New treatments must successfully complete several phases of clinical trials before they can be licensed and recognised for use in standard care.
Before a clinical trial
Extensive laboratory tests will have been carried out before any new cancer treatment is introduced into a clinical trial.
These tests will have proved that the drug can affect cancer cells and have helped to find out the possible side effects. The next step is to trial the treatment with patients in a series of phases. Each phase must be completed with proven results before the next can begin.
Phase 1 or Early Phase looks at whether the trial treatment is safe, has any harmful side effects and tries to find the best dose of the treatment to use. This phase will involve a small group of patients.
Phase 2 considers how well the treatment works, any side effects, the dose and regularity of treatment using a larger group of patients often over several years.
Phase 3 tests the new treatment against the existing standard treatments, monitoring its effectiveness, side effects and impact on the patient’s quality of life. This phase can involve thousands of people in different hospitals, sometimes around the world.
Phase 4 can be needed to further monitor the treatment after it has been approved for use. This phase monitors the long-term safety and effectiveness in a larger population over time.