A clinical trial is a scientific study of how a new medicine or treatment works in people. Through clinical studies, doctors find new and better ways to prevent, detect, diagnose, control, and treat illnesses.
New medicines and treatments that prove helpful and safe in test tubes and in animals must also prove safe and effective in humans before doctors can prescribe them.
In the most common types of clinical trials, scientists seek to determine if new treatments are safe and effective. Also, if new treatments are more effective than other treatments, including standard or alternative therapies. For more information, see “types of clinical trials” and “phases of clinical trials” at the end of this section.
Clinical trials may involve treatments such as new drugs, vaccines, new approaches to surgery or radiation therapy, or new combinations of existing treatments.
In discussing therapy options with our patients, we offer the best available treatment against their disease. In some cases, a new experimental therapy, available in a clinical trial, may be considered. You can view an audiovisual program titled “Entering a clinical trial: Is it right for you?”. It will help you understand what clinical trials are and whether or not to enter a study.
Patients who wish to be considered for a clinical study will be scheduled for a preliminary screening visit. During that visit, “informed consent” and “inclusion/exclusion criteria” will be explained. Members of the study team will also explain the study, the procedures that will be followed, and answer any questions. A full medical history will be taken, and usually a physical exam will be performed. Any necessary laboratory tests will be scheduled.
Payment for participation is rare, primarily because the National Institutes of Health wish to discourage patients from participating in clinical trials solely for financial purposes. However, most sponsors of clinical trials will reimburse participants for reasonable travel and food expenses while they are in the study.
Treatment trials are conducted in people who have cancer. They are designed to answer specific questions about, and evaluate the effectiveness of, a new treatment or a new way of using a standard treatment.
Prevention trials study ways to reduce the risk, or chance, of developing cancer. Most prevention trials are conducted with healthy people who have not had cancer. Some trials are conducted with people who have had cancer and want to prevent the return of cancer (recurrence), or reduce the chance of developing a new type of cancer. Approaches include drugs, vaccines, vitamins, minerals, or other supplements.
Screening/early detection trials are often conducted to determine whether finding cancer before it causes symptoms decreases the chance of dying from the disease. These trials involve people who do not have any symptoms of cancer.
Quality-of-life trials (also called “supportive care” trials) explore ways to improve comfort and quality of life for people with cancer and cancer survivors. These trials may study ways to help people who are experiencing nausea, vomiting, sleep disorders, depression, or other effects from cancer or its treatment.
Genetics trials are sometimes part of another cancer clinical trial. The genetics component of the trial may focus on how genetic makeup can affect detection, diagnosis, or response to cancer treatment.
Testing a new therapy progresses in an orderly series of steps, called “phases.” This allows researchers to ask and answer questions in a way that results in reliable information about the therapy and protects patients. Clinical trials are usually classified into one of four phases by the U.S. Food and Drug Administration, which oversees the approval process.
Phase I trials: In these studies, researchers evaluate how a new drug should be given (by mouth, injected into the blood, or injected into the muscle), how often, and what dose is safe. A Phase I trial also might evaluate a new combination of two drugs where one or both drugs, alone, might be known but doctors have never studied the two together. Phase I trials usually enroll only a small number of patients. These patients often have advanced disease for which no standard therapies are available. Patients should have a reasonable expectation that the new drugs (or drug combinations) may shrink their tumors or reduce their tumor burden. There is no chance they will receive a placebo (inactive “dummy pill”). However the risks associated with being one of the first people to try a new drug — or a new drug combination — should be weighed very carefully because the side effects will not be well understood at the beginning of a Phase I study.
Phase II trials: In these studies, researchers continue to test the safety of the drug and how well it works. They usually focus on a particular aspect of a disease. Like Phase I trials, these trials do not test the difference between two therapies, so the participants will almost always get the experimental treatment. There is still no chance that a participant will receive a placebo.
Phase III trials: In these studies, new drug, a new combination of drugs, or a new surgical procedure is tested in comparison to the current standard for treatment. A participant usually will be assigned at random to the standard treatment group or the new treatment group. Phase III trials often enroll large numbers of people and may be conducted at many doctors' offices, clinics, and disease centers nationwide. Patients rarely receive a placebo (done only when there is no standard therapy for the disease). Participants will either receive the best available standard therapy or the experimental therapy, with an equal chance of receiving either treatment.
Phase IV trials: These are often required when a drug manufacturer wishes to test an already approved therapy for a different medical condition or in a different formulation than it was originally approved for. The manufacturer is not allowed to make new claims about their product until it is properly tested. It is possible (though unlikely) that a placebo may be used in the control group in a Phase IV trial.
Through a process called informed consent, people learn about a study's treatments and tests, and their possible benefits and risks, before deciding whether or not to participate.The informed consent document provides a summary of the clinical trial (including its purpose, the treatment procedures and schedule, potential risks and benefits, alternatives to participation, etc.) and explains study participant’s rights.
It is designed to begin the informed consent process, which consists of conversations between patient and the research team. If a person then decides to enter the trial, they give their official consent by signing the document. They are given a copy of the informed consent document to use as an information resource throughout the course of the trial.
The informed consent process provides ongoing explanations that help people make educated decisions about whether to begin or continue participating in a trial. Every participant in a clinical trial in the United States has the right to informed consent. In fact, nobody should even consider joining a trial without access to key information, which must be provided by the investigators in easy-to-understand language.
This information includes:
Why the research is being done
What researchers are hoping to accomplish
What different therapies are being tested and how researchers believe they work
Any risks associated with the therapies
Potential benefits for the participant
Other available treatments, with a discussion of their effectiveness and side effects
The understanding that participants may leave the study at any time
Each study has its own guidelines for who can participate,called eligibility criteria. Researchers must find a balance between identifying those people most appropriate for testing a new therapy and casting a wide enough net to ensure there will be enough participants to make the study results statistically significant.
These “inclusion/exclusion” criteria are explained to each potential participant in a clinical research trial before they are enrolled. The criteria may be factors such as the participant’s age, for example, many studies will only include people over age 18. Also considered are the date of diagnosis of the illness, other therapies, and other illnesses that participants may have including the stage of their illness, their level of activity in day-to-day routines, and their ability to take oral medications.
The National Institutes of Health have a comprehensive website that deals exclusively with clinical trials and the issues described above. It can be found at http://www.clinicaltrials.gov/
For questions about your rights as a research participant, please contact a representative of the Office for Human Research Studies at DFCI (617) 632-3029. This can include questions about your participation in the study, concerns about the study, a research related injury, or if you feel/felt under pressure to enroll in the study or to continue to participate in the study.
What exactly is a clinical trial?
