The purpose of this study is to determine occurrence of pure red cell aplasia in a group of participants with chronic renal insufficiency and with resistance criteria to epoetin alfa treatment.The investigational product is producted by Bio-Manguinhos / Fiocruz (BIO-EPO) and it is provided by the Unified Health System.

Inclusion Criteria:

• Use of alfa epoetin manufactured by Bio-Manguinhos for at least 8 weeks before the moment of hyporesponsiveness diagnosis;
• Nonuse of alfa epoetin from another manufacturer for at least 24 weeks before hyporesponsiveness diagnosis;
• Presence of the criteria for pure red cell aplasia disease, which is absence of a significant reduction in serum levels of leukocytes and platelets.

Exclusion Criteria:

The screened patients who have at least one of the following criteria will be excluded from the study, and it may be replaced by another participant for the research.

• if there is no legal representative, an intellectual disability that restrain the compliance and signature of informed consent,
• no agreement assigning the informed consent;
• It will be excluded from the study if from the moment of hyporesponsiveness diagnosis the participant have: lactation pregnancy, hypersensitivity or intolerance previously known for alfa epoetin or one of its components, intolerance or allergy to parenteral iron, acute hemorrhage, kidney transplantation, hemolysis defined as the presence of anemia associated with high levels of indirect bilirubin and lactate dehydrogenase , percentage of reticulocytes> 1.5% absolute reticulocyte> 75,000 / microliter.
• deficiency of folate and / or vitamin B12.
• pancytopenia.
• in use with medications known to cause anemia and / or pure red cell aplasia as: Valproic Acid; Azathioprine; Chloramphenicol; Phenytoin; Isoniazid; Mycophenolate mofetil.
• presence of the following comorbidities: Diabetes mellitus; epilepsy; chronic viral hepatitis; secondary hyperparathyroidism uncontrolled; hypertension systolic; inflammation (acute or chronic); myelofibrosis; myelodysplasia; neoplasm and thalassemias;
• severe disease in the 24 weeks before the hyporesponsiveness diagnosis; including: stroke, septic shock, thromboembolic events; acute myocardial infarction
• lack of information or damage to quality data that avoid disease classification as a case of hyporesponsiveness.
• Immunoglobulin M and Immunoglobulin M serology for Parvovirus B19, Epstein-Barr and Cytomegalovirus.
• serology for HIV in the last 12 months.
• established immunological disease.
• dosage of protein C-reactive titrated .
• presence of antinuclear antibody and rheumatoid factor.