In a multi-centered , randomized and positive drug-controlled phase IIb clinical trial on type Y peginterferon -2 b ( NCT01140997 ) , forty-eight CHC patients who participated in pharmacokinetics were randomly divided into 4 cohorts and treated with PegIFN ( type Y peginterferon -2 b 90 g , 135 g , 180 g and PegIFN-2a 180 g , respectively , once a week ) and ribavirin ( < 75 kg , 1000 mg daily and75 kg , 1200 mg daily ) for 48 weeks , and then followed up for 24 weeks .