A clinical trial is a research study with the goal of answering specific questions about new therapies, vaccines or diagnostic procedures, or new ways of using known treatments. Clinical trials (also called medical research and research studies), are used to determine whether new drugs or treatments are both safe and effective. Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people.

Ideas for clinical trials usually come from researchers. After researchers test new therapies or procedures in the laboratory and in animal studies, the treatments with the most promising results are moved into clinical trials. Clinical trials conducted by Roche Pharmaceuticals are broken down into different phases of trials. During a trial, more and more information is gained about the new treatment, its risks and how well it may or may not work.

A regulatory authority must approve a new drug or a new use of that drug, or certify a new diagnostic product, before it can be marketed. The approval process involves several steps including pre-clinical laboratory and animal studies, clinical trials for safety and efficacy, filing of a New Drug Application by the manufacturer of the drug or diagnostic product, review of the application by the regulatory authority, and then approval/rejection of the application.