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.