Clinical Trials

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Clinical Trials

Considerations before entering a clinical trial as a subject

Definition

A clinical trial is a controlled scientific experiment designed to determine the effectiveness of a treatment in curing or lessening the symptoms of a disease or disorder.

Clinical trials typically are used to assess the effectiveness of a new treatment in comparison with the current standard of care or an existing treatment for a disease or disorder. For example, before a new drug is approved by the U.S. Food and Drug Administration (FDA) for release and use in the United States, the drug must first undergo rigorous testing to determine (a) whether or not it is effective in treating the disorder, and (b) what side effects may result from the drug use that make it inadvisable or dangerous to some or all potential patients.

Clinical trials are research studies designed according to professional standards using scientific methods. In clinical trials, as many variables as possible are controlled to determine the effects of the drug or treatment option. For example, a simple experiment to test the effectiveness of a new drug for epilepsy might include the following steps. First, researchers typically randomly divide the research subjects into two groups: one group that receives the new drug and the other group that receives the conventional drug or treatment. The group receiving the new drug is called the experimental group and the group receiving no treatment or conventional treatment is called the control group. Researchers then collect baseline data on the symptoms of the subjects prior to treatment, such as number and frequency of seizures . This phase of the experiment is called the pretest. After the pretest data are collected, the researchers give the new drug (the independent variable) to the experimental group while not changing the treatment of the control group. After an appropriate amount of time for the drug to take effect, the subjects are tested again using the same criteria as were used for the pretest to determine any difference between the two groups as a result of the drug (dependent variable). When all the data are collected, they are statistically analyzed to determine if there is a reasonable basis to say that the effects of the new drug are significantly different from the effects of the old treatment (or no treatment) and not due to chance variations. This basic research design can be made more complicated to simultaneously answer multiple research questions, such as what dose of the new medication is most effective, whether increasing dosage levels of the medication results in more side effects, whether the drug is effective for some demographic groups but not others (e.g., only works well on adult females but not on adult males), or to compare several treatments at once.

KEY TERMS

Control group —A group in a research study that does not receive the experimental treatment. For example, in an experiment testing the effectiveness of a new drug, the control group might receive the current drug of choice while the experimental group receives the new drug under investigation.

Dependent variable —The outcome variable in an experiment. For example, in a test of the effects of a new drug for the treatment of a disease, the effects of the drug on the disease (i.e., the change in symptoms after taking the drug) would be the dependent variable.

Double-blind study —A research study in which neither the participants nor the professional administering the drug or treatment know whether they are receiving the experimental treatment or a placebo or control treatment.

Experimental group —The group of participants in a research study who receive the experimental treatment or drug under investigation.

Independent variable —The variable in an experiment that is manipulated by researchers in order to determine its effects. For example, in a test of the effects of a new drug on the treatment of a disease, whether or not the subjects received the new drug would be the independent variable.

Informed consent —A legal document prepared as an agreement for treatment or nontreatment that requires physicians to disclose the benefits, risks, and alternatives of the treatment. Informed consent allows fully informed, rational patients to be involved in the choices about their health.

Placebo —A preparation without pharmacological effect that is given in place of a drug in clinical trials to determine the effectiveness of the drug under study; a “sugar pill.”

Randomization —The process of randomly assigning participants in an experiment to the various conditions (i.e., experimental and control groups) so that each individual has an equal chance of being assigned to any of the groups. Randomization helps ensure that each of the groups is roughly the same and that the results are due to the treatment, not to the makeup of the groups.

Research subject —A participant in a research experiment or clinical trial.

There are several general types of clinical trials:

treatment trials that test the relative effectiveness of new drugs or treatments or combinations of drugs and/or treatments
prevention trials that investigate ways to prevent a disease in individuals who have not previously had it or to prevent its return in individuals who have previously had the condition
diagnostic trials that seek to find better ways for diagnosing a disorder or illness
screening trials to determine the best way to detect a disease or disorder
quality-of-life trials that investigate how to make life easier or more normal for those with a chronic illness

Clinical trials typically have four phases. In Phase I, the experimental drug or treatment is tested on a small group of people to investigate its safety, determine a recommended dosage or range, and identify potential side effects. In Phase II, the experimental drug or treatment is tested on a larger group of people to further determine its effectiveness and safety. Phase III clinical trials examine the drug or treatment from an even wider perspective. The experimental drug or treatment is given to large groups of people to confirm the findings of the previous studies on a larger population. Phase III clinical trials are also often used to compare the relative effectiveness of treatments and gather safety information. Finally, Phase IV clinical trials are run after a drug has been marketed. At this time a drug may undergo further studies to examine its risks, benefits, and optimal use.

Considerations before entering a clinical trial as a subject

Clinical trials are necessary to help ensure the safety and effectiveness of a drug or treatment before it is put into general use. In addition, joining a clinical trial as a research subject may be of potential benefit to patients who have exhausted available treatment options without success. Clinical trials give patients the opportunity to try a new drug or treatment that may help their condition when conventional methods have failed. However, certain things must be considered before joining a clinical trial as a subject.

First, there is no guarantee that subjects in clinical trials will receive the new drug or treatment. They may

be randomly placed in the control group where they receive a placebo or conventional treatment rather than the new drug or treatment. There is no way to tell whether or not one will be in the experimental group or the control group. Frequently,even researchers or people administrating the treatment do not know which group the subject is in (this is called a double-blind study) so that their expectations will not unintentionally bias the results. Therefore,all other available treatment options should typically be tried before joining a clinical trial as a subject.

In addition, there is always the possibility of encountering unknown negative side effects from the new drug or treatment. For this reason, subjects in clinical trials are required to read, understand, and sign informed consent documents. The decision to join a clinical trial as a subject should always be made in conjunction with one’s health care provider in order to reduce the risk of negative side effects from the treatment.