In part A of the study we randomly assigned HCV-mono-infected patients to receive @ weeks of grazoprevir ( @ mg ) plus elbasvir ( @ mg or @ mg ) with or without ribavirin ( arms A@-@ ) ; in part B we assigned HCV-mono-infected patients to @ or @ weeks of grazoprevir ( @ mg ) plus elbasvir ( @ mg ) with or without ribavirin ( arms B@-@ ) and HIV/HCV co-infected patients to @ weeks of therapy with or without ribavirin .