Dear Editor,  

 Methoxy polyethylene glycol-epoetin beta (Mircera®) is a recombinant erythropoietin that, just like natural erythropoietin, stimulates red blood cell production and increases blood levels of haemoglobin, by interacting with the erythropoietin receptors on marrow progenitor cells, thus resulting in continuous activation.1-3  

 We present the case of a patient with Stage 5 chronic kidney disease (CKD) who had a delayed hypersensitivity reaction on two recombinant erythropoietins. In August 2004, treatment was started with epoetin beta (Neorrecormon©) subcutaneously. Six months later the patient developed pruritus and generalised micropapular lesions in direct relation to the weekly administration of this anti-anaemic medication.  

 The patient was then treated with darbepoetin alpha (Aranesp®) subcutaneously, and, starting with the first dose, developed a similar skin reaction to that described with epoetin beta, for which the medication was suspended. In April 2006, the patient started haemodialysis, and intravenous administration of darbepoetin alpha was started and was well tolerated over several administrations. However, on two occasions, the patient developed palmoplantar pruritus and papular lesions that required withdrawal of the drug. Subsequently, the patient needed monthly red cell transfusions, due to persistent anaemia secondary to CKD. In September 2007, authorisation was requested from the Spanish Ministry of Health and Consumer Affairs for the foreign medication epoetin delta, but authorisation was refused on the grounds that there was a high probability of having a reaction to it given the patient’s history. Faced with this situation, in August 2009 we decided to try pegylated epoetin beta (Mircera®), which has been registered in Spain since July 2007,1 while monitoring for tolerance and effectiveness.  

 Based on recommendations from the Allergy department, escalating doses (12.5, 25 and 37.5μg) of pegylated epoetin beta were administered subcutaneously at seven day intervals until reaching the final dose of 50μg (0.6μg/kg), without any adverse reaction. We continued to administer pegylated epoetin beta at the 50μg dose, but divided into two injections (25μg) for the first three doses.  

 At present, and after eight fortnightly intravenous doses of pegylated epoetin beta, we can state that the patient is tolerating this treatment, maintaining sustained haemoglobin and haematocrit levels within the recommended range for stage 5 CKD on haemodialysis. In this instance, the intravenous administration of pegylated epoetin beta did not result in the appearance of any crossreactions arising from the patient’s intolerance to epoetin beta and darbepoetin alpha. Therefore, we suggest that pegylated epoetin beta may be a good alternative for treating chronic anaemia in patients with CKD and intolerance to epoetin beta and darbepoetin alpha.