TAKA0 TSUJI,~ SADAHITO SHIN,2 MASASHI TA"03, MICKEY s. URDEA,4 AND JANICE A. KOLBERG4
To clarify the viral factors that may predict the therapeutic effect of interferon (IFN) in chronic hepatitis C (CHC) patients, we investigated the quantitative serum hepatitis C virus (HCV) RNA level, genotype, and liver biopsy histological features in 60 patients who were treated with 360 x 10' U of natural IFN-a for 36 to 48 weeks and for more than 12 months after therapy. A branched DNA (bDNA) assay was used to measure HCV RNA levels. All responders, defined as those individuals with normal alanine transaminase (ALT) levels at 48 weeks after therapy, had less than 2 x 10' HCV RNA Eq/ mL before administration of IFN. Of 39 patients with RNA levels (less than 2 x 10' Eq/mL) 23 (59.0%) were responders. The genotype was determined for each patient using type-specific polymerase chain reaction (PCR) primers. There was a significant difference in rate of response between subtype l b and subtypes 2a and 2b (P < .0002); however, all responders had less than 2
x lo6 E q / d independent of genotype. In a multivariate analysis, RNA level was the most statistically significant factor affecting response to IFN. Although disease severity, as defined by histological features, was not statistically correlated with nonresponse, patients that responded to IFN tended to have less severe disease. (HEPATOLOGY 1995;22:1351-1354.)
Although interferon alfa (IFN-a) has been used in the treatment of chronic hepatitis C (CHC), few patients experience long-term response.ls2 Several reports have appeared indicating that low viremia levels tend to correlate with long-term IFN r e ~p o n s e . ~-~ Additionally, the genotype has been indicated as a potential predictor of response.6
In this study, we chose to investigate several criteria Abbreviations: IFN-a, interferon alfa; CHC, chronic hepatitis C; HCV, hepatitis C virus; bDNA, branched DNA RT-PCR, reverse transcription-polymerase chain reaction; ALT, alanine transaminase.