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About Clinical Trials
What Is a Clinical Trial?
A clinical trial is one of the final, but key, stages in the long and extensive process of developing new or better treatment therapies. The clinical trials stage involves testing on patients in order to determine whether or not a therapy is a safe and effective method of cancer treatment and/or prevention.1
Why Are Clinical Trials Important?
It is through clinical trials that doctors have made significant medical discoveries and breakthroughs in the treatment of cancer. Clinical trials provide critical information that these doctors and regulators, like the FDA, need to assess the safety and efficacy of particular therapies in humans. Clinical Trials can also provide patients with new therapies that were not previously available.2
Why Should I Participate?
Clinical trials are a critical step in the clinical development of new treatments. Clinical development, the process of taking a drug from the lab all the way through FDA approval for patients, can be a long process. It begins with extensive laboratory research, and if this research is successful, may reach the clinical trials stage. New therapies may take many years before reaching the clinical trial stage, and several more years before approval.
Clinical trials represent the critical stage where scientific discoveries are translated into better methods for preventing, diagnosing, and treating cancer.
Once a treatment therapy reaches the clinical trials stage, its progress can be hindered by problems in finding patients who are willing to participate in the study. In order for a clinical trial to compile an accurate and comprehensive set of data, it must have a large population to study. With a shortage of eligible patients enrolled in a trial, compiling information on safety and efficacy can be delayed.
The NCI reports that only 5% of cancer patients are enrolled in a clinical trial. According to the Harris Interactive Survey about 80% of cancer patients were either unaware or unsure that participation in a clinical trial was an option.
Participation by patients is critical to successful completion of clinical trials. The more patients that enroll in clinical trials, the faster investigators are able to evaluate a particular protocol which may ultimately lead to better treatment and prevention strategies.
Before entering a clinical trial, however, there are many factors a patient should consider, and the decision should be discussed thoroughly with your physician.
How Does a Clinical Trial Work?
Types of Clinical Trials
The five types of trials are3:
- Treatment trials test experimental treatments, new combinations of drugs, or new approaches to surgery, or radiation therapy
- Prevention trials look for better ways to prevent disease in people who have never had the disease, or to prevent a disease from reccurring. These approaches may include medicines, vaccines, vitamins, minerals, or lifestyle changes.
- Diagnostic trials are conducted to find better tests or procedures for diagnosing a particular disease or condition.
- Screening trials test the best way to detect certain diseases or health conditions.
- Quality of Life trials (or Supportive Care trials) explore ways to improve comfort and the quality of life for individuals with a chronic illness.
Phases of a Clinical Trial
The five phases of a clinical trial are4:
- Phase 0:
Phase 0 studies are not commonly used in clinical trials. They are only implemented in certain trials to test a very low dosage of a drug and its effects at that dosage. Phase 0 studies help researchers discover the results of certain drug therapies. If there are problems with the way the drug is absorbed or acts in the body, this should become clear very quickly in a phase 0 study. This study can help prevent a future delay and further expense that potentially occur if it is discovered that the phase 0 results do not correlate with the results of laboratory testing. Phase 0 trials have little benefit, if any, to participants since a very low dosage is used in this study. Currently, phase 0 studies are not mandated by the FDA.
- Phase I Trials:
These are the first studies in which the safety and the side effects of a treatment therapy are evaluated in patients. In phase I trials, the best mode of administering a drug, the optimum frequency of administration, and the maximum safe dosage are determined. Often, in this trial phase, a small number of participants and multiple cancer types are involved. Since this is the first phase mandated by the FDA, phase I trials primarily measure the safety and not the efficacy of a drug. Consequently, phase I studies pose the highest risk to patients.
- Phase II Trials:
Once a treatment is determined safe, it can begin phase II. Phase II studies continue to measure the safety of a drug but, more importantly, begin to determine a drug's efficacy in a larger population of people with the same cancer type. During this phase, participants usually receive a treatment at the particular dose and by the method determined most effective and safe in phase I.
Some phase II studies can involve randomizing participants into different treatment groups. In a randomized trial, physicians will divide the patient population into two separate groups. Each group can receive a different dose or receive the treatment in a different way in order to determine which dose and method is the most effective.
- Phase III Trials:
Once a drug has been determined effective and safe for patients in phase II, it can begin phase III testing. It is not sufficient to determine that a treatment is effective and safe for patients. It is necessary to see how it compares to standard treatment options. Phase III studies test a new drug or a new combination of drugs in comparison to the current standard in a large population of patients.
Since physicians do not know which treatment option is more effective, patients are randomized into different treatment groups; those who receive the new treatment, and those who will receive the standard (the control group).
Placebos can also be used in phase III trials. Placebos are inactive substances or treatments that mimic the appearance of the trial therapy, but have no effect. Placebos provide physicians with a comparison between the trial therapy and a control therapy.
As in every phase, patients are monitored closely for side effects. If a patient experiences severe side effects, the treatment is stopped.
- Phase IV Trials:
After a treatment has been approved and is being marketed, the drug's maker may study it further in a phase IV trial. The purpose of phase IV trials is to evaluate the side effects, risks, and benefits of a drug over a longer period of time and in a larger number of people than in phase III clinical trials. Thousands of people are involved in a phase IV trial.
What Should I Look for in a Clinical Trial?
It is important to choose a clinical trial that has well defined protocols. Protocols are plans which serve as procedural guidelines for the trial. According to these protocols, doctors develop certain criteria for which participants will be included or excluded from the study. Only certain patients can participate in a particular trial as determined by the criteria of that trial. Common criteria that researchers use to choose their participants are: the stage and type of cancer, age, gender, and previous health conditions.
Clinical trials are conducted by doctors or other health care professionals at various locations, including university hospitals, cancer centers, local medical centers, and physicians' offices. It is important to choose a location that is easily accessible.
One must consider the endpoints of the trial. Endpoints that investigators may evaluate include:
- Tumor response - There are three forms of response that are measured: complete or partial response; stable disease; and tumor progression. Complete response means there are no tumor findings on any diagnostic tests. Partial response means overall tumor bulk or the tumor length has decreased by a certain percentage; Stable disease means the tumor has neither increased nor decreased in size; Tumor progression means the tumor continues to grow in spite of treatment.
- Quality of life - How does a treatment affect a person's daily quality of living?
- Toxicity - What are the side effects of the treatment?
In addition, certain trials may continue to make a therapy available to a patient if a patient has shown marked success with that therapy, while others will discontinue the therapy when the trial is completed.
When evaluating a particular clinical trial, make sure you understand what, if any, other treatment therapies may become unavailable to you if you participate in the trial.
It is critical that you have a comprehensive understanding of the trial and the potential risks and benefits that it poses to you. Doctors performing the trials are required to inform participants about the potential risks and benefits of the study, as well as their rights and responsibilities. This is called informed consent. You are required to sign a document saying that you have been informed, and throughout the clinical trial, researchers continue to inform you about new information that may affect you.5
Before you make any decisions regarding participation in a clinical trial, talk to your physician.
Useful Links and Further Information
American Cancer Society Resources:
National Cancer Institute (NCI) Resources:
- How to Find a Cancer Treatment Trial
- Taking Part in a Clinical Trial
- If You Have Cancer and Have Medicare
- Providing Your Tissue for Research
- A Guide to Understanding Informed Consent – National Cancer Institute
- Different Barriers to Clinical Trials
Food and Drug Administration Resources:
Other NCI Resources: Chemo Therapy:
- Radiation Therapy and You: Support for People With Cancer
- What To Know About External Beam Radiation Therapy
- What To Know About Brachytherapy (A Type of Internal Radiation Therapy)
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