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Cox S, Margot N, Callebaut C. Antiviral activity of tenofovir alafenamide (TAF) against HIV-1 clinical isolates harboring K65R. J Med Virol 2023; 95:e28723. [PMID: 37185867 DOI: 10.1002/jmv.28723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/13/2023] [Accepted: 04/03/2023] [Indexed: 05/17/2023]
Abstract
Tenofovir alafenamide (TAF) is a prodrug of the nucleoside reverse transcriptase (RT) inhibitor tenofovir (TFV). Compared to the earlier TFV prodrug, TFV disoproxil fumarate (TDF), TAF achieves more than fourfold-higher intracellular levels of its active metabolite TFV diphosphate (TFV-DP) in clinical studies, while achieving a significant reduction of TFV systemic exposure. Resistance to TFV has been well established, with the K65R mutation in RT as the signature mutation. Here we evaluated the in vitro activity of TAF and TDF in patient-derived HIV-1 isolates harboring the K65R mutation. Clinical isolates containing K65R were cloned into the pXXLAI construct (n = 42). In vitro phenotypic susceptibility of the constructs to TAF and TDF was evaluated in an MT-2 cell HIV assay and in viral breakthrough assays modeling physiological concentrations of TAF and TDF. TAF and TDF susceptibility were highly correlated in K65R-containing mutants, ranging from 2.7- to 3.0-fold (K65R alone) and 1.2- to 27.6-fold (K65R+ other RT mutations) relative to wild-type. In viral breakthrough assays mimicking differences in physiological concentrations, TAF inhibited breakthrough of 40 of 42 clinical isolates, while the TDF equivalent only inhibited 32 of 42 isolates tested. TAF displayed a higher barrier to resistance than TDF in this panel of K65R-containing clinical isolates.
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Affiliation(s)
- Stephanie Cox
- HIV Clinical Virology, Gilead Sciences, Inc., Foster City, California, USA
| | - Nicolas Margot
- HIV Clinical Virology, Gilead Sciences, Inc., Foster City, California, USA
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Schinazi RF, Patel D, Ehteshami M. The best backbone for HIV prevention, treatment, and elimination: Emtricitabine+tenofovir. Antivir Ther 2022; 27:13596535211067599. [PMID: 35491570 DOI: 10.1177/13596535211067599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The advent of antiretroviral combination therapy has significantly impacted the HIV/AIDS epidemic. No longer a death sentence, HIV infection can be controlled and suppressed using cocktail therapies that contain two or more small molecule drugs. This review aims to highlight the discovery, development, and impact of one such molecule, namely, emtricitabine (FTC, emtriva), which is one of the most successful drugs in the fight against HIV/AIDS and has been taken by over 94% of individuals infected with HIV in the USA. We also pay tribute to Dr. John C. Martin, former CEO and Chairman of Gilead Sciences, who unexpectedly passed away in 2021. A true visionary, he was instrumental in delivering FTC, as part of combination therapy with TDF (tenofovir, viread) to the global stage. As the fight to eradicate HIV marches on, we honor Dr. Martin's legacy of collaboration, achievement, and hope.
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Affiliation(s)
- Raymond F Schinazi
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, 1371Emory University School of Medicine and Children Healthcare of Atlanta, Atlanta, GA, USA
| | - Dharmeshkumar Patel
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, 1371Emory University School of Medicine and Children Healthcare of Atlanta, Atlanta, GA, USA
| | - Maryam Ehteshami
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, 1371Emory University School of Medicine and Children Healthcare of Atlanta, Atlanta, GA, USA
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Switching to Bictegravir/Emtricitabine/Tenofovir Alafenamide (B/F/TAF) From Dolutegravir (DTG)+F/TAF or DTG+F/Tenofovir Disoproxil Fumarate (TDF) in the Presence of Pre-existing NRTI Resistance. J Acquir Immune Defic Syndr 2021; 85:363-371. [PMID: 32701823 DOI: 10.1097/qai.0000000000002454] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Study 4030 was a phase 3, randomized, double-blinded study of 565 HIV-1 RNA-suppressed participants switching to bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) or dolutegravir (DTG)+F/TAF. Nucleoside reverse transcriptase inhibitor (NRTI), non-NRTI, and protease inhibitor resistance (-R) was allowed, but integrase strand transfer inhibitor-R was excluded. Here, we describe the detailed resistance analysis. METHODS Historical plasma HIV-1 RNA genotypes and baseline proviral DNA genotypes were analyzed. Documented or investigator-suspected NRTI-R was grouped for stratification into 3 categories of level of resistance. Viral blips were assessed through week 48. Virologic failures had genotypic and phenotypic resistance analyses at week 48, confirmed failure, or last visit, if HIV-1 RNA did not resuppress to <50 copies/mL while on study drug. RESULTS In total, 83% (470/565) of participants had baseline genotypic data available with NRTI-R detected in 24% (138/565), including 5% (30/565) with K65R/E/N or ≥3 thymidine analog mutations and 19% (108/565) with other NRTI-R mutations. M184V/I was present in 14% (81/565). Pre-existing integrase strand transfer inhibitor-R mutations were found in 4% (20/565) of participants. Primary non-NRTI-R and protease inhibitor-R mutations were present in 21% (118/565) and 7% (38/565) of participants. High rates of viral suppression were maintained in all groups through week 48; blips were observed in only 15 participants (2.7%). Three participants met criteria for resistance analysis (all in DTG+F/TAF arm); none developed treatment-emergent resistance to study drugs. CONCLUSIONS Participants with baseline NRTI resistance, much of which was previously undocumented, maintained suppression 48 weeks after switching to B/F/TAF or DTG+F/TAF triple therapy. Blips and virologic failure were uncommon using either regimen, with no treatment-emergent resistance.
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Pre-treatment drug resistance and HIV-1 genetic diversity in the rural and urban settings of Northwest-Cameroon. PLoS One 2020; 15:e0235958. [PMID: 32692778 PMCID: PMC7373288 DOI: 10.1371/journal.pone.0235958] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 06/26/2020] [Indexed: 01/08/2023] Open
Abstract
Background With the scale-up of antiretroviral therapy (ART), pre-treatment drug resistance (PDR) appears ≥10% amongst ART-initiators in many developing countries, including Cameroon. Northwest region-Cameroon having the second epidemiological burden of HIV infection, generating data on PDR in these geographical settings, will enhance evidence-based decision-making. Objectives We sought to ascertain levels of PDR and HIV-1 clade dispersal in rural and urban settings, and their potential association with subtype distribution and CD4-staging. Methods A cross-sectional study was conducted from February to May 2017 among patients recently diagnosed with HIV-infection and initiating ART at the Bamenda regional Hospital (urban setting) and the Mbingo Baptist hospital (rural setting). Protease and reverse transcriptase sequencing was performed using an in-house protocol and pre-treatment drug resistance mutations were interpreted using Stanford HIVdb.v8.3. Phylogeny was performed for subtype assignation. Results A total of 61 patient sequences were generated from ART initiators (median age: 37 years old; 57.4% female; median CD4 cell count: 184 [IQR: 35–387] in urban vs. 161 [IQR: 96–322] cells/mm3 in rural). Overall, the level of PDR was 9.8% (6/61). Of note, burden of PDR was almost doubled in urban (12.9% [4/31]) compared to rural setting 6.7% (2/30), p = 0.352). Fifteen (15) PDR mutations were found among four patients the urban settings [6 resistance mutations to NRTIs:[M41L (2), E44D (1), K65R (1), K70E (1), M184V/I (2), K219R (1)] and 6 resistance mutations to NNRTIs: K103N (1), E138A/G (2), V179E (1), M230L (1), K238T (1), P225H (1)] against two (02) mutations found in two patients in the rural setting[2 resistant mutations to NNRTIs: E138A (1) and Y188H (1)]. The rural setting showed more genetic diversity (8 subtypes) than the urban setting (5 subtypes), with CRF02_AG being the most prevalent clade (72.1% [44/61]). Of note, level of PDR was similar between patients infected with CRF02_AG and non-CRF02_AG infected (9.1% [4/44]) vs. 11.8% [2/17]), p = 1.000). Moreover, PDR appeared higher in patients with CD4 cell count <200 cells/mm3 compared to those with CD4 cell count ≥200 cells/mm3 (14.7% [5/34]) vs. 3.7% [1/27]), p = 0.214). Conclusions PDR is at a moderate rate in the Northwest region of Cameroon, with higher burden within urban populations. CRF02_AG is the most predominant clade in both urban and rural settings. No effect of HIV molecular epidemiology and CD4-staging on the presence of PDR in patients living in these settings was found. Our findings suggest close monitoring, NNRTI-sparing regimens or sequencing for patients initiating ART, especially in urban settings.
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Antiviral Activity of Tenofovir Alafenamide against HIV-1 with Thymidine Analog-Associated Mutations and M184V. Antimicrob Agents Chemother 2020; 64:AAC.02557-19. [PMID: 31988104 DOI: 10.1128/aac.02557-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 01/21/2020] [Indexed: 01/04/2023] Open
Abstract
Tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) are prodrugs of the HIV-1 nucleotide reverse transcriptase inhibitor tenofovir (TFV). In vivo, TAF achieves >4-fold-higher intracellular levels of TFV diphosphate (TFV-DP) compared to TDF. Since thymidine analog-associated mutations (TAMs) in HIV-1 confer reduced TFV susceptibility, patients with TAM-containing HIV-1 may benefit from higher TFV-DP levels delivered by TAF. Moreover, the presence of the M184V mutation increases TFV susceptibility during TDF- or TAF-based therapy. The susceptibilities to antiviral drugs of site-directed mutants (SDMs) and patient-derived mutants containing combinations of TAMs (M41L, D67N, K70R, L210W, T215Y, and K219Q) with or without the M184V mutation (TAMs±M184V) were evaluated using either 5-day multicycle (MC; n = 110) or 2-day single-cycle (SC; n = 96) HIV assays. The presence of M184V in TAM-containing HIV-1 SDMs (n = 48) significantly increased TAF sensitivity compared to SDMs without M184V (n = 48). The comparison of TAF and TDF resistance profiles was further assessed in viral breakthrough (VB) experiments mimicking clinically relevant drug concentrations. A total of 68 mutants were assayed at physiological concentration in VB experiments, with 15/68 mutants breaking through with TDF (TFV, the in vitro equivalent of TDF, was used in these experiments), and only 3 of 68 mutants breaking through under TAF treatment. Overall, in the VB assay mimicking the 4-fold-higher intracellular levels of TFV-DP observed clinically with TAF versus TDF, TAF inhibited viral breakthrough of most TAM-containing HIV-1, whereas TDF did not. These results indicate that TAF has a higher resistance threshold than TDF and suggest that higher resistance cutoffs should be applied for TAF compared to TDF in genotypic and phenotypic resistance algorithms.
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Hung M, Tokarsky EJ, Lagpacan L, Zhang L, Suo Z, Lansdon EB. Elucidating molecular interactions of L-nucleotides with HIV-1 reverse transcriptase and mechanism of M184V-caused drug resistance. Commun Biol 2019; 2:469. [PMID: 31872074 PMCID: PMC6910994 DOI: 10.1038/s42003-019-0706-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/11/2019] [Indexed: 01/22/2023] Open
Abstract
Emtricitabine (FTC) and lamivudine (3TC), containing an oxathiolane ring with unnatural (-)-stereochemistry, are widely used nucleoside reverse transcriptase inhibitors (NRTIs) in anti-HIV therapy. Treatment with FTC or 3TC primarily selects for the HIV-1 RT M184V/I resistance mutations. Here we provide a comprehensive kinetic and structural basis for inhibiting HIV-1 RT by (-)-FTC-TP and (-)-3TC-TP and drug resistance by M184V. (-)-FTC-TP and (-)-3TC-TP have higher binding affinities (1/Kd) for wild-type RT but slower incorporation rates than dCTP. HIV-1 RT ternary crystal structures with (-)-FTC-TP and (-)-3TC-TP corroborate kinetic results demonstrating that their oxathiolane sulfur orients toward the DNA primer 3'-terminus and their triphosphate exists in two different binding conformations. M184V RT displays greater (>200-fold) Kd for the L-nucleotides and moderately higher (>9-fold) Kd for the D-isomers compared to dCTP. The M184V RT structure illustrates how the mutation repositions the oxathiolane of (-)-FTC-TP and shifts its triphosphate into a non-productive conformation.
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Affiliation(s)
- Magdeleine Hung
- Gilead Sciences, Inc., 333 Lakeside Dr., Foster City, CA 94404 USA
| | - E. John Tokarsky
- The Ohio State Biophysics Program, The Ohio State University, Columbus, OH 43210 USA
| | - Leanna Lagpacan
- Gilead Sciences, Inc., 333 Lakeside Dr., Foster City, CA 94404 USA
| | - Lijun Zhang
- Gilead Sciences, Inc., 333 Lakeside Dr., Foster City, CA 94404 USA
| | - Zucai Suo
- The Ohio State Biophysics Program, The Ohio State University, Columbus, OH 43210 USA
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306 USA
| | - Eric B. Lansdon
- Gilead Sciences, Inc., 333 Lakeside Dr., Foster City, CA 94404 USA
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Pouga L, Santoro MM, Charpentier C, Di Carlo D, Romeo I, Artese A, Alcaro S, Antinori A, Wirden M, Perno CF, Ambrosio FA, Calvez V, Descamps D, Marcelin AG, Ceccherini-Silberstein F, Lambert-Niclot S. New resistance mutations to nucleoside reverse transcriptase inhibitors at codon 184 of HIV-1 reverse transcriptase (M184L and M184T). Chem Biol Drug Des 2018; 93:50-59. [PMID: 30103267 DOI: 10.1111/cbdd.13378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 07/04/2018] [Accepted: 08/04/2018] [Indexed: 11/28/2022]
Abstract
Mutations at HIV-1 reverse transcriptase (RT) codon 184 such as M184V confer resistance to two nucleos(t)ide RT inhibitors (NRTI), lamivudine (3TC) and emtricitabine (FTC). The prevalence of mutations at HIV-1 RT codon 184 was evaluated using three independent RT sequence databases from treatment-experienced (TE) and treatment-naïve (TN) individuals. Data were collected retrospectively from three centers: one in Italy and two in France between 1997 and 2016. In order to highlight the role of these mutations in conferring drug resistance, structural and thermodynamic analyses were conducted by means of computational approaches. Among 32,440 RT sequences isolated from TE and 12,365 isolated from TN patients, the prevalence of HIV-1 RT codon 184 substitutions in each group was 31.21% and 0.72%, respectively. The mutations M184L and M184T have been observed only in TE patients. In all cases but four, M184L and M184T mutations were present during NRTI treatment. Molecular recognition studies on M184L and M184T structures showed both FTC and 3TC thermodynamic profiles unfavorable in comparison with the wild-type sequence, corroborated by molecular dynamic simulations (MDS). In this study, we highlighted two new resistance mutations in vivo for NRTI resistance. The low frequency of this pathway can be related to high impairment of replicative capacity mediated by these mutations.
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Affiliation(s)
- Lydia Pouga
- UPMC Univ Paris 06-UMR_S 1136, Pierre Louis Institute of Epidemiology and Public Health, Sorbonne Universités, Paris, France.,Laboratoire de Virologie, AP-HP, Groupe hospitalier Pitié-Salpêtrière, Paris, France
| | - Maria Mercedes Santoro
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy
| | - Charlotte Charpentier
- IAME, UMR 1137-Université Paris Diderot, Sorbonne Paris Cité, INSERM, Paris, France.,Laboratoire de Virologie, AP-HP, Hôpital Bichat, Paris, France
| | - Domenico Di Carlo
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy
| | - Isabella Romeo
- Department of Health Sciences, University "Magna Grӕcia" of Catanzaro, Catanzaro, Italy
| | - Anna Artese
- Department of Health Sciences, University "Magna Grӕcia" of Catanzaro, Catanzaro, Italy
| | - Stefano Alcaro
- Department of Health Sciences, University "Magna Grӕcia" of Catanzaro, Catanzaro, Italy
| | - Andrea Antinori
- Infectious Diseases Division, National Institute for Infectious Diseases L. Spallanzani, IRCCS, Rome, Italy
| | - Marc Wirden
- UPMC Univ Paris 06-UMR_S 1136, Pierre Louis Institute of Epidemiology and Public Health, Sorbonne Universités, Paris, France.,Laboratoire de Virologie, AP-HP, Groupe hospitalier Pitié-Salpêtrière, Paris, France
| | - Carlo Federico Perno
- Antiretroviral Drugs Monitoring Unit, National Institute for Infectious Diseases L. Spallanzani, IRCCS, Rome, Italy
| | | | - Vincent Calvez
- UPMC Univ Paris 06-UMR_S 1136, Pierre Louis Institute of Epidemiology and Public Health, Sorbonne Universités, Paris, France.,Laboratoire de Virologie, AP-HP, Groupe hospitalier Pitié-Salpêtrière, Paris, France
| | - Diane Descamps
- IAME, UMR 1137-Université Paris Diderot, Sorbonne Paris Cité, INSERM, Paris, France.,Laboratoire de Virologie, AP-HP, Hôpital Bichat, Paris, France
| | - Anne-Geneviève Marcelin
- UPMC Univ Paris 06-UMR_S 1136, Pierre Louis Institute of Epidemiology and Public Health, Sorbonne Universités, Paris, France.,Laboratoire de Virologie, AP-HP, Groupe hospitalier Pitié-Salpêtrière, Paris, France
| | | | - Sidonie Lambert-Niclot
- UPMC Univ Paris 06-UMR_S 1136, Pierre Louis Institute of Epidemiology and Public Health, Sorbonne Universités, Paris, France.,Laboratoire de Virologie, AP-HP, Groupe hospitalier Pitié-Salpêtrière, Paris, France
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Margot N, Cox S, Das M, McCallister S, Miller MD, Callebaut C. Rare emergence of drug resistance in HIV-1 treatment-naïve patients receiving elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide for 144 weeks. J Clin Virol 2018; 103:37-42. [PMID: 29627709 DOI: 10.1016/j.jcv.2018.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 03/17/2018] [Accepted: 03/31/2018] [Indexed: 11/20/2022]
Abstract
BACKGROUND The single tablet regimen (STR) composed of elvitegravir (E), cobicistat (C), emtricitabine (F), and tenofovir alafenamide (TAF) (E/C/F/TAF) was compared to the STR composed of E, C, F, and tenofovir disoproxil fumarate (TDF) (E/C/F/TDF) in 2 phase 3 studies in 1733 HIV-1 infected treatment-naïve adults. Superior efficacy of E/C/F/TAF compared to E/C/F/TDF was demonstrated at Week 144 with 84% treatment success compared to 80%, respectively, along with significantly better outcomes of bone and renal safety. OBJECTIVES Analyze the emergence of HIV-1 resistance in treatment-naïve adults receiving E/C/F/TAF for 144 weeks. STUDY DESIGN We conducted an integrated resistance analysis of the 2 Phase 3 studies, comprising pretreatment HIV-1 sequencing for all participants (N = 1733) and post-baseline HIV-1 resistance analysis for participants with virologic failure (HIV-1 RNA ≥400 copies/mL). RESULTS Primary resistance-associated mutations (RAMs) were observed pre-treatment in 7.4% (NRTI-RAMs), 18.1% (NNRTI-RAMs), and 3.3% (PI-RAMs) of enrolled subjects. Baseline HIV-1 subtype or pre-existing RAMs did not affect E/C/F/TAF treatment response at week 144. Virologic failure resistance analyses were conducted for 28/866 (3.2%) and 30/867 (3.5%) patients in the E/C/F/TAF and E/C/F/TDF arms, respectively. Over the 3-year study, the rate of resistance emergence remained low at 1.4% in each group (12/866 in E/C/F/TAF; 12/867 in E/C/F/TDF). Resistant virus emerged in 24 patients who developed resistance to antiretrovirals in the regimens (E/C/F/TAF: M184V/I [1.3%], INSTI-RAMs [0.9%], K65R/N [0.2%]; E/C/F/TDF: M184V/I [1.0%], INSTI-RAMs [0.9%], K65R/N [0.5%]). CONCLUSIONS Resistance emergence was rare (1.4%) with similar patterns of emergent mutations in both groups. M184V/I was the most prevalent RAM (1.2% overall).
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Affiliation(s)
- Nicolas Margot
- Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA, 94404, USA.
| | - Stephanie Cox
- Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA, 94404, USA
| | - Moupali Das
- Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA, 94404, USA
| | - Scott McCallister
- Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA, 94404, USA
| | - Michael D Miller
- Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA, 94404, USA
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Sharma PL, Nurpeisov V, Schinazi RF. Retrovirus Reverse Transcriptases Containing a Modified YXDD Motif. ACTA ACUST UNITED AC 2016; 16:169-82. [PMID: 16004080 DOI: 10.1177/095632020501600303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The YXDD motif, where X is a variable amino acid, is highly conserved among various viral RNA-dependent DNA polymerases. Mutations in the YXDD motif can abolish enzymatic activity, alter the processivity and fidelity of enzymes and decrease virus infectivity. This review provides a summary of the significant documented studies on the YXDD motif of HIV-1, simian immunodeficiency virus, feline immunodeficiency virus and murine leukaemia virus and the impact of mutation that this motif has had on viral pathogenesis and drug treatment.
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Affiliation(s)
- Prem L Sharma
- Laboratory of Biochemical Pharmacology and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
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10
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Elion R, Cohen C, DeJesus E, Redfield R, Gathe J, Hsu R, Yau L, Ross L, Ha B, Lanier RE, Scott T. Once-Daily Abacavir/Lamivudine/Zidovudine plus Tenofovir for the Treatment of HIV-1 Infection in Antiretroviral-NaïveSubjects: A 48-Week Pilot Study. HIV CLINICAL TRIALS 2015; 7:324-33. [PMID: 17208898 DOI: 10.1310/hct0706-324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To assess the safety and efficacy of a 4-drug, 3-tablet, once-daily (qd) regimen consisting of abacavir/lamivudine/zidovudine (ABC/3TC/ZDV; 2 tablets) and tenofovir (TDF) in antiretroviral-naïve patients with plasma HIV-1 RNA 30,000 copies/mL at 48 weeks. METHOD All participants received ABC/3TC/ZDV (300/150/300 mg) and TDF (300 mg) qd in this pilot, open-label, multicenter study. Intent-to-treat (ITT) analyses were conducted to evaluate virologic and immunologic efficacy. RESULTS Of the 123 participants enrolled, 52 (42%) prematurely discontinued study for adverse events (14), were lost to follow-up (13), had virologic nonresponse (12), and withdrew for other reasons (13). At week 48, by ITT missing=failure analysis, 41% (51/123) and 51% (63/123) of participants had plasma HIV-1 RNA <50 copies/mL and <400 copies/mL, respectively; by ITT-observed analysis, 75% (51/68) and 93% (63/68) had plasma HIV-1 RNA <50 copies/mL and <400 copies/mL, respectively; 11% (14/123) met virologic nonresponse criteria. Median week 48 change in CD4+ cell count from baseline was +127 cells/mm3. Median week 48 changes from baseline for fasting lipids were as follows: cholesterol (-9 mg/dL), HDL (+1 mg/dL), LDL (-9 mg/dL), and triglycerides (-4 mg/dL). CONCLUSION A high rate of premature discontinuations contributed to the overall suboptimal virologic response to ABC/3TC/ZDV+TDF qd; however, the regimen was not associated with high rates of virologic failure previously observed with TDF+ABC/3TC.
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11
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Liegler T, Abdel-Mohsen M, Bentley LG, Atchison R, Schmidt T, Javier J, Mehrotra M, Eden C, Glidden DV, McMahan V, Anderson PL, Li P, Wong JK, Buchbinder S, Guanira JV, Grant RM. HIV-1 drug resistance in the iPrEx preexposure prophylaxis trial. J Infect Dis 2014; 210:1217-27. [PMID: 24740633 PMCID: PMC4176446 DOI: 10.1093/infdis/jiu233] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The iPrEx study demonstrated that combination oral emtricitabine and tenofovir disoproxil fumarate (FTC/TDF) as preexposure prophylaxis (PrEP) protects against HIV acquisition in men who have sex with men and transgender women. Selection for drug resistance could offset PrEP benefits. METHODS Phenotypic and genotypic clinical resistance assays characterized major drug resistant mutations. Minor variants with FTC/TDF mutations K65R, K70E, M184V/I were measured using 454 deep sequencing and a novel allele-specific polymerase chain reaction (AS-PCR) diagnostic tolerant to sequence heterogeneity. RESULTS Control of primer-binding site heterogeneity resulted in improved accuracy of minor variant measurements by AS-PCR. Of the 48 on-study infections randomized to FTC/TDF, none showed FTC/TDF mutations by clinical assays despite detectable drug levels in 8 participants. Two randomized to FTC/TDF had minor variant M184I detected at 0.53% by AS-PCR or 0.75% by deep sequencing, only 1 of which had low but detectable drug levels. Among those with acute infection at randomization to FTC/TDF, M184V or I mutations that were predominant at seroconversion waned to background levels within 24 weeks after discontinuing drug. CONCLUSIONS Drug resistance was rare in iPrEx on-study FTC/TDF-randomized seroconverters, and only as low-frequency minor variants. FTC resistance among those initiating PrEP with acute infection waned rapidly after drug discontinuation. Clinical Trials Registration.NCT00458393.
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Affiliation(s)
- Teri Liegler
- Department of Medicine, University of California AIDS Research Institute, University of California
| | | | | | | | | | | | | | | | - David V Glidden
- Department of Epidemiology, University of California, San Francisco
| | | | - Peter L Anderson
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora
| | - Peilin Li
- Veterans Affairs Medical Center, San Francisco
| | | | - Susan Buchbinder
- Bridge HIV, San Francisco Department of Public Health, California
| | | | - Robert M Grant
- Department of Medicine, University of California J. David Gladstone Institutes
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Li Z, Terry B, Olds W, Protack T, Deminie C, Minassian B, Nowicka-Sans B, Sun Y, Dicker I, Hwang C, Lataillade M, Hanna GJ, Krystal M. In vitro cross-resistance profile of nucleoside reverse transcriptase inhibitor (NRTI) BMS-986001 against known NRTI resistance mutations. Antimicrob Agents Chemother 2013; 57:5500-8. [PMID: 23979732 PMCID: PMC3811251 DOI: 10.1128/aac.01195-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 08/14/2013] [Indexed: 01/03/2023] Open
Abstract
BMS-986001 is a novel HIV nucleoside reverse transcriptase inhibitor (NRTI). To date, little is known about its resistance profile. In order to examine the cross-resistance profile of BMS-986001 to NRTI mutations, a replicating virus system was used to examine specific amino acid mutations known to confer resistance to various NRTIs. In addition, reverse transcriptases from 19 clinical isolates with various NRTI mutations were examined in the Monogram PhenoSense HIV assay. In the site-directed mutagenesis studies, a virus containing a K65R substitution exhibited a 0.4-fold change in 50% effective concentration (EC50) versus the wild type, while the majority of viruses with the Q151M constellation (without M184V) exhibited changes in EC50 versus wild type of 0.23- to 0.48-fold. Susceptibility to BMS-986001 was also maintained in an L74V-containing virus (0.7-fold change), while an M184V-only-containing virus induced a 2- to 3-fold decrease in susceptibility. Increasing numbers of thymidine analog mutation pattern 1 (TAM-1) pathway mutations correlated with decreases in susceptibility to BMS-986001, while viruses with TAM-2 pathway mutations exhibited a 5- to 8-fold decrease in susceptibility, regardless of the number of TAMs. A 22-fold decrease in susceptibility to BMS-986001 was observed in a site-directed mutant containing the T69 insertion complex. Common non-NRTI (NNRTI) mutations had little impact on susceptibility to BMS-986001. The results from the site-directed mutants correlated well with the more complicated genotypes found in NRTI-resistant clinical isolates. Data from clinical studies are needed to determine the clinically relevant resistance cutoff values for BMS-986001.
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Affiliation(s)
- Zhufang Li
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - Brian Terry
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - William Olds
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - Tricia Protack
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - Carol Deminie
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - Beatrice Minassian
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - Beata Nowicka-Sans
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - Yongnian Sun
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - Ira Dicker
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - Carey Hwang
- Bristol-Myers Squibb, Research and Development, Hopewell, New Jersey, USA
| | - Max Lataillade
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
| | - George J. Hanna
- Bristol-Myers Squibb, Research and Development, Princeton, New Jersey, USA
| | - Mark Krystal
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA
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Dang NT, Sivakumaran H, Harrich D, Coombes AG. An Evaluation of Polycaprolactone Matrices for Vaginal Delivery of the Antiviral, Tenofovir, in Preventing Heterosexual Transmission of HIV. J Pharm Sci 2013; 102:3725-35. [DOI: 10.1002/jps.23684] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 05/28/2013] [Accepted: 07/09/2013] [Indexed: 12/23/2022]
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Significant reductions in Gag-protease-mediated HIV-1 replication capacity during the course of the epidemic in Japan. J Virol 2012; 87:1465-76. [PMID: 23152532 DOI: 10.1128/jvi.02122-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) evolves rapidly in response to host immune selection pressures. As a result, the functional properties of HIV-1 isolates from earlier in the epidemic may differ from those of isolates from later stages. However, few studies have investigated alterations in viral replication capacity (RC) over the epidemic. In the present study, we compare Gag-Protease-associated RC between early and late isolates in Japan (1994 to 2009). HIV-1 subtype B sequences from 156 antiretroviral-naïve Japanese with chronic asymptomatic infection were used to construct a chimeric NL4-3 strain encoding plasma-derived gag-protease. Viral replication capacity was examined by infecting a long terminal repeat-driven green fluorescent protein-reporter T cell line. We observed a reduction in the RC of chimeric NL4-3 over the epidemic, which remained significant after adjusting for the CD4(+) T cell count and plasma virus load. The same outcome was seen when limiting the analysis to a single large cluster of related sequences, indicating that our results are not due to shifts in the molecular epidemiology of the epidemic in Japan. Moreover, the change in RC was independent of genetic distance between patient-derived sequences and wild-type NL4-3, thus ruling out potential temporal bias due to genetic similarity between patient and historic viral backbone sequences. Collectively, these data indicate that Gag-Protease-associated HIV-1 replication capacity has decreased over the epidemic in Japan. Larger studies from multiple geographical regions will be required to confirm this phenomenon.
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Persistence versus reversion of 3TC resistance in HIV-1 determine the rate of emergence of NVP resistance. Viruses 2012; 4:1212-34. [PMID: 23012621 PMCID: PMC3446758 DOI: 10.3390/v4081212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/03/2012] [Accepted: 08/06/2012] [Indexed: 11/17/2022] Open
Abstract
When HIV-1 is exposed to lamivudine (3TC) at inhibitory concentrations, resistant variants carrying the reverse transcriptase (RT) substitution M184V emerge rapidly. This substitution confers high-level 3TC resistance and increased RT fidelity. We established a novel in vitro system to study the effect of starting nevirapine (NVP) in 3TC-resistant/NNRTI-naïve clinical isolates, and the impact of maintaining versus dropping 3TC pressure in this setting. Because M184V mutant HIV-1 seems hypersusceptible to adefovir (ADV), we also tested the effect of ADV pressure on the same isolates. We draw four conclusions from our experiments simulating combination therapy in vitro. (1) The presence of low-dose (1 μM) 3TC prevented reversal to wild-type from an M184V mutant background. (2) Adding low-dose 3TC in the presence of NVP delayed the selection of NVP-associated mutations. (3) The presence of ADV, in addition to NVP, led to more rapid reversal to wild-type at position 184 than NVP alone. (4) ADV plus NVP selected for greater numbers of mutations than NVP alone. Inference about the "selection of mutation" is based on two statistical models, one at the viral level, more telling, and the other at the level of predominance of mutation within a population. Multidrug pressure experiments lend understanding to mechanisms of HIV resistance as they bear upon new treatment strategies.
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Hurt CB, Eron JJ, Cohen MS. Pre-exposure prophylaxis and antiretroviral resistance: HIV prevention at a cost? Clin Infect Dis 2011; 53:1265-70. [PMID: 21976467 PMCID: PMC3246871 DOI: 10.1093/cid/cir684] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 08/24/2011] [Indexed: 12/12/2022] Open
Abstract
Pre-exposure prophylaxis (PrEP), the use of antiretrovirals (ARVs) by human immunodeficiency virus (HIV)-uninfected individuals to prevent acquisition of the virus during high-risk sexual encounters, enjoyed its first 2 major successes with the Centre for the AIDS Programme of Research in South Africa (CAPRISA) 004 and the Pre-Exposure Prophylaxis Initiative (iPrEx). These successes were buoyed by additional positive results from the TDF2 and Partners PrEP trials. Although no seroconverters in either arm of CAPRISA developed resistance to tenofovir, 2 participants in iPrEx with undetected, seronegative acute HIV infection were randomized to receive daily oral tenofovir-emtricitabine and resistance to emtricitabine was later discovered in both men. A similar case in the TDF2 study resulted in resistance to both ARVs. These cases prompted us to examine existing literature on the nature of resistance mutations elicited by ARVs used for PrEP. Here, we discuss the impact of signature mutations selected by PrEP, how rapidly these emerge with daily ARV exposure, and the individual-level and public health consequences of ARV resistance.
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Affiliation(s)
- Christopher B Hurt
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7030, USA.
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Combination HBV therapy is linked to greater HBV DNA suppression in a cohort of lamivudine-experienced HIV/HBV coinfected individuals. AIDS 2009; 23:1707-15. [PMID: 19584701 DOI: 10.1097/qad.0b013e32832b43f2] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To determine if highly active antiretroviral therapy (HAART) with combination anti-hepatitis B virus (HBV) therapy compared to HAART with HBV monotherapy leads to greater HBV DNA suppression in an HIV/HBV coinfected cohort. DESIGN A cross-sectional analysis of 122 HIV/HBV coinfected patients from Australia and the United States. METHODS Univariate analysis and ordinal logistic regression were used to determine factors associated with an HBV DNA less than 100 IU/ml. RESULTS The majority of patients were on HAART (85%), had an HIV RNA less than 50 copies/ml, a median CD4 cell count of 438 cells/microl, and had prior or current lamivudine therapy (98%). The majority (89%) of those on HAART were on HBV-active drugs including 54% on tenofovir (TDF) with either lamivudine (LAM) or emtrictabine (FTC), 34% receiving LAM or FTC monotherapy, and 12% on TDF monotherapy. Only 4% of patients in the combination (TDF + LAM/FTC) group had HBV DNA greater than 20 000 IU/ml compared to 54% in the group on no HBV-active therapy, 31% in the LAM or FTC monotherapy group, and 30% in the TDF monotherapy group (P < 0.0001). In an ordinal logistic regression model, monotherapy with either TDF or LAM remained independently associated with higher HBV DNA. CONCLUSION These data suggest that there may be an advantage to using TDF in combination with LAM or FTC in HIV/HBV coinfection, particularly in the setting of previous LAM experience. Continued prospective follow-up in this study will confirm whether the advantage is sustained longer-term.
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Van Rompay KKA. Evaluation of antiretrovirals in animal models of HIV infection. Antiviral Res 2009; 85:159-75. [PMID: 19622373 DOI: 10.1016/j.antiviral.2009.07.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 07/07/2009] [Accepted: 07/13/2009] [Indexed: 01/07/2023]
Abstract
Animal models of HIV infection have played an important role in the development of antiretroviral drugs. Although each animal model has its limitations and never completely mimics HIV infection of humans, a carefully designed study allows experimental approaches that are not feasible in humans, but that can help to better understand disease pathogenesis and to provide proof-of-concept of novel intervention strategies. While rodent and feline models are useful for initial screening, further testing is best done in non-human primate models, such as simian immunodeficiency virus (SIV) infection of macaques, because they share more similarities with HIV infection of humans. In the early years of the HIV pandemic, non-human primate models played a relatively minor role in the antiretroviral drug development process. Since then, a better understanding of the disease and the development of better drugs and assays to monitor antiviral efficacy have increased the usefulness of the animal models. In particular, non-human primate models have provided proof-of-concept for (i) the benefits of chemoprophylaxis and early treatment, (ii) the preclinical efficacy of novel drugs such as tenofovir, (iii) the virulence and clinical significance of drug-resistant viral mutants, and (iv) the role of antiviral immune responses during drug therapy. Ongoing comparison of results obtained in animal models with those observed in human studies will further validate and improve these animal models so they can continue to help advance our scientific knowledge and to guide clinical trials. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.
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Affiliation(s)
- Koen K A Van Rompay
- California National Primate Research Center, University of California, Davis, CA 95616, USA.
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Zaaijer HL, Takkenberg RB, Weegink CJ, Rebers SPH, Menting S, Reesink HW, Schinkel J, Molenkamp R. Susceptibility of hepatitis B virus to lamivudine restored by resistance to adefovir. J Med Virol 2009; 81:413-6. [PMID: 19152408 DOI: 10.1002/jmv.21401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Serial monotherapy and add-on regimes for treatment of chronic hepatitis B virus (HBV) infection may induce the accumulation of viral resistance mutations in patients, reducing the options for ongoing viral suppression. The induction of antiviral resistance by serial application of polymerase inhibitors does not necessarily imply that the subsequent combined use of the drugs will fail. Some HIV strains resistant to one polymerase inhibitor show increased susceptibility to another polymerase inhibitor. After failure of sequential lamivudine and adefovir monotherapy, two patients with hepatitis B changed to treatment with lamivudine plus adefovir and had renewed suppression of HBV. To study the mutational history of resistant HBV subpopulations in the two patients, a part of the HBV polymerase gene was amplified, cloned, sequenced, and analyzed for the presence of mutations, in sequential plasma samples. In both patients serial monotherapy caused the replacement in all HBV clones of wild-type virus by classical lamivudine resistant mutants (L180M and M204V/I), which were replaced subsequently by adefovir resistant mutants (A181V and N236T). When finally lamivudine was added to adefovir, the A181V adefovir mutation persisted in all clones and lamivudine-related mutations did not reappear. During 18 months of combination therapy, HBV-DNA levels decreased 10,000, respectively, 1,000-fold, despite the earlier resistance to lamivudine and adefovir. Although clinically insufficient, this effect indicates that HBV polymerase resistance mutations may be antagonistic, which is relevant if chronic HBV infection is to be treated by a combination of polymerase inhibitors.
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Affiliation(s)
- H L Zaaijer
- Laboratory of Clinical Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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20
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Waters JM, O'Neal W, White KL, Wakeford C, Lansdon EB, Harris J, Svarovskaia ES, Miller MD, Borroto-Esoda K. Mutations in the thumb–connection and RNase H domain of HIV type-1 reverse transcriptase of antiretroviral treatment-experienced patients. Antivir Ther 2009. [DOI: 10.1177/135965350901400215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Antiretroviral therapy that targets HIV type-1 (HIV-1) reverse transcriptase (RT) can be linked to mutations in the thumb–connection (amino acids [AA] 241–426) and RNase H (AA 427–560) domains, which could affect drug resistance. Methods Genotypical and statistical analyses were performed on HIV-1 RT from 100 antiretroviral treatment-naive and 248 antiretroviral treatment-experienced patients, the majority of whom were infected with HIV-1 subtype B. The RT region was analysed in three parts: the polymerase (AA 1–240), thumb–connection (AA 241–426) and RNase H (AA 427–560) domains. Results The polymerase domain had statistically significant changes between the two groups at 24 AA positions that are known resistance sites. Within the thumb–connection domain, R284 and N348 had statistically significant changes between the groups ( P=0.007 and P≤0.001, respectively). In treatment-experienced patients, 17.3% had R284K, whereas 24.5% had N348I substitutions. Both R284 and N348 were 100% conserved in treatment-naive patients. Within the RNase H domain, only K451 showed a statistically significant change ( P≤0.001), with K451R present in 11% of treatment-experienced patients but remaining 100% conserved among treatment-naive patients. Conclusions RT mutations at three positions outside of the polymerase region were associated with antiretroviral therapy: R284K, N348I and K451R. Both R284K and K451R interact with the phosphate backbone of the template or primer in HIV-1 RT crystal structures and could potentially influence the positioning of the primer strand, thus affecting polymerization, the efficiency of nucleoside reverse transcriptase inhibitor excision and/or RNase H activity.
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Abstract
Several groundbreaking trials and over 1 million years of patient experience have established tenofovir as an important component of HIV treatment. Tenofovir has demonstrated potent antiviral efficacy, with a low risk of developing resistance when used as part of an effective combination regimen. It is generally well tolerated, with a low risk of lipoatrophy and a favourable effect on lipid profile compared with older nucleoside analogue agents such as stavudine or zidovudine. Clinical data suggest that switching from thymidine analogues to a tenofovir-containing regimen can benefit patients with lipid abnormalities or lipoatrophy. This article reviews the development of tenofovir, including pivotal studies that have influenced HIV clinical practice.
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Affiliation(s)
- A Pozniak
- Chelsea and Westminster Hospital, Department of HIV/GU Medicine, London, UK.
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22
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Abstract
OBJECTIVE To develop an improved model for the genetic basis of reduced susceptibility to tenofovir in vitro. METHODS A dataset of 532 HIV-1 subtype B reverse transcriptase genotypes for which matched phenotypic susceptibility data were available was assembled, both as a continuous (transformed) dataset and a categorical dataset generated by imposing a cut-off on the basis of earlier studies of in-vivo response of 1.4-fold. Models were generated using stepwise regression, decision tree and random forest approaches on both the continuous and categorical data. Models were compared by mean squared error (continuous models), or by misclassification rates by nested crossvalidation. RESULTS From the continuous dataset, stepwise linear regression, regression tree and regression forest methods yielded models with MSE of 0.46, 0.48 and 0.42 respectively. Amino acids 215, 65, 41, 67, 184 and 151 in HIV-1 reverse transcriptase were identified in all three models and amino acid 210 in two. The categorical data yielded logistic regression, classification tree and forest models with misclassification rates of 26, 24 and 23%, respectively. Amino acids 215, 65 and 67 appeared in all; 41, 184, 210 and 151 were also included in the classification forest model. CONCLUSION The random forests approach has yielded a substantial improvement in the available models to describe the genetic basis of reduced susceptibility to tenofovir in vitro. The most important sites in these models are amino acid sites 215, 65, 41, 67, 184, 151 and 210 in HIV-1 reverse transcriptase.
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HIV-1 reverse transcriptase inhibitor resistance mutations and fitness: a view from the clinic and ex vivo. Virus Res 2008; 134:104-23. [PMID: 18289713 DOI: 10.1016/j.virusres.2007.12.021] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 12/27/2007] [Accepted: 12/28/2007] [Indexed: 01/04/2023]
Abstract
Genetic diversity plays a key role in human immunodeficiency virus (HIV) adaptation, providing a mechanism to escape host immune responses and develop resistance to antiretroviral drugs. This process is driven by the high-mutation rate during DNA synthesis by reverse transcriptase (RT), by the large viral populations, by rapid viral turnover, and by the high-recombination rate. Drugs targeting HIV RT are included in all regimens of highly active antiretroviral therapy (HAART), which helps to reduce the morbidity and mortality of HIV-infected patients. However, the emergence of resistant viruses is a significant obstacle to effective long-term management of HIV infection and AIDS. The increasing complexity of antiretroviral regimens has favored selection of HIV variants harboring multiple drug resistance mutations. Evolution of drug resistance is characterized by severe fitness losses when the drug is not present, which can be partially overcome by compensatory mutations or other adaptive changes that restore replication capacity. Here, we review the impact of mutations conferring resistance to nucleoside and nonnucleoside RT inhibitors on in vitro and in vivo fitness, their involvement in pathogenesis, persistence upon withdrawal of treatment, and transmission. We describe the techniques used to estimate viral fitness, the molecular mechanisms that help to improve the viral fitness of drug-resistant variants, and the clinical implications of viral fitness data, by exploring the potential relationship between plasma viral load, drug resistance, and disease progression.
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Menéndez-Arias L. Mechanisms of resistance to nucleoside analogue inhibitors of HIV-1 reverse transcriptase. Virus Res 2008; 134:124-46. [PMID: 18272247 DOI: 10.1016/j.virusres.2007.12.015] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 12/21/2007] [Accepted: 12/21/2007] [Indexed: 10/22/2022]
Abstract
Human immunodeficiency virus (HIV) reverse transcriptase (RT) inhibitors can be classified into nucleoside and nonnucleoside RT inhibitors. Nucleoside RT inhibitors are converted to active triphosphate analogues and incorporated into the DNA in RT-catalyzed reactions. They act as chain terminators blocking DNA synthesis, since they lack the 3'-OH group required for the phosphodiester bond formation. Unfortunately, available therapies do not completely suppress viral replication, and the emergence of drug-resistant HIV variants is facilitated by the high adaptation capacity of the virus. Mutations in the RT-coding region selected during treatment with nucleoside analogues confer resistance through different mechanisms: (i) altering discrimination between nucleoside RT inhibitors and natural substrates (dNTPs) (e.g. Q151M, M184V, etc.), or (ii) increasing the RT's phosphorolytic activity (e.g. M41L, T215Y and other thymidine analogue resistance mutations), which in the presence of a pyrophosphate donor (usually ATP) allow the removal of chain-terminating inhibitors from the 3' end of the primer. Both mechanisms are implicated in multi-drug resistance. The excision reaction can be modulated by mutations conferring resistance to nucleoside or nonnucleoside RT inhibitors, and by amino acid substitutions that interfere with the proper binding of the template-primer, including mutations that affect RNase H activity. New developments in the field should contribute towards improving the efficacy of current therapies.
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Affiliation(s)
- Luis Menéndez-Arias
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain.
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Delaugerre C, Flandre P, Marcelin A, Descamps D, Tamalet C, Cottalorda J, Schneider V, Yerly S, LeGoff J, Morand-Joubert L, Chaix M, Costagliola D, Calvez V. National survey of the prevalence and conditions of selection of HIV-1 reverse transcriptase K70E mutation. J Med Virol 2008; 80:762-5. [DOI: 10.1002/jmv.21158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ilina T, Parniak MA. Inhibitors of HIV-1 reverse transcriptase. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2008; 56:121-67. [PMID: 18086411 DOI: 10.1016/s1054-3589(07)56005-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Tatiana Ilina
- Department of Molecular Genetics and Biochemistry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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Margot NA, Lu B, Cheng A, Miller MD. Resistance development over 144 weeks in treatment-naive patients receiving tenofovir disoproxil fumarate or stavudine with lamivudine and efavirenz in Study 903. HIV Med 2007; 7:442-50. [PMID: 16925730 DOI: 10.1111/j.1468-1293.2006.00404.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Study 903 was a 144-week, randomized, double-blind, active-controlled study of tenofovir disoproxil fumarate (TDF) therapy in treatment-naive HIV-1-infected patients. Patients received either TDF (n = 299) or stavudine (d4T) (n = 301) with lamivudine (3TC) and efavirenz (EFV). Resistance analyses were performed at baseline and at virological failure to determine the effects of baseline resistance and the patterns of resistance at virological failure. METHODS Plasma HIV-1 from patients at baseline and at virological failure (>400 HIV-1 RNA copies/mL at week 144 or early discontinuation) was analysed phenotypically and by population sequencing. RESULTS Sixteen per cent of patients were classified as having virological failure (47 on TDF and 49 on d4T; P = 0.91). Patients with non-B HIV-1 subtypes or baseline nucleoside reverse transcriptase inhibitor (NRTI)-associated mutations responded similarly to the overall population. Resistance to EFV (K103N and others) or 3TC (M184V) developed most frequently (8.3% and 5.8%, respectively) and similarly in the two arms. In the d4T arm, a variety of NRTI mutations developed: K65R (n = 2), L74V (n = 2), V75M (n = 1), and T69A + Y115H (n = 1). K65R developed in eight TDF patients (2.7%); in seven of these eight patients, within 48 weeks. All eight patients began new regimens with a protease inhibitor (PI) and NRTIs, including two patients who remained on TDF; five of the eight patients achieved HIV RNA <50 copies/mL in second-line therapy with the remaining patients having no follow-up or being nonadherent. CONCLUSIONS Treatment of HIV-1 with TDF, 3TC and EFV was highly effective, with <3% of patients developing resistance to TDF over 144 weeks.
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Affiliation(s)
- N A Margot
- Gilead Sciences, Inc., Foster City, CA 94404, USA
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28
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Marchand B, White KL, Ly JK, Margot NA, Wang R, McDermott M, Miller MD, Götte M. Effects of the translocation status of human immunodeficiency virus type 1 reverse transcriptase on the efficiency of excision of tenofovir. Antimicrob Agents Chemother 2007; 51:2911-9. [PMID: 17517852 PMCID: PMC1932533 DOI: 10.1128/aac.00314-07] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ATP-dependent phosphorolytic excision of nucleoside analogue reverse transcriptase inhibitors can diminish their inhibitory effects on human immunodeficiency virus replication. Previous studies have shown that excision can occur only when the reverse transcriptase complex exists in its pretranslocational state. Binding of the next complementary nucleotide causes the formation of a stable dead-end complex in the posttranslocational state, which blocks the excision reaction. To provide mechanistic insight into the excision of the acyclic phosphonate nucleotide analog tenofovir, we compared the efficiencies of the reaction in response to changes in the translocation status of the enzyme. We found that rates of excision of tenofovir with wild-type reverse transcriptase can be as high as those seen with 3'-azido-3'-deoxythymidine monophosphate (AZT-MP). Thymidine-associated mutations, which confer >100-fold and 3-fold decreased susceptibility to AZT and tenofovir, respectively, caused substantial increases in the efficiency of excision of both inhibitors. However, in contrast to the case for AZT-MP, the removal of tenofovir was highly sensitive to dead-end complex formation. Site-specific footprinting experiments revealed that complexes with AZT-terminated primers exist predominantly pretranslocation. In contrast, complexes with tenofovir-terminated primers are seen in both configurations. Low concentrations of the next nucleotide are sufficient to trap the complex posttranslocation despite the flexible, acyclic character of the compound. Thus, the relatively high rate of excision of tenofovir is partially neutralized by the facile switch to the posttranslocational state and by dead-end complex formation, which provides a degree of protection from excision in the cellular environment.
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Affiliation(s)
- Bruno Marchand
- Department of Microbiology & Immunology, McGill University, Lyman Duff Medical Building, Montreal, QC, Canada
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Perez-Bercoff D, Wurtzer S, Compain S, Benech H, Clavel F. Human immunodeficiency virus type 1: resistance to nucleoside analogues and replicative capacity in primary human macrophages. J Virol 2007; 81:4540-50. [PMID: 17287264 PMCID: PMC1900139 DOI: 10.1128/jvi.01620-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antiretroviral treatment failure is associated with the emergence of resistant human immunodeficiency virus type 1 (HIV-1) populations which often express altered replicative capacity (RC). The resistance and RC of clinical HIV-1 strains, however, are generally assayed using activated peripheral blood mononuclear cells (PBMC) or tumor cell lines. Because of their high proliferation rate and concurrent high deoxynucleoside triphosphate (dNTP) content, both resistance and RC alterations might be misestimated in these cell systems. We have evaluated the resistance of HIV-1 clones expressing a variety of RT resistance mutations in primary human macrophages using a single cycle system. Our experiments indicate that d4T, ddI, and 3TC are more potent in macrophages than in HeLa-derived P4 tumor cells. Mutant viruses bearing thymidine analogue mutations (TAMs) or the K65R mutation had similar resistance levels in the two cell types. Strikingly, however, the M184V mutant, although fully resistant to 3TC in P4 cells, maintained some susceptibility to 3TC in macrophages from 8 of 11 donors. Using the same system, we found that the impact of resistance mutations on HIV RC was minimal in activated PBMC and in P4 cells. In contrast, mutant viruses exhibited strongly impaired RC relative to the wild type (WT) in macrophages, with the following RC order: WT > two TAMs > four TAMs = M184V > K65R. In undifferentiated monocytes, WT virus replication could be detected in three of six donors, but replication of all mutant viruses remained undetectable. Altogether, our results confirm that nucleoside reverse transcriptase inhibitors (NRTIs) are powerful antiviral agents in differentiated macrophages, reveal that HIV resistance to some NRTIs may be less efficient in these cells, and indicate that resistance-associated loss of RC is more pronounced in macrophages than in high-dNTP content cell systems.
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Affiliation(s)
- Danielle Perez-Bercoff
- Antiviral Research Unit, INSERM U552, Hôpital Bichat-Claude Bernard, 46 Rue Henri Huchard, 75018 Paris, France
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Sluis-Cremer N, Sheen CW, Zelina S, Torres PSA, Parikh UM, Mellors JW. Molecular mechanism by which the K70E mutation in human immunodeficiency virus type 1 reverse transcriptase confers resistance to nucleoside reverse transcriptase inhibitors. Antimicrob Agents Chemother 2007; 51:48-53. [PMID: 17088490 PMCID: PMC1797654 DOI: 10.1128/aac.00683-06] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 07/25/2006] [Accepted: 10/23/2006] [Indexed: 11/20/2022] Open
Abstract
The K70E mutation in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) has become more prevalent in clinical samples, particularly in isolates derived from patients for whom triple-nucleoside regimens that include tenofovir (TNV), abacavir, and lamivudine (3TC) failed. To elucidate the molecular mechanism by which this mutation confers resistance to these nucleoside RT inhibitors (NRTI), we conducted detailed biochemical analyses comparing wild-type (WT), K70E, and K65R HIV-1 RT. Pre-steady-state kinetic experiments demonstrate that the K70E mutation in HIV-1 RT allows the enzyme to discriminate between the natural deoxynucleoside triphosphate substrate and the NRTI triphosphate (NRTI-TP). Compared to the WT enzyme, K70E RT showed 2.1-, 2.3-, and 3.5-fold-higher levels of resistance toward TNV-diphosphate, carbovir-TP, and 3TC-TP, respectively. By comparison, K65R RT demonstrated 12.4-, 12.0-, and 13.1-fold-higher levels of resistance, respectively, toward the same analogs. NRTI-TP discrimination by the K70E (and K65R) mutation was primarily due to decreased rates of NRTI-TP incorporation and not to changes in analog binding affinity. The K65R and K70E mutations also profoundly impaired the ability of RT to excise 3'-azido-2',3'-dideoxythymidine monophosphate (AZT-MP) and other NRTI-MP from the 3' end of a chain-terminated primer. When introduced into an enzyme with the thymidine analog mutations (TAMs) M41L, L210W, and T215Y, the K70E mutation inhibited ATP-mediated excision of AZT-MP. Taken together, these findings indicate that the K70E mutation, like the K65R mutation, reduces susceptibility to NRTI by selectively decreasing NRTI-TP incorporation and is antagonistic to TAM-mediated nucleotide excision.
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Affiliation(s)
- Nicolas Sluis-Cremer
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, S817 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA 15261, USA.
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Margot NA, Waters JM, Miller MD. In vitro human immunodeficiency virus type 1 resistance selections with combinations of tenofovir and emtricitabine or abacavir and lamivudine. Antimicrob Agents Chemother 2006; 50:4087-95. [PMID: 16982781 PMCID: PMC1693985 DOI: 10.1128/aac.00816-06] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) resistance development was evaluated in vitro by using combinations of the drugs tenofovir and emtricitabine or abacavir and lamivudine, as well as by using the compounds individually. Emtricitabine- and lamivudine-resistant HIV-1 isolates with the M184I or M184V mutation in reverse transcriptase were readily selected in the cultures with emtricitabine alone, lamivudine alone, and the two drug combinations and conferred high-level resistance to emtricitabine and lamivudine. Tenofovir-resistant HIV-1 isolates with the K65R mutation occurred in both the culture with tenofovir alone and the culture with the combination of emtricitabine and tenofovir. The S68N and S68K mutations were also observed in the tenofovir cultures, with no detectable impact on resistance, suggesting a possible compensatory role in viral fitness. At low concentrations of emtricitabine and tenofovir, the M184I mutation appeared first, followed by the K65R mutation, in a subset of viruses. At intermediate concentrations of emtricitabine and tenofovir, viruses harboring the K65R mutation or a novel K65N and K70R double mutation grew before they gave rise to mutants with K65R and M184V/I double mutations at higher emtricitabine concentrations. Abacavir resistance was characterized by the accumulation of the M184V, Y115F, and K65R mutations in the abacavir culture, while the M184V and L74V mutations were selected in combination with lamivudine. In the presence of the abacavir resistance mutations, viral growth was strong even in the presence of high concentrations of abacavir. In contrast, viral growth was markedly impaired in the cultures with high tenofovir concentrations, even in the presence of K65R. In conclusion, these studies show that HIV-1 mutants with a K65R and M184V genotype are generated under maximum selection pressure from the combination of tenofovir and emtricitabine.
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Affiliation(s)
- N A Margot
- Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA 94404, USA
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32
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White KL, Chen JM, Feng JY, Margot NA, Ly JK, Ray AS, Macarthur HL, McDermott MJ, Swaminathan S, Miller MD. The K65R reverse transcriptase mutation in HIV-1 reverses the excision phenotype of zidovudine resistance mutations. Antivir Ther 2006; 11:155-63. [PMID: 16640096 DOI: 10.1177/135965350601100209] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The HIV-1 nucleoside reverse transcriptase inhibitors (NRTIs) tenofovir (TFV), abacavir, didanosine and stavudine can select for K65R, whereas zidovudine (AZT) and stavudine can select for thymidine analogue mutations (TAMs) in HIV-1 reverse transcriptase (RT). HIV-1 with TAMs shows reduced susceptibility to all NRTIs, most notably AZT, whereas HIV-1 with K65R shows reduced susceptibility to all NRTIs except AZT. K65R and TAMs rarely occur together in patients. However, when present together, K65R can restore susceptibility to AZT. This study characterizes the underlying mechanisms of resistance of these RT mutants to TFV and AZT. K65R mediated decreased binding/incorporation of TFV and AZT (increased Ki/Km of 7.1- and 4.3-fold, respectively), but also decreased excision of TFV and AZT (0.7- and 0.3-fold, respectively) when compared with wild-type RT. By contrast, TAMs mediated increased TFV and AZT excision (11- and 5.4-fold, respectively), and showed no changes in binding/incorporation. When these mutations were combined, K65R reversed TAM-mediated AZT resistance by strongly reducing AZT excision. Molecular modelling studies suggest that K65R creates additional hydrogen bonds that reduce the conformational mobility of RT, resulting in reduced polymerization and excision. Thus, consistent with clinical HIV-1 genotyping data, there appears to be no net NRTI resistance benefit for TAMs and K65R to develop together in patients taking AZT and TFV disoproxil fumarate, where the TAM pathway alone provides the greatest resistance for both drugs.
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Sheldon JA, Corral A, Rodés B, Mauss S, Rockstroh J, Berger F, Schwarze-Zander C, Soriano V. Risk of selecting K65R in antiretroviral-naive HIV-infected individuals with chronic hepatitis B treated with adefovir. AIDS 2005; 19:2036-8. [PMID: 16260913 DOI: 10.1097/01.aids.0000189563.79976.05] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Seven antiretroviral-naive HIV-infected individuals with chronic hepatitis B treated with adefovir for longer than 6 months were assessed. Using bulk population sequencing and a sensitive limiting dilution analysis, the selection of K65R or other resistance mutations did not occur in HIV, suggesting that adefovir can be confidently used as hepatitis B virus (HBV) therapy in HIV/HBV-co-infected patients who do not require antiretroviral therapy.
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Affiliation(s)
- Julie A Sheldon
- Department of Infectious Diseases, Hospital Carlos III, Madrid, Spain
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White KL, Margot NA, Ly JK, Chen JM, Ray AS, Pavelko M, Wang R, McDermott M, Swaminathan S, Miller MD. A combination of decreased NRTI incorporation and decreased excision determines the resistance profile of HIV-1 K65R RT. AIDS 2005; 19:1751-60. [PMID: 16227782 DOI: 10.1097/01.aids.0000189851.21441.f1] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine the mechanisms of resistance of K65R mutant reverse transcriptase (RT) to the currently approved nucleoside and nucleotide RT inhibitors (NRTI). METHODS Susceptibilities of K65R mutant HIV-1 to NRTI were determined in cell culture. The Ki/Km values were measured to determine the relative binding or incorporation of the NRTI, and ATP-mediated excision of incorporated NRTI was measured to determine NRTI stability as chain terminators. RESULTS K65R HIV-1 had decreased susceptibility to most NRTI, but increased susceptibility to zidovudine (ZDV). Ki/Km values were increased 2- to 13-fold for K65R compared to wild-type RT for all NRTI, indicating decreased binding or incorporation. However, K65R also showed decreased excision of all NRTI compared to wild-type, indicating greater stability once incorporated. At physiological nucleotide concentrations, excision of ZDV, carbovir (the active metabolite of abacavir; ABC), stavudine (d4T), and tenofovir was further decreased, while excision of didanosine (ddI), zalcitabine (ddC), lamivudine (3TC), and emtricitabine (FTC) was unchanged. The decreased binding or incorporation of ZDV by K65R appeared counteracted by decreased excision resulting in overall increased susceptibility to ZDV in cell culture. For ABC, tenofovir, and d4T, despite having decreased excision, decreased binding or incorporation resulted in reduced susceptibilities to K65R. For ddI, ddC, 3TC, and FTC, decreased binding or incorporation by K65R appeared responsible for the decreased susceptibilities in cell culture. CONCLUSIONS NRTI resistance in cells can consist of both altered binding or incorporation and altered excision of the NRTI. For K65R, the combination of these opposing mechanisms results in decreased susceptibility to most NRTI but increased susceptibility to ZDV.
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Frankel FA, Marchand B, Turner D, Götte M, Wainberg MA. Impaired rescue of chain-terminated DNA synthesis associated with the L74V mutation in human immunodeficiency virus type 1 reverse transcriptase. Antimicrob Agents Chemother 2005; 49:2657-64. [PMID: 15980333 PMCID: PMC1168713 DOI: 10.1128/aac.49.7.2657-2664.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The L74V and M184V mutations in the reverse transcriptase (RT) gene of human immunodeficiency virus type 1 (HIV-1) are frequently associated with resistance to the nucleoside reverse transcriptase inhibitors abacavir, didanosine, and lamivudine. Yet viruses containing any of these mutations often display hypersusceptibility to zidovudine (ZDV). Two distinct mechanisms have been described to explain HIV-1 drug resistance. One of these involves diminished rates of incorporation of the nucleotide analogue by mutated RT, while the other mechanism involves increased rates of phosphorolytic excision of the drug-terminated primer. To understand the biochemical mechanisms responsible for the hypersensitization of L74V-containing viruses to ZDV, we studied the efficiency of excision of ZDV-monophosphate (ZDV-MP)-terminated primers by recombinant wild-type and mutated HIV-1 RTs in cell-free assays. We observed that the L74V mutation in RT caused reductions in ATP-dependent removal of ZDV-MP from newly synthesized viral DNA. In addition, we determined that the L74V and M184V mutations did not affect the ratio between the populations of RT-DNA/DNA complexes found at pre- and posttranslocational stages; however, they might have affected proper alignment between incorporated chain terminator and pyrophosphate donor, substrate orientation, affinity for ATP, and/or primer-template substrate. Finally, we confirmed previous findings that L74V-containing viruses display diminished replication capacity and that this is associated with reduced levels of synthesis of early reverse-transcribed viral DNA molecules.
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Affiliation(s)
- Fernando A Frankel
- McGill AIDS Centre, Lady Davis Institute-Jewish General Hospital, 3755 Côte-Ste-Catherine Road, Montreal, Quebec H3T 1E2, Canada
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36
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Monie D, Simmons RP, Nettles RE, Kieffer TL, Zhou Y, Zhang H, Karmon S, Ingersoll R, Chadwick K, Zhang H, Margolick JB, Quinn TC, Ray SC, Wind-Rotolo M, Miller M, Persaud D, Siliciano RF. A novel assay allows genotyping of the latent reservoir for human immunodeficiency virus type 1 in the resting CD4+ T cells of viremic patients. J Virol 2005; 79:5185-202. [PMID: 15795302 PMCID: PMC1069549 DOI: 10.1128/jvi.79.8.5185-5202.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A latent reservoir for human immunodeficiency virus type 1 (HIV-1) consisting of integrated provirus in resting memory CD4+ T cells prevents viral eradication in patients on highly active antiretroviral therapy (HAART). It is difficult to analyze the nature and dynamics of this reservoir in untreated patients and in patients failing therapy, because it is obscured by an excess of unintegrated viral DNA that constitutes the majority of viral species in resting CD4+ T cells from viremic patients. Therefore, we developed a novel culture assay that stimulates virus production from latent, integrated HIV-1 in resting CD4+ T cells in the presence of antiretroviral drugs that prevent the replication of unintegrated virus. Following activation, resting CD4+ T cells with integrated HIV-1 DNA produced virus particles for several days, with peak production at day 5. Using this assay, HIV-1 pol sequences from the resting CD4+ T cells of viremic patients were found to be genetically distinct from contemporaneous plasma virus. Despite the predominance of a relatively homogeneous population of drug-resistant viruses in the plasma of patients failing HAART, resting CD4+ T cells harbored a diverse array of wild-type and archival drug-resistant viruses that were less fit than plasma virus in the context of current therapy. These results provide the first direct evidence that resting CD4+ T cells serve as a stable reservoir for HIV-1 even in the setting of high levels of viremia. The ability to analyze archival species in viremic patients may have clinical utility in detecting drug-resistant variants not present in the plasma.
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Affiliation(s)
- Daphne Monie
- Johns Hopkins University School of Medicine, Broadway Research Building, Room 879, 733 North Broadway St., Baltimore, MD 21205, USA
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Daar ES, Richman DD. Confronting the emergence of drug-resistant HIV type 1: impact of antiretroviral therapy on individual and population resistance. AIDS Res Hum Retroviruses 2005; 21:343-57. [PMID: 15929696 DOI: 10.1089/aid.2005.21.343] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Resistance to antiretroviral agents, and in particular the increasing levels of transmitted resistant virus could offset the substantial gains won with potent antiretroviral therapy. Primary and acquired antiretroviral resistance rates reflect the relative usage of different antiretroviral drugs in the population, as well as the inherent genetic barrier to the development of resistance associated with individual drugs. Data on antiretroviral resistance rates, gleaned from the growing HIV-1-infected population treated with a continuously increasing number of antiretroviral drugs and drug combinations, provide insights into patient management approaches for delaying the emergence of resistance and minimizing the degree of resistance. Evolving data suggest that the relative ease by which HIV-1 escapes the selective pressure of chronic drug exposure varies for the different antiretroviral drug classes and individual antiretroviral drugs. The development of resistance in vivo can be anticipated based on these data, in conjunction with the individuals treatment history and resistance testing results. These in turn can guide the judicious use of antiretroviral drugs to attain optimal treatment responses and to preserve therapeutic options for the time when antiretroviral-resistant strains emerge. The recent developments of new antiretroviral drugs, including the use of boosted protease inhibitors, suggest that treatment strategies can limit the development of resistance.
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Affiliation(s)
- Eric S Daar
- Division of HIV Medicine, Department of Medicine, Los Angeles BioMedical Research Institute at Harbor-UCLA Medical Center, Torrance, California 90502, USA.
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38
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Aquaro S, Svicher V, Ceccherini-Silberstein F, Cenci A, Marcuccilli F, Giannella S, Marcon L, Caliò R, Balzarini J, Perno CF. Limited development and progression of resistance of HIV-1 to the nucleoside analogue reverse transcriptase inhibitor lamivudine in human primary macrophages. J Antimicrob Chemother 2005; 55:872-8. [PMID: 15845785 DOI: 10.1093/jac/dki104] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES The aim of this study was to investigate the development and progression of phenotypic resistance to the HIV-1-reverse transcriptase (RT) inhibitor lamivudine, and genotypic variations of HIV-1-RT occurring under lamivudine treatment in HIV-1-infected human primary monocytes-macrophages (M/M). METHODS Cellular passages in the presence of lamivudine were performed every 2 weeks by transferring supernatants of infected M/M to fresh M/M. A fitness assay using wild-type virus and a lamivudine-resistant HIV-1 virus (harbouring the M184V RT mutation) was performed in peripheral blood mononuclear cells. Culture supernatants were tested for p24 antigen production and RT activity. The M184V RT mutant virus was obtained by site-directed mutagenesis on a CCR5-using HIV-1 backbone. RESULTS The mutagenized M184V RT virus showed full resistance to lamivudine in M/M. However, no detectable phenotypic and genotypic resistance (neither virus breakthrough, nor RT resistance-related mutations) developed in M/M infected by HIV-1 and cultured for up to seven passages in vitro (i.e. 105 days). This inefficiency of M/M to develop M184V RT mutated virus is tightly related to the low 2'-deoxynucleotide (dNTP) pool in such cells, which in turn decreases the kinetics of HIV-1-RT. Despite this, the M184V RT mutant virus replicates in M/M, although with a 30% decreased efficiency compared with the wild-type. CONCLUSIONS Our results show that the chances of development of resistance are far lower in M/M than in lymphocytes. This underlines the importance and the peculiar role of M/M as reservoirs of either wild-type or resistant strains in human organs.
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Affiliation(s)
- Stefano Aquaro
- Department of Experimental Medicine and Biochemical Sciences, University of Rome 'Tor Vergata', Via Montpellier 1, 00133 Rome.
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Re MC, Bon I, Schiavone P, Vitone F, Gibellini D. Discordant resistance interpretations in multi-treated HIV-1 patients. Int J Antimicrob Agents 2005; 25:211-5. [PMID: 15737514 DOI: 10.1016/j.ijantimicag.2004.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Accepted: 10/06/2004] [Indexed: 11/23/2022]
Abstract
The routine determination of drug resistance has become an important part of the clinical management of HIV-1 infected patients. Plasma samples from 130 individuals treated for at least 1 year with multiple NRTIs and NNRTIs were tested for the presence of mutations correlated to drug resistance. Since interpretation criteria represent a crucial point for virologists and clinicians, often complicated by the presence of novel and/or complex mutations patterns, we analyzed results interpreted by TruGene HIV-1 (Visible Genetics, Toronto, Ontario, Canada) and VirtualPhenotype (Virco, Mechelen, Belgium). A high degree of concordance was found for NNRTIs whereas NRTIs interpretation was highly discrepant. Since different approaches to monitoring resistance reflect different interpretation of results, the prediction of drugs resistance from a given HIV sequence might be contradictory and requires accurate standardization and unique interpretative rules.
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Affiliation(s)
- M C Re
- Department of Clinical and Experimental Medicine, Section of Microbiology, University of Bologna, St. Orsola Hospital, Massarenti, 9, 40138 Bologna, Italy.
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Delaugerre C, Roudiere L, Peytavin G, Rouzioux C, Viard JP, Chaix ML. Selection of a rare resistance profile in an HIV-1-infected patient exhibiting a failure to an antiretroviral regimen including tenofovir DF. J Clin Virol 2005; 32:241-4. [PMID: 15722030 DOI: 10.1016/j.jcv.2004.05.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2004] [Accepted: 05/10/2004] [Indexed: 10/26/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) resistance profile, K65R, K70E and M184V, on reverse transcriptase gene was associated with the virologic rebound consecutively to the switch of lopinavir/r to tenofovir DF in a stable regimen with nucleoside backbone of abacavir, lamivudine and didanosine. The high selective pressure on the same resistance pathway was probably associated with the loss of antiviral potency, even in well-controlled patient.
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Affiliation(s)
- Constance Delaugerre
- Department of Virology, Necker-Enfants Malades Hospital, 149 rue de Sèvres, 75015 Paris, France.
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41
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Buckheit RW. Understanding HIV resistance, fitness, replication capacity and compensation: targeting viral fitness as a therapeutic strategy. Expert Opin Investig Drugs 2005; 13:933-58. [PMID: 15268633 DOI: 10.1517/13543784.13.8.933] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The increasingly prevalent emergence of drug-resistant virus strains in patients being treated with highly active antiretroviral regimens and the increasing rates of transmission of drug-resistant virus strains have focused attention on the critical need for additional antiretroviral agents with novel mechanisms of action and enhanced potency. Furthermore, novel means of employing highly active antiretroviral therapy are needed to reduce or eliminate the virological treatment failures that currently occur. Over the past several years, evidence has mounted supporting the fact that the emergence of resistant strains is associated with reductions in viral fitness, yielding decreases in plasma virus load in treated patients harbouring resistant populations of the virus. Additional mutations that serve to modify fitness (compensatory mutations) and mutations that impact the viral replication capacity also emerge under the selective pressure of drug treatment, and have both negative and positive effects on virus growth. Fitness is generally accepted to refer to the ability of HIV to replicate in a defined environment and thus is used to describe the viral replication potential in the absence of the drug. Although viral fitness and replication capacity are related in some ways, it is important to recognise that viral fitness is not the same as viral replication capacity. This review will assess the recent literature on antiviral drug resistance, viral fitness and viral replication capacity, and discuss means by which the adaptability of HIV to respond rapidly to antiviral treatment through mutation may be used against it. This would be done by treating patients with an aim to lock the deleterious mutations into the resistant virus genome, resulting in a positive therapeutic outcome despite the presence of resistance to the selecting agents. The review will specifically discuss the literature on nucleoside and non-nucleoside reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors, fusion inhibitors, as well as other biological factors involved in viral fitness.
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Affiliation(s)
- Robert W Buckheit
- ImQuest BioSciences, Inc., 7340 Executive Way, Suite R, Frederick, Maryland 21704, USA.
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Skasko M, Weiss KK, Reynolds HM, Jamburuthugoda V, Lee K, Kim B. Mechanistic differences in RNA-dependent DNA polymerization and fidelity between murine leukemia virus and HIV-1 reverse transcriptases. J Biol Chem 2005; 280:12190-200. [PMID: 15644314 PMCID: PMC1752212 DOI: 10.1074/jbc.m412859200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We compared the mechanistic and kinetic properties of murine leukemia virus (MuLV) and human immunodeficiency virus type 1 (HIV-1) reverse transcriptases (RTs) during RNA-dependent DNA polymerization and mutation synthesis using pre-steady-state kinetic analysis. First, MuLV RT showed 6.5-121.6-fold lower binding affinity (K(d)) to deoxynucleotide triphosphate (dNTP) substrates than HIV-1 RT, although the two RTs have similar incorporation rates (k(pol)). Second, compared with HIV-1 RT, MuLV RT showed dramatic reduction during multiple dNTP incorporations at low dNTP concentrations. Presumably, due to its low dNTP binding affinity, the dNTP binding step becomes rate-limiting in the multiple rounds of the dNTP incorporation by MuLV RT, especially at low dNTP concentrations. Third, similar fold differences between MuLV and HIV-1 RTs in the K(d) and k(pol) values to correct and incorrect dNTPs were observed. This indicates that these two RT proteins have similar misinsertion fidelities. Fourth, these two RT proteins have different mechanistic capabilities regarding mismatch extension. MuLV RT has a 3.1-fold lower mismatch extension fidelity, compared with HIV-1 RT. Finally, MuLV RT has a 3.8-fold lower binding affinity to mismatched template/primer (T/P) substrate compared with HIV-1 RT. Our data suggest that the active site of MuLV RT has an intrinsically low dNTP binding affinity, compared with HIV-1 RT. In addition, instead of the misinsertion step, the mismatch extension step, which varies between MuLV and HIV-1 RTs, contributes to their fidelity differences. The implications of these kinetic differences between MuLV and HIV-1 RTs on viral cell type specificity and mutagenesis are discussed.
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Affiliation(s)
- Mark Skasko
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York 14642, USA
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43
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Ross L, Parkin N, Chappey C, Fisher R, Clair MS, Bates M, Tisdale M, Lanier ER. Phenotypic impact of HIV reverse transcriptase M184I/V mutations in combination with single thymidine analog mutations on nucleoside reverse transcriptase inhibitor resistance. AIDS 2004; 18:1691-6. [PMID: 15280780 DOI: 10.1097/01.aids.0000131355.44834.e4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To analyse the impact of the M184I/V mutation and individual thymidine-associated mutations (TAM) on nucleoside reverse transcriptase inhibitor (NRTI) phenotypic susceptibility and compare these results with those obtained using commercial and public algorithms. DESIGN An HIV genotypic/phenotypic database with over 27 000 samples was used to obtain the median fold change (5-95th percentile) in NRTI phenotypic susceptibility for viruses from patients containing individual TAM with or without the M184I or V mutation and for wild-type patient viruses. RESULTS The resulting data indicated that in vitro, individual TAM do not have an equivalent impact on NRTI resistance, with some individual TAM having little or no impact on NRTI resistance (e.g. M41L or K219Q/E/H/R). In the presence of the M184I/V mutation, re-sensitization to some drugs, including zidovudine, stavudine and tenofovir was observed despite the presence of a TAM. For didanosine and abacavir, the presence of the M184V mutation and a single TAM did not result in a fold-change increase associated with decreased drug susceptibility. Analysis of public and commercial algorithms revealed a lack of concordance regarding the impact of these mutations, and with the observed phenotypic data. CONCLUSION These analyses should assist in the creation of rules for genotypic drug resistance algorithms for a better reflection of the impact of individual TAM and also the impact of M184I/V on resistance. These data provide additional evidence that retaining lamivudine in those treatment regimens in which TAM can be selected may provide some therapeutic benefit by maintaining the M184V mutation.
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Affiliation(s)
- Lisa Ross
- Department of International Clinical Virology at GlaxoSmithKline, Research Triangle Park, North Carolina 27709, USA
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Diallo K, Götte M, Wainberg MA. Molecular impact of the M184V mutation in human immunodeficiency virus type 1 reverse transcriptase. Antimicrob Agents Chemother 2004; 47:3377-83. [PMID: 14576091 PMCID: PMC253767 DOI: 10.1128/aac.47.11.3377-3383.2003] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Karidia Diallo
- McGill AIDS Centre, Lady Davis Institute-Jewish General Hospital and Department of Microbiology and Immunology, McGill University, Montreal, Québec H3T 1E2, Canada
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Julias JG, Boyer PL, McWilliams MJ, Alvord WG, Hughes SH. Mutations at position 184 of human immunodeficiency virus type-1 reverse transcriptase affect virus titer and viral DNA synthesis. Virology 2004; 322:13-21. [PMID: 15063112 DOI: 10.1016/j.virol.2004.01.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2003] [Revised: 12/29/2003] [Accepted: 01/08/2004] [Indexed: 11/24/2022]
Abstract
Methionine at position 184 of human immunodeficiency virus type-1 (HIV-1) reverse transcriptase (RT) was changed to valine, isoleucine, threonine, or alanine in an HIV-1-based vector. The vectors were analyzed for replication capacity and for resistance to the nucleoside analog 2',3'-dideoxy-3'thiacytidine (3TC) using a single-cycle assay. Viruses containing the valine or isoleucine mutations were highly resistant to 3TC and replicated almost as well as the wild-type virus. The virus containing the threonine mutation was resistant to 3TC, but replicated about 30% as well as the wild-type. The alanine mutation conferred partial resistance to 3TC, but replicated poorly. The amounts of viral DNA synthesized decreased in 3TC-treated cells when the cells were infected with wild-type virus and the M184A mutant. The effect of these mutations on the generation of the ends of the linear viral DNA was determined using the sequence of the 2-LTR circle junctions. The M184T mutation increased the proportion of 2-LTR circle junctions containing a tRNA insertion, suggesting that the mutation affected the RNase H activity of RT.
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Affiliation(s)
- John G Julias
- Basic Research Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, MD 21702-1201, USA
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Stone C, Ait-Khaled M, Craig C, Griffin P, Tisdale M. Human immunodeficiency virus type 1 reverse transcriptase mutation selection during in vitro exposure to tenofovir alone or combined with abacavir or lamivudine. Antimicrob Agents Chemother 2004; 48:1413-5. [PMID: 15047556 PMCID: PMC375323 DOI: 10.1128/aac.48.4.1413-1415.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mutations selected or deselected during passage of human immunodeficiency virus strain HXB2 or resistant variants with tenofovir (TFV), abacavir (ABC), and lamivudine (3TC) differed depending on the drug combination and virus genotype. In the wild-type virus, TFV-ABC and TFV-3TC selected K65R (with reduced susceptibility to all three inhibitors) and then Y115F. TFV-containing regimens might increase K65R selection, which confers multiple nucleoside reverse transcriptase inhibitor resistance.
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Affiliation(s)
- Chris Stone
- International Clinical Virology, Medicines Research Centre, GlaxoSmithKline Research and Development, Stevenage, Hertfordshire SG1 2NY, United Kingdom
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White KL, Chen JM, Margot NA, Wrin T, Petropoulos CJ, Naeger LK, Swaminathan S, Miller MD. Molecular mechanisms of tenofovir resistance conferred by human immunodeficiency virus type 1 reverse transcriptase containing a diserine insertion after residue 69 and multiple thymidine analog-associated mutations. Antimicrob Agents Chemother 2004; 48:992-1003. [PMID: 14982794 PMCID: PMC353090 DOI: 10.1128/aac.48.3.992-1003.2004] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two amino acids inserted between residues 69 and 70 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) are rare mutations that may develop in viruses containing multiple thymidine analog (zidovudine [AZT], stavudine)-associated mutations and that confer high-level resistance to all currently approved chain-terminating nucleoside and nucleotide RT inhibitors (NRTIs). The two known mechanisms of resistance to NRTIs are decreased incorporation and increased excision. The mechanism used by RT insertion mutants has not been described for tenofovir (TFV), a recently approved agent in this class. A patient-derived HIV-1 strain (strain FS-SSS) that contained an insertion mutation in a background of additional resistance mutations M41L, L74V, L210W, and T215Y was obtained. A second virus (strain FS) was derived from FS-SSS. In strain FS the insertion and T69S were reverted but the other resistance mutations were retained. The FS virus showed strong resistance to AZT but low-level changes in susceptibilities to other NRTIs and TFV. The FS-SSS virus showed reduced susceptibilities to all NRTIs including TFV. Steady-state kinetics demonstrated that the relative binding or incorporation of TFV was slightly decreased for FS-SSS RT compared to those for wild-type RT. However, significant ATP-mediated excision of TFV was detected for both mutant RT enzymes and followed the order FS-SSS RT > FS RT > wild-type RT. The presence of physiological concentrations of the +1 nucleotide inhibited TFV excision by the wild-type RT and slightly inhibited excision by the FS RT, whereas the level of excision by the FS-SSS RT remained high. Computer modeling suggests that the increased mobility of the beta3-beta4 loop may contribute to the high-level and broad NRTI resistance caused by the T69 insertion mutation.
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De Clercq E. Clinical potential of the acyclic nucleoside phosphonates cidofovir, adefovir, and tenofovir in treatment of DNA virus and retrovirus infections. Clin Microbiol Rev 2004; 16:569-96. [PMID: 14557287 PMCID: PMC207110 DOI: 10.1128/cmr.16.4.569-596.2003] [Citation(s) in RCA: 253] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The acyclic nucleoside phosphonates HPMPC (cidofovir), PMEA (adefovir), and PMPA (tenofovir) have proved to be effective in vitro (cell culture systems) and in vivo (animal models and clinical studies) against a wide variety of DNA virus and retrovirus infections: cidofovir against herpesvirus (herpes simplex virus types 1 and 2 varicella-zoster virus, cytomegalovirus [CMV], Epstein-Barr virus, and human herpesviruses 6, 7, and 8), polyomavirus, papillomavirus, adenovirus, and poxvirus (variola virus, cowpox virus, vaccinia virus, molluscum contagiosum virus, and orf virus) infections; adefovir against herpesvirus, hepadnavirus (human hepatitis B virus), and retrovirus (human immunodeficiency virus types 1 [HIV-1] and 2 [HIV-2], simian immunodeficiency virus, and feline immunodeficiency virus) infections; and tenofovir against both hepadnavirus and retrovirus infections. Cidofovir (Vistide) has been officially approved for the treatment of CMV retinitis in AIDS patients, tenofovir disoproxil fumarate (Viread) has been approved for the treatment of HIV infections (i.e., AIDS), and adefovir dipivoxil (Hepsera) has been approved for the treatment of chronic hepatitis B. Nephrotoxicity is the dose-limiting side effect for cidofovir (Vistide) when used intravenously (5 mg/kg); no toxic side effects have been described for adefovir dipivoxil and tenofovir disoproxil fumarate, at the approved doses (Hepsera at 10 mg orally daily and Viread at 300 mg orally daily).
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium.
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Gandhi RT, Wurcel A, Rosenberg ES, Johnston MN, Hellmann N, Bates M, Hirsch MS, Walker BD. Progressive reversion of human immunodeficiency virus type 1 resistance mutations in vivo after transmission of a multiply drug-resistant virus. Clin Infect Dis 2003; 37:1693-8. [PMID: 14689353 DOI: 10.1086/379773] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2003] [Accepted: 08/11/2003] [Indexed: 11/04/2022] Open
Abstract
Evolution and transmission of multiply drug-resistant human immunodeficiency virus type 1 (HIV-1) may limit therapeutic options as global treatment efforts expand. However, the stability of these mutants in the absence of drug selection pressure is not known. We performed a longitudinal analysis of plasma virus from a person who acquired HIV-1 that contained multiple reverse transcriptase (RT) and protease (PR) mutations. In the absence of therapy, 5 of 12 drug resistance mutations reverted in a stepwise fashion to wild type over the course of 52 weeks. Reversion of the M184V mutation alone did not change viral replicative capacity (RC), but it led to enhanced resistance to zidovudine and tenofovir. However, reversions of a second RT mutation and 3 PR mutations were associated with an increase in viral RC, and this was temporally correlated with a marked decrease in CD4 cell number. This study demonstrates the gradual stepwise back-mutation of certain drug resistance mutations in vivo in the absence of ongoing drug selection pressure. Moreover, it suggests that, despite initially impaired viral fitness, a transmitted HIV-1 isolate with multiple drug resistance mutations can evolve to develop increased RC and significant pathogenicity.
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Affiliation(s)
- Rajesh T Gandhi
- Infectious Diseases Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
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Barrios A, de Mendoza C, Martín-Carbonero L, Ribera E, Domingo P, Galindo MJ, Gálvez J, Estrada V, Dalmau D, Asensi V, Soriano V. Role of baseline human immunodeficiency virus genotype as a predictor of viral response to tenofovir in heavily pretreated patients. J Clin Microbiol 2003; 41:4421-3. [PMID: 12958282 PMCID: PMC193778 DOI: 10.1128/jcm.41.9.4421-4423.2003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus (HIV)-infected patients (n = 153) failing antiretroviral therapy after exposure to compounds from all three drug families were monitored for 6 months after beginning a rescue intervention program including tenofovir (TDF). At 3 months, levels of HIV RNA in plasma dropped by a mean of 0.9 log(10) and the mean CD4 count increased by 52 cells/ micro l. At 6 months, HIV RNA levels had dropped by a mean of 1.06 log(10) and the mean CD4 count had increased by 49 cells/ micro l. Only five (3.7%) patients discontinued TDF use due to adverse events. In the multivariate analysis, the presence of M41L and/or L210W at baseline was the only viral determinant of a lower response to TDF.
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Affiliation(s)
- Ana Barrios
- Service of Infectious Diseases, Instituto de Salud Carlos III, Madrid, Spain
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