I read with interest Lam et al.'s report1 published in a recent issue of HEPATOLOGY. The sustained virological response (SVR) rates of hepatitis C virus genotype 6 (HCV-6) patients treated with peginterferon-α2a/ribavirin were similar in the 24-week arm (70%) and the 48-week arm (79%). However, an early virological response (EVR) was not a negative predictor of SVR in HCV-6 patients, as observed in Fung et al.'s study.2 These findings confused the 12-week stopping rule by EVR in HCV-1 patients.3 Nevertheless, the definition of EVR should be clarified. These two HCV-6 studies1, 2 defined EVR as seronegativity for HCV RNA in week 12. In contrast, almost all other reports have defined EVR as seronegativity for HCV RNA or a ≥2 log10 decline from the baseline in week 12.4, 5 With the consensus EVR definition, the negative predictive value for achieving SVR is ≥97% with the current standard of care4 in both HCV-13, 5 and HCV-2 patients.6 Recently, the consensus EVR definition has been further divided into rapid virological response (HCV RNA seronegativity in treatment week 4), complete EVR (no rapid virological response but HCV RNA seronegativity in week 12), and partial EVR (HCV RNA seropositivity in weeks 4 and 12 but a ≥2 log10 drop in HCV RNA in week 12) to improve the prediction of SVR.7 The SVR rates could reach 90% in both HCV-1 and HCV-2 patients who achieve complete EVR with the standard of care but only approximately 20% in those achieving partial EVR.8 Therefore, the clarification of a universal definition of EVR is very important for reporting data on the on-treatment and off-treatment efficacy for chronic hepatitis C.
To the Editor:
Ming-Lung Yu M.D., Ph.D.* , * Department of Internal Medicine, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung, Taiwan, Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, Faculty of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.