A healthy volunteer is an individual without any known significant disease who voluntarily participates in a clinical trial. Healthy volunteers are typically enrolled in Phase I studies to investigate, for the first time in humans, the safety, tolerability, pharmacokinetics, and pharmacodynamics of a new investigational medicinal product.
The participation of healthy volunteers is ethically justifiable only if the potential risk to them is minimal and they derive no direct therapeutic benefit from participation. However, their contribution is invaluable to drug development, as it enables fundamental characteristics of a new medicine to be understood in a “clean” biological system before it is tested in patients with the target disease. CROs with specialised Phase I units focus on the recruitment and care of healthy volunteers under strictly controlled clinical conditions.