Ribavirin steady-state plasma level is a predictor of sustained virological response in hepatitis C-infected patients treated with direct-acting antivirals.

Background: In the era of highly effective direct-acting antivirals (DAAs) for treatment of patients with chronic hepatitis C virus (HCV) infection, ribavirin (RBV) is still considered beneficial in certain patients.

Aim: To assess the association between RBV steady-state plasma levels and sustained virological response (SVR).

Methods: Consecutive HCV-infected patients treated with DAAs plus RBV from four Dutch academic medical centres were enrolled. RBV steady-state plasma levels were prospectively measured at treatment week 8 using validated assays. Logistic regression analyses were performed to assess the influence of RBV steady-state plasma level on SVR, and RBV therapeutic range was explored using area under the ROC curve analyses.

Results: A total of 183 patients were included, of whom 85% had one or more difficult-to-cure characteristics (ie treatment experienced, HCV genotype 3, cirrhosis). The majority was treated with a sofosbuvir-based regimen and 163 (89%) patients achieved SVR. Median RBV dose was 12.9 (interquartile range 11.2-14.7) mg/kg/d, and median RBV steady-state plasma level was 2.66 (1.95-3.60) mg/L. In multivariable analyses, higher RBV steady-state plasma level (adjusted odds ratio 1.79 [95% CI 1.09-2.93]) was an independent predictor of SVR. With regard to the optimal RBV therapeutic range, 2.28 mg/L was the optimal lower cut-off for achieving SVR and 3.61 mg/L was the upper cut-off for preventing significant anaemia (Haemoglobin < 10 g/dL).

Conclusion: In this cohort of mainly difficult-to-cure patients treated with DAAs plus RBV, higher RBV steady-state plasma level was an independent predictor of SVR.