What is a clinical trial?
Clinical trials are scientific studies in which new treatments — drugs, diagnostic procedures, and other therapies — are tested in patients to determine if they are safe and effective. Such trials help scientists answer a variety of questions about new therapies: what diseases should they be used for? What doses of new drugs are most effective? And which patients can benefit the most from them? Nearly all cancer drugs in use today were tested and made available to patients through clinical trials.
Who can participate in a clinical trial?
To qualify for a particular study, patients must meet a carefully defined set of criteria. Those criteria usually relate to patients' age and gender, the type and severity of their condition, and the types of treatments they have already received.
Where do clinical trials take place?
Studies are currently under way in hospitals, medical centers, clinics, and research institutes around the world including Dana-Farber/Partners CancerCare hospitals — a consortium comprising Dana-Farber Cancer Institute, Massachusetts General Hospital, and Brigham and Women's Hospital.
What information do patients receive about clinical trials?
Patients interested in participating in a clinical trial are informed in advance about the possible risks and benefits of the therapy being studied, and their written consent is obtained before treatment begins. As the trial progresses, participants are given new information that may affect their willingness to stay in the trial. Participants may withdraw from the trial at any time.
How are patients protected?
Before any clinical trial begins, it must be approved by its host institution's Institutional Review Board (IRB), which includes researchers and physicians. The IRB considers whether proposed studies are safe and well planned and whether they will ultimately advance patient care. It also reviews studies to ensure patients are adequately informed about the risks of participating in clinical research. In all studies, the health of each patient is closely monitored during the course of the trial.
What are the rules by which clinical trials proceed?
The rules, known as clinical protocols, vary from study to study. In general, they deal with a study's design, who can participate, and the kind of information people must be given before agreeing to enroll. Every trial has a principal investigator, usually a physician, who prepares the protocol.
What are the different phases of a clinical trial?
Clinical trials are divided into three distinct stages. Only when the third stage has been successfully completed, and the Food and Drug Administration has given its approval, can a new treatment become part of standard therapy.
Phase I trials
Phase I trials are designed to determine only the safety of a new therapy. They evaluate how a new medication should be given (orally, intravenously, or by injection), how often, and at what dosage, but are not designed to test if a new therapy is effective. Phase I trials generally enroll only a small number of patients.
Phase II trials
Phase II trials provide preliminary information about how well a new medication works and generate more information about patient safety. Phase II studies usually focus on a specific type of disease (liver cancer, for example, rather than all types of cancer).
Phase III trials
Phase III trials compare new treatments with standard ones to determine which is safer and more effective for patients. Phase III trials generally involve a large number of participants and often take place at several health centers at the same time. Patients are randomly assigned to receive either the new therapy or a standard one.
Adapted from information published by the National Cancer Institute.