Twice-weekly doses of pegylated interferon alfa-2b are need to achieve adequate suppression of hepatitis C virus (HCV) according to a small study published in the July 2003 edition of the Journal of Viral Hepatitis.
The currently recommended dose of Schering Plough's pegylated interferon formulation (PegIntronTM) for HCV infection is a single injection of 1 mcg/kg per week. The drug can be used by itself or in combination with ribavirin. The recommended standard of care for individuals coinfected with HIV is a dual therapy consisting of pegylated interferon and ribavirin.
In a four week study, investigators at the University of Vienna randomised 20 patients with chronic HCV genotype 1 who had never received interferon therapy to receive either the standard once-weekly dose of pegylated interferon or twice weekly injections of the drug and evaluated after four weeks. Serum concentrations of interferon were then checked, as was the impact of the drug on HCV viral load.
Amongst the ten patients who received once-weekly injections, serum levels of pegylated interferon reached maximum levels 24 hours after the drug was injected, and then declined over subsequent days, with the drug undetectable in the serum of 90% on the day before the next dose.
However, amongst the ten patients treated with twice-weekly injections, the drug was detectable at any point and in higher concentrations than that seen in the individuals on once-weekly therapy (p between 0.1 and
Hepatitis C viral load fell within 24 hours of receiving an injection of pegylated interferon in all patients, but started to rebound within three days. This rebound was suppressed in the ten patients who received a second weekly dose (p
The investigators concluded that HCV viral load increased in parallel with serum levels of pegylated interferon, “clearly indicating that this rebound of HCV RNA is because of insufficient interferon levels in the body. This rebound may be predictive of nonresponse…to therapy.”
Further information on this website
Formann E et al. Twice-weekly administration of peginterferon-alpha-2b improves viral kinetics in patients with chronic hepatitis C genotype 1. Journal of Viral Hepatitis 10, 271, 2003.