Phase II studies are designed to test the effectiveness of a treatment or utility of a diagnostic test, to determine how well it works, and to better understand tolerability and toxicity of the treatment (or diagnostic test) in a larger patient group than in Phase I studies. Phase II studies can be randomized, though most are not. A certain number of patients are planned to be enrolled, and patient outcomes such as survival, cancer-free survival, tumor control, quality of life, and toxicity may be measured. These studies often include a scientific research component, in which tissue from surgery or biopsy, blood or other biologic specimens are analyzed in order to correlate biologic parameters with outcomes. Promising Phase II data often provides the basis for further testing via randomized Phase III studies, though it may be hard to justify Phase III testing if Phase II outcomes prove to be better than other treatments.
Next, read about Phase III trials.