Hepatitis C Cure Rate 93% With Elbasvir/Grazoprevir for Genotype 1 or 4

Sustained virologic response 12 weeks after elbasvir/grazoprevir (EBR/GZR, Zepatier) therapy ended (SVR12) reached 93% among HCV genotype 1 and 4 patients in the double-blind, placebo-controlled C-CORAL trial. SVR12 rates did not differ by sex, age or fibrosis stage.

HCV prevalence in the Asia/Pacific region and Russia ranges from 1% to 5%, with genotype 1b accounting for about half of infections. Fixed-dose one-tablet once-daily EBR/GZR is licensed for treatment of genotype 1 and 4 HCV in the United States, the European Union and elsewhere. C-CORAL collaborators conducted this trial to assess EBR/GZR efficacy and safety in Korea, Taiwan, Vietnam, Thailand, Australia and Russia. EBV is an NS5A inhibitor, and GZR is an NS3/4A protease inhibitor.

The phase 3 trial randomized 250 participants to immediate EBR/GZR and 86 to placebo for 12 weeks, followed by unblinding and EBR/GZR for the placebo group. All patients had HCV genotype 1, 4 or 6 and none had HIV; they could have compensated cirrhosis. The primary endpoint was SVR12 in the immediate EBR/GZR arm.

The immediate and deferred groups were similar in age (mean 49.9 and 50.8 years), proportions of men (42% and 45%), proportions of Asians (59% and 59%) and proportions with the four genotypes (overall 11% 1a, 74% 1b, 1% 4 and 14% 6). About 20% of patients in both treatment arms had cirrhosis.

Overall SVR12 in the immediate EBR/GZR arm was 93% and was high for genotype 1a (89%), 1b (99%) and 4 (100%), but not for genotype 6 (63%). Among 13 patients without SVR12 in the genotype 6 arm, three had virologic breakthroughs, three had rebounds and seven had relapses. SVR12 rates were moderately higher in white patients than Asians (98% versus 89%) but did not differ substantially by sex, age over or under 65 years, cirrhosis status or baseline viral load.

Nearly one quarter of genotype 1a and 1b patients had NS5A resistance-associated variants (RAVs) at baseline, as did one of two patients with genotype 4 and 15 of 34 patients (44%) with genotype 6. Among genotype 1a patients, SVR12 rates were lower in patients with than without RAVs (67% versus 95%), but response rates were similar with and without RAVs in the genotype 1b group (97% and 100%) and the genotype 4 group (100% and 100%). In the genotype 6 group, SVR12 rates were 40% with baseline RAVs and 79% without RAVs.

Half of participants in the immediate and deferred EBR/GZR arms had at least one adverse event, and about 20% in each arm had a drug-related adverse event. The two serious adverse events in the immediate arms were not drug related and one participant in the immediate arm stopped treatment because of an adverse event (elevated alanine aminotransferase and bilirubin).

C-CORAL investigators concluded that "a 12-week regimen of EBR/GZR is effective and well-tolerated in [genotype 1] and [genotype 4]-infected, treatment-naive patients in the Asia Pacific/Russia region."

Mark Mascolini writes about HIV and hepatitis virus infection.