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Covalent inhibitors for eradication of drug-resistant HIV-1 reverse transcriptase: From design to protein crystallography. Proc Natl Acad Sci U S A 2017; 114:9725-9730. [PMID: 28827354 DOI: 10.1073/pnas.1711463114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Development of resistance remains a major challenge for drugs to treat HIV-1 infections, including those targeting the essential viral polymerase, HIV-1 reverse transcriptase (RT). Resistance associated with the Tyr181Cys mutation in HIV-1 RT has been a key roadblock in the discovery of nonnucleoside RT inhibitors (NNRTIs). It is the principal point mutation that arises from treatment of HIV-infected patients with nevirapine, the first-in-class drug still widely used, especially in developing countries. We report covalent inhibitors of Tyr181Cys RT (CRTIs) that can completely knock out activity of the resistant mutant and of the particularly challenging Lys103Asn/Tyr181Cys variant. Conclusive evidence for the covalent modification of Cys181 is provided from enzyme inhibition kinetics, mass spectrometry, protein crystallography, and antiviral activity in infected human T-cell assays. The CRTIs are also shown to be selective for Cys181 and have lower cytotoxicity than the approved NNRTI drugs efavirenz and rilpivirine.
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Babazade R, Turan A. Pharmacokinetic and pharmacodynamic evaluation of sublingual sufentanil in the treatment of post-operative pain. Expert Opin Drug Metab Toxicol 2016; 12:217-24. [DOI: 10.1517/17425255.2016.1134487] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Rovnat Babazade
- Department of Outcomes Research, Cleveland Clinic, Cleveland, OH, USA
| | - Alparslan Turan
- Department of Outcomes Research, Cleveland Clinic, Cleveland, OH, USA
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Iyidogan P, Anderson KS. Recent findings on the mechanisms involved in tenofovir resistance. Antivir Chem Chemother 2014; 23:217-22. [PMID: 23744599 DOI: 10.3851/imp2628] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2013] [Indexed: 12/14/2022] Open
Abstract
Since its approval for clinical use in 2001, tenofovir (TFV) has become one of the most frequently prescribed nucleotide analogues used in combination with other antiretroviral agents against HIV-1 infection. Although reverse transcriptase inhibitors (RTIs) including TFV have been shown to be highly potent with reasonable safety profiles in the clinic, drug resistance hinders the effectiveness of current therapies and even causes treatment failure. Therefore, understanding the resistance mechanisms of RT and exploring the potential antiviral synergy between the different RTIs in combination therapies against the resistance mechanisms would greatly improve the long-term efficacy of existing and future regimens. We have studied the pyrophosphorolytic removal of TFV, a major resistance mechanism that RT utilizes, from two different viral sequences and observed interesting outcomes associated with the sequence context. Furthermore, addition of efavirenz, a non-nucleoside RTI, inhibits this removal process confirming the synergistic antiviral effects. This article highlights our recently published work on the viral sequence context contributing to the study of anti-HIV drug resistance in conjunction with the benefits of combining various RTIs that may have been neglected previously.
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Affiliation(s)
- Pinar Iyidogan
- Department of Pharmacology, School of Medicine, Yale University, New Haven, CT, USA
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Iyidogan P, Sullivan TJ, Chordia MD, Frey KM, Anderson KS. Design, Synthesis, and Antiviral Evaluation of Chimeric Inhibitors of HIV Reverse Transcriptase. ACS Med Chem Lett 2013; 4:1183-8. [PMID: 24900627 DOI: 10.1021/ml4002979] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/04/2013] [Indexed: 02/02/2023] Open
Abstract
In a continuing study of potent bifunctional anti-HIV agents, we rationally designed a novel chimeric inhibitor utilizing thymidine (THY) and a TMC derivative (a diarylpyrimidine NNRTI) linked via a polymethylene linker (ALK). The nucleoside, 5'-hydrogen-phosphonate (H-phosphonate), and 5'-triphosphate forms of this chimeric inhibitor (THY-ALK-TMC) were synthesized and the antiviral activity profiles were evaluated at the enzyme and cellular level. The nucleoside triphosphate (11) and the H-phosphonate (10) derivatives inhibited RT polymerization with an IC50 value of 6.0 and 4.3 nM, respectively. Additionally, chimeric nucleoside (9) and H-phosphonate (10) derivatives reduced HIV replication in a cell-based assay with low nanomolar antiviral potencies.
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Affiliation(s)
- Pinar Iyidogan
- Department
of Pharmacology, School of Medicine, Yale University, New Haven, Connecticut 06520, United States
| | - Todd J. Sullivan
- Department
of Pharmacology, School of Medicine, Yale University, New Haven, Connecticut 06520, United States
| | | | - Kathleen M. Frey
- Department
of Pharmacology, School of Medicine, Yale University, New Haven, Connecticut 06520, United States
| | - Karen S. Anderson
- Department
of Pharmacology, School of Medicine, Yale University, New Haven, Connecticut 06520, United States
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Ripamonti D, Bombana E, Rizzi M. Rilpivirine: drug profile of a second-generation non-nucleoside reverse transcriptase HIV-inhibitor. Expert Rev Anti Infect Ther 2013; 12:13-29. [DOI: 10.1586/14787210.2014.863708] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bailey CM, Sullivan TJ, Iyidogan P, Tirado-Rives J, Chung R, Ruiz-Caro J, Mohamed E, Jorgensen WL, Jorgensen W, Hunter R, Anderson KS. Bifunctional inhibition of human immunodeficiency virus type 1 reverse transcriptase: mechanism and proof-of-concept as a novel therapeutic design strategy. J Med Chem 2013; 56:3959-68. [PMID: 23659183 DOI: 10.1021/jm400160s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) is a major target for currently approved anti-HIV drugs. These drugs are divided into two classes: nucleoside and non-nucleoside reverse transcriptase inhibitors (NRTIs and NNRTIs). This study illustrates the synthesis and biochemical evaluation of a novel bifunctional RT inhibitor utilizing d4T (NRTI) and a TMC-derivative (a diarylpyrimidine NNRTI) linked via a poly(ethylene glycol) (PEG) linker. HIV-1 RT successfully incorporates the triphosphate of d4T-4PEG-TMC bifunctional inhibitor in a base-specific manner. Moreover, this inhibitor demonstrates low nanomolar potency that has 4.3-fold and 4300-fold enhancement of polymerization inhibition in vitro relative to the parent TMC-derivative and d4T, respectively. This study serves as a proof-of-concept for the development and optimization of bifunctional RT inhibitors as potent inhibitors of HIV-1 viral replication.
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Affiliation(s)
- Christopher M Bailey
- Department of Pharmacology, School of Medicine, Yale University, New Haven, Connecticut 06520, USA
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Jayaweera D, Dilanchian P. New therapeutic landscape of NNRTIs for treatment of HIV: a look at recent data. Expert Opin Pharmacother 2013; 13:2601-12. [PMID: 23176566 DOI: 10.1517/14656566.2012.742506] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION A key objective with highly active antiretroviral therapy for the treatment of HIV infection has been the optimization of antiretroviral drug combinations for individual patients. AREAS COVERED Overall, non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens (in combination with two nucleoside reverse transcriptase inhibitors (NRTIs)) have become mainstays for initial ARV regimens. Early NNRTIs, efavirenz and nevirapine, are similarly efficacious, but differ according to their toxicity profiles. Newer NNRTIs, rilpivirine and etravirine are also efficacious. Etravirine was designed to overcome common first-line NNRTI resistance mutations, and serves as a second line agent. EXPERT OPINION As a class, NNRTIs are key components of ARV regimens. Currently, there are 3 NNRTIs that may be used in first-line regimens, and one in second-line regimens. ARV regimen optimization depends on matching individual drug efficacy, safety, resistance, and toxicity profiles to particular patients. Once-daily dosing options are essential to treatment simplification strategies, which have been shown to enhance regimen compliance and durabiltiy. These are especially important due to the low genetic barrier to resistance generally associated with NNRTIs. As newer drugs are introduced, especially as part of once-daily, single-tablet regimens, this will expand the number of convenient and efficacious treatment options available.
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Affiliation(s)
- Dushyantha Jayaweera
- University of Miami Miller School of Medicine, Division of Infectious Diseases, Department of Medicine, Room 857 Clinical Research Bldg, 1120 NW 14th Street, Miami, FL 33136, USA.
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Piao D, Basavapathruni A, Iyidogan P, Dai G, Hinz W, Ray AS, Murakami E, Feng JY, You F, Dutschman GE, Austin DJ, Parker KA, Anderson KS. Bifunctional inhibition of HIV-1 reverse transcriptase: a first step in designing a bifunctional triphosphate. Bioorg Med Chem Lett 2012; 23:1511-8. [PMID: 23380374 DOI: 10.1016/j.bmcl.2012.12.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 12/04/2012] [Accepted: 12/10/2012] [Indexed: 11/28/2022]
Abstract
The onset of resistance to approved anti-AIDS drugs by HIV necessitates the search for novel inhibitors of HIV-1 reverse transcriptase (RT). Developing single molecular agents concurrently occupying the nucleoside and nonnucleoside binding sites in RT is an intriguing idea but the proof of concept has so far been elusive. As a first step, we describe molecular modeling to guide focused chemical syntheses of conjugates having nucleoside (d4T) and nonnucleoside (TIBO) moieties tethered by a flexible polyethylene glycol (PEG) linker. A triphosphate of d4T-6PEG-TIBO conjugate was successfully synthesized that is recognized as a substrate by HIV-1 RT and incorporated into a double-stranded DNA.
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Affiliation(s)
- Dongyuan Piao
- Brown University, Department of Chemistry, Providence, RI 02912, United States
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Maga G, Veljkovic N, Crespan E, Spadari S, Prljic J, Perovic V, Glisic S, Veljkovic V. New in silico and conventional in vitro approaches to advance HIV drug discovery and design. Expert Opin Drug Discov 2012; 8:83-92. [PMID: 23167743 DOI: 10.1517/17460441.2013.741118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Recently, the new concept of the long-range intermolecular interactions in biological systems has been proposed. Combined use of molecular modeling techniques and the screening techniques based on the long-range interaction concept could significantly improve and accelerate discovery of new HIV drugs. However, any hit identified in silico needs to be characterized with respect to its biological target by enzymatic studies. Combined use of the in silico screening and the enzymatic studies allows an efficient selection of new anti-HIV drugs. AREAS COVERED The focus of this article is on the in silico screening of molecular libraries for candidate new HIV drugs, which is based on the molecular descriptors determining the long-range interaction between the drugs and their therapeutic target. This article also reviews the techniques for enzyme kinetic studies which are required for optimization of in silico selected candidate anti-HIV drugs. EXPERT OPINION The novel approach of combining in silico screening techniques with enzymatic studies enables the accurate measurement of the quantitative descriptors of ligand-enzyme interactions. This novel method is a powerful tool for new anti-HIV drug discovery which can also reduce the drug development costs.
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Affiliation(s)
- Giovanni Maga
- Institute of Molecular Genetics, IGM-CNR, DNA Enzymology & Molecular Virology, Pavia, Italy
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10
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Abstract
The efficacy of an antiretroviral (ARV) treatment regimen depends on the activity of the regimen's individual ARV drugs and the number of HIV-1 mutations required for the development of resistance to each ARV - the genetic barrier to resistance. ARV resistance impairs the response to therapy in patients with transmitted resistance, unsuccessful initial ARV therapy and multiple virological failures. Genotypic resistance testing is used to identify transmitted drug resistance, provide insight into the reasons for virological failure in treated patients, and help guide second-line and salvage therapies. In patients with transmitted drug resistance, the virological response to a regimen selected on the basis of standard genotypic testing approaches the responses observed in patients with wild-type viruses. However, because such patients are at a higher risk of harbouring minority drug-resistant variants, initial ARV therapy in this population should contain a boosted protease inhibitor (PI) - the drug class with the highest genetic barrier to resistance. In patients receiving an initial ARV regimen with a high genetic barrier to resistance, the most common reasons for virological failure are nonadherence and, potentially, pharmacokinetic factors or minority transmitted drug-resistant variants. Among patients in whom first-line ARVs have failed, the patterns of drug-resistance mutations and cross-resistance are often predictable. However, the extent of drug resistance correlates with the duration of uncontrolled virological replication. Second-line therapy should include the continued use of a dual nucleoside/nucleotide reverse transcriptase inhibitor (NRTI)-containing backbone, together with a change in the non-NRTI component, most often to an ARV belonging to a new drug class. The number of available fully active ARVs is often diminished with each successive treatment failure. Therefore, a salvage regimen is likely to be more complicated in that it may require multiple ARVs with partial residual activity and compromised genetic barriers of resistance to attain complete virological suppression. A thorough examination of the patient's ARV history and prior resistance tests should be performed because genotypic and/or phenotypic susceptibility testing is often not sufficient to identify drug-resistant variants that emerged during past therapies and may still pose a threat to a new regimen. Phenotypic testing is also often helpful in this subset of patients. ARVs used for salvage therapy can be placed into the following hierarchy: (i) ARVs belonging to a previously unused drug class; (ii) ARVs belonging to a previously used drug class that maintain significant residual antiviral activity; (iii) NRTI combinations, as these often appear to retain in vivo virological activity, even in the presence of reduced in vitro NRTI susceptibility; and rarely (iv) ARVs associated with previous virological failure and drug resistance that appear to have possibly regained their activity as a result of viral reversion to wild type. Understanding the basic principles of HIV drug resistance is helpful in guiding individual clinical decisions and the development of ARV treatment guidelines.
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Affiliation(s)
- Michele W Tang
- Stanford University, Division of Infectious Diseases, Stanford, CA 94305-5107, USA.
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11
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Lersivirine, a nonnucleoside reverse transcriptase inhibitor with activity against drug-resistant human immunodeficiency virus type 1. Antimicrob Agents Chemother 2010; 54:4451-63. [PMID: 20660667 DOI: 10.1128/aac.01455-09] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nonnucleoside reverse transcriptase inhibitors (NNRTIs) are key components of highly active antiretroviral therapy (HAART) for the treatment of human immunodeficiency virus type 1 (HIV-1). A major problem with the first approved NNRTIs was the emergence of mutations in the HIV-1 reverse transcriptase (RT), in particular K103N and Y181C, which led to resistance to the entire class. We adopted an iterative strategy to synthesize and test small molecule inhibitors from a chemical series of pyrazoles against wild-type (wt) RT and the most prevalent NNRTI-resistant mutants. The emerging candidate, lersivirine (UK-453,061), binds the RT enzyme in a novel way (resulting in a unique resistance profile), inhibits over 60% of viruses bearing key RT mutations, with 50% effective concentrations (EC(50)s) within 10-fold of those for wt viruses, and has excellent selectivity against a range of human targets. Altogether lersivirine is a highly potent and selective NNRTI, with excellent efficacy against NNRTI-resistant viruses.
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Radzio J, Yap SH, Tachedjian G, Sluis-Cremer N. N348I in reverse transcriptase provides a genetic pathway for HIV-1 to select thymidine analogue mutations and mutations antagonistic to thymidine analogue mutations. AIDS 2010; 24:659-67. [PMID: 20160634 DOI: 10.1097/qad.0b013e328336781d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Several nonnucleoside (e.g. Y181C) and nucleoside (e.g. L74V and M184V) resistance mutations in HIV-1 reverse transcriptase are antagonistic toward thymidine analogue mutations (TAMs) that confer zidovudine (ZDV) resistance. The N348I mutation in the connection domain of reverse transcriptase also confers ZDV resistance; however, the mechanisms involved are different from TAMs. In this study, we examined whether N348I compensates for the antagonism of the TAM K70R by Y181C, L74V and M184V. DESIGN AND METHODS The ZDV monophosphate and ribonuclease H activities of recombinant-purified HIV-1 reverse transcriptase-containing combinations of K70R, N348I and Y181C, L74V or M184V were assessed using standard biochemical and antiviral assays. RESULTS As expected, the introduction of the Y181C, L74V or M184V mutations into K70R HIV-1 reverse transcriptase significantly diminished the ATP-mediated ZDV monophosphate excision activity of the enzyme. However, the N348I mutation compensated for this antagonism on RNA/DNA template/primers by significantly decreasing the frequency of secondary ribonuclease H cleavages that reduce the overall efficiency of the excision reaction. CONCLUSION The acquisition of N348I in HIV-1 reverse transcriptase - which can occur early in therapy, oftentimes before TAMs - may provide a simple genetic pathway that allows the virus to select both TAMs and mutations that are antagonistic toward TAMs.
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TMC278, a next-generation nonnucleoside reverse transcriptase inhibitor (NNRTI), active against wild-type and NNRTI-resistant HIV-1. Antimicrob Agents Chemother 2009; 54:718-27. [PMID: 19933797 DOI: 10.1128/aac.00986-09] [Citation(s) in RCA: 239] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nonnucleoside reverse transcriptase inhibitors (NNRTIs) have proven efficacy against human immunodeficiency virus type 1 (HIV-1). However, in the setting of incomplete viral suppression, efavirenz and nevirapine select for resistant viruses. The diarylpyrimidine etravirine has demonstrated durable efficacy for patients infected with NNRTI-resistant HIV-1. A screening strategy used to test NNRTI candidates from the same series as etravirine identified TMC278 (rilpivirine). TMC278 is an NNRTI showing subnanomolar 50% effective concentrations (EC50 values) against wild-type HIV-1 group M isolates (0.07 to 1.01 nM) and nanomolar EC50 values against group O isolates (2.88 to 8.45 nM). Sensitivity to TMC278 was not affected by the presence of most single NNRTI resistance-associated mutations (RAMs), including those at positions 100, 103, 106, 138, 179, 188, 190, 221, 230, and 236. The HIV-1 site-directed mutant with Y181C was sensitive to TMC278, whereas that with K101P or Y181I/V was resistant. In vitro, considerable cross-resistance between TMC278 and etravirine was observed. Sensitivity to TMC278 was observed for 62% of efavirenz- and/or nevirapine-resistant HIV-1 recombinant clinical isolates. TMC278 inhibited viral replication at concentrations at which first-generation NNRTIs could not suppress replication. The rates of selection of TMC278-resistant strains were comparable among HIV-1 group M subtypes. NNRTI RAMs emerging in HIV-1 under selective pressure from TMC278 included combinations of V90I, L100I, K101E, V106A/I, V108I, E138G/K/Q/R, V179F/I, Y181C/I, V189I, G190E, H221Y, F227C, and M230I/L. E138R was identified as a new NNRTI RAM. These in vitro analyses demonstrate that TMC278 is a potent next-generation NNRTI, with a high genetic barrier to resistance development.
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Abstract
Etravirine is a next-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) that demonstrates potent in vitro activity against wild-type strains of HIV type 1 (HIV-1), as well as against numerous strains resistant to available NNRTIs. Furthermore, the potential for resistance to etravirine developing appears to be lower than for first-generation NNRTIs. In treatment-experienced patients infected with HIV-1 with NNRTI resistance, HIV-1 RNA levels of <50 copies/mL (primary endpoint) and <400 copies/mL were achieved by a significantly greater proportion of patients receiving etravirine 200 mg twice daily plus background therapy (BT) than placebo plus BT, according to the planned pooled and individual 24-week analyses of two large, well designed, continuing phase III trials (DUET-1 and DUET-2). In the pooled 24-week analysis, patients receiving etravirine plus BT achieved a significantly greater mean reduction in viral load from baseline and a significantly greater mean increase in CD4+ cell counts from baseline than patients receiving placebo plus BT. The pooled and individual findings of the DUET studies at 48 weeks indicate that the efficacy of etravirine is maintained with regard to these endpoints. In the DUET studies, etravirine was generally well tolerated in treatment-experienced patients infected with HIV-1, with a tolerability profile generally similar to that of placebo. Adverse events were mostly of mild or moderate severity.
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Affiliation(s)
- Emma D Deeks
- Wolters Kluwer Health, Adis, Auckland, New Zealand.
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Minuto JJ, Haubrich R. Etravirine: a second-generation NNRTI for treatment-experienced adults with resistant HIV-1 infection. ACTA ACUST UNITED AC 2008; 2:525-537. [DOI: 10.2217/17469600.2.6.525] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Etravirine, a second-generation non-nucleoside reverse transcriptase inhibitor (NNRTI), was approved in the USA in January, 2008, with approval in Europe expected later this year. It is dosed at 200 mg (two 100 mg tablets) twice daily foll owing a meal. It is approved for treatment of HIV-1 infection in adults failing a stable antiretroviral regimen with resistance to other NNRTIs and other antiretroviral agents. Etravirine is active against HIV with single mutations in the reverse transcriptase (e.g., K103N) that confer class resistance to first-generation NNRTIs. Clinical efficacy in Phase III trials has been demonstrated for up to 48 weeks of follow-up. In these Phase III trials, rash was the only adverse event that was significantly more prevalent with etravirine than with placebo. Etravirine has a tolerability and safety profile comparable to placebo with the exception of rash. Rash was generally grade 1 or 2, was not associated with prior NNRTI-related rash, was more common in women than in men, appeared a median of 12 days after treatment initiation and resolved spontaneously with continued therapy. Etravirine is the first agent in the NNRTI class that can be used for HIV-1 virus with resistance to other NNRTIs owing to a higher genetic barrier to resistance.
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Affiliation(s)
- Joshua J Minuto
- University of California, San Diego, Division of Infectious Diseases, Antiviral Research Center, 150 Washington Street, Suite 100, San Diego, CA 92103, USA
| | - Richard Haubrich
- Professor of Medicine University of California, San Diego, Division of Infectious Diseases, Antiviral Research Center, 150 Washington Street, Suite 100, San Diego, CA 92103, USA
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Abstract
Numerous pathological states, including cancer, autoimmune diseases, and viral/bacterial infections, are often attributed to uncontrollable DNA replication. Inhibiting this essential biological process provides an obvious therapeutic target against these diseases. A logical target is the DNA polymerase, the enzyme responsible for catalyzing the addition of mononucleotides to a growing polymer using a DNA or RNA template as a guide for directing each incorporation event. This review provides a summary of therapeutic agents that target polymerase activity. A discussion of the biological function and mechanism of polymerases is first provided to illustrate the strategy for therapeutic intervention as well as the rational design of various nucleoside analogues that inhibit various polymerases associated with viral infections and cancer. The development of nucleoside and non-nucleoside inhibitors as antiviral agents is discussed with particular emphasis on their mechanism of action, structure-activity relationships, toxicity, and mechanism of resistance. In addition, commonly used anticancer agents are described to illustrate the similarities and differences associated with various nucleoside analogues as therapeutic agents. Finally, new therapeutic approaches that include the inhibition of selective polymerases involved in DNA repair and/or translesion DNA synthesis as anticancer agents are discussed.
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Affiliation(s)
- Anthony J Berdis
- Department of Pharmacology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA.
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Murakami E, Bao H, Basavapathruni A, Bailey CM, Du J, Steuer HMM, Niu C, Whitaker T, Anderson KS, Otto MJ, Furman PA. Mechanism of action of (-)-(2R,4R)-1-(2-hydroxymethyl-1,3-dioxolan-4-yl) thymine as an anti-HIV agent. Antivir Chem Chemother 2007; 18:83-92. [PMID: 17542153 DOI: 10.1177/095632020701800204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
(-)-(2R,4R)-1-(2-Hydroxymethyl-1,3-dioxolan-4yl)thymine (DOT) is a thymidine analogue that has potent in vitro activity against wild-type and nucleoside reverse transcriptase inhibitor (NRTI)-resistant HIV. For nucleoside analogues to inhibit viral replication, they must be metabolized to the active triphosphate, which inhibits the viral reverse transcriptase (RT). Using purified enzymes, the kinetics of DOT phosphorylation, inhibition of wild-type and drug-resistant HIV-1 reverse transcriptase activity, and excision of DOT-5'-monophosphate (DOT-MP) from a chain-terminated primer were examined. DOT was phosphorylated by human thymidine kinase-1 (TK-1) but not by other pyrimidine nucleoside kinases, including the mitochondrial thymidine kinase (TK-2). Resistance to NRTIs involves decreased binding/incorporation and/or increased excision of the chain-terminating NRTI. RTs containing the D67N/K70R/T215Y/K219Q or T695-SS/T215Y mutations show enhanced removal of DOT-MP from terminated primer as well as approximately four-fold decreased binding/incorporation. The Q151M and K65R mutations appear to cause decreased inhibition by DOT-TP. However, both the K65R and Q151M mutations show decreased excision, which would confer greater stability on the terminated primer. These opposing mechanisms could offset the overall resistance profile and susceptibility. Little or no resistance was observed with the enzymes harbouring mutations resistant to lamivudine (M184V) and non-nucleoside RT inhibitors (K103N).
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Interactions between non-nucleoside reverse transcriptase inhibitor and nucleoside reverse transcriptase inhibitor mutations: phenotypes and mechanisms. Curr Opin HIV AIDS 2007; 2:88-93. [PMID: 19372872 DOI: 10.1097/coh.0b013e328055505c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Antiretroviral regimens that combine nucleoside reverse transcriptase inhibitors and non-nucleoside reverse transcriptase inhibitors have consistently been the most effective regimens for the initial treatment of HIV-1 infection. Such combinations have been manufactured in several fixed-dose combinations and are the most commonly used treatments worldwide. The success of these regimens may partly be a result of the synergistic manner in which the two classes of compounds inhibit the HIV-1 reverse transcriptase enzyme. RECENT FINDINGS Multiple synergistic effects have been described in the mechanisms and pathways of drug resistance. This review outlines what is currently known about the interactions between nucleoside reverse transcriptase inhibitor and non-nucleoside reverse transcriptase inhibitor resistance. SUMMARY These synergistic interactions are likely to be the driving force behind the potency and durability of the nucleoside reverse transcriptase inhibitor/non-nucleoside reverse transcriptase inhibitor combinations used in clinical practice.
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