After the drug is get approved and permission for its marketing is obtained, Clinical studies of the 4th Phase can be carried out – post-marketing studies (post approval).
The objective of Clinical studies
The objective of such studies is to gather as much additional information as possible about the drug in terms of its efficacy and safety. This is done for the possible expansion of the indications for drug use, optimization of the dosage regimen, the search for new ways for international pharmaceutical market penetration, etc. Information on the adverse effect of the drug, its impact on the patients’ survival and the quality of remission are subjected to the most careful analysis. Such studies usually involve a very large number of patients (tens of thousands) and are conducted over many years.
According to their orientation, studies can be:
concurrent (prospective) studies – Clinical studies are planned prior to the recruitment of patients and are carried out according to the protocol in specially selected groups;
nonconcurrent (retrospective) studies – are based on past experience of drug administration according to patient medical records.