Prolongation of the dosing interval of rhEPO - influence on the effectiveness in patients on hemodialysis?

The main reason of renal anemia in patients with kidney impairment lies in the reduced ability of the peritubular cells to produce sufficient amounts of erythropoietin. The engineering of recombinant human erythropoietin mark s an important progress in the treatment of renal anemia, rhEPO leads to a great improvement of quality of life, a dramatic decrease in blood transfus ion with all associated risks, and a reduction of cardiovascular morbidity and mortality. Patients on hemodialysis are usually treated with s.c. appli ed rhEPO three times per week on occasion of every dialysis treatment. This investigation tested, whether the reduction in the frequency of applicatio n to once weekly with the linked prolongation of the dosing interval had le d to an additional requirement of rhEPO. A retrospektive analysis of 26 chr onic hemodialysis patients, who were treated on an outpatient base in our d ialysis center, showed that a prolongation of the dosing interval of rhEPO from one application per dialysis treatment to a once per week schedule did not lead to an increased consumption of rhEPO. During a 6 months observati on period neither a significant decrease in the objective hematocrit, nor a n influence of the background variable transferrin saturation as a possible explanation for the unchanged erythropoietin requirement was noticed. The missing difference in the biological effectiveness of rhEPO given once vers us thrice weekly implies that, based on the characteristic pharmacokinetics of the s.c. application, the concentration of the cytokine on the erythrop oietin-receptor over time is sufficient to induce an adequate stimulation o f the erythropoiesis. Future studies will show, whether the dosing schedule can be further optimized by the use of hyperglycosilated erythropoietin.