What are clinical trials?

Clinical trials are research studies that test new drugs and treatments for both safety and effectiveness in human beings. Clinical trials are carefully controlled and conducted by physicians, nurses, and other health care professionals. The results of clinical trials help determine if a particular treatment should be approved and made available for broader use to improve the overall standard of care.

What are the potential benefits of participating in a clinical trial?

  • Clinical trials allow access to new treatments before they become available to the public and allow you to expand your treatment options.
  • Clinical trials offer the possibility of quality medical care at leading institutions.
  • Clinical trials provide an opportunity to contribute to science and medical research for future disease prevention and treatment.

What are the potential drawbacks of participating in a clinical trial?

  • You may find that the drug or treatment does not work for you.
  • You may not receive the treatment being studied (see placebos and controls).
  • You may experience side effects or adverse reactions to medications or treatments.
  • You may be required to visit a physician and have tests and evaluations more often than you would otherwise.

Who conducts a clinical trial?

Clinical trials are typically sponsored by government agencies (such as the National Institutes of Health) and by biotechnology, pharmaceutical, and medical device companies that develop new drugs and treatments. Clinical trials take place at a variety of investigative sites such as hospitals, medical centers, and doctors' offices. As a participant, your contact is the health care provider (investigator) at the investigative site.

What does clinical trial "phase" mean?

Before any drug, device, or treatment is tested in humans, it is tested in animals. This is done to ensure the basic safety of the treatment. No treatment is given to animals or humans unless the researchers have a scientific basis for believing that the treatment will have a positive rather than a negative effect. Once the treatment has been determined to be safe for testing in humans, clinical trials are conducted in up to four standard phases:

  • Phase I trials involve a small number of people (fewer than 100) and are used to evaluate the safety of the treatment, determine the appropriate dose, and identify side effects.
  • Phase II trials are larger (100–300 people) and involve further evaluation of the safety and efficacy of the treatment.
  • Phase III is the largest phase (with trials involving 1,000–3,000 people). Again, researchers evaluate the efficacy of the treatment, compare it to other existing treatments, and monitor the rate of side effects.
  • Phase IV trials are conducted after a treatment has been approved by the Food and Drug Administration (FDA) and is available to the public. This phase continues to test the treatment and collect valuable information on its effects in different people, including any side effects associated with long-term use.

What are placebos and controls?

Not all participants in a clinical trial will receive the same treatment. In order to evaluate how the treatment being studied (target treatment) compares to existing treatments, investigators usually gather data from participants receiving different treatments. Some participants receive the target treatment and some receive existing treatments or other care. A process called randomization determines what treatment a participant receives. Randomization means participants are randomly assigned to a treatment group. This process ensures that researchers get accurate data and results.

Participants receiving other types of care are in "control" groups. Some control groups may receive an inactive treatment, such as a sugar pill, which is called a "placebo." Placebos are used to help researchers determine whether the active target treatment is safer or more effective than receiving no treatment at all.

Giving some participants a placebo helps researchers rule out the "placebo effect," which is when participants think they are improving simply because they are receiving medical care and taking a pill—even if it’s not the active treatment. Using a placebo helps researchers better understand how the target treatment is affecting patients. Not all clinical trials include placebos; if you are concerned about this possibility, ask the investigator for more information.

What is a "blind" or "masked" clinical trial?

You may hear that a treatment is being tested through a "blind" or "masked" clinical trial. This means that participants don't know whether the treatment they are receiving is the target treatment or a control treatment.

If a trial is "double-blind" or "double-masked," that means that neither the trial participants nor the investigators know who is receiving the target versus control treatments. This is done so that results will not be interpreted based on participants' or researchers' expectations or hopes that one treatment will be proven more effective than others. In blind/double-blind or masked/double-masked clinical trials, treatments typically are not revealed except in extreme circumstances.

What happens to the clinical trial data?

Researchers review the clinical trial data after each phase of research to determine if the next phase should begin. After Phase III has been completed and researchers determine that the treatment is safe, effective, and an improvement upon existing treatments, the treatment is submitted for review by the FDA. The FDA may then approve the treatment for use in the general public or require that additional research be conducted. Results of clinical trials are sometimes published in medical journals.

How are trial participants selected?

Investigators develop a set of eligibility criteria for selecting clinical trial participants. These criteria are used to ensure that the treatment is appropriate and safe for participants. For example, researchers may choose to investigate the effect of a drug on female stroke patients without a history of other illnesses, rather than on stroke patients with other complications.

In some cases, researchers need to restrict participation in a clinical trial to protect patients from known risks. For example, some drugs can only be given to patients with healthy kidneys; patients with kidney disease would therefore not meet the eligibility criteria for clinical trials involving those drugs.

What are inclusion and exclusion criteria?

Inclusion criteria are characteristics that a patient must have to participate in the trial. For example, a patient must have a confirmed diagnosis of breast cancer in order to be a candidate for a trial testing a drug's effectiveness in treating breast cancer.

Exclusion criteria are characteristics that a patient cannot have in order to participate in the trial. If a treatment requires that a patient have no history of high blood pressure, for example, then a participant with high blood pressure will not be eligible.

How are clinical trial participants protected?

IRB Review: Before a treatment is given to patients in a clinical trial, all aspects of the treatment are thoroughly reviewed by a qualified panel of experts, called an Institutional Review Board, or IRB.

Informed Consent: Before participating in a trial, you are asked to provide your "informed consent." This means that you agree to participate in the clinical trial and that you have been provided with extensive information about the trial.

It is also important to know that agreeing to participate in a clinical trial doesn't mean you have to begin or complete the trial process. You have the right to withdraw from the trial at any time without penalty. You must be given the following information:

  • Goals of the trial
  • Why it is being conducted
  • Information about the treatment you will be given
  • Exactly what participation will involve
  • The known risks and benefits of participation
  • Alternative treatments that are currently available
  • Contact information for the trial investigators

What is a clinical trial protocol?

A clinical trial protocol is a document that describes the purpose and objectives of the clinical trial: why the research is being done, how the research is going to be done, and the requirements and responsibilities of study participants. It includes details about what medications study participants will receive, what tests and procedures they will have, the number of times they will have to visit the study site, what will happen at study visits, and the length of the clinical trial.

What types of treatment will I receive?

The actual treatment you receive varies a great deal from trial to trial. In general, however, you can expect that:

  • A team of health care professionals, such as physicians and nurses, will run the trial.
  • You will receive an evaluation at the beginning of the trial to determine your health status at the time.
  • You will be given specific, easy-to-follow instructions on how to proceed through the trial.
  • You can expect to be monitored carefully during the trial and you may be contacted for follow-up after the trial has ended.
  • Your participation in a clinical trial may mean you will visit a health care professional or receive medications or procedures more frequently than you otherwise would.
  • The trial is likely to continue for several months.

Are there any costs involved in participation?

Research costs, such as the cost of hiring personnel and managing data, are covered by the organization sponsoring the clinical trial. Some clinical trials will pay you for joining the trial, although this is not something all trials do, and it is not required.

You may also receive reimbursement for expenses you have as a result of participation, such as transportation costs. Patient care costs may be covered by medical insurance, although this varies by policy and by trial. You should seek more information about this arrangement from the trial investigator and from your insurance provider. For some clinical trials, medical insurance is not required.

Do I need to coordinate with or notify my physician?

If the health care provider who has been treating your condition is not the one conducting the clinical trial, you are strongly encouraged to talk to him/her about trial participation.

How does the drug development process work?

The First Step: Laboratory Work—Before a drug can be prescribed to patients, it must go through a lengthy development process. The first step is a discovery phase, where scientists conduct laboratory work to identify compounds that have some potential to become a medicine that benefits human health care. Molecular biologists, organic chemists, toxicologists, and other scientists do this work.

The Second Step: Animal Studies—Only a small percentage of the chemical compounds studied by scientists show promise for eventual use as treatment for human disease. These drugs are then studied further in animals. Researchers take this step very seriously, giving the treatment to as few animals as possible and taking care to treat each animal humanely. This stage allows researchers not only to identify side effects, but also to learn how the drug interacts in a living being—how it is absorbed in the blood, for example.

The Third Step: Request to the FDA to Conduct Human Studies—The FDA, which will provide ultimate approval for wide use of a drug, becomes involved in the development process at this stage. Drug developers and researchers must present the results of their laboratory and animal research to the FDA, which can then approve a plan for testing the drug in humans.

The Fourth Step: Clinical Trials—Clinical trials occur pretty late in the process of drug development, at a point when the treatment has already gone through extensive laboratory and animal testing. As discussed above, clinical trials must occur in three or four phases, each of which has a different objective. A phase cannot begin until the results of the previous phase have been received and studied to determine the impact of the treatment on humans.

The Fifth Step: Application for FDA approval—Before a drug can gain approval from the FDA, its developers must demonstrate through clinical trial research and results that it is safe and effective. Officials review the risks and benefits to patients and will approve a drug or treatment only if its proven benefits outweigh its risks. Although the FDA considers its role to be of major importance, it also recognizes that delaying drugs with years of testing may be detrimental to patients. Efforts are often made to complete the evaluation process as quickly as possible.

Where can I find more information about clinical trials?

It is important to understand the clinical trial process, as well as the features of the particular trial you are considering, before you agree to become a participant. For more information, the website clinicaltrials.gov includes a list of questions to ask about trial participation and links to additional resources. Also, remember that you should discuss trial participation with your health care provider, as well as with your loved ones.

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 04 Dec 2007

Last Modified: 13 Nov 2014