title: Dead-end complexes contribute to the synergistic inhibition of HIV-1 RT by the combination of rilpivirine, emtricitabine, and tenofovir.
abstract: The single tablet regimen of the nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) tenofovir disoproxil fumarate (TDF), emtricitabine (FTC), and the non-nucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine (RPV) is approved for the treatment of HIV-1 infection in treatment-naïve adults. Previous studies have shown that two-drug combinations of these drugs show additive to synergistic HIV-1 antiviral activity in cell culture. In this study, two-drug combinations of tenofovir (TFV)+FTC, RPV+TFV, and RPV+FTC inhibited HIV-1 replication in cell culture with strong synergy and no evidence of antagonism. The triple drug combination of RPV+FTC+TFV displayed moderate synergy comparable to efavirenz (EFV)+FTC+TFV. The formation of dead-end complexes (DEC) of HIV-1 reverse transcriptase (RT), NRTI chain-terminated primer/template, and the next complementary nucleotide or NNRTIs was studied using gel mobility shift assays. DEC formation was seen with TFV-terminated DNA primer/template, HIV-1 RT, and FTC-triphosphate (TP) in addition to the natural nucleotide dCTP, thus stabilizing chain-termination. The NNRTI RPV also formed DEC-like complexes with TFV- and FTC-monophosphate (MP)-terminated DNA primer/templates and HIV-1 RT, and stabilized chain-termination by both NRTIs. Overall, the combinations of RPV, FTC, and TFV inhibit HIV-1 replication with moderate to strong synergy. This may be partially explained by enhanced DEC formation of NRTI chain-terminated DNA primer/template and HIV-1 RT in the presence of the other drugs in the combination, leading to more stable chain-termination and replication inhibition by NRTIs.
authors.affiliation: Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA 94404, USA. Electronic address: Rima.Kulkarni@gilead.com.
authors.forename: Rima
authors.initials: R
authors.lastname: Kulkarni
authors.affiliation: Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA 94404, USA. Electronic address: Joy.Feng@gilead.com.
authors.forename: Joy Y
authors.initials: JY
authors.lastname: Feng
authors.affiliation: Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA 94404, USA. Electronic address: Michael.Miller@gilead.com.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Miller
authors.affiliation: Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA 94404, USA. Electronic address: Kirsten.White@gilead.com.
authors.forename: Kirsten L
authors.initials: KL
authors.lastname: White
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004357:Drug Synergism; D000068679:Emtricitabine; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors*; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D009570:Nitriles / Q000494:pharmacology*; D063065:Organophosphonates / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D048348:Reverse Transcription / Q000187:drug effects*; D000068696:Rilpivirine; D000068698:Tenofovir; D014776:Virus Cultivation
chemical_list: D019380:Anti-HIV Agents; D009570:Nitriles; D063065:Organophosphonates; D011743:Pyrimidines; D003841:Deoxycytidine; D000068698:Tenofovir; D054303:HIV Reverse Transcriptase; D000068696:Rilpivirine; D000068679:Emtricitabine; D000225:Adenine
keywords: Emtricitabine; HIV; Reverse transcriptase; Rilpivirine; Synergy; Tenofovir