S. C. Gordon, E. M. Yoshida, E. J. Lawitz, B. R. Bacon, M. S. Sulkowski, M. Davis, F. Poordad, J.-P. Bronowicki, R. Esteban, V. Sniukiene, M. H. Burroughs, W. Deng, F. J. Dutko, C. A. Brass, J. K. Albrecht, K. Rajender Reddy
Aliment Pharmacol Ther. 2013;38(1):16-27.
Abstract and Introduction
Background Adherence to therapeutic regimens affects the efficacy of peginterferon alfa (P) and ribavirin (R) therapy in patients with chronic hepatitis C virus genotype 1.
Aim To determine if medication adherence impacts efficacy [sustained virological response (SVR)] with triple therapy that includes boceprevir (BOC) plus P/R.
Methods Adherence was determined in two Phase 3 clinical studies with BOC: SPRINT-2 (previously untreated patients) and RESPOND-2 (patients who failed previous therapy with P/R). Adherence to the assigned duration of the dosing regimen and adherence to the three times a day (t.d.s.) dosing interval of 7–9 h for BOC were assessed by the recording of data from patients' dosing diaries and by the amount of study drug dispensed and returned.
Results Most patients (63–71%) adhered to ≥80% of their assigned treatment duration and achieved SVR rates of 86–90%. In contrast, patients who adhered to <80% of their assigned treatment duration achieved SVR rates of 8–32% (P < 0.0001), particularly low in patients who failed previous therapy (SVR = 8–15%). Different rates of adherence (<60% to >80%) to the t.d.s. dosing interval (7–9 h) with BOC did not influence the SVR rates (SVR = 60–83%) with the exception of patients who failed previous treatment and adhered to <60% of the t.d.s. dosing interval with BOC (SVR = 48–50%; P = 0.005).
Conclusions The achievement of an SVR is more dependent on adherence to the assigned duration of treatment than adherence to the t.d.s. dosing interval with boceprevir. Adherence to >60% of t.d.s. dosing with boceprevir is important in patients who failed previous therapy.