Clinical Trial Types And Designs

All clinical trials have the same basic goal: to test the safety and effectiveness of a new medical product. However, a clinical trial can be classified into different types, depending on the clinical trial design or function of the treatment being tested.

Clinical Trial Classification

In the United States, the National Institutes of Health (2007) have defined five different clinical trial types, based on the medical function of the product:

  • Compassionate use trials provide experimental care to terminally ill patients (these aren’t common and require special approval).
  • Diagnostic trials identify the best diagnostic test for a particular medical condition.
  • Prevention trials test products or procedures that prevent disease.
  • Quality of life trials test products or procedures that improve quality of life for the chronically ill.
  • Screening trials identify the most accurate way of screening for a particular medical condition.
  • Treatment trials test products or procedures that treat disease.

Clinical Trial Classification: Another Angle

Another way to classify clinical trials is according to the type of medical product being tested. Here are some products that may require a clinical trial:

  • Diagnostic tests: Diagnostic tests are used to diagnose a particular medical condition. A clinical trial for a diagnostic test measures how accurate, invasive and cost effective the test is, compared to existing diagnostic procedures for the same condition.
  • Drugs and biologics: Drugs are small molecules that are produced synthetically. Biological products, by comparison, are molecules that can be synthesized in a living cell (such as insulin). When possible, the clinical trial design for a drug or biologic includes a comparison to a placebo.
  • Medical devices: A medical device is any piece of equipment used in patients, such as pacemakers or artery stents. Not all new medical devices require a clinical trial.
  • Treatment protocols: A treatment protocol is a defined procedure for treating a particular medical condition. For example, a protocol may call for a particular medication for a set of number of weeks, followed by a different medication for another set period of time. This clinical trial design aims to determine the optimal set of conditions for use in a treatment.

Resources

Blake-Michaels, M. (2010). Considerations for medical device trials. Retrieved December 6, 2010, from http://appliedclinicaltrialsonline.findpharma.com/appliedclinicaltrials/article/articleDetail.jsp?id=682817

CenterWatch. (2010). Overview of clinical trials. Retrieved December 6, 2010, from http://www.centerwatch.com/clinical-trials/overview.aspx

ClinicalTrials. (2007). Understanding clinical trials. Retrieved December 6, 2010, from http://clinicaltrials.gov/ct2/info/understand

National Cancer Institute. (2010). Cancer clinical trials. Retrieved December 6, 2010, from http://www.cancer.gov/cancertopics/factsheet/Information/clinical-trials

National Cancer Institute. (2007). New approaches to cancer drug development: Questions and answers. Retrieved December 6, 2010, from http://www.cancer.gov/newscenter/qa/2007/phasezeronextqa

National Marrow Donor Program. (2010). What is a clinical trial? Retrieved December 6, 2010, from http://www.marrow.org/PATIENT/Undrstnd_Disease_Treat/Undrstnd_Treat_Opt/Lrn_Clinical_Trials/What_is_a_Clinical_Trial/index.html