SVR24

SVR24, or sustained virologic response at 24 weeks, is a virologic endpoint used in the treatment of hepatitis C virus (HCV) infection. It is defined as undetectable hepatitis C virus RNA in the blood 24 weeks after the end of antiviral therapy. Achieving SVR24 is widely interpreted as a virologic cure and is associated with reduced risk of liver failure, hepatocellular carcinoma, and liver-related mortality, particularly in patients with advanced fibrosis or cirrhosis.

Measurement and timing involve quantifying HCV RNA using PCR assays. SVR24 requires a documented undetectable HCV RNA at a scheduled visit 24 weeks after ending treatment; the assay’s lower limit of detection varies, commonly around 15 IU/mL. The exact timing may differ by study protocol or guideline.

Relationship to SVR12 is important. SVR12, assessed 12 weeks after end of treatment, is now the most widely used endpoint because it correlates strongly with SVR24 and allows earlier assessment. Most patients who relapse by SVR24 would have shown detectable HCV RNA by SVR12, but rare late relapses between weeks 12 and 24 can occur, so SVR24 is still reported in some trials and guidelines.

Limitations and considerations include the fact that SVR24 is not a guaranteed cure for every individual, especially in the presence of reinfection or certain coexisting conditions. Reinfection after cure is possible, so ongoing risk-reduction counseling remains important. In most cases, patients with cirrhosis require continued hepatocellular carcinoma surveillance regardless of SVR status. Historical use of SVR24 has diminished in favor of SVR12, though SVR24 data continue to be reported for completeness.