People participate in clinical research for a variety of reasons. People who volunteer for phase II and phase III trials can gain access to promising drugs long before these compounds are approved for the marketplace. They typically get excellent care from the physicians during the course of the study.
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.