Comparison of an antiviral activity of recombinant consensus interferon with recombinant interferon-alpha-2b

Pharmacokinetics, tissue distribution, excretion, and antiviral activity of pegylated recombinant human consensus interferon-α variant in monkeys, rats and guinea pigs

The study aims to characterize the pharmacokinetic, tissue distribution, excretion, and antiviral activity properties of a novel pegylated recombinant human consensus interferon-α variant (PEG-IFN-SA) following a single subcutaneous administration to monkeys, rats and guinea pigs. Studies included: (1) pharmacokinetic properties of PEG-IFN-SA and comparison with those of non-pegylated IFN-SA in rhesus monkeys and rats; (2) tissue distribution and urinary, fecal, and biliary excretion patterns of (125)I-PEG-IFN-SA in guinea pigs; and (3) antiviral activity assessment of PEG-IFN-SA in cynomolgus monkeys. The pegylated protein exhibited improved pharmacokinetic properties compared to IFN-SA in both monkeys and rats, with a 12-fold and 15-fold increase in elimination half-life, and a 100-fold and 10-fold decrease in serum clearance, as well as a 2.5-fold and 10-fold increase in the time to reach peak serum concentration, respectively. (125)I-PEG-IFN-SA was found to be distributed to most of the tissues examined and has character of targeting special distribution, and urinary appeared to be a major route for the excretion of PEG-IFN-SA in guinea pigs. Serum sample analysis from PEG-IFN-SA-treated monkeys showed dose-dependent antiviral activity for one week. These findings demonstrate that pegylation of IFN-SA results in more desirable pharmacokinetic properties, enhanced drug exposure and sustained-efficacy of in vivo antiviral action.

[Interferon alfacon-1 (Advaferon): a novel synthetic interferon for the treatment of hepatitis C, its pharmacological and clinical profile]

Interferon alfacon-1 (Advaferon, also referred to as consensus interferon) is a novel synthetic recombinant type-I interferon (IFN) developed by comparing the amino acid sequences of several natural IFN-alpha subtypes and assigning the most frequently observed amino acid in each corresponding position to generate a consensus molecule. Interferon alfacon-1 binds with high affinity to type-I IFN receptors and has greater biological activity than naturally occurring IFN-alpha as assessed by its increased antiviral, anti-proliferative, and natural killer cell activities, as well as its stronger IFN-stimulated gene induction. In a multicenter, randomized, controlled study, the safety and efficacy of interferon alfacon-1 in comparison with lymphoblastoid interferon-alpha [IFN-alpha (NAMALWA)] was evaluated in patients infected with high-titer chronic hepatitis C virus (HCV). Interferon alfacon-1 (18 MIU) was superior in efficacy without additional toxicity to IFN-alpha (NAMALWA) (9 MIU) in high-titer chronic HCV patients, particularly those infected with genotype 1b. A multicenter open-label study showed that treatment with interferon alfacon-1 (12 MIU) was an effective and tolerable therapy in chronic HCV patients with low viral titers. Another multicenter open-label study showed that re-treatment with interferon alfacon-1 (18 MIU) was an effective and tolerable therapy in chronic HCV patients who relapsed after traditional IFN therapy. Collectively, these clinical studies indicate that interferon alfacon-1, as a novel synthetic interferon, may be a useful therapeutic alternative for the effective treatment of hepatitis C.

Interferon alfacon-1: a review of its pharmacology and therapeutic efficacy in the treatment of chronic hepatitis C

Interferon alfacon-1 (consensus interferon) is a non-naturally occurring, synthetic, type 1 interferon (IFN)alpha that is used for the treatment of patients with chronic hepatitis C. The efficacy of subcutaneously administered interferon alfacon-1 has been demonstrated in clinical trials during the treatment of LFN-naive patients (interferon alfacon-1 9microg 3 times a week for 24 weeks) and retreatment of nonresponders and relapsers to previous interferon therapy (interferon alfacon1 15 microg 3 times a week for up to 48 weeks). Higher and more frequent interferon alfacon-1 dosages have also been investigated. Results from a pivotal double-blind randomised trial in 704 patients with chronic hepatitis C showed that interferon alfacon-19 microg 3 times a week achieved virological and biochemical response rates of 34.9 and 42.2%, respectively, at treatment end-point (week 24). Sustained virological and biochemical responses (week 48) were reported in 12.1 and 20.3% of the patients, respectively. In general, response rates in recipients of interferon alfacon-1 9 microg 3 times a week were similar to those achieved with IFN-alpha2b 3 MIU 3 times a week. However, interferon alfacon-1 was more effective in the subgroup of patients infected with hepatitis C virus (HCV) genotype 1 at end-point (virological response, 24 vs 15%; p < 0.05) and post-treatment observation period (8 vs 4%) although the difference between treatment groups was statistically significant only at treatment end-point. The sustained virological response rate achieved in patients with high baseline levels of serum HCV RNA receiving interferon alfacon-1 was statistically superior to that exhibited in the IFN-alpha2b treatment group (7 vs 0%; p < Interferon alfacon-1 also showed efficacy during the retreatment of non-responders and relapsers to previous IFN therapy in a large nonblind multicentre trial. Sustained virological response (week 72) was observed among 13 and 58% of nonresponders and relapsers, respectively, after 48 weeks of treatment with interferon alfacon-1 15 microg 3 times a week. Interferon alfacon-1 has been generally well tolerated in clinical trials. As with other IFNs, adverse events were reported frequently but were usually considered of mild to moderate severity, decreased with time and caused a small percentage of patients to withdraw from the treatment. Fever, fatigue, arthralgia, myalgia, headache and rigors were the most frequently reported adverse events. Psychiatric adverse events appeared to be dose-related and caused the majority of treatment withdrawals.

CONCLUSION

Interferon alfacon-1 is generally well tolerated and is an effective agent in the treatment of patients with chronic hepatitis C. Comparative data from a pivotal randomised trial indicate that the drug has at least equivalent efficacy to IFNalpha-2b, and a statistically significant advantage was demonstrated at treatment end-point in patients infected with HCV genotype 1. A number of ongoing trials with interferon alfacon-1 are evaluating issues such as the optimal dosage regimen and duration of therapy in an effort to improve sustained virological response to therapy, a goal for IFNs in general.