O-13 : Switching from Tenofovir Disoproxil Fumarate (TDF) or Other Oral Antiviral Therapy (OAV) to Tenofovir Alafenamide (TAF) in Virally Suppressed CHB Patients with Hepatic Impairment

Aims: TAF, a novel tenofovir (TFV) prodrug, has greater plasma stability, more targeted delivery of TFV to hepatocytes, and reduced circulating levels of TFV compared to TDF. We evaluated efficacy and safety when virally suppressed CHB (Chronic Hepatitis B) patients with hepatic impairment were switched to TAF. Methods: In this Phase 2 study (NCT03180619) CHB patients with a ChildTurcottePugh (CTP) score of ³7 and £12 at screening (or past history of CTP ³7 and any score £12 at screening) who were taking TDF and/or other OAVs for ³48 weeks, with HBV DNA ULN at baseline; eHBeAg-positive at baseline. fSerum C-type collagen sequence (bone resorption marker); gSerum procollagen type 1 N-terminal propeptide (bone formation marker); hUrine retinol binding protein/creatinine (tubular marker); iUrine beta-2 microglobulin/creatinine (tubular marker). BMD, bone mineral density by DXA scan; sCr, serum creatinine; PO4, serum phosphorus; eGFRCG, estimated creatinine clearance (Cockcroft-Gault method) Conclusions: In CHB patients with hepatic impairment switched to TAF from TDF or other OAVs, viral suppression was well maintained and improved bone and renal safety was seen at Week 24.