What are the phases of a clinical trial?
What are the phases of a clinical drug trial?
Most clinical drug research progresses in an orderly series of steps or
- Phase I trials are studies to evaluate how a new drug should be
given, and how safe it is to humans.
- Phase II trials provide preliminary information about how well the
new drug works, and generates more information about its safety and benefits.
- Phase III trials compare a promising new drug, combination of
drugs, or procedure with a current standard of treatment.
- Phase IV trials include the continuing evaluation that takes place
after FDA approval, when the drug is already on the market and available for