How Clinical Trials Work
A clinical trial is a research study designed to evaluate a new treatment. However, it is important to remember that, in most cases, the new treatment being tested has already shown promise of being an improvement over the current therapy. It is not just an unregulated experiment. In fact, many clinical trials are tests to see how much better a new treatment works than the current therapy. People in clinical trials are among the first to receive new treatments, and are closely monitored by physicians and other researchers involved in the trial.
Clinical trials are usually set up in the following way: Patients are randomly assigned to a group that will receive either the accepted standard of care or an experimental treatment; the first group receives the best current therapy (the current standard of care), while patients in the experimental treatment group receive a new treatment. What is new about the treatment can mean any number of things, depending on how the trial is designed - new drugs, new dosages, new combinations or procedures, even a new way of administering a drug.
Clinical trials take place in four phases, generally with a larger number of people participating in each successive phase.
Phase I trials:
Is it safe? This first phase generally determines the safest dose or best way to give a new treatment. This phase will also look closely at harmful side effects. Because it is the first step in testing a new treatment in people, Phase I trials are generally open to a limited number of individuals for whom standard treatments would not be helpful.
Phase II trials:
Is it effective? Phase II trials study whether the treatment is effective. Because the safe dosage has been determined from Phase I, this phase now examines whether the treatment can shrink the tumor or lessen the symptoms.
Phase III trials:
How good is it? Phase III trials compare the new treatment with the standard available treatment. This phase involves randomly assigning the patient to one of the treatments in order to determine which is more effective. Most often, only trials that show promise in the first two phases move to the third phase. There are often large numbers of participants in Phase III trials.
Phase IV trials:
The purpose of a phase IV clinical trial is to monitor the long-term effects of the new treatment after the Food and Drug Administration has approved if for general use. Phase IV trials are designed to better understand the treatment's long-term safety and effectiveness and may monitor aspects of the drug or treatment such as how it interacts with other drugs, in certain groups of people (e.g., pregnant women), or in very large populations. Phase IV trials are not always performed, especially if the results of the Phase III trial include long-term evaluation of the new therapy. However, because sometimes rare or long-term adverse effects of a new treatment do not become apparent until after it has been in approved use for a number of years, Phase IV trials are an important step in ongoing surveillance of new treatments.
A clinical trial ends when enough information has been gathered to answer whether this drug is effective against cancer. Scientists look for a number of things when considering this question:
- Does the drug cure the cancer and/or allow people to live longer?
- Is the drug better at treating cancer than the standard drug already being used?
- Does the drug have positive effects on quality of life, such as less fatigue, fewer side effects, maintenance of normal body weight, etc.?
- Does the drug increase the amount of time a patient's cancer stays in remission?
- Does the drug increase the number of people who have a complete response (all evidence of disease disappears for more than one month) and does it increase the amount of time this response continues?
