It wasn’t until the mid-20th century when the concept of doing carefully designed trials held as a framework for determining safety and efficacy and ensuring that the observed effects were real and not due to chance. The first randomized, controlled clinical trial in modern medicine began in the late 1940s. Clinical trials are based on a number of key principles and methods. For example, observing treatment effects among a large enough group of people reduces the likelihood of chance occurrences. Doctors and researchers typically compare results between a group of people who receives an experimental treatment (treatment group) and a group who receives an older treatment or no treatment at all (control group). Studies that involve a control group are called “controlled” studies.
Initially, doctors and researchers simply gave all their patients with a certain illness a new treatment and then compared their results to those of people with the illness treated at an earlier time (either by the same or different doctors). For example, if doctors found that 80% of their patients survived malaria after receiving a new treatment, whereas previously only 60% survived, then they would conclude that the newer treatment was more effective. Studies that compare current treatment results to past results are called retrospective or historical studies.
A problem with historical studies is that the treatment group also has the benefit of other advances in medical care that had since been developed. It doesn’t make sense to compare the treatment results of people receiving a therapy in 2006 with those who received a therapy in 1966. Medical advances during the intervening period may be responsible for any improvement in outcome. To avoid this problem with historical studies, doctors and researchers try to create treatment groups and control groups at the same time. Such studies are called prospective studies.
The biggest concern with all types of medical studies, including historical studies, is that similar groups of people should be compared. In the previous example, if the group of people who received the new treatment (treatment group) for malaria was made up of mostly young people who had mild disease, and the previously treated (control) group was made up of older people who had severe disease, it might well be that people in the treatment group fared better simply because they were younger and healthier. As a result, a new treatment could falsely appear to work better. Many other factors besides age and severity of illness also must be taken into account including the overall health of people being studied (people with chronic diseases such as diabetes or kidney failure tend to fare worse than healthier people); the specific doctor and hospital providing care (some may be more skilled and have better facilities than others); the percentages of men and women that comprise the study groups (men and women may respond differently to treatment); and the socioeconomic status of the people involved (people with more resources to help support them tend to fare better).
Doctors and researchers have tried many different methods to ensure that the groups being compared are as similar as possible. It might seem sensible to specifically choose people for treatment groups and control groups by matching them on various characteristics. For example, if a doctor was studying a new treatment for high blood pressure (hypertension), and one person in the treatment group was 42 years old and had diabetes, then the doctor would try to ensure the placement of a person near 40-years-of-age with hypertension and diabetes in the control group. These types of studies are called case-control studies. However, there are so many differences among people, including differences that are often not even considered, that it is nearly impossible to ensure an exact match.
Instead, doctors and researchers take advantage of the laws of probability and randomly assign - typically with the assistance of a computer application—people who have the same disease to different study groups. If a large enough group of people is divided up randomly, the odds are that people in each group will have similar characteristics. Studies that use these methods are called "randomized.” Prospective, randomized studies are the best way to make sure that a treatment or test is being compared between equivalent groups.
Once doctors and researchers have created equivalent groups, they must make sure that the only difference they allow is the experimental treatment itself. That way, they can be sure that any difference in outcome is due to the specific treatment under investigation, and not to some other factor, such as the quality or frequency of follow-up care.
Doctors and researchers must also account for the Placebo effect. People who know they are receiving an active experimental treatment rather than no treatment (or an older, presumably less effective treatment) often expect to feel better. Some people, on the other hand, may expect to experience more side effects from a new, experimental treatment. In either case, these expectations can exaggerate the effects of treatment, causing it to seem more effective or to have more complications than it really does.
To avoid the problems of the placebo effect, people in a study are "blinded"; they do not know whether they are receiving the active experimental treatment. Blinding is usually accomplished by giving people in the control group a pill or substance that is identical in appearance to the experimental treatment. However, when an effective treatment for a disease already exists, it is not ethical to give the control group a placebo. In those situations, the control group is given the standard or established treatment.
But whether a placebo or an established drug is used, the substance must appear identical to the study drug, except for the active ingredient. That is necessary so that people cannot tell whether they are taking the study drug. If the treatment group receives a red, bitter liquid, then the control group should also receive a red, bitter liquid. If the treatment group receives a clear solution given by injection, then the control group should receive a similar injection.
Because the doctor or nurse might accidentally let a person know what treatment they are receiving, it is better if all healthcare practitioners involved in a clinical trial remain unaware of what is being given. This type of blinding is called ‘double-blinding’. Double-blinding usually requires a person separate from the study, such as a pharmacist, to prepare identical-appearing substances that are labeled only by a special number code. The number code is broken only after the study is completed.
An additional reason for double-blinding is that the placebo effect can even affect the doctor, who may unconsciously think a person receiving treatment is doing better than a person receiving no treatment, even if both are faring exactly the same. Not all medical studies can be double-blinded. For example, surgeons studying two different procedures obviously know which procedure they are performing (although the people undergoing the procedures can be kept unaware). In such cases, doctors at least make sure that the people evaluating the outcome of treatment are blinded as to what has been done so they cannot unconsciously bias the results.
*Excerpt taken from The Gift of Participation - A Guide to Making Informed Decisions About Volunteering for a Clinical Trial by Kenneth Getz. Copyright CISCRP 2013, All rights reserved. To learn more and to order a copy, go to www.ciscrp.org.
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There are four clinical trial phases, each with a different set of objectives and requirements—from simple outpatient studies requiring only a couple of hours a month to situations requiring overnight or extended stays at medical facilities.
During phase I studies, a drug is tested for the first time in small numbers (20 to 100) of healthy volunteers—often college students. Phase I trials typically last from several months up to one year. The goal of these trials is to learn about safe dosage ranges in which a drug can be administered, the method of absorption and distribution in the body and the possible toxicity of a new treatment. Researchers start by giving volunteers a single dose of the drug. Then they gradually increase the dosage level until minor side effects like nausea or headaches start to occur. That’s how researchers learn about the more common side effects that limit the treatment dosage levels. Payment to participants in this phase of the process is also common because it’s often the only way to get enough volunteers.
Only certain new, very toxic treatments for cancer and infectious diseases are tested on actual patients in phase I trials. And only in terminally ill cancer patients—where there are often no other options available—is the dosage amount increased until it is literally intolerable. For these cancer patients, the greatest hope of survival lies in destroying the highest possible number of cancer cells in the body just short of death. Researchers are usually leading experts in their field.
Until 1993, mostly males were enrolled as study subjects in phase I clinical trials because it was considered unethical to allow women to do so. Researchers were concerned that women might become pregnant during a clinical trial and put both the subject and her child at risk. Today, however, more women are allowed to make that decision for themselves. But they must not get pregnant while participating in a clinical trial. During the trial, female study subjects are typically expected to use some form of birth control—contraception or abstinence. Phase I studies are conducted in numerous locations—frequently in academic settings or in private, specialty centers.
Participants are often confined for 24-hour periods to a special inpatient unit—complete with kitchen and recreational facilities— where they may undergo frequent blood and urine tests. These tests help researchers understand how the investigational drug is absorbed, distributed, metabolized and excreted by the human body. This will assist researchers in determining if a new drug will have to be given one, two, three or more times a day. But how safe the drug truly is remains a mystery because so few people have taken it. Due to safety and toxicity problems, many investigational drugs are abandoned during phase I testing. According to the FDA, approximately 70%of newmedical treatments pass this testing stage.
In phase II studies, researchers begin to understand how safe and effective an investigational drug will be for patients for whom the drug is intended. Similar to phase I, safety is still the primary goal. Phase II studies are conducted on a relatively small number of volunteers—usually 100 to 300 patients who have the disease or condition targeted by the newmedical therapy. Clinical trials in this phase take between one and three years to complete. Phase II studies look to answer such basic questions as “Do patients improve?” and “What are the usual side effects?” Researchers also learn if the treatment dosage needs to be lowered or raised.
Eligibility requirements tend to be strict in phase II trials. These scientifically demanding studies are usually “randomized,” meaning that volunteers are assigned to different groups—of which only a subset will receive the investigational drug. The control group will get another standard treatment or a placebo for part of, or perhaps throughout, the entire study. This method helps take the bias out of study results due to human choices or other factors unrelated to the treatments being tested. Typically, the study is double-blinded, meaning that neither the patient nor the researcher knows who is getting the investigational drug and who is getting the placebo or standard treatment.
A phase II study may measure something that isn’t the drug’s ultimate clinical value, such as improving survival after a heart attack. It would instead look at how well the drug opens blood vessels after a heart attack. Overall, it’s shorter than a phase III study and involves a smaller population of people. Phase II trials are also the period when researchers look at the body’s response to different doses of a drug.
Only about one-third of drugs that enter clinical testing ever successfully complete phase II and progress to larger-scale phase III studies. This stage provides hard, statistical facts about a drug. Phase III clinical trials involve extensive testing to assess safety, efficacy and dosage levels in a large group of patients facing a specific illness. The study drug is tested on as many as several thousand people over a period of two to five years. Often, “real world” results—such as how long a person can sit at a basketball game, write a letter, or hike up and down stairs—are seen as equally important as clinical findings (lower blood pressure or higher white cell count, for example) inmeasuring a drug’s usefulness. Phase III trials are most often conducted in a doctor’s office.
The goal in this research phase is often to have an investigational treatment evaluated by practicing physicians who might one day prescribe it. These trials often involve a more diverse patient group for whom the treatment is initially intended. The number of volunteers needed for a phase III study depends on howmany people have the targeted disease. Compared to studies of medications designed to prevent heart attacks, those for asthma would be smaller because researchers can learn something from every single participant, and every enrollee will actually have the disease.
Phase III studies almost always involve a relatively large number of participants with similar demographic characteristics. At this stage, researchers may also look to compare the drug’s safety and effectiveness in different subsets of patients—men versus women, blacks versus whites, elderly versus young—and how well the treatment works in mild, moderate and severe forms of the same disease. Researchers are also able to test different dosage levels of the drug so that they know, quite precisely, how much of it most people need to get the good effects with as few bad effects as possible.
Drugs tested in phase III clinical trials may include remedies already approved by the FDA to treat a different medical condition— such as a study of a multipurpose antimicrobial to treat a specific opportunistic infection in AIDS patients. Phase III studies usually test a new drug in comparison with a placebo or an existing treatment.
Therapies that have reached phase III have already passed toxicity testing and have proved to be at least somewhat effective. But subjects in phase III trials still usually have no better than a 50% chance of getting the investigational treatment versus a placebo or standard therapy. About 80% of drugs that enter phase III will successfully complete this stage. Once clinical trials are completed and the results are analyzed, the company sponsoring the research may submit a New Drug Application (NDA) to the Food and Drug Administration if there is enough positive information about the safety and effectiveness of the treatment. The NDA is given to one of two groups within the FDA: (1) The Center for Drug Evaluation and Research (CDER) and (2) The Center for Biologics Evaluation and Research (CBER). The former review group is responsible for evaluating prescription and over-the-counter drugs. The latter group is responsible for evaluating blood and blood products, vaccines, allergenics and medical treatments made from living organisms. The FDA will also look to advisory committees made up of medical experts to assist in determining whether a treatment should be approved for sale on the market. Applications for newmedical devices are submitted to the Center for Devices and Radiological Health.
The FDA review period usually lasts about one year for most NDAs. The FDA also has an expedited review process for priority drugs—usually lasting under six months. Priority drugs are those that represent a notable treatment benefit for critical and severe illnesses. FDA review and approval doesn’t always happen as quickly as pharmaceutical and biotechnology companies would like. The FDA withheld its approval for an effective nasal flu vaccine aimed at toddlers, for example. The agency asked the company to conduct more studies looking at how well the new treatment combined with other vaccines and whether there was a rare risk of pneumonia or asthma among certain children. The FDA would also be skeptical, for example, if a high blood pressure medication caused a higher-than-expected rate of facial swelling among a minority population. It wouldn’t matter if researchers believed they could fix the problem by changing the dose. To prove it to the FDA, the pharmaceutical company would have to conduct a large-scale study of the drug specifically targeting that population.
After pharmaceutical companies receive FDA approval to market a drug, they will sometimes conduct phase IV studies. These clinical trials are performed to uncover additional information about a new treatment.What is the long-termsafety and effectiveness of a drug?What impact does it have on improving patients’ day-to-day lives? When do physicians decide to prescribe the new treatment relative to others in the market? How does the new treatment compare with other similar treatments available to patients? Phase IV clinical trials typically involve large numbers of patients who are routinely taking the medical treatment under investigation. Although these types of studies often have happened at the FDA’s urging, recent drug safety concerns surrounding popular painkillers and antidepressants have left many companies wanting to invest resources to better understand potential risks. In some cases, phase IV studies are conducted to see if a drug causes unique problems for a certain patient subgroup. The results of these studies may be used to revise product labeling or to further support claims and comparisons that pharmaceutical companies make in package inserts and product advertisements. The offices of communitybased physicians are particularly well suited for phase IV studies because they provide routine care for patients and they administer prescriptions regularly.
*Excerpt taken from The Gift of Participation - A Guide to Making Informed Decisions About Volunteering for a Clinical Trial by Kenneth Getz. Copyright CISCRP 2013, All rights reserved. To learn more and to order a copy, go to www.ciscrp.org.
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*Definitions taken from The Gift of Participation - A Guide to Making Informed Decisions About Volunteering for a Clinical Trial by Kenneth Getz. Copyright CISCRP 2013, All rights reserved. To learn more and to order a copy, go to www.ciscrp.org.
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Created in 2012, the FDA Patient Network is part of the Office of Health and Constituent Affairs (OHCA). formerly the Office of Special Health Issues. They work to help patients, patient advocates, and their health professionals connect with FDA science and policy staff. Through this network, the FDA Patient Network:
Below is a list of helpful links associated with the FDA Patient Network:
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Office for Human Research Protections (OHRP) Resources:
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Here you can find, read, and comment on regulations and related documents produced by the FDA. To learn more, CLICK HERE.
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