Pegylated interferon-α2b:: Pharmacokinetics, pharmacodynamics, safety, and preliminary efficacy data

Aims: The objectives of this study were to assess the safety, pharmacokinetic and pharmacodynamic profiles, and antiviral efficacy of pegylated interferon-alpha 2b monotherapy in patients with chronic hepatitis C. Methods: Fifty-eight patients (38 men, 20 women; age range, 25 to 65 years) with compensated chronic hepatitis C were enrolled in this open-label, randomized, active controlled study. Patients received 0.035 to 2.0 mug/kg pegylated interferon-alpha 2b subcutaneously weekly or the active control, interferon-alpha 2b 3 million TU subcutaneously three times/week, for 24 weeks. Safety and antiviral efficacy assessments were performed during treatment and in a subsequent 4-week follow-up period. Detailed pharmacokinetic assessments were performed at weeks 1 and 4. Results: Pegylated interferon-alpha 2b produced dose-related reductions in white blood cells, neutrophils, and platelets, and dose-related increases in oral temperature, serum neopterin, and serum 2'5'-oligoadenylate synthetase activity, which were qualitatively similar to those produced by nonpegylated interferon-alpha 2b. Reported adverse events (flu-like symptoms, asthenia) were qualitatively similar in pegylated interferon-alpha 2b- and nonpegylated interferon-alpha 2b-treated groups. Dose-related antiviral activity, as measured by loss of detectable serum hepatitis C virus RNA (<100 copies/mL), was noted at the end of treatment and after 4 weeks of follow-up. Both pegylated and nonpegylated interferon-<alpha>2b were rapidly absorbed, with maximal concentrations occurring similar to8 to 12 hours after dose administration. Pegylated interferon-alpha 2b had sustained maximal serum concentrations for 48 to 72 hours after dose administration, whereas nonpegylated interferon-alpha 2b concentrations declined rapidly. Volume of distribution for both compounds was similar (similar to1 L/kg). Pegylated interferon-alpha 2b elimination half-life was approximately 10-fold greater, and mean apparent clearance was one tenth that of nonpegylated interferon-alpha 2b. Conclusions: Pegylated and nonpegylated interferon-alpha 2b safety and pharmacodynamic profiles were comparable. Pegylated interferon-alpha 2b demonstrated delayed clearance compared with nonpegylated interferon-alpha 2b, consistent with once-weekly administration.