What Are Clinical Trials

Clinical trials are biomedical research studies conducted on human subjects to test the safety and efficacy of a medical treatment, device or procedure.

Before a new drug, device or procedure can be approved for use, many countries require that it first be tested in a clinical trial and yield satisfactory results. Consequently, clinical trials are often initiated and paid for by the company that developed the product in question. The National Institutes of Health and the National Cancer Institute provide financial support for many clinical trials in the United States.

Clinical Trial Design

The primary purpose of clinical trials is to determine whether treatments work as they should. To ensure integrity of the results, many such studies are designed so that participants aren’t told whether they’re receiving the test treatment or the non-therapeutic placebo. This type of clinical trial design is called a blind study.

In a double-blind study, not even medical professionals know which treatment (the tested treatment or the placebo) they’re administering. This type of clinical trial design tends to eliminate any bias that may skew the results.

How Clinical Trials are Conducted

Before a clinical trial can begin, researchers must create a “protocol,” which is a document describing the clinical trial design and its goals. Depending on the country, the appropriate regulatory agency must review this document and the researchers may have to register the trial in an official registry database. This clinical trial registration makes the study’s details accessible by the public.

Clinical trials are often conducted at hospitals, clinics or research institutions. Participants may have to live at the facility for a period of time, or simply visit as necessary. As long as no safety concerns arise, clinical trials advance through several phases, with the number of volunteers increasing in each phase.

In order to monitor a study’s progress, regulatory agencies review the researchers’ data on a regular basis. If the treatment, device or procedure is deemed safe and effective by the review panel, it’s then approved for sale in the country.


Clinical Trials. (2007). Understanding clinical trials. Retrieved November 29, 2010, from http://clinicaltrials.gov/ct2/info/understand

Food and Drug Administration. (2009). Basic questions and answers about clinical trials. Retrieved November 29, 2010, from http://www.fda.gov/ForConsumers/byAudience/


National Cancer Institute. (2010). Approval process for new cancer treatments. Retrieved November 29, 2010, from http://www.cancer.gov/clinicaltrials/understanding/approval-process-for-cancer-drugs

National Cancer Institute. (2010). Cancer clinical trials. Retrieved November 29, 2010, from http://www.cancer.gov/cancertopics/factsheet/Information/clinical-trials