Assessing the effect of darbepoetin alfa on patient-reported fatigue in chemotherapy-induced anemia in four randomized, placebo-controlled clinical trials
Purpose This analysis examined the effects of darbepoetin alfa on hemoglobin and fatigue outcomes in patients with cancer using latent growth curve modeling (LGM).
Methods Data from 4 clinical trials of darbepoetin alfa in lung cancer (2 studies; n = 547; n = 288), lymphoproliferative malignancies (n = 339), and non-myeloid malignancies (n = 320) were analyzed separately. Fatigue was assessed using the FACT-Fatigue (FACT-F) scale. Effects of darbepoetin alfa on changes in hemoglobin and FACT-F scores were evaluated using LGM, controlling for age, gender, Eastern Cooperative Oncology Group performance status, health status, and total transfusions.
Results Patients receiving darbepoetin alfa had higher rates of change in hemoglobin (standardized regression coefficient [[^(b)] ] = 0.30 to 0.53, all P < 0.05) than placebo. Patients with greater rates of change in hemoglobin reported improvements in fatigue outcomes ([^(b)] = 0.28 to 0.59, all P < 0.05). The total standardized effect of darbepoetin alfa on fatigue outcomes corresponded to a mean change of 0.9 to 3.5 points in FACT-F scores, with one trial demonstrating changes exceeding the minimal important difference of 3 points.
Conclusions Darbepoetin alfa improved hemoglobin which was associated with improved fatigue across the 4 trials. Clinically, meaningful improvement in fatigue was seen in 2 trials. More complex statistical analysis models of treatment may assist in understanding the effects of erythropoiesis-stimulating agents on patient-reported outcomes.