatments or medical devices to ensure better patient care. It is carried out according to a very precise study protocol and is only conducted under certain conditions. It must:
They enhance the knowledge of the disease and its evolution over time. They are carried out within the framework of the follow-up or retrospective review of the patients in the study centers.
These studies are conducted with a rationale to provide scientific evidence of the efficacy and safety of a new drug, a device or a novel treatment method of the disease. This is the necessary step for a new molecule to become a drug or a new medical device to be marketed.
As part of the development of new drugs, clinical trials are conducted in 4 steps:
Phase I studies are carried out to evaluate the effect of the new drug molecules in humans. It is performed on healthy subjects. These studies help to determine the biological tolerance of the drug and safety dosages. Bioequivalence studies can also be categorized under phase 1 trials, these studies determine the in vivo biological response of two proprietary drug preparations. Phase I study usually enroll around 20- 50 healthy volunteers
Phase II studies usually require between 100-500 subjects. These studies are conducted in patients to evaluate efficacy and ongoing safety profile of the new drug.
Phase III randomized controlled trials assess the new drug against the standard of care and include 1000 to several thousand patients. These trials determine the clinical safety and effectiveness of the new drug in large populations to establish if the new drug can perform better than the standard of care. Each subject is monitored closely and in case of significant benefits in one group or high incidence of side effects in one group, the trial can be stopped early.
Phase IV are large surveillance studies, conducted to evaluate the long term effects of the drug. For this reason, these studies are also called post marketing studies. They evaluate drug effectiveness, safety and generalizability.