Types of Clinical Research Trials

Clinical studies generally fall into two groups: Comparative studies and Open Label studies. Here, we will explain to you what Comparative studies and Open Label studies are, as well as outline the difference between the two types of clinical research trials. We will also outline the four phases of clinical trials involved with the testing of drugs or medications.

Comparative Clinical Research Trials

In Comparative or “controlled” clinical trials, one group of participants receives the investigational treatment, while a similar “control” group receives either traditional treatment or none at all. (The control group may be given a placebo. This is an inactive pill, injection or infusion that appears identical to the investigational treatment.) To avoid biased results, studies are often conducted as “double-blind.” This means that neither the patient nor the physician knows who is receiving the investigational treatment.

Open Label Clinical Research Trials

In an Open Label trial, no attempt is made to disguise the investigational treatment and no placebo or control treatment is used. As a result, both physician and patient know which treatment is being provided.

The Four Phases of Clinical Research Trials

There are four phases of clinical trials: Phase I, Phase II, Phase III and Phase IV. The four phases of the drug approval process are separate clinical trials, and the entire process typically spans eight to 10 years. The four clinical trial phases are:

Phase I: Learn more about Phase I trials. Phase I clinical trials are the first stage in testing treatments for safety and dosing on an inpatient basis.

Phase II: Click here to read more about Phase II trials. Phase II trials continue evaluating the safety of drugs, as well as test their efficacy and toxicity.

Phase III: Educate yourself on Phase III trials, which ultimately determine the efficacy of the drug by testing large patient groups in multicenter trials.

Phase IV: Click here to learn more about Phase IV trials, where testing and surveillance of the drug is continued after being approved for sale.

Common Questions:

What are Clinical Research Trials?
Why Participate in a Clinical Study?
What’s the difference between a Clinical Trial and Treatment?
How are Drugs Tested?
Additional Questions for Your Primary Physician

Learn About Clinical Studies:

Florida Clinical Research Resources
Clinical Trial Glossary
Clinical Trials History
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Patient Rights
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NIH Patient Bill of Rights
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