Differences between interferon-α and-β treatment for patients with chronic hepatitis C virus infection

To compare virological, biochemical, and immune responses to human lymphoblastoid interferon (IFN-α) and human fibroblast interferon (IFN-β) in patients with chronic hepatitis C virus (HCV) infection, 120 patients were randomly assigned to three groups (group A, 60 patients receiving IFN-α, 6 million units (MU) once a day, daily for one month and thrice weekly for five months; group B, 40 patients receiving 6 MU IFN-β once a day daily for two months; and group C, 20 patients receiving 3 MU IFN-β twice a day (6 MU/day) daily for two months). Serum soluble interleukin-2 receptor (sIL-2R) and interleukin-6 (IL-6) levels were measured by enzyme-linked immunosorbent assay. Patients with sustained clearance of serum HCV RNA detected by polymerase chain reaction (PCR) at six months after IFN treatment were defined as having complete response to IFN treatment. A low level of HCV RNA (≤10⁴ copies/50 μl, measured by competitive PCR) and HCV RNA of genotype 2a were favorable factors for a complete response to both IFNs. Complete response in group A treatment was strongly associated with early HCV RNA clearance, in contrast with group B. A significantly higher HCV RNA negativity at the second week from start of treatment was noted in group C (80.0%), compared with groups A (41.6%) and B (27.5%). sIL-2R levels rose in each group during IFN administration. In group C, alanine aminotransferase (ALT) and IL-6 levels were remarkably elevated. These findings indicate that timing of serum HCV RNA negativity in sustained response differs between IFN- α and IFN-β administrations and that early HCV RNA clearance was induced by twice-a-day IFN-β treatment.