According to the National Institutes of Health, a clinical trial is "a research study to answer specific questions about vaccines or new therapies or newways of using known treatments." These studies allow researchers to determinewhether new drugs or treatments are safe and effective. When conducted carefully, clinical trials can provide fast and safe answers to these questions.
Ideas for clinical trials usually originate with medical researchers. After researchers have tested new therapies or procedures in their own laboratories,they begin planning first-phase clinical trials if the new therapies or procedures seem to hold promise. Tests on humans are carried out only if laboratory and animal studies show promising results.
Clinical trials must adhere to a set of rules called protocols. The protocolsdefine the requirements for participating in the trial; the schedules of tests, procedures, medications, and dosages; and the duration of the study. In the course of the clinical trial, the research staff monitors the health of the participants and ascertains the safety and effectiveness of the treatment.
Clinical trials involving experimental drugs proceed through four phases: InPhase I, researchers conduct their first tests on from 20 to 80 volunteers inorder to evaluate the drug's safety, determine a safe dosage range, and identify side effects. In Phase II, the drug under study is given to a larger population (100-300 volunteer patients) to test its effectiveness and to acquirefurther data about its safety. In Phase III, the study drug is administeredto an even larger group of patients (1,000-3,000) to further study the drug'seffectiveness, monitor its side effects, compare it to other commonly used treatments, and collect data that will allow the drug to be used safely. PhaseIV clinical studies are conducted after the drug has been marketed to collect information about its effect in various populations and about any side effects associated with long-term use.
The federal government has established strict guidelines and instituted safeguards to protect participants in clinical trials. All clinical trials carriedout in the United States must be approved and monitored by an independent committee of physicians, statisticians, community advocates, and others to ensure that the clinical trial is ethical and that the rights of study participants are protected. Federal regulations require that any institution that conducts or supports biomedical research on human beings have such a committee inplace to initially approve and periodically review the research.
Participants in clinical trials must be informed about the key facts of the clinical trial before they decide whether or not to participate. These facts include the purpose of the research; the goal of the research; the plan and duration of the trial; any potential risks; potential benefits; as well as theexistence of any alternative treatments. In addition, the participant in theclinical trial must be informed that he or she has the right to withdraw fromthe trial at any time.
All clinical trials place restrictions on who can participate in the programbased on such factors as age, type of disease, medical history, and current medical condition. Some clinical trials need volunteers with illnesses or conditions to be studied in the clinical trial, whereas Phase I trials, vaccine studies, and research on preventive care may seek healthy volunteers.
Clinical trials are sponsored by government agencies such as the National Institutes of Health; pharmaceutical companies; individual physicians; health care institutions; and organizations that develop medical devices or equipment.Trials typically take place in hospitals, universities, doctors' offices, and community clinics.
Controls, i.e., standards by which experimental observations are evaluated, play an important role in clinical research. In many clinical studies, participants in a control group receive an inactive pill, liquid, or powder (a placebo) that has no treatment value instead of an active drug or treatment. Thisis because experimental treatments are often compared with placebos to assessthe treatment's effectiveness. If the clinical trial is blind or masked, participants are not informed whether they are in the experimental or control group. In double-blind or double-masked studies, neither the participants nor the study staff know which participants are receiving the experimental treatment and which ones are receiving either a standard treatment or placebo.