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Clinical Trials  

As a UC Irvine Health cancer patient, you may be eligible to take part in one of the many clinical trials underway at the Chao Family Comprehensive Cancer Center. By participating in a clinical trial, patients have access to leading-edge treatments and therapies long before they are available to the general public.

The more you know about clinical trials, the better informed you will be when deciding whether to participate in a specific trial. Learn more about clinical trials below.

What is a clinical trial?

A clinical trial is a medical research study in which patient volunteers test a new medical approach to determine whether it is safe and effective. Some clinical trials study a drug, a medical device or a new way of doing surgery. Others test new ways to prevent disease, diagnose cancer, improve quality of life or help people with cancer manage difficult psychological and social issues.

In a therapeutic clinical trial, patients receive either the standard of care — treatment that doctors agree is appropriate, accepted and widely used — or a new drug, procedure or device being studied.  

During a clinical trial, more information is gathered about a new treatment, its risks and how well it may work.  Patients who take part in cancer clinical trials also have an opportunity to help scientists learn more about cancer — how it grows, how it acts and what influences its growth and spread.  Many of the approaches that doctors use to treat cancer today are available only because of clinical trials.

What are the types of clinical trials?

Cancer clinical trials differ according to their primary purpose. They include:

  • Treatment
    Treatment trials test the effectiveness of new therapies or new ways of using current treatments in people who have cancer. The trial may include new drugs or new combinations of existing drugs, new surgery or radiation therapy techniques, as well as vaccines or other treatments that stimulate a person’s immune system to fight cancer. Combinations of different treatment types may also be tested in such trials.

  • Prevention
    Prevention trials test new interventions (medicines, vitamins, minerals or other supplements) that may lower the risk of developing certain types of cancer. Most cancer prevention trials involve healthy people who have not had cancer; however, they often are designed for people whose risk of developing a specific type of cancer is higher than average.

    Some cancer prevention trials involve people who have had cancer in the past; these trials test interventions that may help prevent the return (recurrence) of the original cancer or reduce the chance of developing a new type of cancer.

  • Screening
    These trials test new ways of finding cancer early. When cancer is found early, it may be easier to treat and there may be a better chance of long-term survival. Cancer screening trials usually involve people who do not have any signs or symptoms of cancer. However, participation in these trials is often limited to people who have a higher than average risk of developing a certain type of cancer because they have a family history of that type of cancer or they have a history of exposure to cancer-causing substances (e.g., cigarette smoke).

  • Diagnostic
    These trials study new tests or procedures that may help identify, or diagnose, cancer more accurately. Diagnostic trials usually involve people who have some signs or symptoms of cancer.

  • Quality of life or supportive care

    These trials focus on the comfort and quality of life of cancer patients and cancer survivors. New ways to decrease the number or severity of side effects of cancer or its treatment are often studied in these trials. How a specific type of cancer or its treatment affects a person’s everyday life may also be studied.

In addition to answering questions about the effectiveness of new interventions, clinical trials provide the opportunity for additional studies.  These additional research studies, called correlative or ancillary studies, may use blood, tumor, or other tissue specimens (also known as “biospecimens”) obtained from trial participants before, during, or after treatment. For example, the molecular characteristics of tumor specimens collected during a trial might be analyzed to see if there is a relationship between the presence of a certain gene mutation or the amount of a specific protein and how trial participants responded to the treatment they received. Information obtained from these types of studies could lead to more accurate predictions about how individual patients will respond to certain cancer treatments, improved ways of finding cancer earlier, new methods of identifying people who have an increased risk of cancer, and new approaches to try to prevent cancer.

Clinical trial participants must give their permission before biospecimens obtained from them can be used for research purposes.

What are the phases of clinical trials?

New interventions are often studied in a stepwise fashion, with each step representing a different “phase” in the clinical research process. These are highly regulated activities that allow researchers to pose questions that result in reliable information about the drug and protect patients. The following phases are used for cancer treatment trials:

  • Phase 0 clinical trials

    These trials represent the earliest step in testing new treatments in humans. In a phase 0 trial, a very small dose of a chemical or biologic agent is given to a small number of people (approximately 10-15) to gather preliminary information about how the agent is processed by the body (pharmacokinetics) and how the agent affects the body (pharmacodynamics). Because the agents are given in such small amounts, no information is obtained about their safety or effectiveness in treating cancer. Phase 0 trials are also called micro-dosing studies, exploratory Investigational New Drug (IND) trials, or early phase I trials. The people who take part in these trials usually have advanced disease, and no known, effective treatment options are available to them.
  • Phase I clinical trials

    These trials are conducted mainly to evaluate the safety of chemical or biologic agents or other types of interventions (e.g., a new radiation therapy technique). They help determine the maximum dose that can be given safely (also known as the maximum tolerated dose) and whether an intervention causes harmful side effects. Phase I trials enroll small numbers of people (20 or more) who have advanced cancer that cannot be treated effectively with standard (usual) treatments or for which no standard treatment exists. Although evaluating the effectiveness of interventions is not a primary goal of these trials, doctors do look for evidence that the interventions might be useful as treatments.
  • Phase II clinical trials

    These trials test the effectiveness of interventions in people who have a specific type of cancer or related cancers. They also continue to look at the safety of interventions. Phase II trials usually enroll fewer than 100 people but may include as many as 300. The people who participate in phase II trials may or may not have been treated previously with standard therapy for their type of cancer. If a person has been treated previously, their eligibility to participate in a specific trial may depend on the type and amount of prior treatment they received. Although phase II trials can give some indication of whether or not an intervention works, they are almost never designed to show whether an intervention is better than standard therapy.
  • Phase III clinical trials

    These trials compare the effectiveness of a new intervention, or new use of an existing intervention, with the current standard of care (usual treatment) for a particular type of cancer. Phase III trials also examine how the side effects of the new intervention compare with those of the usual treatment. If the new intervention is more effective than the usual treatment and/or is easier to tolerate, it may become the new standard of care.

    Phase III trials usually involve large groups of people (100 to several thousand), who are randomly assigned to one of two treatment groups, or “trial arms”: 1) a control group, in which everyone in the group receives usual treatment for their type of cancer, or 2) an investigational or experimental group, in which everyone in the group receives the new intervention or new use of an existing intervention. The trial participants are assigned to their individual groups by random assignment, or randomization. Randomization helps ensure that the groups have similar characteristics. This balance is necessary so the researchers can have confidence that any differences they observe in how the two groups respond to the treatments they receive are due to the treatments and not to other differences between the groups.

    Randomization is usually done by a computer program to ensure that human choices do not influence the assignment to groups. The trial participants cannot request to be in a particular group, and the researchers cannot influence how people are assigned to the groups. Usually, neither the participants nor their doctors know what treatment the participants are receiving.

    People who participate in phase III trials may or may not have been treated previously. If they have been treated previously, their eligibility to participate in a specific trial may depend on the type and the amount of prior treatment they received.

    In most cases, an intervention will move into phase III testing only after it has shown promise in phase I and phase II trials.
  • Phase IV clinical trials

    These trials study a treatment after the FDA has approved it.  Phase IV trials evaluate the side effects, risks, and benefits of a drug or other therapy over a long period of time and in a larger number of people than in phase III trials.  Thousands of people are involved in a phase IV trial, and randomization is generally not used.

Learn more about clinical trials

We hope this guide will help you understand some of the basics of clinical trials.

Should you have any questions about clinical trials or trials offered, please contact us at The Sue and Ralph Stern Center for Cancer Clinical Trials and Research:

Toll free:           877-UC-STUDY 

Email:               ucstudy@uci.edu

Additionally, the National Cancer Institute (NCI) has an expansive website of information. NCI-Clinical Trials

Key questions to ask your doctor

Anyone considering a clinical trial should feel free to ask any questions or bring up any issues concerning the trial at any time. NCI has some suggestions of questions to ask your doctor that may give you various ideas as you think about your own questions.

NCI Questions to Ask Your Doctor

Find a clinical trial

Search our database of clinical trials at the Chao Family Comprehensive Cancer Center that are currently enrolling new participants. 

Please note that our clinical trials information is updated periodically, so there is the potential that a trial listed as open on this site may not be open any longer. Similarly, there may be trials available in addition to those listed here. We recommend contacting the Clinical Trials toll free number at 877.UC.STUDY  (877.827.8839) or email ucstudy@uci.edu to confirm clinical trial availability and/or to get further information about specific trials.

Search for open clinical trials


Additional Resources
Helpful resources, including a podcast, from the American Society of Clinical Oncology
Registry of all clinical trials — for cancer and other medical conditions — from the National Institutes of Health (NIH)