Resistance to reverse transcriptase inhibitors used in the treatment and prevention of HIV-1 infection

Inhibitors that target the retroviral enzyme reverse transcriptase (RT) have played an indispensable role in the treatment and prevention of HIV-1 infection. They can be grouped into two distinct therapeutic groups， namely the nucleoside and nucleotide RT inhibitors (NRTIs)， and the non-nucleoside RT inhibitors (NNRTIs). NRTIs form the backbones of most first- and second-line antiretroviral therapy (ART) regimens formulated for the treatment of HIV-1 infection. They are also used to prevent mother-to-child transmission， and as pre-exposure prophylaxis in individuals at risk of HIV-1 infection. The NNRTIs nevirapine (NVP)， efavirenz and rilpivirine also used to form part of first-line ART regimens， although this is no longer recommended， while etravirine can be used in salvage ART regimens. A single-dose of NVP administered to both mother and child has routinely been used in resource-limited settings to reduce the rate of HIV-1 transmission. Unfortunately， the development of HIV-1 resistance to RT inhibitors can compromise the efficacy of these antiviral drugs in both the treatment and prevention arenas. Here， we provide an up-to-date review on drug-resistance mutations in HIV-1 RT， and discuss their cross-resistance profiles， molecular mechanisms and clinical significance.