5. Patients who have not responded to previous treatment with erythropoietin (EPO): With a response profile based on basal erythropoietin (EPO) levels of > 250 u/L, with no response alter 12 weeks of treatment at maximum doses (60.000 U or 250 µg darbepoetin (DAB), in combination with Granulocyte colony-stimulating factor (G-CSF) in cases of refractory anaemia with ringed sideroblasts (RARS)) , or with loss of the response obtained after an initial optimum response.