Simple SummaryIt is still controversial whether tenofovir disoproxil fumarate (TDF) has a lower risk of hepatocellular carcinoma (HCC) development than entecavir (ETV) in patients with chronic hepatitis B (CHB). Furthermore, other antiviral treatment-related outcomes need to be evaluated between the two antivirals to provide essential information for clinical practice. Using a multicenter cohort of 4210 CHB patients, we demonstrated that ETV and TDF are comparable in terms of HCC development as well as mortality, incidence of liver-related outcome, extrahepatic malignancy or new decompensation events, and seroconversion rates. Patients treated with TDF experienced more side effects than those treated with ETV. The results of this study can be applied to the development of a personalized antiviral treatment strategy for CHB patients.AbstractTenofovir disoproxil fumarate (TDF) is reportedly superior or at least comparable to entecavir (ETV) in preventing hepatocellular carcinoma (HCC) among chronic hepatitis B (CHB) patients; however, it remains controversial. This study aimed to conduct comprehensive comparisons between the two antivirals. CHB patients initially treated with ETV or TDF between 2012 and 2015 at 20 referral centers in Korea were included. The primary outcome was the cumulative incidence of HCC. The secondary outcomes included death or liver transplantation, liver-related outcome, extrahepatic malignancy, development of cirrhosis, decompensation events, complete virologic response (CVR), seroconversion rate, and safety. Baseline characteristics were balanced using the inverse probability of treatment weighting (IPTW). Overall, 4210 patients were enrolled: 1019 received ETV and 3191 received TDF. During the median follow-ups of 5.6 and 5.5 years, 86 and 232 cases of HCC were confirmed in the ETV and TDF groups, respectively. There was no difference in HCC incidence between the groups both before (p= 0.36) and after IPTW was applied (p= 0.81). Although the incidence of extrahepatic malignancy was significantly higher in the ETV group than in the TDF group before weighting (p= 0.02), no difference was confirmed after IPTW (p= 0.29). The cumulative incidence rates of death or liver transplantation, liver-related outcome, new cirrhosis development, and decompensation events were also comparable in the crude population (p= 0.24–0.91) and in the IPTW-adjusted population (p= 0.39–0.80). Both groups exhibited similar rates of CVR (ETV vs. TDF: 95.1% vs. 95.8%,p= 0.38), and negative conversion of hepatitis B e antigen (41.6% vs. 37.2%,p= 0.09) or surface antigen (2.8% vs. 1.9%,p= 0.10). Compared to the ETV group, more patients in the TDF group changed initial antivirals due to side effects, including decreased kidney function (n = 17), hypophosphatemia (n = 20), and osteoporosis (n = 18). In this large-scale multicenter study, ETV and TDF demonstrated comparable effectiveness across a broad range of outcomes in patients with treatment-naïve CHB during similar follow-up periods.