In a prospective study of patients with chronic HCV genotype 1a infection and cirrhosis ( 48 % African American and 61 % prior null responders ) , a 12-week regimen of simeprevir and sofosbuvir produced a significantly higher rate of SVR12 and was better tolerated , with a lower viral relapse rate , than a 12-week regimen of peginterferon , ribavirin , and sofosbuvir .