Which peptide‑based erythropoiesis‑stimulating agents and other biologic regulators are used in the management of renal failure?

Peptide and Biologic Regulators for Renal Failure

Erythropoiesis-stimulating agents (ESAs) are the primary peptide-based biologics used in renal failure, with epoetin alfa, epoetin beta, darbepoetin alfa, and methoxy polyethylene glycol-epoetin beta (CERA) being the established options, while newer HIF-prolyl hydroxylase inhibitors (HIF-PHIs) like daprodustat, roxadustat, and vadadustat represent emerging alternatives. 1

Primary ESAs for Anemia Management

First-Generation Short-Acting ESAs

Epoetin alfa and epoetin beta are recombinant human erythropoietin molecules that require 1-3 times weekly administration, though extended intervals up to every 4 weeks are possible in some patients. The critical caveat: dose requirements increase substantially as dosing intervals lengthen. Subcutaneous administration is more effective than intravenous for these short-acting agents. 2

These agents:

• Probably reduce blood transfusion requirements compared to placebo (epoetin alfa OR 0.28, epoetin beta OR 0.19) 3
• May increase hypertension risk (epoetin alfa OR 2.10, epoetin beta OR 2.17) 3
• Have uncertain effects on mortality 3

Second-Generation Long-Acting ESAs

Darbepoetin alfa contains increased carbohydrate content allowing every 2-week dosing, with dose requirements independent of administration route (subcutaneous or intravenous). 2, 4

Methoxy polyethylene glycol-epoetin beta (CERA) incorporates a large polyethylene glycol moiety enabling monthly administration. 4

Both agents:

• Probably reduce transfusion needs (darbepoetin alfa OR 0.27) 3
• May increase hypertension risk 3
• Show no difference in mortality compared to placebo 3

Biosimilar ESAs

EMA and FDA-approved biosimilar epoetins demonstrate comparable efficacy and safety to originators. Critical warning: Follow-on epoetins manufactured in Asia and Latin America have caused alarming increases in pure red cell aplasia (PRCA) in Thailand, with cases also occurring with EMA-approved biosimilars like HX575. Only use biosimilars approved through stringent regulatory pathways. 2

Novel HIF-Prolyl Hydroxylase Inhibitors

Daprodustat (GlaxoSmithKline)

Oral agent dosed 1-4 mg once daily, studied in both dialysis and non-dialysis CKD patients. In the ASCEND-D trial (n=2964), showed non-inferiority for MACE (HR 0.96,95% CI 0.88-1.05) compared to ESAs. 1

Roxadustat (FibroGen/AstraZeneca)

Dosed 70-100 mg three times weekly based on weight. Pooled analysis showed time to first MACE HR 1.10 (95% CI 0.96-1.27), meeting non-inferiority margin of HR 1.30. However, on-treatment MACE showed HR 1.38 (95% CI 1.11-1.70), raising safety concerns. 1

Vadadustat (Akebia/Otsuka)

Starting dose 300 mg once daily, adjusted to 150-600 mg. In PROTECT trials (n=3476), failed to meet non-inferiority for MACE (HR 1.17,95% CI 1.01-1.36) against the 1.25 margin. 1

The HIF-PHIs show promise in reducing cardiovascular risks compared to traditional ESAs and offer oral administration, but cardiovascular safety concerns persist, particularly with roxadustat and vadadustat. 5

Adjunctive Peptide: Peginesatide

Peginesatide is a pegylated synthetic peptide-based ESA with no structural homology to erythropoietin. Phase III trials raised significant safety concerns in non-dialysis CKD patients, though not in dialysis patients, limiting its clinical utility. 2, 6

Iron Supplementation

While not peptides, intravenous iron compounds are essential biologic regulators used alongside ESAs. The 2021 KDIGO conference emphasized that functional iron deficiency due to hepcidin-mediated sequestration versus kinetic iron deficiency from ESA-stimulated erythropoiesis requires different management approaches. 7

Practical Algorithm

1. For dialysis patients: Start with darbepoetin alfa or CERA for convenient dosing schedules
2. For non-dialysis CKD: Consider HIF-PHIs (daprodustat preferred based on safety profile) or traditional ESAs
3. Avoid high ESA doses: Two large cohorts demonstrated greater mortality hazard with high ESA doses 8
4. Monitor for hypertension: All ESAs increase hypertension risk approximately 2-fold
5. Target hemoglobin conservatively: Avoid aggressive targets given cardiovascular risks
6. Ensure adequate iron: Address functional iron deficiency before escalating ESA doses

Critical Pitfalls

• Never use non-EMA/FDA approved biosimilars due to PRCA risk
• Avoid subcutaneous administration of biosimilars when possible given immunogenicity concerns
• Do not pursue aggressive hemoglobin targets (cardiovascular event risk increases)
• Recognize ESA resistance early: Consider alternative diagnoses and avoid dose escalation beyond recommended limits