Early Hemoglobin Response to Erythropoiesis-Stimulating Therapies (ESTs) and Outcomes in Cancer Patients with Anemia: Results from a Prospective, Observational Study.
Authors: Wang Qin , Larholt Kay , Pashos Chris , Forlenza Jamie , Bookhart Brahim , McKenzie Scott 
Published: October 2019

Abstract
Background: Previous clinical trial research in cancer patients with anemia receiving epoetin alfa has reported an association of early hemoglobin (Hb) response (ER) (≥1 g/dL within four weeks of initiating ESTs) and improved clinical outcomes (e.g., lower transfusion requirements, better overall hematologic response rates). To evaluate ER and outcomes in the prospective, observational setting, clinical outcomes were compared between patients achieving an ER and those not achieving an ER. Data were analyzed from the Dosing and Outcomes Study of Erythropoiesis-Stimulating Therapies (D.O.S.E.) Registry, an ongoing, prospective registry collecting data on real-world practice patterns and outcomes in cancer patients treated with ESTs, epoetin alfa and darbepoetin alfa.
Methods: Data from U.S. hospital and community-based outpatient practices were assessed from 1/04–5/06. Adult patients with a non-myeloid malignancy, baseline anemia (Hb < 11 g/dL), receipt of at least two doses of either EST, three Hb values (baseline, prior to or on day 32, following day 32) and study completion were included. ER was defined as an Hb increase ≥ 1 g/dL within 32 days of baseline independent of RBC transfusion. This analysis stratified patients based on attainment of an ER (ER group versus No ER group). Outcomes assessed included proportion of patients requiring RBC transfusion (Week 5 to end of treatment), mean treatment duration, proportion of patients achieving an Hb ≥ 12 g/dL or Hb increase ≥ 2 g/dL, proportion of patients achieving a Hb increase ≥ 2 g/dL, proportion of patients achieving a Hb ≥ 11 g/dL, and time to achieving a Hb ≥ 11 g/dL.
Results: 494 patients were eligible for analysis. 59% achieved an ER. Patients who had an ER had a significantly shorter mean treatment duration compared to those without an ER. The ER group also had a significantly lower proportion of patients requiring RBC transfusion, higher proportion of patients achieving an Hb ≥ 12 g/dL or Hb increase ≥ 2 g/dL, higher proportion of patients achieving a Hb increase ≥ 2 g/dL, higher proportion of patients achieving a Hb ≥ 11 g/dL, and shorter time to achieving a Hb ≥ 11 g/dL compared to the No ER group.
Conclusion: Consistent with clinical trial findings, data from this prospective observational study demonstrate that patients with an ER had significantly better outcomes than patients without an ER, making ER a desirable goal. These findings provide further evidence that the proportion of patients achieving an ER for a given treatment, dose and regimen should be a useful metric for comparisons of EST treatments in anemic patients with cancer.
Table ER (n=293) No ER (n=201) p value % requiring RBC transfusion 9% 17% 0.009 Mean treatment duration 61 days 69 days 0.0003 % achieving an Hb ≥ 12 g/dL or Hb increase ≥ 2 g/dL 85% 40% < 0.0001 % achieving an Hb increase ≥ 2 g/dL 70% 29% < 0.0001 % achieving an Hb ≥ 11 g/dL 94% 73% < 0.0001 Mean time to achieving an Hb ≥ 11 g/dL 19 days 39 days < 0.0001