The 8-week trial in cirrhotic patients with or without ribavirin was mainly testing sofosbuvir/lediparsvir with addition of GS9669, not necessarily indicator how great 12-week of sofosbuvir/lediparsvir in cirrhotic patients were IMO.
As of new FDC of sofosbuvir/GS5816 trials, for treatment naive with both 8-week and 12-week arms, ribavirin was added to 8-week arm but not 12-week arm later on; for treatment experienced, no 8-week arm, ribavirin was added to 12-week arm later on; as I previously noted this probably indicates ribavirin is still needed in many instances even with the new FDC.