Considerations on Interim Evaluation of OS in Pivotal Oncology Trials

:Overall survival (OS) is considered a gold standard clinical endpoint for evaluating the effectiveness of a drug. In oncology studies, OS is relatively simple and straightforward to measure in a clinical trial. Recent advancements in medical sciences and cancer care have significantly prolonged the lifespan of cancer patients. As a result, it is becoming challenging to measure OS due to its long course in some cancer diseases. In addition, it may be challenging to interpret OS in some circumstances; for example, when patients switch from the control arm to the experiment arm to receive a novel therapy, a detrimental effect might be observed in OS in the experimental arm with uncertainty, or discrepancy between OS and other clinical endpoints can be observed. This manuscript will provide an overview of the challenges of using OS as a clinical endpoint in pivotal oncology trials. Discussions will focus on using OS as both a safety and efficacy endpoint for decision-making.