http://youtu.be/5zXuON7Rueo Our Drawn to Science series shows you some of the cool things Roche scientists do in their labs and clinics to discover and develop innovative medicines. In this video, learn about how clinical trials are essential to providing the scientific data required to determine whether new drugs, diagnostics or procedures are safe and effective when used to diagnose and treat people. Carefully conducted clinical trials provide answers to important questions. They are performed with human volunteers. Every new treatment is tested in multi-phase clinical trials (usually three phases in duration) before regulatory agencies consider it safe and effective. Depending on the product type and development stage, investigators initially enroll volunteers and/or patients into small pilot studies and subsequently conduct progressively larger-scale comparative studies. As positive safety and efficacy data are gathered, the number of patients typically increases. Clinical trials can vary in size, involving a single research entity in one country or multiple entities in multiple countries. To learn more about science and innovation at Roche, watch our other Drawn to Science videos at https://www.youtube.com/watch?v=w4iCian4tnQ&list=PLmXzuVn0p6GBB6iJfzyzx6U2XmUiohli7. For more information about clinical trials at Roche, visit http://www.roche.com/research_and_development/who_we_are_how_we_work/clinical_trials.htm.