Phase I trials are the first step in testing a prevention agent in people. Phase II trials focus on learning whether the agent has a biologic effect in prevention. This is the group taking the study agent.
Clinical trials follow strict guidelines for science and ethics.
These guidelines deal with many areas, including the study's design and who can be in the study. They serve as neutral reviewers and ensure that that the study is managed fairly and that no one is likely to be harmed who may decide to participate in a clinical trial. Informed consent is a process during which you learn key factors about a clinical study before you decide whether or not to join. These facts include details about the study approach and tests you may have, and the benefits and risks that could result. The principal investigator or the nurse will give you a form that goes over key facts.