Biochemical and viral response to consensus interferon (CIFN) therapy in chronic hepatitis C patients: Effect of baseline viral concentration

OBJECTIVE: The effect of baseline viral concentration on response was asses sed as part of a multicenter phase 3 trial evaluating the safety and effica cy of CIFN therapy for chronic HCV infection. METHODS: Patients (n = 472) received either CIFN 9 mu g or IFN alpha-2b 3 M U subcutaneously t.i.w. for 24 wk, followed by 24 wk of observation. RESULTS: Efficacy was assessed by the percentage of patients who achieved n ormal ALT values or undetectable HCV RNA values (using RT-PCR with a sensit ivity of 100 copies/ml). There was a clear relationship between baseline vi ral concentration and either ALT or HCV RNA response; patients with lower t iter HCV RNA had better response rates. End-of-treatment HCV RNA responses were better for patients with low viral concentrations treated with CIFN (5 1%) than for patients treated with IFN alpha-2b (31%) (p = 0.03). ALT respo nses in patients with low viral concentrations were 60% for CIFN-treated pa tients and 27% for IFN alpha-2b-treated patients (p < 0.01) at the end of t reatment. Patients with high titer HCV RNA were more likely to have a susta ined HCV RNA response after treatment with CIFN 9 mu g, compared with those treated with IFN alpha-2b (7% vs 0%, p = 0.03). CONCLUSIONS: Both genotype and baseline viral concentration were independen t factors that affected response to interferon. (Am J Gastroenterol 1999;94 :3583-3588. (C) 1999 by Am. Coll. of Gastroenterology).