Tenofovir alafenamide fumarate (GS-7340 fumarate) is an orally available Tenofovir precursor compound Tenofovir alafenamide fumarate has anti-HIV activity and can be used to prevent HIV infection.

Tenofovir alafenamide fumarate antiviral activity was similar in all cell types, ranging from 5 to 7 nM, whereas CC50 varied from 4.7 to 42 μM for MT-4 and MT-2 cells. The antiviral activity of TAF was evaluated against a panel of HIV-1 and HIV-2 isolates, including HIV-1 M group subtypes A to G, as well as group N and O isolates. Overall, TAF EC50 ranged from 0.1 to 12 nM, with an average EC50 of 3.5 nM, compared to an average EC50 of 11.8 nM for AZT, used as an internal control, for 29 major HIV-1 isolates tested in PBMC. For HIV-2 isolates, the average EC50 is 1.8 nM for TAF and 6.4 nM for AZT.[2]

Tenofovir alafenamide fumarate (GS-7340 fumarate), an amidate prodrug of Tenofovir, has good oral bioavailability and increases plasma stability compared to Tenofovir disoproxil fumarate (TDF) [1].