Effect of patient exclusion criteria on the efficacy of erythropoiesis-stimulating agents in patients with cancer-related anemia.

Comparison of the efficacies of erythropoiesis-stimulating agents (ESAs) between different clinical trials is becoming increasingly common, although differences in study design and populations evaluated can have a considerable effect on results. A comparison of two seemingly similar trials of ESAs, one of epoetin alfa and the other of epoetin beta, showed that only 27% of the 115 patients with hematologic malignancies who received epoetin alfa in the epoetin alfa trial met the inclusion criteria for the epoetin beta trial. The mean hemoglobin increase from baseline to week 16 of epoetin alfa therapy in the patients who met these inclusion criteria was 3.3 g/dl. This is substantially higher than the mean hemoglobin increase of 2.2 g/dl from baseline to week 16 of epoetin alfa therapy in the patients who did not meet the epoetin beta study inclusion criteria. These results demonstrate the considerable effects that exclusion criteria can have on trial results and highlight the value of scrutinizing the study design details of clinical trials before comparing outcome data between trials.