Tenofovir vs. Tenofovir Plus Entecavir in Entecavir-Resistant Chronic Hepatitis B

Summary

With the availability of potent nucloes(t)ide analogues (NA), such as tenofovir disoproxil fumarate (TDF) and entecavir (ETV), suppression of serum HBV DNA to undetectable levels by polymerase chain reaction (PCR) assays became achievable in most NA treatment-naïve patients. Until recently, however, many patients commenced antiviral treatment with inferior NAs prior to the availability of TDF or ETV, such as lamivudine (LAM) which has a low genetic barrier to resistance. ETV resistance increase up to 51% of patients after 5 years of ETV treatment in lamivudine-refractory patients. Resistance to ETV appears to occur through a two-hit mechanism with initial selection of M204V/I mutation followed by amino acid substitutions at rtT184, rtS202, or rtM250. In vitro studies showed that ETV-resistant mutations are susceptible to TDF, but there are little clinical data on the efficacy of TDF monotherapy in patients with ETV-resistance. On the other hand, there was a retrospective cohort study reporting that, with the combination of TDF and ETV, most of patients became HBV DNA undetectable after median 6 months of treatment. Probability of reaching complete HBV DNA suppression was not decreased in patients with ADV or ETV-resistance. Thus, there is no consistent treatment recommendation for patients with ETV-resistance. In this clinical trial, the investigators will clarify whether tenofovir monotherapy is as effective as tenofovir plus entecavir in inducing complete virologic response in CHB patients with genotypic resistance to ETV and partial virologic response to ongoing treatment.

Timeline

Start

2012-09-28

Primary completion

2018-03-29

Completion

2018-03-29

Publications

• Results Lim YS, Byun KS, Yoo BC, Kwon SY, Kim YJ, An J, Lee HC, Lee YS. Tenofovir monotherapy versus tenofovir and entecavir combination therapy in patients with entecavir-resistant chronic hepatitis B with multiple drug failure: results of a randomised trial. Gut. 2016 May;65(5):852-60. doi: 10.1136/gutjnl-2014-308353. Epub 2015 Jan 16.
• Lim YS, Gwak GY, Choi J, Lee YS, Byun KS, Kim YJ, Yoo BC, Kwon SY, Lee HC. Monotherapy with tenofovir disoproxil fumarate for adefovir-resistant vs. entecavir-resistant chronic hepatitis B: A 5-year clinical trial. J Hepatol. 2019 Jul;71(1):35-44. doi: 10.1016/j.jhep.2019.02.021. Epub 2019 Mar 13.

Drugs

Indications