Phases of clinical research

The phases of clinical research are the stages in which scientists conduct experiments with a health intervention to obtain sufficient evidence for a process considered effective as a medical treatment.^[1] For drug development, the clinical phases start with testing for drug safety in a few human subjects, then expand to many study participants (potentially tens of thousands) to determine if the treatment is effective.^[1] Clinical research is conducted on drug candidates, vaccine candidates, new medical devices, and new diagnostic assays.