ENTA has disclosed the royalty-rate tiers for the 50% of Mavyret sales attributable to Glecaprevir (ENTA’s HCV protease inhibitor): https://www.sec.gov/Archives/edgar/data/1177648/000156459018021062/enta-10q_20180630.htm (page 12): investorshub.advfn.com/uimage/uploads/2018/8/9/eyn[nENTA_royalty_tiers.png