Will there still be a role for the originator erythropoiesis-simulating agents after the biosimilars and the hypoxia-inducible factor stabilizers approval?

A Phase 3, Multicenter, Randomized, Two-Arm, Open-Label Study of Intermittent Oral Dosing of Roxadustat for the Treatment of Anemia in Japanese Erythropoiesis-Stimulating Agent-Naïve Chronic Kidney Disease Patients Not on Dialysis

INTRODUCTION

Roxadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor approved for the treatment of anemia in Japan for patients with dialysis-dependent (DD) chronic kidney disease (CKD).

OBJECTIVE

Multicenter, randomized, open-label, noncomparative, phase 3 study to evaluate roxadustat for anemia of non-dialysis-dependent (NDD) CKD in Japan.

METHODS

Erythropoiesis stimulating agent (ESA)-naïve NDD-CKD patients were randomized to roxadustat (initial dose, 50 or 70 mg 3 times weekly), titrated to maintain hemoglobin (Hb) within 10.0-12.0 g/dL, for ≤24 weeks. Patients with either transferrin saturation of ≥5% or serum ferritin of ≥30 ng/mL during the screening period were eligible. Endpoints included response rate (proportion of patients achieving Hb ≥10.0 or ≥10.5 g/dL and Hb increase ≥1.0 g/dL from baseline) at end of treatment; average Hb (weeks 18-24); change of average Hb from baseline to weeks 18-24; maintenance rate (proportion of patients achieving Hb 10.0-12.0 g/dL at weeks 18-24); rate of rise (RoR) of Hb from weeks 0-4, discontinuation, or dose adjustment. Adverse events were monitored throughout the study.

RESULTS

Of 135 patients who provided informed consent, 100 were randomized and 99 received roxadustat (50 mg, n = 49; 70 mg, n = 50). The mean (SD) dose of roxadustat per intake at week 22 was 36.3 (22.7) mg in the roxadustat 50 mg group and 36.8 (16.0) mg in the roxadustat 70 mg group. Prior medications included oral iron therapy (20.2%) and intravenous iron therapy (1.0%). Overall response rate (95% CI) was 97.0% (91.4, 99.4; Hb ≥10.0 g/dL) and 94.9% (88.6, 98.3; Hb ≥10.5 g/dL). Mean (SD) Hb (weeks 18-24) was 11.17 (0.62) g/dL. Mean (SD) change of Hb from baseline (weeks 18-24) was 1.34 (0.86) g/dL. Maintenance rate (95% CI) was 88.8% (80.3, 94.5) among patients with ≥1 Hb measurement during weeks 18-24. Mean (SD) RoR of Hb was 0.291 (0.197) g/dL/week (50 mg) and 0.373 (0.235) g/dL/week (70 mg). Nasopharyngitis and hypertension were the most common adverse events.

CONCLUSION

Roxadustat increased and maintained Hb in ESA-naïve, partially iron-depleted NDD-CKD patients with anemia.

The multifaceted role of iron in renal health and disease

Iron is an essential element that is indispensable for life. The delicate physiological body iron balance is maintained by both systemic and cellular regulatory mechanisms. The iron-regulatory hormone hepcidin assures maintenance of adequate systemic iron levels and is regulated by circulating and stored iron levels, inflammation and erythropoiesis. The kidney has an important role in preventing iron loss from the body by means of reabsorption. Cellular iron levels are dependent on iron import, storage, utilization and export, which are mainly regulated by the iron response element-iron regulatory protein (IRE-IRP) system. In the kidney, iron transport mechanisms independent of the IRE-IRP system have been identified, suggesting additional mechanisms for iron handling in this organ. Yet, knowledge gaps on renal iron handling remain in terms of redundancy in transport mechanisms, the roles of the different tubular segments and related regulatory processes. Disturbances in cellular and systemic iron balance are recognized as causes and consequences of kidney injury. Consequently, iron metabolism has become a focus for novel therapeutic interventions for acute kidney injury and chronic kidney disease, which has fuelled interest in the molecular mechanisms of renal iron handling and renal injury, as well as the complex dynamics between systemic and local cellular iron regulation.