What are controlled clinical trials
and why are they important?

Before medications are approved for widespread use, they are typically tested in a controlled clinical trial. Controlled trials are considered necessary to show that a medication's effects are not subjective (relying on the patient's or physician's interpretation). Otherwise, a researcher might (perhaps unintentionally) test the medication only in patients who already show signs of responding well to treatment. Or a patient, knowing that the medication is supposed to reduce pain, could experience pain relief due to some other factor, but attribute the relief solely to the new medication.

The preferred way to avoid subjectivity is to do a controlled study. In a controlled study, or trial, patients in one group receive the investigational drug, while patients in another group-- the control group-- receive no drug at all, a placebo (an inactive substance that looks like the investigational drug), another drug known to be effective, or a different dose of the investigational drug. This arrangement allows researchers to compare the health of the group receiving the new drug with the control group. If the group receiving the new drug shows clear and measurable improvements in symptoms, but the control group does not, researchers can reasonably conclude that the new drug was responsible for improving the health of the treatment group.

To ensure that comparisons between a treatment group and control group are scientifically valid, researchers select people for both groups who are similar in age, weight, health status, and other factors. The most common way to accomplish this is through randomization. Researchers first gather a group of people with similar characteristics. They then randomly assign each person to either the treatment group or the control group. This ensures that certain patients aren't "hand picked" for a group because of their characteristics.

The final step in ensuring that a research study is objective is blinding. Blinding is used to eliminate the effects of personal beliefs and biases (on the part of both researchers and patients). In a single-blind study, the patients do not know whether they are in the treatment group or the control group, but the researchers do know. In a double-blind study, no one involved-- not the patients, researchers, or data analysts-- know which patients are receiving the new drug and which are not. A controlled, randomized, double-blind trial therefore produces the most objective and scientifically valid results.

Choosing to participate in a clinical trial, or to have your child do so, is not an easy decision. If a new medication is ultimately proven to be effective, then those who were randomly assigned to the control group must live with knowing that, for the length of the trial, they did not receive treatment that could have improved their health. Those assigned to the treatment group risk experiencing adverse effects from the medication, or learning that the treatment was not effective. In addition to the potential health risks, trials may require significant investments of time and money (for example, transportation to and from a study site), as well as physical discomfort (such as having regular blood tests or bone biopsies). Those who decide to participate must be willing to accept the risks and costs in return for knowing that they are helping to advance medical treatments not only for themselves, but for others living with the same condition. All clinical trials teach us something-- even if the medication turns out to be ineffective, those results help guide researchers away from treatments that don't work, allowing them to explore other possibilities.

The decision to participate in a trial or not ultimately rests with individuals, after they have been fully informed of what is involved. If you are considering participating, or having your child participate in a study related to OI, discuss the idea with your physician(s) and gather as much information as you can about the study. The researchers should provide you with detailed information about the potential risks and benefits of participation.

The FDA (www.fda.gov) and the National Cancer Institute (www.cancertrials.nci.nih.gov) provide information on participating in clinical trials. Much of the information for this fact sheet is excerpted from the U.S. Food and Drug Administration's web site, which posts numerous articles on the drug approval process. These articles provide easy-to-read information on drug approvals and related issues. To learn more, go to www.fda.gov/fdac/special/newdrug/ndd_toc.html.


This information is brought to you by
the NIH Osteoporosis and Related Bone Diseases~National Resource Center (ORBD~NRC)
and the Osteogenesis Imperfecta Foundation

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 Osteoporosis and Related Bone Diseases
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The National Resource Center is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases with contributions from the National Institute of Child Health and Human Development, National Institute of Dental and Craniofacial Research, National Institute of Environmental Health Sciences, NIH Office of Research on Women's Health, Office of Women's Health, PHS, and the National Institute on Aging. The Resource Center is operated by the National Osteoporosis Foundation, in collaboration with the Paget Foundation and the Osteogenesis Imperfecta Foundation.

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