Tenofovir-based rescue therapy in chronic hepatitis B patients with suboptimal responses to adefovir with prior lamivudine resistance.

We evaluated the efficacy of tenofovir (TDF)-based rescue therapy and compared the outcomes of TDF monotherapy and TDF-based nucleoside analog (NA) combination therapy in patients with suboptimal response (SOR) to adefovir (ADV) with or without NAs in lamivudine (LAM)-resistant chronic hepatitis B. All study subjects received ADV with or without NAs due to prior LAM resistance, and were then switched to TDF-based rescue therapy due to SOR (hepatitis B virus DNA >20 IU/ml after at least 6 months of therapy). A total of 125 patients were eligible. The overall cumulative proportion of complete virologic response (CVR) was 64 of 74 patients (86.5%) at 48 weeks of treatment. During the follow-up period of 48 weeks, there was no significant difference in CVR rate (P = 0.750) between the TDF monotherapy (n = 18) and the TDF with NA groups (n = 107). Patients with ADV genotypic mutations showed inferior antiviral responses to TDF compared with the patients without ADV genotypic mutations, but this was not statistically significant (P = 0.069). Partial virological response to prior ADV therapy showed higher CVR rates compared to patients with non-response at 12 weeks (P = 0.013), but there was no significant difference after 24 (P = 0.076) and 48 weeks (P = 0.198) of treatment. TDF monotherapy is as effective as TDF plus NA combination therapy in patients with SOR to ADV-based rescue therapy and LAM resistance. TDF, with or without NAs, was effective even in cases of ADV resistance.