Sektion Hepatologie, Klinik und Poliklinik für Gastroenterologie und RheumatologieUniversitätsklinikum Leipzig, Leipzig, Germany. Electronic address: email@example.com.
BACKGROUND & AIMS:
Suboptimal virologic response to nucleos(t)ide analogs may represent a significant risk factor for resistance development in patients with chronic hepatitis B virus infection; treatment options have not been well studied. We evaluated long-term efficacy and safety of tenofovir alone and in combination with emtricitabine in a prospective, placebo-controlled trial in patients who remained viremic on adefovir therapy.
Hepatitis B e antigen-positive and -negative patients with hepatitis B virus DNA ⩾1000 copies/mL despite up to 96 weeks of adefovir were randomized to double-blind tenofovir or emtricitabine/tenofovir for 168 weeks. Patients with hepatitis B virus DNA ⩾400 copies/mL (⩾69 IU/mL) at or after week 24 could switch to open-label emtricitabine/tenofovir.
Overall, 90/105 (86%) patients (46/53 tenofovir and 44/52 emtricitabine/tenofovir) completed the 168-week study period, including 74/105 (70%) patients (35/53 tenofovir and 39/52 emtricitabine/tenofovir) who completed the study on their initial randomized treatment. Long-term viral suppression (hepatitis B virus DNA <400 copies/mL) was maintained at week 168 in 84% and 82% of patients receiving either emtricitabine/tenofovir combination or tenofovir monotherapy, respectively (non-completer equal to failure analysis). Baseline viral load as well as the presence of lamivudine and/or adefovir resistance-associated mutations at baseline had no impact on long-term treatment response. No resistance to tenofovir was observed through 168 weeks. Both treatments had a favorable safety profile.
Tenofovir monotherapy is as effective as emtricitabine/tenofovir combination therapy in maintaining long-term viral suppression in patients with a suboptimal response to adefovir, and is well tolerated in this population.