In total, 14 patients receiving vaniprevir reported an AE of vomiting (mild, n = 12; moderate, n = 2). The time to onset ranged between days 1 and 27, with no clear relationship between dose and onset of vomiting. There were no serious AEs or treatment discontinuations resulting from an AE during the vaniprevir dosing
period, and there were no deaths. Ten serious AEs were reported in 9 patients; however, all became apparent after completion of the vaniprevir dose period and 14-day safety follow-up period. None of these serious AEs was considered by the investigator to be related to vaniprevir or placebo. There were also no clinically meaningful differences in vital signs or in ECG parameters between treatment groups during the vaniprevir treatment and 14-day safety follow-up period. Changes in laboratory values were generally XL184 purchase comparable between vaniprevir and placebo (Supporting Table 2). The first HCV protease
inhibitors approved recently (boceprevir and telaprevir) have strong antiviral potency, but have to be given every 8 hours with fatty meals and add to the side-effect profile of Peg-IFN-α plus RBV. Anemia, dysgeusia, and skin rashes have been variously associated with boceprevir and/or telaprevir.4, 6 Vaniprevir is a macrocyclic HCV NS3/4A protease inhibitor (administered QD or BID) that has demonstrated strong antiviral potency and a good safety RXDX-106 solubility dmso profile in phase I studies.17, 18 In the present phase II study, patients receiving vaniprevir achieved significantly higher rates of RVR, compared to placebo, regardless of dose or administration frequency. The highest rates of RVR were reported in patients receiving the higher doses of vaniprevir of
600 mg BID or 800 mg QD (79% and 83%, respectively), compared to 5.6% in the placebo control arm. Patients in all four vaniprevir treatment medchemexpress arms also achieved numerically higher EVR and SVR results, compared to the control arm; however, these differences were not statistically significant because of the low number of enrolled patients and the high rates of SVR observed for the placebo control arm. In addition, the study was not powered to assess differences in rates of SVR between treatment arms. Regardless, these data suggest that the addition of vaniprevir to a Peg-IFN-α plus RBV backbone for 4 weeks, followed by 44 weeks of Peg-IFN-α plus RBV, results in improved rates of SVR, compared with Peg-IFN-α plus RBV alone, although the optimum duration of HCV protease inhibitor therapy is almost certainly longer than 4 weeks, and extending vaniprevir treatment duration may result in further improvements in SVR rates.9 Alternatively, achieving SVR rates >70% with a relatively short 28-day treatment duration of vaniprevir may be considered advantageous and of particular benefit in patients who do not tolerate direct-acting antiviral agents.