Integrated Analysis of Elbasvir/Grazoprevir Clinical Trials in Korean Participants with Hepatitis C Virus Genotype 1b Infection

Abstract

Aims: All-oral direct-acting antiviral medications have transformed the treatment of hepatitis C virus (HCV) infection; however, local evidence is limited in some regions, including Korea. We conducted an integrated analysis of the efficacy of elbasvir (EBR)/grazoprevir (GZR) in Korean participants with HCV infection enrolled in EBR/GZR phase 3 clinical studies. Methods: Participants with HCV GT1b infection enrolled at Korean study centers who received EBR/GZR 50 mg/100 mg for 12 weeks were included. The primary endpoint of all studies was sustained virologic response (HCV RNA <15 IU/mL) 12 weeks after end of therapy (SVR12) in the full analysis set (all participants who received ≥1 dose of study medication). Results: A total of 74 Korean participants were included. Mean age was 55 years (SD, 11 years), 25 (33.8%) had cirrhosis, and 70 (94.6%) were treatment-naïve. There were no participants with HCV/HIV coinfection. SVR12 was achieved by 73 of 74 (98.6%) participants; and only 1 participant, who withdrew consent, failed to achieve SVR12. Therefore, in the modified full analysis set (excluding participants who discontinued for reasons unrelated to study medication), SVR12 was 100% (73/73). SVR remined high among participants with cirrhosis (25/25, 100%), baseline viral load >2,000,000 IU/mL (34/34 (100%), and age >65 years (16/16, 100%). Baseline NS5A resistance associated substitutions (RASs) were detected in 16 of 73 participants (22%) who had a treatment outcome of SVR or virologic failure; all 16 achieved SVR12. Rates of SVR12 among Korean participants in this analysis (73/74, 98.6%) were similar to those in non-Korean Asian participants with GT1b infection (378/388, 97.4%), and to non-Asian participants with GT1b infection (589/608, 96.9%) enrolled in phase 2/3 EBR/GZR clinical trials. Conclusions: The combination of EBR/GZR was highly effective in Korean participants with HCV GT1b infection, with high rates of SVR12 across all subgroups examined, including those with NS5A RASs.