“…However, in settings where efficacy is not ascertained in a short period of time, it is frequent to employ two‐stage designs where, a set of maximum tolerated dose combinations is first selected, and then tested for efficacy in a second stage with possibly a different population of patients than the one used in the first stage (see Chen, Zhao, Cui, & Kowalski, 2012; Le Tourneau, Lee, & Siu, 2009; Rogatko, Ghosh, Vidakovic, & Tighiouart, 2008). For drug combination trials, different methodologies for two‐stage designs have been proposed for binary efficacy endpoints (see, e.g., Shimamura, Hamada, Matsui, & Hirakawa, 2018; Tighiouart, 2019; Yuan & Yin, 2011; Zhang & Yuan, 2016) but not for time to event endpoints in the second stage of the trial.…”