Regulatory agencies have for years granted preliminary approvals to new anti-cancer drugs based on single-arm trials in the settings of rare diseases and/or an unmet medical need where conducting a randomized study is considered infeasible or unethical. Results from new experimental therapies in single-arm trials are often considered in the context of what might be expected from a standard of care. The advent of robust real world data in drug development allows for improved comparisons with standards of care by providing better alignment of comparator groups in terms of disease status, patient characteristics, regional differences, and prognostic factors. However, regulatory agencies have not fully embraced this approach in oncology, especially for time-to-event endpoints which are difficult to ascertain from single-arm trials. Using a case study where an analysis of a single-arm trial and historical control was later followed up by a randomized study involving similar treatment groups and disease setting, we will evaluate the promise and pitfalls of using real world historical data for oncology drug development with an emphasis on the improvements of “standard of care” over time.