Urology Care Foundation The Official Foundation of the American Urological Association

Urology Care Foundation The Official Foundation of the American Urological Association


What aRe Clinical Trials?

Development of drugs to a point when they can be safely used in humans to treat disease is a complex process that requires years of study and evaluation.  Detailed below, the process is typically divided into 4 discrete steps:  Drug Discovery; Preclinical testing; Clinical Trial testing; and Approval. 

To search for information on current or recent clinical trials for a particular urologic condition or in a specific geographic area, view our UrologyHealth.org Clinical Trials Resource Center.


Armed with an understanding of the disease, scientists can take the first step in finding drug candidates, which is to identify a specific but vulnerable target that plays a crucial role in the disease. Teams of researchers then create new molecules or select existing molecules that may be effective against the targets. This process, which can start with 5,000 to 10,000 molecules, results in identification of about 250 compounds that may be effective. 


Preclinical Testing

The compounds identified in the discovery phase, are subjected to extensive laboratory and animal studies in the preclinical phase to evaluate safety and demonstrate that the drugs have biological activity against the disease target.  This phase of the process further reduces the number of molecules to between 1 and 5 candidate drugs.


Clinical Trials

The candidate drugs now enter the clinical trial phase which is the phase of the process that involves human testing.  During this portion of the process teams of physicians test the drug in humans to determine if the drug is safe and effective.  

There are three phases of clinical trials:

 Phase I: The candidate drug is tested in a small group (20-100) of healthy volunteers - often in a hospital setting - to determine several characteristics about the drug including its safety and dose range. Phase I studies can take from six months to one year to complete.  

Phase II: These trials involve 100 to 500 volunteer patients who have the disease being studied. The goal is to establish if the drug effectively treats the disease. Researchers continue to evaluate the drug's safety and look for side effects, and determine the most effective dose strength and dose schedule. Phase II studies can take from six months from one year to complete.  

Phase III: These trials involve from 1,000 to 5,000 patient volunteers. The large numbers are required to confirm that the drug is effective and to identify side effects.  Phase III studies can take from one to four years to complete, depending on the disease, length of the study, and the number of volunteers.

At this point, the single drug that emerges from the 5,000 to 10,000 that entered the discovery phase we began with must be approved by the FDA.  FDA scientists review and analyze the results of all the studies that have been done to make sure that the drug is safe and effective.  Once FDA approval is achieved it becomes available to physicians and patients.

From discovery to treatment, development of a drug can take up to 15 years with an estimated cost of $800 million. 

 The clinical trial phase of this process is a critical step that ensures that the drugs being used are safe and effective treatments.  Voluntary participation of people in clinical trial is a complex and personal decision that only the patient can make for himself or herself.  If you have questions about clinical trials and about participating in a clinical trial seek input from family, friends, physicians and other health care providers. 


    CFC     ICA     Health & Medical Research Charities of America     View our Awards
Urology Care Foundation, Inc.
  • Click here for permission to duplicate or reprint content.
  • © 2015 Urology Care Foundation, Inc. All Rights Reserved.

© 2015 Urology Care Foundation, Inc. All Rights Reserved.