Anemia in Placebo Arms of Cancer Studies

Abstract

Background/Aim: Adverse event (AE) frequencies observed in interventional clinical trials are difficult to interpret when the placebo control is missing. Materials and Methods: Systematic literature review of AEs reported from the placebo arms of randomized cancer trials between 2008 and 2021. Imputation of missing values assuming normal distribution of hemoglobin values. Results: Anemia grade 1 or higher was reported in 46 of 100 placebo monotherapy cohorts with a mean frequency of 23.4% (SD=27%) of the enrolled patients. The reported frequency depended on the type of cancer; other demographic variables had no significant influence on anemia frequency. Conclusion: External controls for anemia in clinical trials should be disease specific.