The CRO for data-intensive, early phase clinical studies. The Centre for Human Drug Research (CHDR) is a full service, early-stage contract research organisation, located in Leiden, the Netherlands. We provide a full range of high quality, data intensive clinical pharmacology services to the (bio-)pharmaceutical industry. Combining innovative methods and technologies, state-of-the-art facilities, and talented, motivated researchers helps us maximise our clients’ success. In addition, we place the highest priority on our subjects’ comfort and safety, and we play an active role in helping educate the medical and clinical research communities.