TAF has shown less bone and renal effects with similar efficacy rates compared to TDF in Phase 3 studies after 96 weeks of double-blind (DB) treatment. We evaluated patients who completed 96 weeks of DB treatment with TAF or TDF and switched to open label (OL) treatment with TAF, including those with 1 year of data (through Week 144) to determine changes in bone mineral density (BMD), creatinine clearance (CrCL), and the maintenance of viral suppression.Methods
1298 CHB patients who were HBeAg-negative or HBeAg-positive were randomised and treated with TAF or TDF. At Week 96, 541 (42%; TAF 361; TDF 180) patients had completed DB treatment with TAF or TDF and switched to OL TAF. Analyses included subjects with values at Week 96 and at Week 144 for creatinine clearance (n=401), spine BMD (n=288) or hip BMD (n=287), HBV DNA (n=394) and ALT normalisation by AASLD criteria (n=398).Results
CrCL improved in patients who switched from DB TDF to OL TAF at Week 144 compared to Week 96 (n=122, median (Q1, Q3) change=+3.6 (-4.2,+8.4) ml/min, p<0.001); (figure 1 and 2b ). (HBV DNA <29 IU/mL) were maintained in both treatment groups at Week 144 (TDF 87% vs 88% and TAF 91% vs 89%). One year after switching the rate of ALT normalisation increased in the TDF group relative to Week 96 (n=122; 65% vs 47%; p<0.001) and did not differ from the TAF group (65% vs 66%; p=0.83) at Week 144.Conclusions
Patients who switched from TDF to TAF demonstrated continued improvements in BMD and CrCL over 48 weeks of treatment, virologic control was maintained, and rates of ALT normalisation increased.