Due to administrative, ethical, and financial reasons, research investigators often perform interim analyses to obtain overwhelming evidence of efficacy or futility of an experimental drug before the pre-planned end date of a clinical trial. Repeated significance testing and stochastic curtailment are the two most widely used approaches to achieve such purpose. In the literature, these approaches have been well-studied for normal- and binary- endpoints in two-arm phase-III clinical trials. In addition, repeated significance tests have been studied for time to event endpoints. To our knowledge, however, little attention has been paid towards stochastic curtailment approaches (including conditional power, predictive power, and Bayesian predictive probability) for futility testing in time to event framework. In this poster presentation, we will discuss these approaches in the context of single-arm clinical trials with time to event primary endpoint using Weibull model. Assuming various censoring mechanisms specific to survival analysis, some examples will also be presented to demonstrate these approaches.