What is a clinical trial?
A clinical trial (also clinical research) is a research study in human volunteers to answer specific health questions. Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people and ways to improve health. Interventional trials determine whether experimental treatments or new ways of using known therapies are safe and effective under controlled environments. Observational trials address health issues in large groups of people or populations in natural settings.
Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.
Treatment trials - test experimental treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.
Prevention trials - look for better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vitamins, vaccines, minerals, or lifestyle changes.
Diagnostic trials are conducted to find better tests or procedures for diagnosing a particular disease or condition.
Screening trials test the best way to detect certain diseases or health conditions.<
Quality of life trials (also called supportive care trials) explore ways to improve comfort and the quality of life for individuals with a chronic illness.
Clinical trials are conducted in phases. The trials at each phase have a different purpose and help scientists answer different questions:
Phase I trials – Researchers test an experimental drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase II trials – The experimental study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.
Phase III trials – The experimental study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely.
Phase IV trials– Post marketing studies delineate additional information including the drug's risks, benefits, and optimal use.
How is a clinical trial planned and carried out?
In order to make a decision about whether to participate in a clinical trial, it helps to understand more about how trials are conceived and run. You will also want to know what happens when a trial is over..
The ideas for clinical trials often originate in the laboratory. Researchers develop a clinical trial protocol (the plan for a trial) after laboratory studies indicate the promise of a new drug or procedure. The first trials of a particular drug or procedure are focused on safety (phase I), and later trials focus on whether the drug or procedure is effective (phase II or phase III).
Every trial has a person in charge, usually a doctor, who is called the protocol chair or principal investigator. Phase I and phase II studies generally refer to the person in charge as the principal investigator. Phase III studies generally have a protocol chair, under whose direction multiple principal investigators carry out the protocol in participating sites. The protocol chair or principal investigator prepares a plan for the study, called a protocol. The protocol explains what the study will do, how it will be carried out, and why each part of the study is necessary. For example, the protocol includes:
- The reason for doing the study.
- How many people will be in the study.
- Who is eligible to participate in the study.
- What study drugs participants will take, if any.
- What medical tests they will have, if any, and how often.
- What information will be gathered.
Clinical trials are sponsored or funded by a variety of organizations or individuals such as physicians, medical institutions, foundations, voluntary groups, and pharmaceutical companies, in addition to federal agencies such as the National Institutes of Health (NIH), the Department of Defense (DOD), and the Department of Veteran's Affairs (VA). Trials can take place in a variety of locations, such as hospitals, universities, doctors' offices, or community clinics.
After a phase I or phase II trial is completed, the researchers look carefully at the data collected during the trial and decide whether to:
- Move on to the next trial with the treatment, OR
- Stop testing the treatment because it is not safe or effective.
When a phase III trial comes to an end, the researchers must look at the data and decide if the results have medical importance. When the analysis of a phase I, phase II, or phase III trial is complete, the researchers will inform the medical community and the public of the study results. In most cases, the results of trials are published in scientific or medical journals. To find out if the results of a study you participated in was published:
- Ask the doctor or nurse in charge of your treatment.
- Find out the official name of your study and search for the study in the PubMed database of medical publications. If you have trouble searching for/locating the study, the research librarian at a university or medical library may be able to help.
- Use the advanced search form to search for the trial among the closed protocols (change the status of the trial from active to closed on the advanced search form) More than 7,800 closed protocols have reference citations for published results.
Most medical and scientific journals have in place a process of peer review, in which experts critique the report before it is published, to make sure that the analysis and conclusions are sound. Particularly important results are likely to be featured by the print or electronic media, and widely discussed at scientific meetings and by patient advocacy groups. Once an intervention is proven safe and effective in a clinical trial, it may become the new standard of practice. In this way the development of better interventions for prevention, for treatment, or for detection and diagnosis is an ongoing, continuous process that builds progressively on itself to improve the quality of cancer care and prevention available to us all.
How do I take part in a clinical trial?
Once you've decided that participating in a clinical trial could prove beneficial to you, there are other factors to consider that might affect your participation:
All clinical trials have guidelines about who can participate. Using inclusion/exclusion criteria is an important principle of medical research that helps to produce reliable results. The factors that allow someone to participate in a clinical trial are called "inclusion criteria" and those that disallow someone from participating are called "exclusion criteria". These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. Before joining a clinical trial, a participant must qualify for the study. Some research studies seek participants with illnesses or conditions to be studied in the clinical trial, while others need healthy participants. It is important to note that inclusion and exclusion criteria are not used to reject people personally. Instead, the criteria are used to identify appropriate participants and keep them safe. The criteria help ensure that researchers will be able to answer the questions they plan to study.
If you were to participate in a clinical trial, you might do so at a large cancer center, a university hospital, or your local medical center or physician's office.
The trial may include participants at one or two highly specialized centers or it may involve hundreds of locations at the same time. You would participate in the trial under the guidance of a team including your physician and other health professionals, who would report your experience during the trial back to the center responsible for the trial's overall coordination. Experts then use the information from all of the participants to evaluate the intervention that the trial is testing.
The trial sponsor usually pays for the cost of the intervention being studied (for example, any drugs being compared). The sponsor also usually pays for the cost associated with any special testing or extra doctor visits that are required.
"Routine patient care costs" are the usual costs of medical care, such as doctor visits, hospital stays, clinical laboratory tests, x-rays, etc., that you would receive whether or not you were participating in a clinical trial. Some health plans don't cover these costs once you join a trial, even though studies have shown that they are not appreciably higher than costs for patients who are not enrolled in trials.
Ask the staff at your health plan whether your insurance will cover these routine costs if you enroll in a trial.
Should I take part in a clinical trial?
Only you can make the decision about whether or not to participate in a clinical trial. Before you make your decision, you should:
- Learn as much as possible about your disease and the trials that are available to you.
- Talk about this information and how you feel about it with your doctor and/or nurse, family members and friends to help you determine what is right for you.
Potential benefits include:
- Playing an active role in your own health care.
- Gaining access to new research treatments before they are widely available.
- Obtaining expert medical care at leading health care facilities during the trial.
- Helping others by contributing to medical research.
The potential risks include:
- Unpleasant, serious or even life-threatening side effects to experimental treatment.
- Ineffectiveness of experimental treatment for the participant.
- Requiring more time and attention than a non-protocol treatment, including trips to the study site, more treatments, hospital stays or complex dosage requirements.
The government has a system designed to protect human research subjects. Before a government-funded clinical trial can begin, the trial plan (also called a protocol) must be approved. During the trial, review committees make sure that the plan is being followed and participants are being protected.
Regulations require the researchers performing studies to thoroughly inform patients about a study's treatments and tests and their possible benefits and risks before a patient decides whether or not to participate in any study. This process is called informed consent.
Informed consent is a process in which you learn the key facts about a clinical trial before you decide whether or not to participate. In addition to talking about these facts with the research doctor or nurse, they will be included in a written consent form that you can take home to read and discuss. The consent form will include details about:
- The study approach.
- The intervention given in the trial.
- The possible risks and benefits.
- The tests you may have.
Don't hesitate to ask questions until you have all the information you need (see Participating in a Trial: Questions to Ask Your Doctor). While informed consent begins before you agree to participate in a trial, you should feel free to ask the health-care team any questions you have at any point. Informed consent continues as long as you are in the study. You can change your mind and leave the study whenever you want -- before the study starts or at any time during the study or follow-up period.
A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the experimental treatment's effectiveness. In some studies, the participants in the control group will receive a placebo instead of an active drug or experimental treatment.
If you decide to participate in a clinical trial, you will work with a research team. Team members may include doctors, nurses, social workers, dieticians, and other health care professionals. They will provide your care, monitor your health carefully, and give you specific instructions about the study.
Participating in a trial may mean that you might have more tests and doctor visits than you would if you weren't in the study. Team members also may continue to stay in contact with you after the trial ends. To make the trial results as reliable as possible, it is important for participants to follow the research team's instructions. That means having all doctor visits and tests, taking medicines on time, and completing logs or answering questionnaires.