Additional instances of ECAs used to provide contextualization for single‐arm trials have been retrospectively demonstrated in the reanalyses of clinical trials across various cancer sites, including leukemia, Merkel cell carcinoma, myeloma, non‐small cell lung cancer, and early‐stage hormone receptor‐positive breast cancer.21, 61, 65, 66. This evidence concerns the gene NR4A1 and leukemia.