The rate of sustained virologic response was @ % ( @ % confidence interval -LSB- CI -RSB- , @ to @ ) with @ weeks of ledipasvir-sofosbuvir , @ % ( @ % CI , @ to @ ) with @ weeks of ledipasvir-sofosbuvir plus ribavirin , and @ % ( @ % CI , @ to @ ) with @ weeks of ledipasvir-sofosbuvir .