Tenofovir alafenamide fumarate(TAF) is the only new hepatitis B drug approved in the world in recent 10 years, which should also be considered as the best hepatitis B drug so far. Tenofovir alafenamide fumarate (trade name: vemlidy) is an innovative, targeted and tenofovir prodrug. It is an upgraded version of tenofovir disoprox (TDF) of the previous product.

TAF is a reverse transcriptase inhibitor. After entering hepatocytes, the drug can be hydrolyzed to tenofovir. Tenofovir is then phosphorylated by intracellular kinases to form tenofovir diphosphate with pharmacological activity. Tenofovir diphosphate is integrated into virus DNA by HBV reverse transcription, which leads to DNA strand synthesis terminal and achieves the purpose of inhibiting virus replication.

Clinical data show that tenofovir alafenamide fumarate (TAF) has greater plasma stability and can deliver tenofovir to hepatocytes more effectively. At the same time, since TAF has been proved to have a very high antiviral connection when taking a tenth of the dose of tenofovir dipivoxil (TDF), the drug resistance rate is the same as that of tenofovir dipivoxil dipivoxil (TDF), which can reduce the concentration of tenofovir in the blood more. Therefore, compared with tenofovir dipivoxil fumarate (TDF), TAF can effectively improve the safety parameters of kidney and bone of patients.

On November 10, 2016, the US fad approved TAF for the treatment of chronic hepatitis B in the US.

On December 19, 2016, MHLW of Japan approved TAF for the treatment of chronic hepatitis B in Japan.

On September 1, 2017, the European EMA approved TAF for the treatment of chronic hepatitis B in the EU Member States