What are phases?
Clinical trials investigate different questions in different stages, and later phases build on earlier research. The phases of clinical trials are as follows: In Phase I trials, researchers determine the safe dose of the new drug or agent and learn about its side effects. These trials usually include usually from 20 to 80 patients with a range of cancer types. Patients are usually divided into groups. Each group of patients is treated with different doses of the drug or agent so that the safest dose can be found. The highest dose of the drug that can be given safely to people (knowns as the maximum tolerated dose) is also determined. Phase II clinical trials test the effectiveness of the new drug or agent in stopping or controlling the growth of tumor cells in a certain type of cancer. These studies typically involve 100-300 people. The goal of Phase III clinical trials is to find which treatment – the new or the standard cancer treatment – is better. To gather information as quickly a
