Table 8.
Virological Responses During Therapy and Definitions
| Rapid virological response (RVR) | HCV RNA negative at treatment week 4 by a sensitive PCR-based quantitative assay | May allow shortening of course for genotypes 2&3 and possibly genotype 1 with low viral load |
| Early virological response (EVR) | ≥ 2 log reduction in HCV RNA level compared to baseline HCV RNA level (partial EVR) or HCV RNA negative at treatment week 12 (complete EVR) | Predicts lack of SVR |
| End-of-treatment response (ETR) | HCV RNA negative by a sensitive test at the end of 24 or 48 weeks of treatment | |
| Sustained virological response (SVR) | HCV RNA negative 24 weeks after cessation of treatment | Best predictor of a long-term response to treatment |
| Breakthrough | Reappearance of HCV RNA in serum while still on therapy | |
| Relapse | Reappearance of HCV RNA in serum after therapy is discontinued | |
| Nonresponder | Failure to clear HCV RNA from serum after 24 weeks of therapy | |
| Null responder | Failure to decrease HCV RNA by < 2 logs after 24 week of therapy | |
| Partial responder | Two log decrease in HCV RNA but still HCV RNA positive at week 24 |