PO-030: Comparison of Long-term Efficacy of Tenofovir Monotherapy between Nucleos(t)ide-naive and Nucleos(t)ide-resistant Chronic Hepatitis B Patients

Aims: Tenofovir (TDF) is a nucleotide analog used in the treatment of chronic hepatitis B (CHB) infection regardless of whether nucleos( t)ide resistance. This study compared the long-term efficacy of TDF in nucleos(t)ide analog (NA)-naive and NA-resistant chronic hepatitis B (CHB) patients. Methods: Of the 540 eligible patients, 452 were NA-naive and 88 were resistance to NA therapy prior to TDF rescue therapy. Results: The median follow-up period during TDF therapy was 23.0 months (range, 6-45 months). VR occurred in 443 patients (369 patients belonged to the NA-naive group and 74 patients belonged to the NA-resistant group) during the treatment period. There was no statistically significant difference in VR between the NA-naive group and the NA-resistant group (86.8% vs. 89.4%; P = 0.802); however, the former subgroup had significantly higher baseline HBV DNA values (mean, 6.35 ± 1.40 vs. mean, 4.12 ± 1.65 log10 IU/mL for NA-naive and the NA-resistant groups, respectively, P< 0.001). ALT normalization rates also did not differ between both groups (80.0% and 63.6% in the NA-naive group and the NA-resistant group, respectively; P = 0.502). During TDF therapy, 16.4% (43 of 262) of patients in the NA-naive group, and 7.5% (4 of 53) of patients in the NA-resistant group achieved HBeAg seroconversion, respectively (P = 0.137). Multivariate logistic regression analysis using selected baseline factors identified absolute HBV-DNA levels at baseline (P < 0.001; OR, 0.671; 95% CI, 0.592-0.759), NA-resistant group (P = 0.021; OR, 1.568; 95% CI, 1.048-2.344), and HBeAg positivity (P = 0.033; OR, 1.498; 95% CI, 1.034-2.172) as factors showing significant association with VR. There were no significant clinical adverse events during rescue treatment in the NA-naive group and the NA-resistant group. Conclusions: TDF was effective and safe for patients regardless of whether they were NA-naive or resistant. Especially, the lower HBV DNA levels at baseline, HBeAg-negative, and NA-naive patients were significantly associated with VR.