All medicines are subject to rigorous testing before they are approved by regulatory authorities (such as the US Food and Drug Administration, the EMA for EU and local agencies from other countries). Before a medicine is given to patients, findings from early laboratory studies are carefully analysed by Roche scientists and discussed with regulatory authorities. The medicine then undergoes a monitored process of investigation using well-designed and controlled clinical trials. Controlled trials are those which compare the new medicine to a placebo or existing medicines. They are usually “double blind” so that neither the patient nor the doctor knows which medicine the patient is receiving. This ensures the results are not biased. These studies gather information about the efficacy and safety (e.g. side effects) of new medicines compared to existing treatments. In addition, information is gathered by studying different patient populations (e.g. young, elderly, gender), different dosages and the use of a drug in combination with other medicines to see which patients benefit the most or have side effects.