Modeling of treatment response to erythropoiesis-stimulating agents in older (age≥70years) and younger (age<70years) patients with cancer and anemia: findings from the Anemia Cancer Treatment study

INTRODUCTION: The Anemia Cancer Treatment study assessed hemoglobin (Hb) outcomes following treatment with erythropoiesis-stimulating agents (ESA) in anemic (Hb≤11g/dL) patients in Europe. We replicated the original analyses stratifying by age, namely patients aged ≥70 (n=637) versus those aged<70 (n=1555).

MATERIALS AND METHODS: A secondary analysis of Hb outcomes was assessed over 8-10weeks. Treatment response criteria included increases of Hb≥1g/dL, Hb≥1g/dL over 8weeks, and Hb≥2g/dL over the course of the study period.

RESULTS: Mean Hb increased from similar levels of 9.5g/dL [p=not significant (ns)] at visit one to 10.9g/dL (p=ns) at visit three (both p<0.001). Patients aged≥70 had higher mean Hb at visit two (10.6g/dL vs. 10.3g/dL, p<0.001). Cohorts did not differ in treatment response rates (all p=ns). Mean performance status differed between cohorts at each visit (all p≤0.011); both groups showed significant improvements (both p<0.001). Immediacy of response was a consistent determinant but was more pronounced among patients aged≥70. Less consistent determinants included performance status in the age≥70 group, as well as hematological malignancy and Hb at ESA start in the age<70 group. The proportion of variance in Hb outcomes attributable to treatment center ranged from 0.090 to 0.289 in the age≥70 cohort and 0.126 to 0.361 in the age<70 cohort.

CONCLUSIONS: Both groups achieved similar Hb levels with the age≥70 cohort showing a higher initial evolution rate and potentially a different Hb response trajectory. Patients age≥70 were more likely to benefit from ESAs if showing an early erythropoietic response and exhibiting no or little impairment in performance status. Differential attribution of variability in older vs. younger adults suggests that individualization of ESA therapy may facilitate Hb response in geriatric patients with cancer.