Pharmacokinetics and Safety of Velpatasvir and Sofosbuvir/Velpatasvir in Subjects with Hepatic Impairment

Background: 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. Methods: 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 100 mg. 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 12 weeks or sofosbuvir/velpatasvir for 24 weeks. 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]. Results: 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; AUC_tau) 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. Conclusions: No sofosbuvir/velpatasvir dose modification is warranted for patients with any degree of hepatic impairment.