Boceprevir plus peginterferon α-2b/ribavirin in chronic hepatitis C genotype 1: impact of baseline viral load on sustained virologic response.

BACKGROUND: Baseline viral load is a predictor of treatment outcome in patients with hepatitis C virus (HCV) infection receiving peginterferon and ribavirin. The impact of baseline viral load on sustained virologic response (SVR) after boceprevir-based therapy is unknown. METHODS: This retrospective analysis included patients with chronic HCV genotype 1 infection who were previously untreated or were previous treatment failures. Virologic response was assessed according to baseline viral load (≤1 million IU/mL, >1 to ≤5 million IU/mL, >5 to ≤10 million IU/mL, and >10 million IU/mL). RESULTS: SVR was higher in patients receiving boceprevir plus peginterferon and ribavirin than in those receiving peginterferon and ribavirin alone, regardless of baseline viral load. Patients with a baseline viral load ≤1 million IU/mL had the highest SVR (boceprevir plus peginterferon and ribavirin, 78% to 83%; peginterferon and ribavirin, 33% to 63%). Among patients with baseline viral load >1 million IU/mL, SVR rates were 57% to 68% in patients receiving boceprevir plus peginterferon and ribavirin, and 11% to 41% in patients receiving peginterferon and ribavirin. Relapse was higher in patients receiving peginterferon and ribavirin (previously untreated, 12% to 40%; previous treatment failures, 17% to 67%) than in those receiving boceprevir plus peginterferon and ribavirin (previously untreated, 3% to 12%; previous treatment failure, 9% to 16%), irrespective of baseline viral load. CONCLUSIONS: The efficacy of boceprevir plus peginterferon and ribavirin was unaffected by baseline viral loads >1 million IU/mL, whereas viral burden >1 million IU/mL was associated with lower SVR with peginterferon and ribavirin. Relapse rates were lower with boceprevir plus peginterferon and ribavirin than with peginterferon and ribavirin, and were unaffected by baseline viral load.