“…Although the TVR C min was not lower than the reported 90% inhibitory concentration (IC 90 ) of 564 ng/mL [15] in any of the study patients, since the pharmacokinetics of HCV PIs, particularly the concentration at the end of the dosage interval (C trough ), was described as the best predictive parameter of HCV-RNA decline during phase 1 and 2 studies [16,17], even a small reduction of TVR plasma levels should raise a concern. Indeed, in this small case file the SVR12 rate was 53.3%, in line with previous studies on patients not responding to prior pegIFN + RBV treatment [18], also considering the high proportion of prior null or partial responders among our patients. We extend previous findings by documenting for the first time that no clinically relevant drug-drug interactions between TVR and highly active antiretroviral therapy can be expected not only when looking at total drug amount but also at the single TVR isomers, which are the most active forms [8,19].…”