SAN FRANCISCO, CAA higher dose of ribavirin for treatment-naïve patients receiving simeprevir and pegylated interferon plus ribavirin for chronic hepatitis C virus (HCV) genotype 1 can increase rates of sustained virologic response at 12 weeks after treatment ends (SVR12), according to data presented at The Liver Meeting® 2015.

Extending treatment duration from 24 to 48 weeks for patients who do not initially respond can also raise SVR12 rates, noted Yuki Tahata, Department of Gastroenterology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.

In Japan, simeprevir and pegylated interferon plus ribavirin “is recommended as first-line interferon-based therapy” for patients with HCV genotype 1 (GT1), the coauthors noted.

However, factors associated with an SVR “have not been fully examined,” they explained in introducing the rationale for their multicenter study, which was conducted at Osaka University Hospital and institutions participating in the Osaka Liver Forum.

The study enrolled 531 patients with chronic HCV treated with the triple-drug combination. Of the patients, 244 were male, mean age was 62.2 ± 10.0 years, 229 were treatment-naïve, and 212 had previously received pegylated interferon plus ribavirin.

“SVR[12] was defined as serum HCV-RNA negativity at 12 weeks after the end of treatment,” the researchers noted. 

Patients who were treatment-naïve and those who had previously relapsed were treated for 24 weeks (12 weeks of triple therapy, followed by 12 weeks of Peg-IFN plus ribavirin) and those who did not respond to previous therapies were treated for 24 (n=64) or 48 weeks (n=23).

“SVR12 rates were 87% for treatment-naïve patients, 95% for relapsers, and 42% for non-responding patients,” the team reported. Among both treatment-naïve and non-responding patients, “SVR12 rates were significantly higher in patients with the IL28B TT genotype than in those with the IL28B non-TT genotype” [TT vs. non-TT genotypes in both treatment-naïve patients and non-responders: P<0.05].

In patients with IL28B TT genotype, “the SVR12 rate was more than 90% irrespective of ribavirin dose, whereas in patients with the IL28B non-TT genotype, the ribavirin dose raised the SVR12 rate dose-dependently in stratified analysis (P=0.015),” the coauthors reported.

In patients with IL28B non-TT genotype who were administered <10mg/kg/day of ribavirin, SVR12 rates were 44%; for those given 10–12mg/kg/day of ribavirin, rates were 78%, and 100% for those given ≥12mg/kg/day of ribavirin, the coauthors reported.