Purpose: A prospective randomized trial was undertaken to test the efficacy of low and standard doses of pegylated interferon alpha-2b in combination with ribavirin for the initial treatment of chronic hepatitis C. By nature of its design the study also provided data on response to therapy over a spectrum of doses of both pegylated interferon alpha-2b and ribavirin calculated on a body weight basis.
Subjects and methods: Fifty micrograms of pegylated interferon alpha-2b or 100 microg for patients weighing<75 kg or 150 microg for patients>or=75 kg were administered weekly with 1000 mg ribavirin daily for 48 wk if serum hepatitis C virus (HCV) RNA was undetectable after the first 24 wk of therapy.
Results: Overall sustained viral response (SVR) was 45% for standard dose and 33% for low dose, p=0.02. For genotypes 2 and 3 SVR was 65% for standard dose, and 56% for low dose, p=0.51. For genotype 1 SVR was 38% for standard dose, and 24% for low dose, p=0.03. For genotype 1 patients whose doses exceeded the 1-2-5 threshold, that is >or=1.25 microg/kg body weight pegylated interferon alpha-2b weekly and >or=12.5 mg/kg body weight ribavirin daily, SVR was 51%.
Conclusion: The results of this study underscore the importance of adequate dosing of ribavirin as well as pegylated interferons in achieving an SVR when treating genotype 1 chronic hepatitis C patients with combination therapy.