Overall Survival (OS) is an efficacy endpoint in clinical trials, particularly in oncology, that measures the time from the start of treatment (often the time of randomization) until the patient’s death from any cause. It is considered the ‘gold standard’ among efficacy endpoints, as it represents the most direct and clinically relevant benefit for the patient: prolongation of life.
OS is objective, clearly measurable, and free from interpretation. Studies demonstrating a significant improvement in overall survival have the highest clinical and regulatory validity. The disadvantage is that measuring OS often requires long follow-up periods, making studies expensive and time-consuming. For this reason, surrogate endpoints such as progression-free survival (PFS) are often used to enable a faster assessment of efficacy. For a CRO, precise tracking of the survival status of all patients is an important task of data management and monitoring.