Reverse Transcriptase Inhibitors

When HIV infects a cell, reverse transcriptase copies the viral single-stranded RNA genome into a double-stranded viral DNA. The viral DNA is then integrated into the host chromosomal DNA, which then allows host cellular processes to reproduce the virus. RTIs block reverses transcriptase’s enzymatic function and prevent completion of synthesis of the double-stranded viral DNA, thus preventing HIV from multiplying. RTIs are not biologics by convention since they are small chemical entities.

Reverse-transcriptase inhibitors (RTIs) are a class of antiretroviral drugs used to treat HIV infection or AIDS, and in some cases, hepatitis B. RTIs inhibit activity of reverse transcriptase, a viral DNA polymerase that is required for replication of HIV and other retroviruses. The inhibitory mechanism is depicted in the sketch. There are two types of RTIs: Competitive RTIs compete with the incorporation of viral DNA into host T cell DNA, such as zidovudine (nucleoside RTI) and Tenofovir (Nucleotide RTI). Non-competitive RTIs inhibit the movement of protein domains of reverse transcriptases, such as efavirenz. Currently authorized by the FDA for passionate use in COVID19 infection, remdesivir is a transcriptase inhibitor.