Compass Research

The pharmacokinetics and safety of velpatasvir, a potent pangenotypic hepatitis C virus NS5A inhibitor, were evaluated in two hepatic impairment studies: a phase I study in hepatitis C virus-uninfected subjects and a phase III study (ASTRAL-4) in hepatitis C virus-infected patients. In the phase I study, subjects with moderate or severe hepatic impairment (Child-Pugh-Turcotte Class B or C), and demographically matched subjects with normal hepatic function received a single dose of velpatasvir 100mg. Pharmacokinetics and safety assessments were performed, and pharmacokinetic parameters were calculated using non-compartmental methods and summarized using descriptive statistics and compared statistically by geometric least-squares mean ratios and 90% confidence intervals. In ASTRAL-4, subjects with decompensated cirrhosis (Child-Pugh-Turcotte Class B) were randomized to receive treatment with either sofosbuvir/velpatasvir±ribavirin for 12weeks or sofosbuvir/velpatasvir for 24weeks. Pharmacokinetic and safety assessments were performed and pharmacokinetic parameters were calculated using a non-compartmental analysis and summarized using descriptive statistics and were compared to pharmacokinetics from ASTRAL-1 [subjects without cirrhosis or with compensated (Child-Pugh-Turcotte Class A) cirrhosis]. In the phase I study, plasma exposures (area under the concentration-time curve) were similar in subjects with Child-Pugh-Turcotte Class B (n=10) or Child-Pugh-Turcotte Class C hepatic impairment (n=10) compared with normal hepatic function (n=13). Percent free velpatasvir was similar in subjects without or with any degree of hepatic impairment. In the phase III study, velpatasvir overall exposure (area under the concentration-time curve over the 24-h dosing interval; AUCtau) was similar and sofosbuvir exposures were higher (~100%) for patients with Child-Pugh-Turcotte Class B hepatic impairment compared with the ASTRAL-1 population, which was not considered clinically relevant. No sofosbuvir/velpatasvir dose modification is warranted for patients with any degree of hepatic impairment.