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

To compare virological, biochemical, and immuneresponses 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 threegroups (group A, 60 patients receiving IFN-α, 6million units (MU) once a day, daily for one month andthrice weekly for five months; group B, 40 patients receiving 6 MU IFN-β once a day daily fortwo months; and group C, 20 patients receiving 3 MUIFN-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 byenzyme-linked immunosorbent assay. Patients withsustained clearance of serum HCV RNA detected bypolymerase chain reaction (PCR) at six months after IFNtreatment were defined as having complete response to IFNtreatment. A low level of HCV RNA (≤10-4copies/50 mul, measured by competitive PCR) and HCV RNAof genotype 2a were favorable factors for a completeresponse to both IFNs. Complete response in group Atreatment was strongly associated with early HCV RNAclearance, in contrast with group B. A significantlyhigher 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-2Rlevels rose in each group during IFN administration. Ingroup C, alanine aminotransferase (ALT) and IL-6 levels were remarkably elevated. These findingsindicate that timing of serum HCV RNA negativity insustained response differs between IFN-α andIFN-β administrations and that early HCV RNAclearance was induced by twice-a-day IFN-βtreatment.