A clinical trial is a drug study sponsored by a pharmaceutical or biotechnology company. There are cases, however, where health-related government agencies provide funding and other resources for a clinical trial. 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.
After a study is complete the information is reviewed and decision is made whether to continue or halt the drug's development. If it remains in development, the manufacturer may build in a "compassionate use" extension for the study. This means that eligible patients may receive the study drug for a predefined amount of time without having to undergo any typical study procedures, such as blood tests or clinical ratings. This usually occurs in later studies, such as Phase III and Phase IV (post-marketing surveillance). In some cases, a study doctor may dispense approved medication samples and provide additional care at no charge.