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A clinical trial is a research study designed to evaluate a new treatment approach. Clinical trials are the only way new treatments can emerge that improve the lives of people with cancer.

A clinical trial often starts with a scientific idea, based on the results of laboratory research. The researchers who bring forth these ideas usually work in cancer centers, universities, hospitals, community clinics or pharmaceutical company labs.

There are many types of cancer clinical trials, including treatment, screening, prevention, symptom management and quality of life. This booklet focuses on cancer treatment trials that evaluate medications (drugs). However, it is important to note that other treatment methods—including surgery and radiation—are also evaluated in clinical trials.

Many clinical trials test an already-approved drug, for use in a different way or to treat a different disease. Other trials evaluate a drug (or a combination of drugs) not previously given to humans, to make sure the approach is safe and will provide benefit to patients.

Many times, researchers and doctors study a new drug in the laboratory before a human clinical trial is designed and proposed. Among other things, they want to know how the drug is absorbed into the body, how long it remains in the body, the maximum tolerated dose and whether it should be given by mouth or intravenously (through a needle into a vein).

If supported by the results of the laboratory study, researchers and doctors create a Clinical Protocol, a detailed blueprint of every aspect of the trial. The clinical trial sponsor then submits an Investigational New Drug (IND) application and the Clinical Protocol to the U.S. Food and Drug Administration (FDA). The FDA has 30 days to review the IND and Clinical Protocol to both provide input and to assure that the trial will safely and ethically evaluate the drug and that the trial participants will not be subjected to unreasonable risk. (A clinical trial sponsor is a person, group, company, institution, organization or government agency that oversees or pays for a clinical trial, and collects and analyzes the data.)

When discussing your treatment options with your oncologist, ask if a clinical trial might be right for you. Clinical trials are routinely integrated into the treatment plan for people with cancer.

Here a few things to consider:

  • Most clinical trials are designed to test a new treatment approach to find out whether the approach is safe and has any added benefit.

  • Often, people who take part in clinical trials gain access to—and potential benefit from—new treatments that are not otherwise available.

  • All clinical trials have eligibility requirements, and you may or may not qualify to participate in any specific trial.

  • Before you participate in a clinical trial, you will be fully informed of the risks and benefits of the trial, including any possible side effects.

  • You have the right to stop taking part in a clinical trial at any time for any reason.

The Resource section of this booklet provides websites that allow you and your doctor to search for a clinical trial that might be right for your individual circumstances, including your type of cancer and your geographic location.

Clinical trials that evaluate new treatment approaches are done in phases. Each phase has a different purpose, helping researchers to answer different questions. If a new drug or treatment approach does not seem promising in an early-phase trial, the research can be stopped. Every clinical trial, regardless of its phase, has a Principal Investigator (often a medical doctor), who is responsible for leading the trial.

Clinical trials, including those focused on cancer, follow these established phases:

Phase I. In phase I trials, researchers study the safety of a new drug (or drug combination) or a new dose of a currently-approved drug. Researchers try to find the lowest dose that will still be effective, determine the tolerability of the drug and study side effects that might occur. These trials usually include a small number of participants and take place in research centers, where the participants can be closely monitored.

Phase II. The purpose of this phase is to determine if the treatment is effective and to learn more about its safety. In some phase II trials, participants are “randomized,” meaning they are selected by chance to either receive the treatment being studied, or one that is already being used to treat their type of cancer. Phase II trials typically involve many more patients than a phase I trial and tend to be conducted in research centers. It is important to note that in cancer clinical trials, participants are generally not given a placebo, which is a pill or liquid that contains no active ingredient. A placebo is only used when there is no standard treatment against which a new treatment can be compared.

Phase III. In this phase, the treatment being tested is given to hundreds or even thousands of participants, who are often randomized as in phase II trials. There are a number of purposes of this phase:

  • To confirm how well the treatment works against the cancer.
  • To learn about side effects that might not have been seen during earlier phases.
  • To compare the new treatment approach with current approaches.
  • To collect information that will allow the new treatment approach to be used safely.

Because of the large number of participants, phase III studies are often carried out in multiple sites, including by doctors in private practice, in community hospitals and in designated cancer centers.

Phase IV. In phase IV trials, researchers study treatments after they have been approved by the FDA. These trials are designed to learn more about the treatment’s risks and benefits and the best way for it to be used. Phase IV trials help doctors understand how safe and effective the treatment will be over the long term.

Clinical trials help identify new cancer therapies and provide people diagnosed with cancer an opportunity to access the latest treatment approaches. These trials are the standard by which we measure the worth of new treatments and the quality of life of people as they receive those treatments.

Many trials include an assessment of the genetic or molecular characteristics of a person’s cancer that could be linked to the success of a specific type of treatment.

The American Society of Clinical Oncology (ASCO), a leading professional organization representing physicians who care for people with cancer, has identified the five most important accomplishments made through clinical trials over the last 50 years:

  • As a result of chemotherapy advancements, 90 percent of Hodgkin lymphoma cases can now be cured regardless of whether they are diagnosed early or at an advanced stage.

  • Cervical cancer can be prevented by the human papilloma virus (HPV) vaccine.

  • Imatinib, a targeted therapy, results in long-term remission of most cases of chronic myelogenous leukemia (CML) and is used in the treatment of many other types of cancer.

  • A three-drug regimen (the chemotherapies cisplatin and vinblastine and the anti-tumor antibiotic bleomycin) cures almost 100 percent of men with advanced testicular cancer.

  • Anti-nausea drugs that have been developed, evaluated and approved by the FDA have improved the quality of life for people with cancer.

If you have been diagnosed with cancer, there are a number of benefits associated with clinical trial participation, including:

  • Access to promising new cancer treatments. Clinical trials often evaluate cutting-edge therapies that are not available outside of the clinical trial setting, providing you with a treatment option that may be more effective than your current therapy.

  • The chance to play a more active role in your health care. Participating in a clinical trial is educational and informative, and allows you to gain a greater understanding of your cancer and its treatment. It can also increase the control you have over your situation, which can lead to reduced stress levels and a better quality of life.

  • Close observation by cancer experts. Although your oncologist will likely still be responsible for providing your overall cancer care, clinical trial participants are closely observed by the trial team. This is, in part, because a clinical trial must follow a strict protocol (plan) and researchers need to be sure that the information they get from the trial is accurate and complete.

  • Contributing to cancer research. People who participate in clinical trials are vital to advancing medical care for people with cancer. The information gathered in clinical trials adds to scientific knowledge and leads to the approval of new treatment approaches.

As with all drugs, there may be risks associated with drugs used in clinical trials. These risks include side effects and the possibility that the treatment may not work as well as the researchers had hoped. Before you agree to enter a trial, a member of your health care team will carefully explain these potential risks.

Weighing the risks and benefits of a clinical trial is a very personal process. There is no right or wrong answer. Only you can decide if a trial is right for you.

When people are thinking about enrolling in a clinical trial, they often need someone to talk with who can help them sort through all of their concerns. That’s where CancerCare can help.

CancerCare is a national nonprofit organization providing free, professional services to anyone affected by cancer. Our licensed oncology social workers can help you understand the clinical trial process, provide guidance on coping with potential treatment side effects once the trial begins, and refer you to other valuable informational resources, including:

Support groups. Talking with other people who have taken part in clinical trials can help reduce the feeling that you are going through it alone. These groups provide reassurance, suggestions and insight—all in a safe and supportive environment. At CancerCare, people with cancer and their families take part in support groups in person, online, or on the telephone. All groups are facilitated by licensed oncology social workers.

Connect Education Workshops. Delivered by leading medical experts, these one-hour presentations cover a number of valuable topics for people coping with cancer, including updates on FDA-approved treatments for specific cancer types and research currently being conducted in clinical trials. You can listen live by telephone or online, and you’ll have the chance to ask the experts your own questions. You can also download past workshops from our website.

Publications. Free booklets and fact sheets from CancerCare provide up-to-date, easy-to-read information about clinical trials, treatment updates, managing side effects and improving your quality-of-life while coping with cancer.

Financial help. For those who qualify, CancerCare provides limited financial assistance to help with some treatment-related costs such as transportation and child care.

To speak with one of CancerCare’s oncology social workers, call us at 800-813-HOPE (4673).

Q: I’m in a clinical trial and have experienced side effects from the drug I’m taking. What should I do?

A: All cancer treatments, including those given in a clinical trial, can cause side effects. It’s important that you immediately report any side effects that you are experiencing to a doctor or other designated person at the clinical trial site. By doing so, you are helping yourself and contributing significantly to the work of the researchers. It’s also important to report these side effects to your health care team so they can help you manage them. Doing so will improve your quality of life while you are participating in the trial.

Q: Can trials exclude people with certain medical conditions?

A: The safety of clinical trial participants comes first. If the researchers believe that a medical condition puts a person at risk, they will exclude that person from the trial. If you have been excluded, talk to your oncologist about other possible options. Each clinical trial has its own set of enrollment standards, so you might qualify for another trial.

Q: What is a quality of life clinical trial?

A: Quality of life trials do not evaluate any specific therapy; rather, they address such issues as short and long-term effects of therapy, prevention of pain and issues related to nutrition and stress. These types of trials are often available to people being treated for cancer.

Q: I’m in treatment for my cancer and doing well. Is there any reason for me to participate in a clinical trial?

A: This is a good topic to discuss with your oncologist. There could be a current or upcoming clinical trial for a treatment that may be of additional benefit to you. Also, some clinical trials evaluate treatments that may prevent the return of cancer after your initial treatment is complete. Your oncologist may suggest you take part in one of these trials in the future.

Q: I’m 75 years old. Is there an upper age limit for participating in a clinical trial?

A: In general, age alone does not exclude a person from participating in a clinical trial. Other factors, including overall health and existing medical conditions, are taken into consideration when the decision is made to include or exclude a potential trial participant. As researchers are interested in learning about the safety and effectiveness of the drug or drugs being tested in older people, some trials are designed to focus on people in an older age range.

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Thumbnail of the PDF version of Clinical Trials: Improving the Care of People Living With Cancer

Download a PDF(533 KB) of this publication.

This booklet is supported by Bristol Myers Squibb, an educational grant from Daiichi Sankyo, Inc. and Pharmacyclics LLC, an AbbVie Company and Janssen Biotech, Inc., administered by Janssen Scientific Affairs, LLC.

Last updated Saturday, April 30, 2022

The information presented in this publication is provided for your general information only. It is not intended as medical advice and should not be relied upon as a substitute for consultations with qualified health professionals who are aware of your specific situation. We encourage you to take information and questions back to your individual health care provider as a way of creating a dialogue and partnership about your cancer and your treatment.

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