Nucleic acid testing to confirm sustained virological response (SVR) after HCV therapy is technical, often expensive, and frequently unavailable where disease prevalence is highest. Alternative surrogate biomarkers merit evaluation. In a short-treatment trial in Vietnam (SEARCH-1; n = 52) we analysed how changes in alanine transaminase (ΔALT) and aspartate transaminase (ΔAST), from end of treatment (EOT) to EOT + 12 weeks, related to SVR, defined as HCV RNA < lower limit of quantification 12 weeks after EOT. In a separate UK trial (STOPHCV1; n = 202), we then tested the hypothesis that any elevation in ALT or AST between EOT and EOT12 is a sensitive screen for treatment failure. In SEARCH-1, among 48 individuals with data, 13 failed to achieve SVR. Median ΔALT and ΔAST were negative in cured patients but elevated when treatment failed [median ΔALT (IQR): -2 IU/L (-6, +2)] versus +17 IU/L (+7.5, +38) (p< 0.001). Amongst treatment failures, 12/13 had increase in ALT and 13/13 had increase in AST after EOT, compared with 12/35 in those cured. In STOPHCV1, 196/202 patients had evaluable data, of which 57 did not achieve SVR. A rise in ALT after EOT was 100% sensitive (95% C.I. [93.7 - 100%]) and 51% specific (42.4 - 59.7%) for detecting treatment failure. ΔAST >0 IU/L was 98.1% (89.9 - 99.9%) sensitive and 35.8% (27.3 - 45.1%) specific. A rise in ALT or AST after HCV therapy is a highly sensitive screen for treatment failure in mild liver disease. This finding could reduce costs and complexity of managing HCV.
