Effect of Hepatic Impairment on the Pharmacokinetics of Grazoprevir, a Hepatitis C Virus Protease Inhibitor.

Grazoprevir (GZR) plus elbasvir is an approved treatment for chronic infection with hepatitis C virus (HCV) genotype 1 or 4. HCV infection complications include liver cirrhosis, end-stage liver disease, and hepatocellular carcinoma. The objective of this study was to evaluate the pharmacokinetics and safety of multiple-dose GZR (200, 100, or 50 mg) in non-HCV participants with mild, moderate, or severe hepatic impairment (HI), respectively, and in healthy matched controls (protocol MK-5172_p013; Merck & Co., Inc., Kenilworth, NJ). Participants with mild, moderate, or severe HI and controls (aged 18 to 65 years) matched for race, age, sex, and body mass index were enrolled in a 3-part, open-label, sequential-panel pharmacokinetic study. Participants received oral doses of GZR 200 mg (two 100-mg tablets), 100 mg (one 100-mg tablet), or 50 mg (two 25-mg tablets) once daily for 10 days. A total of 50 participants were enrolled: 8 with mild HI, 9 with moderate HI, 8 with severe HI, and a corresponding number of healthy matched controls for each hepatic cohort. Participants with HI demonstrated higher GZR exposure than healthy matched controls and showed an increase in exposure with increasing HI severity. The steady-state GZR AUC0-24 (area under the concentration-time curve from 0 to 24 h) for participants with mild, moderate, or severe HI was ≈2-, ≈5-, or ≈12-fold higher, respectively, than that for healthy matched controls. GZR was generally well tolerated in participants with HI. No dose adjustment is required for GZR in people with HCV with mild HI. GZR is contraindicated for those with moderate or severe HI (Child-Pugh class B or C), since they may have significantly increased GZR exposures that may lead to an increased risk of transaminase elevation.