Clinical trials are conducted to collect data regarding the safety and efficacy of new drug and device development. There are several steps and stages of approval in the clinical trials process before a drug or device can be sold in the consumer market.
Drug and device testing begins with extensive laboratory research that can involve years of experiments in animals and human cells. If the initial laboratory research is successful, researchers send the data to the Food and Drug Administration (FDA) for approval to continue research and testing in humans.
Once approved, human testing of experimental drugs and devices can begin and is typically conducted in four phases. Each phase is considered a separate trial and, after completion of a phase, investigators are required to submit their data for approval from the FDA before continuing to the next phase.
Phase I studies assess the safety of a drug or device. This initial phase of testing, which can take several months to complete, usually includes a small number of healthy volunteers (20 to 100) who are generally paid for participating in the study. The study is designed to determine the effects of the drug or device on humans including how it is absorbed, metabolized, and excreted. This phase also investigates the side effects that occur as dosage levels are increased. About 70% of experimental drugs pass this phase of testing.
Phase II studies test the efficacy of a drug or device. This second phase of testing can last from several months to two years, and involves up to several hundred patients. Most phase II studies are randomized trials where one group of patients receives the experimental drug while a second "control" group receives a standard treatment or placebo. Often these studies are "blinded", which means that neither the patients nor the researchers know who has received the experimental drug. This allows investigators to provide the pharmaceutical company and the FDA with comparative information about the relative safety and effectiveness of the new drug. About one-third of experimental drugs successfully complete both Phase I and Phase II studies.
Phase III studies involve randomized and blind testing in several hundred to several thousand patients. This large-scale testing, which can last several years, provides the pharmaceutical company and the FDA with a more thorough understanding of the effectiveness of the drug or device, the benefits and the range of possible adverse reactions. 70% to 90% of drugs that enter Phase III studies successfully complete this phase of testing. Once Phase III is complete, a pharmaceutical company can request FDA approval for marketing the drug.
Phase IV studies, often called postmarketing surveillance trials, are conducted after a drug or device has been approved for sale. Pharmaceutical companies have several objectives at this stage: (1) to compare a drug with other drugs already in the market; (2) to monitor a drug's long-term effectiveness and impact on a patient's quality of life; and (3) to determine the cost-effectiveness of a drug therapy relative to other traditional and new therapies. Phase IV studies can result in a drug or device being taken off the market or restrictions of use could be placed on the product depending on the findings in the study.
People participate in clinical trials for different reasons. Some have a medical condition and after trying several different treatments that didn’t work, they opt for clinical trials. Some volunteer as social responsibility to advance medical care through research for future generations, others opt to participate because they have a personal interest in science.
Funding for clinical research comes from the federal government, such as the National Institutes of Health, the Department of Defense, the Department of Veterans Affairs, and private industry such as pharmaceutical and biotech companies, medical institutions, and foundations.
Volunteers participating in a clinical trial receive investigational treatments under the supervision of a physician and other research professionals. These treatments are developed by pharmaceutical and biotechnology companies who select qualified physicians, also known as investigators, to conduct clinical trials to determine the benefits of investigational drugs or devices.
When considering volunteering for a clinical trial, it is important to make an informed decision. Below are answers to frequently asked questions that many potential volunteers have about participating in a study.
All clinical trials have guidelines about who can participate. Before joining a clinical trial, a volunteer must qualify for the study. The factors that allow volunteers to participate in a clinical trial are called inclusion criteria and the factors that disallow volunteers from participating are called exclusion criteria. These criteria can include age, gender, the type and stage of a disease, previous treatment history, and other medical conditions.
Some research studies seek participants with specific illnesses or conditions to be studied in a clinical trial, while others require healthy participants. It is important to note that inclusion and exclusion criteria are used to identify appropriate participants, promote participants' safety, and ensure that researchers learn the information they need.
In a clinical trial, a volunteer is usually assigned a specific study group. Volunteers in one study group may receive an investigational treatment or study drug while other volunteers may receive a placebo or a treatment already available.
A placebo is an inactive product used to assess the experimental treatment's effectiveness. The participant, physician, and research staff may not know which volunteer receives a placebo and which receives the active treatment. Not knowing which participants are receiving the active treatment allows the physician and research staff to objectively observe the volunteers during the study. Regardless of which treatment volunteers receive, however, the level of medical attention and care that each receives is the same.
Patients considering participating in a clinical trial should talk about it with their physicians and medical caregivers. Potential volunteers should also understand the credentials and experience of the staff and the facility involved in conducting the study.
Questions to ask a physician or medical caregiver:
In some studies, participants receive a physical examination and their medical histories are reviewed by either the study physician or a research staff member once they are enrolled in the study. The volunteers' health will continue to be monitored during and after the trial. A detailed description of what's expected of volunteers will be outlined in consent forms along with specific clinical trial information.
Volunteers in a clinical trial participate in the development of medical therapies that may offer better treatments or cures for life-threatening and chronic diseases. There are risks involved but participants can leave a trial at any time.
Possible benefits for volunteers:
Possible risks for volunteers:
Access to personal information is usually available to the investigator and research team conducting the clinical trial. In some circumstances, the IRB overseeing the research and the sponsor or contract research organization coordinating the trial will also have access to personal information. This is explained more specifically in the consent form that participating volunteers are asked to sign. As a clinical trial progresses, researchers report the aggregate results of the trial at scientific meetings, to medical journals, and to various government agencies.
After a study phase is complete, the data are collected to determine the drug's effectiveness, if it is safe and if there are any side effects. Depending on the results, researchers then determine whether to stop testing or move to the next phase of study. After phase III of a study is complete, researchers decide if the results are medically important and may submit them to journals for peer review. Data then may be submitted to the Food and Drug Administration (FDA) for approval.
If a drug is approved, pharmaceutical companies may continue to conduct studies that compare the new drug—in terms of its safety, effectiveness, and cost—to other drugs already on the market or assess a drug's long-term effectiveness and its impact on the quality of a person's life.
Informed consent is an ethical and a legal process of communication between a clinical trial volunteer and the health care provider conducting the trial that then leads to the volunteer’s permission for care and treatment services. This process helps the participant fully understand and be informed about the clinical trial the participant is about to participate in and thereby decide whether to participate in the trial or not.
If you have given consent to participate in a clinical trial, or if you have given consent on behalf of another person, you both are entitled to the following rights:
When you give written consent to participate in a clinical trial, you are acknowledging that you understand and accept all aspects of the research study—including any risks or benefits involved. However, informed consent is not strictly about signing a document. It is a process that involves ongoing conversations between the research staff and you before, and even after, you decide to become a study volunteer.
To begin, the research staff is obligated to discuss all the pertinent information about the trial—its purpose, the procedures involved, the potential risks and benefits—with you. It is your responsibility to ask questions if there is something you do not understand.
If you do not understand any part of the process, ask the researcher to repeat the information or to explain it in another way, using everyday words. If English is not your first language, inform the researcher that you are not comfortable speaking about a clinical trial in English. Upon request, research centers can and should produce documents that explain every aspect of the study and study personnel should be able to explain the information to you in your preferred language. If this is not possible, you should not participate in the study.
It is the responsibility of the research staff to help you understand the information they provide you and to give you enough time to ask any additional questions you may have. In some instances, this may not be possible to accomplish in a single visit, therefore it is essential to take the time you need to make an informed decision. You may discover important concerns that you did not think about during the first visit.
The following represents a sample list of questions that you should ask during the informed consent process about the clinical trial:
About your care:
About personal matters:
About compensation and costs:
A WCG CenterWatch survey of 672 study volunteers offers insight into the informed consent process and whether or not it is working to help volunteers understand their roles and responsibilities. Some key takeaways from the study are:
Research studies are very involved so it is important to learn as much as possible about the study you may participate in before you consent. The Food and Drug Administration (FDA) guidelines state that study volunteers should understand the risks they're taking, which may mean spending additional time with the research staff to make sure you get the information you need. If you want to know details, such as any documented side effects of a particular drug observed in earlier clinical trials, you must ask for that information as well as any other information you may want to know.
The decision to participate in a clinical trial is a personal one and one that you are entitled to make freely, without influence or coercion. Being properly informed so that you fully understand the responsibilities of becoming a study volunteer is the best way to ensure that you are making the right decision for you.
The Food and Drug Administration (FDA) regulates the approval and marketing of all the drugs and complex medical devices that are sold in the market. These drugs and devices must be proven safe and effective to the FDA before companies can put them out on the market. For a listing of drugs approved by the Food and Drug Administration (FDA) for sale in the U.S., click here.
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