A randomized trial of 24 versus 48 weeks of peginterferon α-2a in patients infected with chronic hepatitis C virus genotype 2 or low viral load genotype 1: a multicenter national study in Japan

In a country such as Japan with the average age of patients with chronic hepatitis C treated with antivirals sometimes well above 60 years, the standard combination therapy is not well tolerated. In this randomized, prospective, controlled trial, we investigated the efficacy of 24-week peginterferon α monotherapy for easy-to-treat patients. A total of 132 patients chronically infected with hepatitis C virus (HCV) genotype 2 (n = 115) or low viral load HCV genotype 1 (<100 kIU/ml, n = 17) were treated with peginterferon α-2a (180 μg/week). Patients with a rapid virological response (RVR, HCV RNA negative or <500 IU/ml at week 4) were randomized for a total treatment duration of 24 (group A) or 48 (group B) weeks. Patients who did not show RVR (group C) were treated for 48 weeks. Sustained virological response (SVR) was assessed by qualitative reverse-transcription polymerase chain reaction. One hundred eight of 132 (82%) patients with RVR were randomized. SVR rates were 60% (group A), 79% (group B), and 27% (group C), respectively. Similar SVR rates were achieved in patients infected with HCV genotype 2 with low pretreatment viral load (<1000 kIU/ml) in group A (81%) and group B (79%) (P = 0.801), whereas in those with higher viral load (≥1000 kIU/ml), a lower SVR rate was identified in group A (26%) than in group B (67%) (P = 0.041). In conclusion, in patients infected with HCV genotype 2 and pretreatment viral load below 1000 kIU/ml who achieve RVR, 24-week treatment with peginterferon α-2a alone is clinically sufficient. Those who show no RVR or have higher baseline viral load, require alternative therapies.