Anemia associated with pegylated interferon-?2a and ?2b therapy in hemodialysis patients

Abstract

Anemia is a well-known side effect of interferon therapy since interferons are potent inhibitors of erythropoiesis. The aim of this study was to compare the anemia associated with pegylated interferon (PEG-IFN) (alpha2a versus alpha2b therapy in hemodialysis patients (HD) with chronic hepatitis C. In order to study the anemia, doses of erythropoietic growth factors (EGF), hemoglobin (Hb) and erythropoietin resistance index (ERI) were compared at baseline and after PEG-IFN-alpha2a or alpha2b therapy in 16 HD patients with chronic C hepatitis. Pharmacokinetic studies were performed in 4 of those treated with PEG-IFN-alpha2b and 2 patients treated with PEG-IFN-alpha2a. Secondary end-points were viral response and serious adverse events. At 4-6 months after the beginning of therapy, both PEG-IFN-alpha induced a significant increment in the erythropoietin resistance index. This increment was significantly higher in patients treated with PEG-IFN-alpha2a when compared with alpha2b (45 vs 9.9, p = 0.012). The pharmacokinetics of PEG-IFN-alpha2a and alpha2b in HD patients were different, the C(max), C(min) and the area under the serum concentration time curve, were all higher in patients treated with PEG-IFN-alpha2a compared with PEG-INF-alpha2b. Discontinuation of therapy occurred in 2 (28.5%) of the 7 patients in the PEG-IFN-alpha2a group and in 4 (44%) of the 9 patients in the PEG-IFN-alpha2b group. Three (42%) subjects in the alpha2a group and 5 (55%) in the alpha2b group had a response at the end of the 48 weeks of therapy. In 4 (44.4%) of the 9 patients treated with alpha2b the viral response was sustained. In summary, patients treated with PEG-IFN-alpha2a have a major inhibitory effect on erythropoiesis. This could be explained by the different pharmacokinetic properties of PEG-IFN-alpha2a and alpha2b. Further studies are needed to clarify how these findings influence the efficacy, safety and cost-effectiveness of the PEG-IFN-alpha2.