A clinical trial is the investigation of a new medication for the treatment of a disease. The work might be sponsored by a pharmaceutical or biotechnology company, government or a private foundation. The purpose of these studies is to find out whether a medication is safe to use and effective against various diseases or medical conditions. In order to study the medication, several questions need to be answered first. For example, what patient population or disease is the drug meant to treat? What criteria should be used for accepting participants into the study? What general and disease-specific information are the study doctors going to obtain?

Essentially, once these and other important study questions are answered, the study doctors (investigators) are chosen, the regulatory documents are approved and the study is ready to begin.