Background Rilpivirine (RPV) is the latest non-nucleoside reverse transcriptase inhibitor (NNRTI) to be FDA-approved to combat HIV-1 infections. NNRTIs inhibit the chemical step in viral DNA synthesis by binding to an allosteric site located about 10 Å from the polymerase active site of reverse transcriptase (RT). Although NNRTIs potently inhibit the replication of WT HIV-1, the binding site is not conserved, and mutations arise in the binding pocket. Doravirine (DOR) is a new a NNRTI in phase III clinical trials. Methods Using a single round HIV-1 infection assay, we tested RPV and DOR against a broad panel of NNRTI resistant mutants to determine their respective activities. We also used molecular modeling to determine if the susceptibility profile of each compound was related to how they bind RT. Results Several mutants displayed decreased susceptibility to DOR. However, with the exception of E138K, our data suggest that the mutations that reduce the potency of DOR and RPV are non-overlapping. Thus, these two NNRTIs have the potential to be used together in combination therapy. We also show that the location at which DOR and RPV bind with the NNRTI binding pocket of RT correlates with the differences in their respective susceptibility to the panel of NNRTI resistance mutations. Conclusions This shows that (1) DOR is susceptible to a number of well-known NNRTI resistance mutations and (2) an understanding of the mutational susceptibilities and binding interactions of NNRTIs with RT could be used to develop pairs of compounds with non-overlapping mutational susceptibilities.

BackgroundNonnucleoside reverse transcriptase inhibitors (NNRTIs) are a class of antiretroviral compounds that bind in an allosteric binding pocket in HIV-1 RT, located about 10 Å from the polymerase active site. Binding of an NNRTI causes structural changes that perturb the alignment of the primer terminus and polymerase active site, preventing viral DNA synthesis. Rilpivirine (RPV) is the most recent NNRTI approved by the FDA, but like all other HIV-1 drugs, suboptimal treatment can lead to the development of resistance. To generate better compounds that could be added to the current HIV-1 drug armamentarium, we have developed several RPV analogs to combat viral variants that are resistant to the available NNRTIs.ResultsUsing a single-round infection assay, we identified several RPV analogs that potently inhibited a broad panel of NNRTI resistant mutants. Additionally, we determined that several resistant mutants selected by either RPV or Doravirine (DOR) caused only a small increase in susceptibility to the most promising RPV analogs.ConclusionsThe antiviral data suggested that there are RPV analogs that could be candidates for further development as NNRTIs, and one of the most promising compounds was modeled in the NNRTI binding pocket. This model can be used to explain why this compound is broadly effective against the panel of NNRTI resistance mutants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12977-016-0244-2) contains supplementary material, which is available to authorized users.