Background/Aim: Primary treatment failure to entecavir is known to occur in chronic hepatitis B virus (HBV) infection. Although the prevalence is low, the optimal management of this select group is unknown. This study aimed to determine the efficacy of tenofovir disoproxil in those with primary treatment failure to entecavir.

Methods: This study included 14 patients with primary treatment failure to entecavir. They were switched over the tenofovir disoproxil for 48 weeks.

Results: All 14 patients (100%) had reduction in serum HBV DNA by more than 2 log10 IU/ml at week 12 after tenofovir disoproxil treatment. All 14 patients (100%) still had elevated alanine aminotransaminase (ALT) levels at the time they were switched over to tenofovir disoproxil. At week 48 of tenofovir disoproxil, normalization of serum ALT levels occurred in 12 of these 14 patients (85.7%), and, 10 of the 14 patients (71.4%) had achieved both undetectable serum HBV DNA and normalization of serum ALT levels.

Conclusion: Tenofovir disoproxil is a safe and effective choice for the treatment of chronic HBV patients with primary treatment failure to entecavir treatment