Safety and antiviral activity of albinterferon alfa-2b in prior interferon nonresponders with chronic hepatitis C.

Background & Aims Pegylated interferon alfa-2a/2b is used in combination with ribavirin to treat patients with chronic hepatitis C (CHC), although many do not achieve a sustained virologic response (SVR). Albinterferon alfa-2b, a recombinant protein consisting of interferon alfa-2b fused to human albumin, may increase drug exposure. This phase 2 study evaluated the safety/efficacy of albinterferon in CHC patients who had not responded to interferon-based regimens. Methods A total of 115 patients were assigned to 5 groups given 1200 μg albinterferon every 4 weeks or 900, 1200, 1500, or 1800 μg every 2 weeks, plus oral ribavirin, for 48 weeks. The primary efficacy end point was achievement of an SVR after 24 weeks. Treatment was extended to 72 weeks for 6 slow responders who were negative for hepatitis C virus RNA after 24 weeks. Results The types of adverse events were similar across groups; the overall discontinuation rate as a result of adverse events was 10.4%. Reductions in absolute neutrophil counts were less frequent in the every 4 weeks group and comparable among the every 2 weeks groups. The overall SVR rate was 17% (11% for previous nonresponders to pegylated interferon-alfa/ribavirin with genotype 1 infection). An SVR occurred in 3 of 6 slow responders by 72 weeks. The greatest reductions in hepatitis C virus RNA in nonresponders to pegylated interferon-alfa/ribavirin with genotype 1 infection were observed in the 1800-μg group. Conclusions In patients with CHC who did not respond to interferon-based regimens, higher doses of albinterferon had significant early antiviral activity and a low incidence of adverse events, with the types of adverse events similar to those observed with interferon.