According to researcher Stefan Sarafianos, "Patients who are treated for HIV infections with (the drug) Tenofovir, eventually develop resistance to the drugs that prevent an effective or successful defense against the virus. EFdA, the molecule we are studying, is less likely to cause resistance in HIV patients because it is more readily activated and is less quickly broken down by the body as similar existing drugs.”
EFdA, along with eight existing HIV drugs, is part of the class of compounds called nucleoside reverse transcriptase inhibitors (NRTIs).
NRTIs 'hijack' the HIV replicating process by 'tricking' building blocks inside the virus. Since EFdA appears similar to those building blocks, the virus is misled into using the imposter, which prevents HIV replication and halts the spread of the virus.
So far tests with EFdA has tested well on using human immunodeficiency viruses that have become resistant to Tenofovir as well as on non-drug-resistant forms of HIV.