Wiesner, Rusell H

Albumin-interferon-α (alb-IFN) is a novel recombinant protein derived from IFN-α2b genetically fused to human albumin. The resulting single polypeptide combines in one molecule the antiviral properties of IFN-α with the long serum half-life of albumin. IFN-mediated biological responses stem from the engagement of IFN-α with its target receptor and subsequent modulation of IFN-specific gene (ISG) expression. To evaluate the pharmacodynamics of alb-IFN during the Phase I/II study conducted in patients with chronic hepatitis C (CHC) who had previously failed IFN-α-containing regimens, ISG induction was evaluated in peripheral blood and compared with antiviral response. Whole blood was obtained at day 0, day 7 and day 28 from 21 patients enrolled in the higher dose (500–900 μg) alb-IFN cohort, who received two injections on day 0 and day 14. Taqman real-time PCR was used to assess candidate ISG expression. There was sustained induction on day 7 and day 28 of the ISG's OAS1, IRF-7, IFI44 and IFI27. Although all patients showed a molecular response to alb-IFN, individual variability in pretreatment gene expression levels and fold of modulation during treatment was observed. At day 28, induction of OAS1, IFI44 and IRF7 showed pairwise correlation in individual patients ( P<0.05). Moreover, the induction of expression at day 28, and pretreatment levels of OAS1 and IFI44 correlated with hepatitis C virus RNA reduction at day 28 ( P<0.05). In conclusion, alb-IFN demonstrated robust induction of ISG that was consistent with the response associated with an IFN-α.

Albumin-interferon-α (IFN-α) is a novel 85.7–kDa recombinant protein consisting of IFN-α that is genetically fused to human serum albumin. In this Phase I/II, multicentre, open-label study, we evaluated the safety and tolerability, pharmacokinetics and pharmacodynamics of albumin-IFN-α in IFN-α-experienced patients with chronic hepatitis C. Albumin-IFN-α was administered in 22 escalating doses (7–900 μg) in a single injection or in two injections 14 days apart. In the 119 patients studied, there were no discontinuations because of adverse events, and albumin-IFN-α had a favourable safety profile at doses up to 900 μg. The most common adverse events were headache (56%), fatigue (52%), injection site erythema (38%), arthralgias (32%) and pyrexia (27%). Reduced clearance resulted in a mean elimination half-life of 159h, which supports dosing at 2- to 4-week intervals. Induction of the IFN-specific gene OAS1 was maintained for ≥28 days following a single injection of albumin-IFN-α at doses of ≥40 μg. Dose-dependent antiviral activity was observed in this IFN-α-experienced study population. Antiviral activity of ≥1.0–log reductions in HCV RNA was observed in 47% (37/78) of patients in the 120- to 900-μg cohorts and in 59% (16/27) in the 400- to 900-μg double-injection cohorts. These results support further clinical studies of albumin-IFN-α for the treatment of patients with chronic hepatitis C.