Timing-adjusted iron dosing enhances erythropoiesis-stimulating agent-induced erythropoiesis response and iron utilization

Iron Parameters in Patients Treated with Roxadustat for Anemia of Chronic Kidney Disease

Roxadustat is a novel agent with a distinct mechanism of action compared to erythropoiesis-stimulating agents (ESAs) and a potentially different combination of effects on iron parameters. This narrative review describes the effects of roxadustat on iron parameters and on hemoglobin levels in the context of iron supplementation in patients with anemia of non-dialysis-dependent (NDD) or dialysis-dependent (DD) chronic kidney disease (CKD). Roxadustat use was associated with a greater reduction in serum ferritin levels than seen with ESAs and an increase in serum iron levels compared to a decrease with ESAs. Decreases in transferrin saturation in patients treated with roxadustat were relatively small and, in the case of patients with NDD CKD, not observed by Week 52. These changes reflect the concomitant increases in both serum iron and total iron-binding capacity. Compared to placebo and an ESA, roxadustat improved iron availability and increased erythropoiesis while requiring less intravenous iron use. Hepcidin levels generally decreased in patients who received roxadustat compared to baseline values in all CKD populations; these decreases appear to be more robust with roxadustat than with an ESA or placebo. The mechanisms behind the effects of roxadustat and ESAs on iron availability and stores and erythropoiesis appear to differ and should be considered holistically when treating anemia of CKD.

Changes in Iron Availability with Roxadustat in Nondialysis- and Dialysis-Dependent Patients with Anemia of CKD

Background

Roxadustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor, increases hemoglobin by stimulating erythropoietin synthesis and improving iron availability through facilitation of iron uptake and/or release from stores. In this exploratory analysis, we assessed the effect of roxadustat treatment on laboratory parameters related to iron metabolism in patients with anemia of chronic kidney disease (CKD).

Methods

Data were pooled from pivotal, randomized, phase 3 roxadustat trials: three placebo-controlled, double-blind trials in nondialysis-dependent (NDD) CKD and three open-label, active-comparator (epoetin alfa) trials in dialysis-dependent (DD) CKD. In this exploratory analysis, mean changes from baseline in hemoglobin, iron parameters, and hepcidin, and intravenous (iv) iron use were evaluated. Pooled results in NDD CKD and DD CKD patients are reported.

Results

Overall, 4277 patients with NDD CKD and 3890 patients with DD CKD were evaluated. Hemoglobin increases with roxadustat treatment were accompanied by increases in serum iron and total iron-binding capacity (TIBC) and decreases in serum ferritin and hepcidin from baseline through week 52. With epoetin alfa, the hemoglobin increase was accompanied by decreases in serum ferritin and hepcidin, but serum iron decreased, and there was no change in TIBC. With placebo, there were no changes in hemoglobin, iron parameters, or hepcidin. During treatment, iv iron use was reduced with roxadustat versus placebo and epoetin alfa.

Conclusions

In patients with NDD CKD and DD CKD, roxadustat treatment is associated with increases in serum iron and TIBC, accompanied by reduced hepcidin and indicative of improved iron kinetics. Patients treated with roxadustat achieved target hemoglobin levels with less iv iron use versus comparators. Practitioners treating patients with anemia of CKD with roxadustat should consider its unique effects when interpreting iron parameters.

Management of iron deficiency anemia in hemodialysis patients based on mean corpuscular volume

Background

To manage the anemic status in hemodialysis (HD) patients, a well-balanced combination therapy based on the use of erythropoiesis-stimulating agents (ESAs) and iron supplementation is essential. Serum ferritin level and transferrin saturation rate (TSAT) are the current standard tests for screening iron deficiency status. However, these are not included in frequently checked regular blood measurements in many HD centers. Other parameters that could predict a hemoglobin (Hb) increase response from iron supplementation have yet to be established. To determine a frequently checked and regularly measured biomarker for predicting iron deficiency status, this study investigated the value of mean corpuscular volume (MCV) as a clinical parameter for HD patients receiving intravenous iron supplementation (Fe-IV) therapy.

Methods and results

One hundred thirty four HD patients, 88 non-HD patients with anemia, and 50 HD patients on Fe-IV therapy from the Nozatomon clinic were assessed. Comparison of MCV values of anemic HD patients and anemic non-chronic kidney disease (CKD) patients showed that anemic HD patients had significantly higher MCV values (93.9 ± 7.3 fL) compared with anemic non-CKD patients (82.8 ± 8.8fL). Fifty HD patients, who received Fe-IV therapy at ten consecutive HD sessions (inclusion criteria: Hb ≤ 12.0 g/dL, TSAT < 20%, and serum ferritin < 100 ng/mL) showed a rapid increase during the Fe-IV period in MCV, Hb, and TSAT levels. After the completion of the Fe-IV therapy, MCV persisted at the increased levels, whereas Hb levels further increased and peaked at 1 month with a gradual decline after, largely influenced by ESA dosage reductions. The 50 patients were divided into three groups according to the MCV levels obtained immediately prior to the Fe-IV therapy (MCV ≤ 85 fL, 85 fL < MCV ≤ 90 fL, MCV > 90 fL), and Hb changes at 50 days after the initiation of the Fe-IV therapy were compared. All the patients in the MCV ≤ 85 fL group and most of the patients in the 85 fL < MCV ≤ 90 fL group showed linear and consistent Hb increase during the 50-day period. In marked contrast, patients in the MCV > 90 fL group showed dispersed trends in their Hb increase. The present study also revealed that successful ESA dosage reduction could be achieved after the Fe-IV therapy in both the MCV ≤ 85 fL and 85 fL < MCV ≤ 90 fL groups.

Conclusions

The present study underscored the value of MCV in perceiving iron deficiency status as well as predicting iron-based therapeutic response in HD patients.