Clinical Study Design and Evaluation of the Efficacy in the Treatment

Irritable bowel syndrome (IBS) is diagnosed based on subjective symptoms, and the aim of treatment is to improve the symptoms of IBS. Patients’ symptom reporting is essential to evaluate the severity of symptoms. Furthermore, study design and endpoint are very important in IBS clinical trials. Both the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) released a general guidance on the evaluation of medical products for the treatment of IBS based on patient-reported outcome (PRO) measures. The primary endpoint should be clinically meaningful and demonstrate the efficacy of therapeutic agents, and the best endpoint for IBS clinical trials need to be determined.