How are clinical trials designed? Read the 'Overview of clinical trial process' presentation from the Action Duchenne International Conference. Participants who partake in a clinical trial are allocated to a treatment group or placebo group (also known as a control group). Sometimes there can be more than two groups, with different groups given different drugs or doses of drugs compared to placebo. There are a number of stages in the clinical trial process. Randomisation of participants in a clinical trial is important. Randomisation ensures differences observed between each group are due to the treatment being studied and not differences between participants. Bias must be avoided during a clinical trial. Clinical trial studies are double-blinded, ensuring the assessor of the potential treatment and participant do not know which group they are in. The clinical trial process can take up to 10 years before potential regulatory approval, however this time scale can be variable, particularly with rare disorders. This process is vital to determine if potential treatments are well tolerated, safe and to highlight any side effects in patient groups or healthy individuals before drugs can be approved.