PeptidePeptidePegylated proteinErythropoiesis-stimulating agent

Methoxy Polyethylene Glycol-Epoetin Beta (Mircera)

Also known as CERA · Mircera · Continuous erythropoietin receptor activator · PEG-epoetin beta

Written by enwyReviewed 5 Aug 20262 sources0 comments

Mircera is a continuous erythropoietin receptor activator (CERA): epoetin beta conjugated to a large methoxy-PEG polymer, giving a very long half-life and monthly dosing for renal anaemia. Its stability made it a doping target, and it featured in cycling positives at the 2008 Tour de France. Prohibited by WADA at all times.

01 Overview

By attaching a single large PEG chain to epoetin beta, Mircera achieves a half-life of roughly a week, allowing once-monthly administration in chronic kidney disease. It interacts with the EPO receptor differently — slower association and dissociation — which is described as continuous receptor activation.\n\nSeveral riders tested positive for Mircera at the 2008 Tour de France after a detection assay was rapidly developed, demonstrating that even novel ESAs are catchable. The cardiovascular hazard profile is the ESA-class profile: thrombosis, hypertension and, in trials targeting higher haemoglobin, excess cardiovascular events.

02 Mechanism

The PEGylated epoetin beta binds the erythropoietin receptor with slow on/off kinetics, providing prolonged, continuous erythropoietic stimulation from a single infrequent dose.

03 Dosing

Tier	Dose	Route	Notes
Renal anaemia (medical)	0.6–1.2 mcg/kg	SubQ	Once every 2-4 weeks; titrated to haemoglobin
Maintenance (medical)	50–360 mcg	IV	Monthly; medical use only

04 Effects

Effect	Magnitude	Evidence
Long-lasting red cell mass expansionA single dose sustains erythropoiesis for weeks, raising haemoglobin and oxygen delivery.	Hb +1-2 g/dL	Clinical
Reduced injection frequencyIts very long half-life allows once-monthly administration, improving convenience over EPO or darbepoetin.	Monthly dosing	Clinical

05 Side effects

Effect	Severity	Frequency	Evidence	Countermeasures
Thromboembolic eventsESA-class clotting risk: stroke, MI, DVT, PE, worsened by dehydration.	Life-threatening	Dose-dependent	Clinical
HypertensionBlood pressure rise typical of ESAs.	Moderate	Common	Clinical

06 Legal status

United States

Prescription biologic (FDA)

WADA-prohibited in sport · as of Jan 2026

07 References

CERA (methoxy polyethylene glycol-epoetin beta) pharmacologyClinical Pharmacokinetics, 2008

WADA Prohibited List — S2World Anti-Doping Agency

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.