All Times EDT
Keywords: Group Sequential Design, Early Stopping, Logrank, max-Combo Test.
Randomized clinical trials in oncology typically utilize time-to-event endpoints as their primary efficacy endpoints, and the most commonly used statistical test to analyze these endpoints is the logrank test. The power of the logrank test depends on the behavior of the hazard ratio of the treatment arm to the control arm. Under the assumption of proportional hazards (PH) , the logrank test is asymptotically fully efficient. However, this proportionality assumption does not hold true if there is a delayed treatment effect. Moreover, recent new immuno-oncology compounds have been shown to be very effective in prolonging overall survival. Therefore it is desirable to implement a group sequential design with the possibility of early stopping for overwhelming efficacy. As an alternate to the logrank test, the max-combo test, which utilizes the maximum of two weighted log-rank statistics, is a robust alternative to the logrank test. This new test was assessed for two-stage designs with possible early stopping at the interim analysis time point. Two classes of weights are investigated for the max-combo test; the Fleming and Harrington (1981) weights, and the Magirr and Burman (2019) modest weights. In this presentation, we will show the results and make recommendation about the preference of weights for the max combo test.