HBeAg (+) or HBeAg (-), untreated or previously treated with LMV were treated with TDF 426 in three Phase III clinical trials 144 weeks after treatment, and no resistance or clinical resistance was detected by drug resistance after treatment. In rtA194T mutation was detected in two cases of mixed HIV and HBV infection in early years as the site of resistance. In vitro studies, rtA194T mutation single or combined with lamivudine resistance mutations, the experimental results can not prove tenofovir resistance.
In addition, in vitro studies have found that some of the mutation sites reduce the sensitivity to tenofovir but have not been clinically proven; some of the variations found in the clinical treatment of virus rebound do not affect the effect on TDF in vitro. As a nucleoside drug is always resistant, but tenofovir resistance is particularly high threshold of foreign countries from 2008 for chronic hepatitis B, there is no report of primary resistance.