AIM:To compare the efficacy and safety of tenofovir disoproxil fumarate(TDF)in Asian and non-Asian chronic hepatitis B(CHB)patients.METHODS:The efficacy and safety of the initial 48wk of treatment with TDF was compared in a posthoc analysis of combined data from 217 Asians and299 non-Asians included in Studies 102 and 103and a post-approval,open-label trial(Study 123).Patient groups were compared according to baseline hepatitis B e antigen(HBe Ag)status and viral load.The main outcome measures included the proportion of patients who achieved a hepatitis B virus(HBV)DNA level<400 copies/m L at Week 48 of treatment.Secondary measures included:HBV DNA and alanine aminotransaminase(ALT)levels over time;proportion of patients with normal ALT levels;proportion of patients with HBe Ag loss/seroconversion and proportion of patients with hepatitis B surface antigen loss/seroconversion;changes in liver histology.Safety and tolerability were evaluated by the occurrence of adverse events(AEs),serious AEs,laboratory abnormalities,discontinuation of the study drug due to AEs,or death.The primary efficacy and safety analysis set included all patients who were randomly assigned to treatment and received at least one dose of study drug.RESULTS:At week 48,similar proportions of Asians and non-Asians reached HBV DNA<400 copies/m L(96%of Asian and 97%of non-Asian patients with HBe Ag-negative CHB and 83%of Asian and 79%of non-Asian patients with HBe Ag-positive CHB had HBV DNA)and normal ALT(78%of Asian and 81%of nonAsian patients with HBe Ag-negative CHB and 71%of Asian and 74%of non-Asian patients with HBe Agpositive CHB had normal ALT).On-treatment HBV DNA decline rates were similar between Asians and nonAsians regardless of baseline HBe Ag status and viralload.HBV DNA decline during the first four weeks was2.9 log10 copies/m L in HBe Ag-negative Asians and nonAsians,and in HBe Ag-positive non-Asians,and 3.1log10 copies/m L in HBe Ag-positive Asians.HBe Ag loss and seroconversion was achieved in 14%of Asians vs 26%and 24%,respectively,in non-Asians.Liver histology improved in 77.2%of Asians and 71.5%of non-Asians.No resistance to TDF developed.No renal safety signals were observed.CONCLUSION:TDF demonstrated similar viral suppression,normalization of ALT,improvements in liver fibrosis,and no detectable resistance in Asian and non-Asian patients regardless of baseline HBe Ag status. AIM: To compare the efficacy and safety of tenofovir disoproxil fumarate (TDF) in Asian and non-Asian chronic hepatitis B (CHB) patients. METHHODS: The efficacy and safety of the initial 48 wk of treatment with TDF was compared in a posthoc analysis of Combined data from 217 Asians and 299 non-Asians included in Studies 102 and 103 and a post-approval, open-label trial (Study 123). Patient groups were compared according to baseline hepatitis B e antigen (HBe Ag) status and viral load. primary outcome measures included the proportion of patients who achieved a hepatitis B virus (HBV) DNA level <400 copies / m L at Week 48 of treatment. Secondary measures included: HBV DNA and alanine aminotransaminase (ALT) levels over time; proportion of patients with normal ALT levels; proportion of patients with HBe Ag loss / seroconversion and proportion of patients with hepatitis B surface antigen loss / seroconversion; changes in liver histology. Safety and tolerability were evaluated by the occurrence of adverse events (AEs), seri ous AEs, laboratory abnormalities, discontinuation of the study drug due to AEs, or death.The primary efficacy and safety analysis set included all patients who were randomly assigned to treatment and received at least one dose of study drug .RESULTS: At week 48, similar proportions of Asians and non-Asians reached HBV DNA <400 copies / mL (96% of Asian and 97% of non-Asian patients with HBe Ag-negative CHB and 83% of Asian and 79% of non-Asian patients with HBe Ag-positive CHB had HBV DNA) and normal ALT (78% of Asian and 81% of nonAsian patients with HBe Ag-negative CHB and 71% of Asian and 74% of non-Asian patients with HBe Agpositive CHB had normal ALT) .On-treatment HBV DNA decline rates were similar between Asians and nonAsians regardless of baseline HBe Ag status and viralload. HBV DNA decline during the first four weeks was 2.9 log10 copies / mL in HBe Ag-negative Asians and nonAsians, and in HBe Ag-positive non-Asians, and 3.1 log10 copies / mL in HBe Ag-positive Asians. HBe Ag loss and seroconversion was achieved in 14% of Asians vs 26% and 24%, respectively, in non-Asians.Liver histology improved in 77.2% of Asians and 71.5% of non- Asians. No resistance to TDF developed. No renal safety signals were observed. CONCLUSION: TDF demonstrated more similar suppression, normalization of ALT, improvements in liver fibrosis, and no detectable resistance in Asian and non-Asian patients regardless of baseline HBe Ag status.