Issues in analyzing time-to-event endpoint involving non-proportional hazard
Kun He, FDA  Rajeshwari Sridhara, US Food and Drug Administration  *Vivian Yuan, FDA 

Keywords: non-proportional hazard, time-to-event

Cox’s (1972) proportional hazards model has become a popular tool in the analysis of time-to-event endpoints in clinical trials. However, there are many cases where hazard ratios are not constant over time and the treatment effect may be transient. In this talk we will present some of the critical issues in the analysis of data when the proportional hazard assumption is violated, and present some case examples.