EFdA-TP, a highly potent nucleoside reverse transcriptase (RT) inhibitor, exerts its inhibitory effect on RT-catalyzed DNA synthesis through both immediate and delayed chain termination mechanisms, commonly referred to as ICT and DCT, respectively. Additionally, EFdA-TP demonstrates its efficacy in inhibiting HIV-1 RT through multiple pathways.

EFdA-TP, in concentrations ranging from 0.05 to 10 μM for a duration of 15 minutes, acts as an immediate chain terminator (ICT) or delayed chain terminator (DCT) to inhibit reverse transcriptase (RT)-catalyzed DNA synthesis [1]. As a translocation-defective RT inhibitor, it significantly decelerates DNA synthesis, effectively acting as an immediate chain terminator, while also possessing the capability to function as a delayed chain terminator by permitting the addition of one more deoxynucleotide triphosphate (dNTP) prior to halting DNA synthesis [1].