Lymphoblastoid interferon alfa-n1 improves the long-term response to a 6-month course of treatment in chronic hepatitis C compared with recombinant interferon alfa-2b: results of an international randomized controlled trial. Clinical Advisory Group for the Hepatitis C Comparative Study.

The aim of this study was to compare the short-term and long-term efficacy and safety of lymphoblastoid interferon with a recombinant interferon alfa (IFN-alpha) in a 24-week treatment course for chronic hepatitis C. One thousand seventy-one patients with chronic hepatitis C were randomized to receive lymphoblastoid IFN-alpha n1 or recombinant IFN-alpha2b at the same dosing regimen, 3 million units administered subcutaneously three times a week for 24 weeks. Hepatitis C viral (HCV) genotype (by line probe assay) was determined at baseline, and serum HCV RNA level (by quantitative reverse-transcriptase polymerase chain reaction) was measured at baseline and weeks 24, 48, and 72. Primary end points were normalization of serum alanine aminotransferase (ALT) levels at end of therapy (week 24) and sustained ALT normalization at weeks 48 and 72. Secondary end points were nondetectability of serum HCV RNA at 24, 48, and 72 weeks, and histological improvement at weeks 24 and 72. The two treatment groups were similar with respect to demographic, clinical, and histological variables (10% had cirrhosis at entry), baseline serum HCV RNA levels, and distribution of HCV genotypes. Intent-to-treat analysis showed that ALT response at end of treatment was 35.3% for IFN-alpha n1 and 37.9% for IFN-alpha2b (P = .38). Histological improvement and nondetectability of HCV RNA were also similar between the two treatment groups at the end of treatment, as were the type and frequency of reported adverse experiences. Among treatment responders, post-treatment relapse was significantly less frequent with IFN-alpha n1 than with IFN-alpha2b. Thus, sustained ALT responses (SR) to IFN-alpha n1 were significantly more frequent than SR to IFN-alpha2b (12.0% vs. 7.6% at 48 weeks, P = .02; 10.3% vs. 6.7% at 72 weeks, P = .04). SR were associated with viral loss and histological improvement, and more patients treated with IFN-alpha n1 were HCV RNA negative at week 72 compared with patients treated with IFN-alpha2b (P = .03). SR at week 72 were two- to sixfold better with other HCV genotypes relative to type 1, but the improved long-term efficacy of IFN-alpha n1 compared with IFN-alpha2b was evident for all major HCV genotypes. It is concluded that IFN-alpha n1 and IFN-alpha2b have similar end-of-treatment response rates and safety profiles but the sustained response rate is higher with IFN-alpha n1. SR to IFN-alpha treatment are associated with clearance of HCV RNA, and histological improvement was maximal in patients who exhibited sustained ALT normalization and clearance of HCV RNA.