Racial differences in responses to interferon‐ β ‐1a in chronic hepatitis C unresponsive to interferon‐ α : a better response in Chinese patients

Summary.  Re‐treatment with interferon‐ α alone for chronic hepatitis C nonresponders to interferon‐ α monotherapy is almost ineffective. This multicentre, randomized, parallel‐group, dose‐finding study evaluated the efficacy of interferon‐ β ‐1a in the treatment of chronic hepatitis C patients unresponsive to interferon‐ α . A total of 267 patients were randomized to one of four groups: subcutaneous interferon‐ β ‐1a 12 MIU (44  μ g) or 24 MIU (88  μ g) administered three times weekly or daily. Patients were treated for 48 weeks and then followed up for an additional 24 weeks. There was a trend towards a dose–response relationship regarding virological [loss of detectable serum hepatitis C virus (HCV) RNA] and biochemical response (normalization of serum alanine aminotransferase). Overall, 22 patients (8.3%) had a virological response at the end of treatment; nine patients (3.4%) had a sustained virological response (SVR). Strikingly, 21.7% (5/23) of Chinese patients achieved SVR. Univariate analysis revealed that race was the only variable related to SVR [odds ratio (OR) 16.6; 95% CI 4.1–67.3; P  < 0.0001]. Multiple logistic regression analysis also confirmed that more Chinese patients achieved SVR than non‐Chinese patients (OR 12.3; 95% CI 2.6–59.3; P  = 0.0017). In addition, complete clearance of HCV‐RNA occurred earlier in Chinese than in non‐Chinese responders (median 2 vs 30 weeks; P  = 0.020). Thirty‐six patients were withdrawn from treatment because of adverse events. Most adverse events were mild or moderate in severity. In conclusion, interferon‐ β ‐1a provided considerable clinical benefit in Chinese patients with chronic hepatitis C unresponsive to interferon‐ α . The evaluation of interferon‐ β ‐1a in this setting is progressing.