257 : Development of a hyperglycosylated interferon ALFACON1: Towards monthly dosing for antiviral therapies in diseases such as chronic hepatitis C
Type 1 interferons (IFN) have been shown to be efficacious against many viruses. However, a significant drawback is the short duration of exposure. We have improved the PK of IFN ALFACON1 (CIFN) by glycoengineering. ALS-624 was generated by introducing four glycosylation sites, which demonstrated a significantly increased Molecular Weight of 30–45 kD compared to 19 kD for CIFN. ALS-624 was purified and fractionated to yield 4-Gly, 3-Gly and 2-Gly fractions by size exclusion chromatography. In a rat PK study, four groups were subcutaneously dosed with the three glycosylated ALS-624 fractions plus a non-glycosylated CIFN control. The high MW fraction of 4-Gly exhibited a 6-fold increase of AUC and over an 11-fold increase in T 1/2 over CIFN suggesting the potential for QW dosing. In a Yellow Fever Virus study, hamsters were injected intraperitoneally with virus. All compounds were administered i.p. at a dose of 1.25 × 10 6  IU/kg/dose, given QW (4 Gly and Peg-IFN-α-2a), BIW (3 Gly), or QD (IFN alfacon-1 and placebo) beginning at −4 h and ending 14 days post infection. Animals were observed for mortality for 21 days. QW dosing of 4-Gly achieved similar efficacy to QD CIFN and QW Peg-IFN-α-2a in overall survival rate and reduction of ALT level. Further refinement resulted in development of ALS-683 which has a MW in the 60–90 kD range and maintains undiminished biological potency. In mouse PK/PD study, both ALS-683 mouse homolog and unglycosylated mouse IFNα1 were dosed at 1000 IU/g. Animals ( N  = 3) were sacrificed at pre-dose and various time points post-dose. Mouse plasma and liver were analyzed for PK and PD markers. ALS-683 homolog has ∼37-fold improvement in T 1/2 and ∼33-fold improvement in AUC when compared with unglycosylated mouse IFN α 1. Significantly improved PD responses were also observed. ALS-683 can be further developed for possible once a month dosing.