Clinical Trial Phases: What Happens in Phase 1, 2, 3 and 4?

What are the 4 Clinical Trial Phases? graphic

Clinical trials are research studies of medications, vaccines, medical devices, procedures, diagnostics (tests), and other health-related products. These studies involve participants (also known as patients, volunteers, or subjects) to determine whether certain experimental products are safer and/or more effective than currently approved products. Without clinical trials, it would be impossible to develop new medicines, cures, vaccines, and other medical products — including everything from COVID-19 and flu vaccines, to infant formula, medications for diabetes, and pacemakers. Clinical trials happen in four stages. Each stage, called a phase, serves … Read more