In cohort 1 , we randomly assigned 60 patients to the 12-week regimen ( 31 with ribavirin and 29 with no ribavirin ) and 63 to the 18-week regimen ( 32 with ribavirin and 31 with no ribavirin ) ; in cohort 2 , we randomly assigned 65 patients to the 12-week regimen ( 32 with ribavirin and 33 with no ribavirin ) and 65 to the 18-week regimen ( 33 with ribavirin and 32 with no ribavirin .