A phase 2 study to evaluate the antiviral activity, safety, and pharmacokinetics of recombinant human albumin-interferon alfa fusion protein in genotype 1 chronic hepatitis C patients

Background/Aims: Recombinant human albumin-interferon alfa (alb-IFN) is a novel 85.7-kD recombinant protein consisting of interferon alfa-2b genetically fused to human serum albumin. Methods: A phase 2, open-label, dose-ranging study was conducted in IFN-alfa-naïve patients with genotype 1 chronic hepatitis C to evaluate the antiviral activity, safety, and pharmacokinetics of alb-IFN. Fifty-six patients were enrolled to receive two subcutaneous injections of alb-IFN 14 days apart in five dose cohorts of 200, 450, 670, 900, and 1200 μg. Results: A 2 log₁₀ IU/mL or greater reduction in hepatitis C virus (HCV) RNA at Week 4 was observed in 69% (18/26) of patients who received the higher alb-IFN doses of 900 and 1200 μg. The mean HCV RNA reduction at Week 4 in these two higher-dose cohorts was 3.2 log₁₀ IU/mL. Modeling of viral kinetics demonstrated a biphasic response that was dose dependent. Adverse events were mostly mild to moderate in severity. The most common adverse events were headache (73%), chills (63%), fatigue (61%), and arthralgia (55%). The median terminal half-life was 141 h consistent with previous alb-IFN data from IFN-alfa-experienced patients. Conclusions: Alb-IFN demonstrated significant antiviral activity and was well tolerated in patients with HCV genotype 1 infection.