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Johnson VA, Cramer YS, Rosenkranz SL, Becker S, Klingman KL, Kallungal B, Coakley E, Acosta EP, Calandra G, Saag MS, Bedimo R, Owens S, Ferguson E, Kessels L, Shugarts D, Parrillo V, Upton K, White V, Goldman M, Zwickl W, del Rio C, Turkia A, Zadzilk A, Darren Hazelwood J, Lu D. Antiretroviral Activity of AMD11070 (An Orally Administered CXCR4 Entry Inhibitor): Results of NIH/NIAID AIDS Clinical Trials Group Protocol A5210. AIDS Res Hum Retroviruses 2019; 35:691-697. [PMID: 31099252 DOI: 10.1089/aid.2018.0256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AMD11070 binds to the chemokine receptor CXCR4, with anti-HIV-1 activity in vitro and in vivo. We conducted a phase IB/IIA proof-of-concept dose-escalating, open-label study to determine safety and antiviral activity of AMD11070 administered over 10 days to HIV-1-infected participants who harbored CXCR4-tropic virus. Primary endpoints were ≥1 log10 rlu (relative luminescence units) reduction in CXCR4-tropic virus during 10 days of AMD11070 treatment or in the 7 days following treatment discontinuation, rlu changes over 10 days of treatment, and safety. Plasma pharmacokinetic parameters, HIV-1 RNA, and safety labs were obtained over 90 days of study. The study was stopped early due to emerging AMD11070 animal toxicity data. Six HIV-infected participants with plasma HIV-1 RNA ≥5,000 copies/mL on no antiretroviral therapy for 14 days before entry were treated. AMD11070 was well-tolerated when administered at 200 mg orally every 12 h for 10 days. All enrolled participants had dual/mixed (D/M) viruses. Reductions of almost 1 log10 rlu or more in CXCR4 virus were seen in three of six participants after 10 days of treatment. No participants had ≥1 log10 decline in plasma HIV-1 RNA from baseline at day 10. No clear relationship between pharmacokinetic parameters and response to therapy (X4 log rlu reduction) was observed. AMD11070 demonstrated in vivo activity as measured by reductions in CXCR4 rlu signal. Despite the finding of discordant rlu and plasma HIV RNA responses in these participants with D/M viruses, exploration of other HIV-1 CXCR4 antagonist therapies is possible.
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Affiliation(s)
- Victoria A. Johnson
- Birmingham Veterans Affairs Medical Center, Birmingham, Alabama
- Department of Pharmacology and Toxicology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Yoninah S. Cramer
- Statistical and Data Management Center, Harvard TH Chan School of Public Health, Boston, Massachusetts
| | - Susan L. Rosenkranz
- Statistical and Data Management Center, Harvard TH Chan School of Public Health, Boston, Massachusetts
| | | | | | | | - Eoin Coakley
- Monogram Biosciences, Inc., South San Francisco, California
| | - Edward P. Acosta
- Department of Pharmacology and Toxicology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | | | - Michael S. Saag
- Department of Pharmacology and Toxicology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
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2
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Rashad AA, Song LR, Holmes AP, Acharya K, Zhang S, Wang ZL, Gary E, Xie X, Pirrone V, Kutzler MA, Long YQ, Chaiken I. Bifunctional Chimera That Coordinately Targets Human Immunodeficiency Virus 1 Envelope gp120 and the Host-Cell CCR5 Coreceptor at the Virus-Cell Interface. J Med Chem 2018; 61:5020-5033. [PMID: 29767965 DOI: 10.1021/acs.jmedchem.8b00477] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To address the urgent need for new agents to reduce the global occurrence and spread of AIDS, we investigated the underlying hypothesis that antagonists of the HIV-1 envelope (Env) gp120 protein and the host-cell coreceptor (CoR) protein can be covalently joined into bifunctional synergistic combinations with improved antiviral capabilities. A synthetic protocol was established to covalently combine a CCR5 small-molecule antagonist and a gp120 peptide triazole antagonist to form the bifunctional chimera. Importantly, the chimeric inhibitor preserved the specific targeting properties of the two separate chimera components and, at the same time, exhibited low to subnanomolar potencies in inhibiting cell infection by different pseudoviruses, which were substantially greater than those of a noncovalent mixture of the individual components. The results demonstrate that targeting the virus-cell interface with a single molecule can result in improved potencies and also the introduction of new phenotypes to the chimeric inhibitor, such as the irreversible inactivation of HIV-1.
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Affiliation(s)
| | - Li-Rui Song
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica , Chinese Academy of Science , Shanghai 201203 , China.,College of Pharmaceutical Sciences , Soochow University Medical College , Suzhou 215123 , China.,University of Chinese Academy of Sciences , Number 19A Yuquan Road , Beijing 100049 , China
| | | | | | - Shiyu Zhang
- School of Biomedical Engineering, Science and Health Systems , Drexel University , Philadelphia , Pennsylvania 19104 , United States
| | - Zhi-Long Wang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica , Chinese Academy of Science , Shanghai 201203 , China
| | | | - Xin Xie
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica , Chinese Academy of Science , Shanghai 201203 , China
| | | | | | - Ya-Qiu Long
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica , Chinese Academy of Science , Shanghai 201203 , China.,College of Pharmaceutical Sciences , Soochow University Medical College , Suzhou 215123 , China
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Ahn KW, Root MJ. Complex interplay of kinetic factors governs the synergistic properties of HIV-1 entry inhibitors. J Biol Chem 2017; 292:16498-16510. [PMID: 28696261 DOI: 10.1074/jbc.m117.791731] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 07/09/2017] [Indexed: 01/04/2023] Open
Abstract
The homotrimeric HIV-1 envelope glycoprotein (Env) undergoes receptor-triggered structural changes that mediate viral entry through membrane fusion. This process is inhibited by chemokine receptor antagonists (CoRAs) that block Env-receptor interactions and by fusion inhibitors (FIs) that disrupt Env conformational transitions. Synergy between CoRAs and FIs has been attributed to a CoRA-dependent decrease in the rate of viral membrane fusion that extends the lifetime of the intermediate state targeted by FIs. Here, we demonstrated that the magnitude of CoRA/FI synergy unexpectedly depends on FI-binding affinity and the stoichiometry of chemokine receptor binding to trimeric Env. For C-peptide FIs (clinically represented by enfuvirtide), synergy waned as binding strength decreased until inhibitor combinations behaved additively. Curiously, this affinity dependence on synergy was absent for 5-Helix-type FIs. We linked this complex behavior to the CoRA dependence of Env deactivation following FI binding. For both FI classes, reducing chemokine receptor levels on target cells or eliminating competent chemokine receptor-binding sites on Env trimers resulted in a loss of synergistic activity. These data imply that the stoichiometry required for CoRA/FI synergy exceeds that required for HIV-1 entry. Our analysis suggests two distinct roles for chemokine receptor binding, one to trigger formation of the FI-sensitive intermediate state and another to facilitate subsequent conformational transitions. Together, our results could explain the wide variety of previously reported activities for CoRA/FI combinations. These findings also have implications for the combined use of CoRAs and FIs in antiviral therapies and point to a multifaceted role for chemokine receptor binding in promoting HIV-1 entry.
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Affiliation(s)
- Koree W Ahn
- From the Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Michael J Root
- From the Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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Mucosal Topical Microbicide Candidates Exert Influence on the Subsequent SIV Infection and Survival by Regulating SIV-Specific T-Cell Immune Responses. J Acquir Immune Defic Syndr 2016; 71:121-9. [PMID: 26413849 DOI: 10.1097/qai.0000000000000851] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To determine whether mucosal topical microbicides have any influence on disease progression during subsequent simian immunodeficiency virus (SIV) infection. DESIGN A 2-phase study was performed in primate monkeys. The first phase mimicked microbicide efficacy studies; the second phase served to determine the disease progression in a productive infection model. METHODS During the first phase, monkeys were intrarectally pretreated with tenofovir, sifuvirtide (SFT), or maraviroc-formulated microbicides and then challenged with low-dose SHIV-1157ipd3N4. Second, all monkeys were rechallenged with a single high dose of SIVmac239 to generate productive infections. The survival rate, viral loads, CD4(+) T-cell counts, and SIV-specific T-cell responses were determined during the 104-week following up. RESULTS Repeated rectal challenges did not result in productive infection in all groups, evidenced by undetectable viral loads with occasional viral blips during the first phase of this study. All monkeys were productively infected after the high-dose rechallenge with SIVmac239. Two groups, including maraviroc-treated and tenofovir-treated groups, experienced 100% mortality during the 104-week following up. In contrast, the SFT-treated group showed significantly higher survival, and only 25% died at week 95. Interestingly, SIV-specific T-cell responses were also significantly higher in the SFT group. Transcriptomic analyses evidenced immune imprint in immune system among different microbicide-treated groups. CONCLUSIONS This study provides preliminary but important evidence for the influence of prophylactically applied microbicides on disease progression of subsequent SIV infection and suggests that the long-term immune safety concern for microbicides should be also considered in the effort to develop effective microbicides.
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Sepúlveda-Crespo D, Sánchez-Rodríguez J, Serramía MJ, Gómez R, De La Mata FJ, Jiménez JL, Muñoz-Fernández MÁ. Triple combination of carbosilane dendrimers, tenofovir and maraviroc as potential microbicide to prevent HIV-1 sexual transmission. Nanomedicine (Lond) 2015; 10:899-914. [PMID: 25867856 DOI: 10.2217/nnm.14.79] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
AIM To research the synergistic activity by triple combinations of carbosilane dendrimers with tenofovir and maraviroc as topical microbicide. METHODS Cytotoxicity, anti-HIV-1 activity, vaginal irritation and histological analysis of triple combinations were determined. Analysis of combined effects and the median effective concentration were performed using CalcuSyn software. RESULTS Combinations showed a greater broad-spectrum anti-HIV-1 activity than the single-drug, and preserved this activity in acid environment or seminal fluid. The strongest combinations were G2-STE16/G2-S24P/tenofovir, G2-STE16/G2-S16/maraviroc and G2-STE16/tenofovir/maraviroc at 2:2:1, 10:10:1 10:5:1 ratios, respectively. They demonstrated strong synergistic activity profile due to the weighted average combination indices varied between 0.06 and 0.38. No irritation was detected in female BALB/c mice. CONCLUSION The three-drug combination increases their antiviral potency and act synergistically as potential microbicide.
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Affiliation(s)
- Daniel Sepúlveda-Crespo
- Laboratorio InmunoBiología Molecular, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Spanish HIV-HGM Biobank, Networking Research Center on Bioengineering, Biomaterials & Nanomedicine (CIBER-BBN), Madrid, Spain
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Engineering Cellular Resistance to HIV-1 Infection In Vivo Using a Dual Therapeutic Lentiviral Vector. MOLECULAR THERAPY-NUCLEIC ACIDS 2015; 4:e236. [DOI: 10.1038/mtna.2015.10] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 02/25/2015] [Indexed: 11/08/2022]
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7
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Synergistic combinations of the CCR5 inhibitor VCH-286 with other classes of HIV-1 inhibitors. Antimicrob Agents Chemother 2014; 58:7565-9. [PMID: 25267674 DOI: 10.1128/aac.03630-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Here, we evaluated the in vitro anti-HIV-1 activity of the experimental CCR5 inhibitor VCH-286 as a single agent or in combination with various classes of HIV-1 inhibitors. Although VCH-286 used alone had highly inhibitory activity, paired combinations with different drug classes led to synergistic or additive interactions. However, combinations with other CCR5 inhibitors led to effects ranging from synergy to antagonism. We suggest that caution should be exercised when combining CCR5 inhibitors in vivo.
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8
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Targeting CCR5 for anti-HIV research. Eur J Clin Microbiol Infect Dis 2014; 33:1881-7. [PMID: 25027072 DOI: 10.1007/s10096-014-2173-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 05/26/2014] [Indexed: 10/25/2022]
Abstract
Highly active antiretroviral therapy (HAART) is the only approach for human immunodeficiency virus (HIV) infection treatment at present. Although HAART is effective in controlling the progression of infection, it is impossible to eradicate the virus from patients. The patients have to live with the virus. Alternative ways for the cure of HIV infection have been investigated. As the major co-receptor for HIV-1 infection, C-C motif chemokine receptor 5 (CCR5) is naturally an ideal target for anti-HIV research. The first CCR5 antagonist, maraviroc, has been approved for the treatment of HIV infection. Several other CCR5 antagonists are in clinical trials. CCR5 delta32 is a natural genotype, conferring resistance to CCR5 using HIV-1 strains. Gene therapy research targeting this mutant has been conducted for HIV infection treatment. A Berlin patient has been cured of HIV infection by the transplantation of stem cells from a CCR5 delta32 genotype donor. The infusion of an engineered zinc finger nuclease (ZFN)-modified autologous cluster of differentiation 4 (CD4) T cells has been proved to be a promising direction recently. In this study, the anti-HIV research targeting CCR5 is summarized, including CCR5 antagonist development, stem cell transplantation, and gene therapy.
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9
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Approaches for identification of HIV-1 entry inhibitors targeting gp41 pocket. Viruses 2013; 5:127-49. [PMID: 23344560 PMCID: PMC3564113 DOI: 10.3390/v5010127] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/03/2013] [Accepted: 01/03/2013] [Indexed: 01/08/2023] Open
Abstract
The hydrophobic pocket in the HIV-1 gp41 N-terminal heptad repeat (NHR) domain plays an important role in viral fusion and entry into the host cell, and serves as an attractive target for development of HIV-1 fusion/entry inhibitors. The peptide anti-HIV drug targeting gp41 NHR, T-20 (generic name: enfuvirtide; brand name: Fuzeon), was approved by the U.S. FDA in 2003 as the first HIV fusion/entry inhibitor for treatment of HIV/AIDS patients who fail to respond to the current antiretroviral drugs. However, because T20 lacks the pocket-binding domain (PBD), it exhibits low anti-HIV-1 activity and short half-life. Therefore, several next-generation HIV fusion inhibitory peptides with PBD have been developed. They possess longer half-life and more potent antiviral activity against a broad spectrum of HIV-1 strains, including the T-20-resistant variants. Nonetheless, the clinical application of these peptides is still limited by the lack of oral availability and the high cost of production. Thus, development of small molecule compounds targeting the gp41 pocket with oral availability has been promoted. This review describes the main approaches for identification of HIV fusion/entry inhibitors targeting the gp41 pocket and summarizes the latest progress in developing these inhibitors as a new class of anti-HIV drugs.
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10
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Is there a future for antiviral fusion inhibitors? Curr Opin Virol 2012; 2:50-9. [DOI: 10.1016/j.coviro.2012.01.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 01/05/2012] [Accepted: 01/05/2012] [Indexed: 12/20/2022]
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Ketas TJ, Holuigue S, Matthews K, Moore JP, Klasse PJ. Env-glycoprotein heterogeneity as a source of apparent synergy and enhanced cooperativity in inhibition of HIV-1 infection by neutralizing antibodies and entry inhibitors. Virology 2011; 422:22-36. [PMID: 22018634 DOI: 10.1016/j.virol.2011.09.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2011] [Revised: 08/19/2011] [Accepted: 09/17/2011] [Indexed: 10/16/2022]
Abstract
We measured the inhibition of infectivity of HIV-1 isolates and derivative clones by combinations of neutralizing antibodies (NAbs) and other entry inhibitors in a single-cycle-replication assay. Synergy was analyzed both by the current linear and a new non-linear method. The new method reduced spurious indications of synergy and antagonism. Synergy between NAbs was overall weaker than between other entry inhibitors, and no stronger where one ligand is known to enhance the binding of another. However, synergy was stronger for a genetically heterogeneous HIV-1 R5 isolate than for its derivative clones. Enhanced cooperativity in inhibition by combinations, compared with individual inhibitors, correlated with increased synergy at higher levels of inhibition, while being less variable. Again, cooperativity enhancement was stronger for isolates than clones. We hypothesize that genetic, post-translational or conformational heterogeneity of the Env protein and of other targets for inhibitors can yield apparent synergy and increased cooperativity between inhibitors.
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Affiliation(s)
- Thomas J Ketas
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10065-4896, USA
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12
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Vigant F, Lee B. Hendra and nipah infection: pathology, models and potential therapies. Infect Disord Drug Targets 2011; 11:315-336. [PMID: 21488828 PMCID: PMC3253017 DOI: 10.2174/187152611795768097] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Accepted: 03/24/2010] [Indexed: 05/30/2023]
Abstract
The Paramyxoviridae family comprises of several genera that contain emerging or re-emerging threats for human and animal health with no real specific effective treatment available. Hendra and Nipah virus are members of a newly identified genus of emerging paramyxoviruses, Henipavirus. Since their discovery in the 1990s, henipaviruses outbreaks have been associated with high economic and public health threat potential. When compared to other paramyxoviruses, henipaviruses appear to have unique characteristics. Henipaviruses are zoonotic paramyxoviruses with a broader tropism than most other paramyxoviruses, and can cause severe acute encephalitis with unique features among viral encephalitides. There are currently no approved effective prophylactic or therapeutic treatments for henipavirus infections. Although ribavirin was empirically used and seemed beneficial during the biggest outbreak caused by one of these viruses, the Nipah virus, its efficacy is disputed in light of its lack of efficacy in several animal models of henipavirus infection. Nevertheless, because of its highly pathogenic nature, much effort has been spent in developing anti-henipavirus therapeutics. In this review we describe the unique features of henipavirus infections and the different strategies and animal models that have been developed so far in order to identify and test potential drugs to prevent or treat henipavirus infections. Some of these components have the potential to be broad-spectrum antivirals as they target effectors of viral pathogenecity common to other viruses. We will focus on small molecules or biologics, rather than vaccine strategies, that have been developed as anti-henipaviral therapeutics.
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Affiliation(s)
- Frederic Vigant
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA 90095
| | - Benhur Lee
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA 90095
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, CA, USA 90095
- UCLA AIDS Institute, UCLA, Los Angeles, CA, USA 90095
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13
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Combinatorial approaches to the prevention and treatment of HIV-1 infection. Antimicrob Agents Chemother 2011; 55:1831-42. [PMID: 21343462 DOI: 10.1128/aac.00976-10] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The discovery of the human immunodeficiency virus type 1 (HIV-1) in 1982 soon led to the identification and development of antiviral compounds to be used in treatment strategies for infected patients. Early in the epidemic, drug monotherapies frequently led to treatment failures because the virus quickly developed resistance to the single drug. Following the advent of highly active antiretroviral therapy (HAART) in 1995, dramatic improvements in HIV-1-infected patient health and survival were realized as more refined combination therapies resulted in reductions in viral loads and increases in CD4+ T-cell counts. In the absence of an effective vaccine, prevention of HIV-1 infection has also gained traction as an approach to curbing the pandemic. The development of compounds as safe and effective microbicides has intensified and has focused on blocking the transmission of HIV-1 during all forms of sexual intercourse. Initial preclinical investigations and clinical trials of microbicides focused on single compounds effective against HIV-1. However, the remarkable successes achieved using combination therapy to treat systemic HIV-1 infection have subsequently stimulated the study and development of combination microbicides that will simultaneously inhibit multiple aspects of the HIV-1 transmission process by targeting incoming viral particles, virus-infected cells, and cells susceptible to HIV-1 infection. This review focuses on existing and developing combination therapies, covering preclinical development, in vitro and in vivo efficacy studies, and subsequent clinical trials. The shift in focus within the microbicide development field from single compounds to combination approaches is also explored.
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Abstract
Enveloped viruses penetrate their cell targets following the merging of their membrane with that of the cell. This fusion process is catalyzed by one or several viral glycoproteins incorporated on the membrane of the virus. These envelope glycoproteins (EnvGP) evolved in order to combine two features. First, they acquired a domain to bind to a specific cellular protein, named "receptor." Second, they developed, with the help of cellular proteins, a function of finely controlled fusion to optimize the replication and preserve the integrity of the cell, specific to the genus of the virus. Following the activation of the EnvGP either by binding to their receptors and/or sometimes the acid pH of the endosomes, many changes of conformation permit ultimately the action of a specific hydrophobic domain, the fusion peptide, which destabilizes the cell membrane and leads to the opening of the lipidic membrane. The comprehension of these mechanisms is essential to develop medicines of the therapeutic class of entry inhibitor like enfuvirtide (Fuzeon) against human immunodeficiency virus (HIV). In this chapter, we will summarize the different envelope glycoprotein structures that viruses develop to achieve membrane fusion and the entry of the virus. We will describe the different entry pathways and cellular proteins that viruses have subverted to allow infection of the cell and the receptors that are used. Finally, we will illustrate more precisely the recent discoveries that have been made within the field of the entry process, with a focus on the use of pseudoparticles. These pseudoparticles are suitable for high-throughput screenings that help in the development of natural or artificial inhibitors as new therapeutics of the class of entry inhibitors.
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Affiliation(s)
- François-Loic Cosset
- Université de Lyon, UCB-Lyon1, IFR128, Lyon, France,INSERM, U758, Lyon, France,Ecole Normale Supérieure de Lyon, Lyon, France
| | - Dimitri Lavillette
- Université de Lyon, UCB-Lyon1, IFR128, Lyon, France,INSERM, U758, Lyon, France,Ecole Normale Supérieure de Lyon, Lyon, France
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Psomas KC, Corbeau P, Reynes J. [CCR5 antagonists and HIV-1 infection: Bases and consequences of this therapeutic approach]. ACTA ACUST UNITED AC 2010; 12:27-41. [PMID: 32288525 PMCID: PMC7146793 DOI: 10.1016/j.antib.2010.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
La molécule CCR5 est un récepteur de chimiokines qui joue un rôle important en pathologie infectieuse : corécepteur des souches du VIH-1 à tropisme R5, il est également impliqué dans la défense immunitaire contre certains agents transmissibles. Les antagonistes de CCR5 constituent une nouvelle approche thérapeutique antirétrovirale. Trois inhibiteurs du CCR5 ont atteint les phases IIb et III de développement clinique : aplaviroc (GlaxoSmithKine), vicriviroc (Schering-Plough) et maraviroc (Pfizer). Le développement de l’aplaviroc a été interrompu pour toxicité hépatique. Les essais ACTG 5211 et Motivate ont démontré une amélioration de la réponse antirétrovirale par l’addition respectivement de vicriviroc (actuellement en phase III) et de maraviroc (ayant déjà obtenu l’Autorisation de Mise sur le Marché) à un traitement optimisé chez des patients en échec thérapeutique. Le rôle de cette nouvelle cible thérapeutique dans les stratégies de traitement initial, de substitution ou de sauvetage reste à préciser, de même que leur intérêt chez des patients ayant une réponse immunovirologique dissociée, en immunodépresssion sévère ou infectés par des souches à tropisme non-R5. Plusieurs points sont également à éclaircir comme la tolérance à long terme, le risque d’induire une commutation R5-X4, en particulier dans les tissus, le risque d’interférer avec les réponses immunitaires, ainsi que l’impact d’une discordance de tropisme entre le plasma et les autres compartiments de l’organisme.
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Affiliation(s)
- K C Psomas
- Institut de génétique humaine, CNRS, 142, rue de la Cardonille, 34396 Montpellier cedex 5, France.,Service des maladies infectieuses et tropicales, CHU Gui-de-Chauliac, 80, avenue Augustin-Fliche, 34295 Montpellier cedex 5, France
| | - P Corbeau
- Institut de génétique humaine, CNRS, 142, rue de la Cardonille, 34396 Montpellier cedex 5, France.,Fonctionnelle d'immunologie, hôpital Carémeau, place du Pr-Robert-Debré, 30029 Nîmes cedex, France.,Faculté de médecine, université Montpellier 1, 2, rue École-de-Médecine, 34060 Montpellier cedex 2, France
| | - J Reynes
- Faculté de médecine, université Montpellier 1, 2, rue École-de-Médecine, 34060 Montpellier cedex 2, France.,Service des maladies infectieuses et tropicales, CHU Gui-de-Chauliac, 80, avenue Augustin-Fliche, 34295 Montpellier cedex 5, France.,UMR 145, 911, avenue Agropolis, 34394 Montpellier cedex 5, France
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Pan C, Liu S, Jiang S. HIV-1 gp41 Fusion Intermediate: A Target for HIV Therapeutics. J Formos Med Assoc 2010; 109:94-105. [DOI: 10.1016/s0929-6646(10)60029-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 09/25/2009] [Accepted: 09/25/2009] [Indexed: 11/28/2022] Open
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Kümmerle T, Lehmann C, Hartmann P, Wyen C, Fätkenheuer G. Vicriviroc: a CCR5 antagonist for treatment-experienced patients with HIV-1 infection. Expert Opin Investig Drugs 2009; 18:1773-85. [DOI: 10.1517/13543780903357478] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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19
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Combinations of the first and next generations of human immunodeficiency virus (HIV) fusion inhibitors exhibit a highly potent synergistic effect against enfuvirtide- sensitive and -resistant HIV type 1 strains. J Virol 2009; 83:7862-72. [PMID: 19493996 DOI: 10.1128/jvi.00168-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T20 (generic name, enfuvirtide; brand name, Fuzeon) is a first-generation human immunodeficiency virus (HIV) fusion inhibitor approved for salvage therapy of HIV-infected patients refractory to current antiretroviral drugs. However, its clinical use is limited because of rapid emergence of T20-resistant viruses in T20-treated patients. Therefore, T1249 and T1144 are being developed as the second- and third-generation HIV fusion inhibitors, respectively, with improved efficacy and drug resistance profiles. Here, we found that combinations of T20 with T1249 and/or T1144 resulted in exceptionally potent synergism (combination index, <0.01) against HIV-1-mediated membrane fusion by 2 to 3 orders of magnitude in dose reduction. Highly potent synergistic antiviral efficacy was also achieved against infection by laboratory-adapted and primary HIV-1 strains, including T20-resistant variants. The mechanism underlying the synergistic effect could be attributed to the fact that T20, T1249, and T1144 all contain different functional domains and have different primary binding sites in gp41. As such, they may work cooperatively to inhibit gp41 six-helix bundle core formation, thereby suppressing virus-cell fusion. Therefore, these findings strongly imply that, rather than replacing T20, combining it with HIV fusion inhibitors of different generations might produce synergistic activity against both T20-sensitive and -resistant HIV-1 strains, suggesting a new therapeutic strategy for the treatment of HIV-1 infection/AIDS.
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20
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Rusconi S, Cicero ML, Viganò O, Sirianni F, Bulgheroni E, Ferramosca S, Bencini A, Bianchi A, Ruiz L, Cabrera C, Martinez-Picado J, Supuran CT, Galli M. New macrocyclic amines showing activity as HIV entry inhibitors against wild type and multi-drug resistant viruses. Molecules 2009; 14:1927-37. [PMID: 19471212 PMCID: PMC6254439 DOI: 10.3390/molecules14051927] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 05/20/2009] [Accepted: 05/21/2009] [Indexed: 11/25/2022] Open
Abstract
Considering as a lead molecule the chemokine CXCR4 receptor antagonist AMD-3100, which shows significant anti-HIV activity in vitro and in vivo, we investigated a series of structurally related macrocyclic polyamines incorporating o,o’-phenanthroline or 2,2’-bipyridyl scaffolds as potential antiviral agents with lower toxicity and increased activity against both wild type X4-tropic and dual tropic HIV strains. The antiviral activity of these compounds was evaluated by susceptibility assays in PBMC (Peripheral Blood Mononuclear Cells) and compared to that of AMD-3100. The newly investigated compounds showed IC50s values in the low micromolar range and significantly inhibited the viral replication of wild type X4-tropic isolate and dual tropic strains. These macrocyclic polyamines constitute a promising class of HIV entry inhibitors.
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Affiliation(s)
- Stefano Rusconi
- Dipartimento di Scienze Cliniche “Luigi Sacco”, Sezione di Malattie Infettive e Immunopatologia, Università degli Studi, Ospedale Luigi Sacco, via G.B. Grassi 74, 20157 Milano, Italy
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-02-39042668; Fax: +39-02-50319758
| | - Mirko Lo Cicero
- Dipartimento di Scienze Cliniche “Luigi Sacco”, Sezione di Malattie Infettive e Immunopatologia, Università degli Studi, Ospedale Luigi Sacco, via G.B. Grassi 74, 20157 Milano, Italy
| | - Ottavia Viganò
- Dipartimento di Scienze Cliniche “Luigi Sacco”, Sezione di Malattie Infettive e Immunopatologia, Università degli Studi, Ospedale Luigi Sacco, via G.B. Grassi 74, 20157 Milano, Italy
| | - Francesca Sirianni
- Dipartimento di Scienze Cliniche “Luigi Sacco”, Sezione di Malattie Infettive e Immunopatologia, Università degli Studi, Ospedale Luigi Sacco, via G.B. Grassi 74, 20157 Milano, Italy
| | - Elisabetta Bulgheroni
- Dipartimento di Scienze Cliniche “Luigi Sacco”, Sezione di Malattie Infettive e Immunopatologia, Università degli Studi, Ospedale Luigi Sacco, via G.B. Grassi 74, 20157 Milano, Italy
| | - Stefania Ferramosca
- Dipartimento di Scienze Cliniche “Luigi Sacco”, Sezione di Malattie Infettive e Immunopatologia, Università degli Studi, Ospedale Luigi Sacco, via G.B. Grassi 74, 20157 Milano, Italy
| | - Andrea Bencini
- Università degli Studi di Firenze, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy; E-mail: (C-T.S.)
| | - Antonio Bianchi
- Università degli Studi di Firenze, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy; E-mail: (C-T.S.)
| | - Lidia Ruiz
- IrsiCaixa Foundation, University Hospital Germans Trias i Pujol, Badalona, Spain; E-mail: (J.M-P.)
| | - Cecilia Cabrera
- IrsiCaixa Foundation, University Hospital Germans Trias i Pujol, Badalona, Spain; E-mail: (J.M-P.)
| | - Javier Martinez-Picado
- IrsiCaixa Foundation, University Hospital Germans Trias i Pujol, Badalona, Spain; E-mail: (J.M-P.)
| | - Claudiu T. Supuran
- Università degli Studi di Firenze, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy; E-mail: (C-T.S.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-02-39042668; Fax: +39-02-50319758
| | - Massimo Galli
- Dipartimento di Scienze Cliniche “Luigi Sacco”, Sezione di Malattie Infettive e Immunopatologia, Università degli Studi, Ospedale Luigi Sacco, via G.B. Grassi 74, 20157 Milano, Italy
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Lederman MM, Jump R, Pilch-Cooper HA, Root M, Sieg SF. Topical application of entry inhibitors as "virustats" to prevent sexual transmission of HIV infection. Retrovirology 2008; 5:116. [PMID: 19094217 PMCID: PMC2637900 DOI: 10.1186/1742-4690-5-116] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Accepted: 12/18/2008] [Indexed: 11/10/2022] Open
Abstract
With the continuing march of the AIDS epidemic and little hope for an effective vaccine in the near future, work to develop a topical strategy to prevent HIV infection is increasingly important. This stated, the track record of large scale "microbicide" trials has been disappointing with nonspecific inhibitors either failing to protect women from infection or even increasing HIV acquisition. Newer strategies that target directly the elements needed for viral entry into cells have shown promise in non-human primate models of HIV transmission and as these agents have not yet been broadly introduced in regions of highest HIV prevalence, they are particularly attractive for prophylaxis. We review here the agents that can block HIV cellular entry and that show promise as topical strategies or "virustats" to prevent mucosal transmission of HIV infection.
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Affiliation(s)
- Michael M Lederman
- Department of Medicine, Case Western Reserve University, 1100 Euclid Ave, Cleveland, OH 44118, USA
| | - Robin Jump
- Department of Medicine, Case Western Reserve University, 1100 Euclid Ave, Cleveland, OH 44118, USA
| | - Heather A Pilch-Cooper
- Department of Medicine, Case Western Reserve University, 1100 Euclid Ave, Cleveland, OH 44118, USA
| | - Michael Root
- Kimmel Cancer Center, Thomas Jefferson University, 233 South 10th Street, Philadelphia PA, 19107, USA
| | - Scott F Sieg
- Department of Medicine, Case Western Reserve University, 1100 Euclid Ave, Cleveland, OH 44118, USA
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Potent synergistic anti-human immunodeficiency virus (HIV) effects using combinations of the CCR5 inhibitor aplaviroc with other anti-HIV drugs. Antimicrob Agents Chemother 2008; 52:2111-9. [PMID: 18378711 DOI: 10.1128/aac.01299-07] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Aplaviroc (AVC), an experimental CCR5 inhibitor, potently blocks in vitro the infection of R5-tropic human immunodeficiency virus type 1 (R5-HIV-1) at subnanomolar 50% inhibitory concentrations. Although maraviroc is presently clinically available, further studies are required to determine the role of CCR5 inhibitors in combinations with other drugs. Here we determined anti-HIV-1 activity using combinations of AVC with various anti-HIV-1 agents, including four U.S. Food and Drug Administration-approved drugs, two CCR5 inhibitors (TAK779 and SCH-C) and two CXCR4 inhibitors (AMD3100 and TE14011). Combination effects were defined as synergistic or antagonistic when the activity of drug A combined with B was statistically greater or less, respectively, than the additive effects of drugs A and A combined and drugs B and B combined by using the Combo method, described in this paper, which provides (i) a flexible choice of interaction models and (ii) the use of nonparametric statistical methods. Synergistic effects against R5-HIV-1(Ba-L) and a 50:50 mixture of R5-HIV-1(Ba-L) and X4-HIV-1(ERS104pre) (HIV-1(Ba-L/104pre)) were seen when AVC was combined with zidovudine, nevirapine, indinavir, or enfuvirtide. Mild synergism and additivity were observed when AVC was combined with TAK779 and SCH-C, respectively. We also observed more potent synergism against HIV-1(Ba-L/104pre) when AVC was combined with AMD3100 or TE14011. The data demonstrate a tendency toward greater synergism with AVC plus either of the two CXCR4 inhibitors compared to the synergism obtained with combinations of AVC and other drugs, suggesting that the development of effective CXCR4 inhibitors may be important for increasing the efficacies of CCR5 inhibitors.
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de la Tribonnière X, Yazdanpanah Y, Reynes J. [CCR5 antagonists: a new class of antiretrovirals]. Med Mal Infect 2008; 38 Suppl 1:S1-6. [PMID: 18455055 DOI: 10.1016/s0399-077x(08)70537-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Inhibition of CCR5 co-receptor which is also a chemokine receptor, is a new way for inhibition of HIV-1 replication. Small antagonist molecules exert non competitive inhibition of the HIV co-receptor CCR5, which is essential for HIV entry. The CCR5 antagonists aplaviroc (GlaxoSmithKine), vicriviroc (Schering-Plough), and maraviroc (Pfizer) have reached phases III of clinical development. The development of aplaviroc was stopped because of its hepatotoxicity in some of the HIV-infected patients. In ACTG 5211 and MOTIVATE trials, treatment-experienced subjects who added respectively vicriviroc and maraviroc demonstrated substantially greater reductions in plasma HIV-1 RNA levels than those who received the placebo ; maraviroc currently having obtained European authorization. The place of this new class in the strategies of initial, switch or rescue treatment remains to be clarified. The limitations of the use of these small molecules depend on their mechanism of action : obligation for monitoring the evolution of coreceptor usage, risk of failure by emergence of pre-existing strains with CXCR4 (X4) tropism or by resistant strains with CCR5 tropism, potential risks related to blocking of the physiological functions of this chemokine receptor.
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Affiliation(s)
- X de la Tribonnière
- Service des Maladies Infectieuses et du Voyageur, Centre hospitalier Gustave Dron, Tourcoing, France.
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Affiliation(s)
- George Panos
- Chelsea & Westminster Hospital, St Stephen’s Centre, 369 Fulham Road, London, SW10 9NH, UK
| | - Mark Nelson
- Chelsea & Westminster Hospital, St Stephen’s Centre, 369 Fulham Road, London, SW10 9NH, UK
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Gantlett KE, Weber JN, Sattentau QJ. Synergistic inhibition of HIV-1 infection by combinations of soluble polyanions with other potential microbicides. Antiviral Res 2007; 75:188-97. [PMID: 17408760 DOI: 10.1016/j.antiviral.2007.03.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Revised: 02/28/2007] [Accepted: 03/06/2007] [Indexed: 11/21/2022]
Abstract
Several polyanionic compounds with potential for use as topically applied microbicides to prevent HIV-1 sexual transmission, such as PRO 2000, are currently in phase III clinical efficacy trials. Microbicidal formulations may well comprise combinations of inhibitors to increase potency, reduce dose and minimize problems of HIV-1 resistance. We have therefore evaluated in vitro, the anti-HIV-1 activity of two leading polyanionic microbicides combined with other antiretroviral agents with microbicidal potential. Dextran sulfate (DS) and PRO 2000 were combined with the neutralizing antibody IgG1b12, the peptide-based fusion inhibitor T20, the CCR5 antagonist TAK779 and the cyanobacterial protein cyanovirin-N. Anti-HIV-1 activity was assessed in a single cycle replication assay using pseudoviruses carrying a luciferase reporter gene and the envelope glycoproteins from HIV-1 isolates JR-FL (R5) and HxB2 (X4), against both immortalized and primary CD4+ cell targets. The data were analyzed for synergy using Calcusyn software. Results indicate that PRO 2000 and DS can act synergistically with most inhibitors tested, although the degree of synergy depends on inhibitor concentration and combination. These data provide a rational basis for testing of microbicide combinations in vivo.
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Affiliation(s)
- Katherine E Gantlett
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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26
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Ketas TJ, Schader SM, Zurita J, Teo E, Polonis V, Lu M, Klasse PJ, Moore JP. Entry inhibitor-based microbicides are active in vitro against HIV-1 isolates from multiple genetic subtypes. Virology 2007; 364:431-40. [PMID: 17428517 DOI: 10.1016/j.virol.2007.03.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 02/26/2007] [Accepted: 03/02/2007] [Indexed: 11/27/2022]
Abstract
Inhibitors of viral entry are under consideration as topical microbicides to prevent HIV-1 sexual transmission. Small molecules targeting HIV-1 gp120 (BMS-378806) or CCR5 (CMPD167), and a peptide fusion inhibitor (C52L), each blocks vaginal infection of macaques by a SHIV. A microbicide, however, must be active against multiple HIV-1 variants. We therefore tested BMS-C (a BMS-378806 derivative), CMPD167, C52L and the CXCR4 ligand AMD3465, alone and in combination, against 25 primary R5, 12 X4 and 7 R5X4 isolates from subtypes A-G. At high concentrations (0.1-1 microM), the replication of most R5 isolates in human donor lymphocytes was inhibited by >90%. At lower concentrations, double and triple combinations were more effective than individual inhibitors. Similar results were obtained with X4 viruses when AMD3465 was substituted for CMPD167. The R5X4 viruses were inhibited by combining AMD3465 with CMPD167, or by the coreceptor-independent compounds. Thus, combining entry inhibitors may improve microbicide effectiveness.
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Affiliation(s)
- Thomas J Ketas
- Dept of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA
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27
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Heredia A, Gilliam B, DeVico A, Le N, Bamba D, Flinko R, Lewis G, Gallo RC, Redfield RR. CCR5 density levels on primary CD4 T cells impact the replication and Enfuvirtide susceptibility of R5 HIV-1. AIDS 2007; 21:1317-22. [PMID: 17545708 DOI: 10.1097/qad.0b013e32815278ea] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE AND DESIGN Studies in cell lines have demonstrated that CCR5 coreceptor levels influence the replication efficiency and Enfuvirtide (T-20) susceptibility of R5 HIV-1 strains. At present, however, the role that CCR5 levels on primary CD4 T cells--which are markedly lower than in cell lines and vary only approximately fivefold among most donors--may play in virus replication levels or susceptibility to T-20 is not known. In the present study we evaluated the impact of differences in CCR5 levels among donor CD4 T cells on the infection efficiency and T-20 susceptibility of R5 HIV-1. METHODS CD4 and CCR5 density levels were determined by Quantitative FACS analysis. Virus infectivity assays were conducted in cell lines and primary cells. Associations between coreceptor density, virus replication and T-20 sensitivity were tested using the Spearman's correlation test. RESULTS We found a positive correlation (r, 0.55; P = 0.011) between CCR5 density levels on primary CD4 T cells and replication of R5 HIV-1. In cell lines expressing physiologically relevant levels of CD4 and CCR5, T-20 was significantly more potent in cells with low CCR5 levels. In addition, T20 50% inhibitory concentrations for R5 HIV-1 replication varied approximately 100-fold among primary cells from different donors and they were positively correlated with CCR5 density values (r, 0.84; P = 0.00004). CONCLUSIONS These results suggest that CCR5 density levels in HIV-1 patients may impact the activity of T-20 against R5 strains and that therapeutic approaches to alter CCR5 density may potentiate T-20.
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Affiliation(s)
- Alonso Heredia
- Institute of Human Virology, University of Maryland, 725 W. Lombard Street, Baltimore, MD 21201, USA
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28
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Heredia A, Gilliam B, Latinovic O, Le N, Bamba D, Devico A, Melikyan GB, Gallo RC, Redfield RR. Rapamycin reduces CCR5 density levels on CD4 T cells, and this effect results in potentiation of enfuvirtide (T-20) against R5 strains of human immunodeficiency virus type 1 in vitro. Antimicrob Agents Chemother 2007; 51:2489-96. [PMID: 17485501 PMCID: PMC1913226 DOI: 10.1128/aac.01602-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The CCR5 chemokine receptor plays a pivotal role in human immunodeficiency virus type 1 (HIV-1) infection. Several studies have suggested that CCR5 density levels in individuals are rate limiting for infection. In addition, CCR5 density levels influence the antiviral activity of the HIV-1 fusion inhibitor enfuvirtide (T-20) against R5 strains. In the present study we demonstrate that rapamycin (RAPA), a drug approved for the treatment of renal transplantation rejection, reduces CCR5 density levels on CD4 T cells and inhibits R5 HIV-1 replication. In addition, RAPA increased the antiviral activity of T-20 against R5 strains of the virus in a cell-cell fusion assay and as shown by quantification of early products of viral reverse transcription. Median-effect analysis of drug interaction between RAPA and T-20 in infectivity assays using donor peripheral blood mononuclear cells demonstrated that the RAPA-T-20 combination is synergistic against R5 strains of HIV-1 and this synergy translates into T-20 dose reductions of up to approximately 33-fold. Importantly, RAPA effects on replication levels and T-20 susceptibility of R5 strains of HIV-1 were observed at drug concentrations that did not inhibit cell proliferation. These results suggest that low concentrations of RAPA may potentiate the antiviral activity of T-20 against R5 strains of HIV-1, which are generally present throughout the course of infection and are less sensitive to T-20 inhibition than are X4 strains.
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Affiliation(s)
- Alonso Heredia
- Institute of Human Virology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21201, USA
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Citterio P, Rusconi S. Novel inhibitors of the early steps of the HIV-1 life cycle. Expert Opin Investig Drugs 2007; 16:11-23. [PMID: 17155850 DOI: 10.1517/13543784.16.1.11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Considerable advances have been made on compounds that are active as inhibitors of HIV entry and fusion. The discovery of chemokines a few years ago focused the attention on coreceptor inhibitors in addition to fusion and attachment blockers. During the last 5 years, there has been an intense research activity from both private companies and academic institutions to find effective compounds that are capable of inhibiting the initial steps in the HIV life cycle. Some of the presented compounds demonstrated in vitro synergism, thus there is the rationale of their combined use in HIV-infected individuals. Many entry and fusion inhibitors of HIV are being investigated in controlled clinical trials and there are a number of them that are bioavailable as oral formulations. This is an essential feature for an extended use of these compounds with the purpose of ameliorating patients' adherence to medications; therefore, preventing the development of drug resistance. Among the many compounds that are being investigated, some are in the preclinical arena and others are more advanced in development stages. Overall, the main aim is to establish the action of these compounds on the immune system (e.g., the balance of the system after shutting off CCR5 or CXCR4 coreceptors) and the possible burden of unexplained side effects. This review focuses on the recent developments in this field with a particular attention on promising compounds in preclinical and clinical trials.
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Affiliation(s)
- Paola Citterio
- Università degli Studi, Dipartimento di Scienze Cliniche Luigi Sacco, Sezione di Malattie Infettive e Immunopatologia, Ospedale Luigi Sacco, 20157 Milan, Italy
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30
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Perros M. CCR5 antagonists for the treatment of HIV infection and AIDS. ADVANCES IN ANTIVIRAL DRUG DESIGN 2007. [DOI: 10.1016/s1075-8593(06)05005-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Imai M, Baranyi L, Okada N, Okada H. Inhibition of HIV-1 infection by synthetic peptides derived CCR5 fragments. Biochem Biophys Res Commun 2006; 353:851-6. [PMID: 17210123 DOI: 10.1016/j.bbrc.2006.12.084] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Accepted: 12/07/2006] [Indexed: 01/09/2023]
Abstract
HIV-1 infection requires interaction of viral envelope protein gp160 with CD4 and a chemokine receptor, CCR5 or CXCR4 as entry coreceptor. We designed HIV-inhibitory peptides targeted to CCR5 using a novel computer program (ANTIS), which searched all possible sense-antisense amino acid pairs between proteins. Seven AHBs were found in CCR5 receptor. All AHB peptides were synthesized and tested for their ability to prevent HIV-1 infection to human T cells. A peptide fragment (LC5) which is a part of the CCR5 receptor corresponding to the loop between the fifth and sixth transmembrane regions (amino acids 222-240) proved to inhibit HIV-1IIIB infection of MT-4 cells. Interaction of these antisense peptides could be involved in sustaining HIV-1 infectivity. LC5 effectively indicated dose-dependent manner, and the suppression was enhanced additively by T20 peptide, which inhibits infection in vitro by disrupting the gp41 conformational changes necessary for membrane fusion. Thus, these results indicate that CCR5-derived AHB peptides could provide a useful tool to define the mechanism(s) of HIV infection, and may provide insight which will contribute to the development of an anti-HIV-1 reagent.
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Affiliation(s)
- Masaki Imai
- Department of Molecular Biology, Nagoya City University School of Medicine, Nagoya, Aichi 467-8601, and Choju Medical Institute, Fukushimura Hospital, Toyohashi, Japan
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Murga JD, Franti M, Pevear DC, Maddon PJ, Olson WC. Potent antiviral synergy between monoclonal antibody and small-molecule CCR5 inhibitors of human immunodeficiency virus type 1. Antimicrob Agents Chemother 2006; 50:3289-96. [PMID: 17005807 PMCID: PMC1610098 DOI: 10.1128/aac.00699-06] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chemokine receptor CCR5 provides a portal of entry for human immunodeficiency virus type 1 (HIV-1) into susceptible CD4(+) cells. Both monoclonal antibody (MAb) and small-molecule CCR5 inhibitors have entered human clinical testing, but little is known regarding their potential interactions. We evaluated the interactions between CCR5 MAbs, small-molecule CCR5 antagonists, and inhibitors of HIV-1 gp120, gp41, and reverse transcriptase in vitro. Inhibition data were analyzed for cooperative effects using the combination index (CI) method and stringent statistical criteria. Potent, statistically significant antiviral synergy was observed between the CCR5 MAb PRO 140 and the small-molecule CCR5 antagonists maraviroc (UK-427,857), vicriviroc (SCH-D), and TAK-779. High-level synergy was observed consistently across various assay systems, HIV-1 envelopes, CCR5 target cells, and inhibition levels. CI values ranged from 0.18 to 0.64 and translated into in vitro dose reductions of up to 14-fold. Competition binding studies revealed nonreciprocal patterns of CCR5 binding by MAb and small-molecule CCR5 inhibitors, suggesting that synergy occurs at the level of receptor binding. In addition, both PRO 140 and maraviroc synergized with the chemokine RANTES, a natural ligand for CCR5; however, additive effects were observed for both small-molecule CCR5 antagonists and PRO 140 in combination with other classes of HIV-1 inhibitors. The findings provide a rationale for clinical exploration of MAb and small-molecule CCR5 inhibitors in novel dual-CCR5 regimens for HIV-1 therapy.
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Affiliation(s)
- Jose D Murga
- Progenics Pharmaceuticals, Inc, Tarrytown, NY 10591, USA
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Chou TC. Theoretical basis, experimental design, and computerized simulation of synergism and antagonism in drug combination studies. Pharmacol Rev 2006; 58:621-81. [PMID: 16968952 DOI: 10.1124/pr.58.3.10] [Citation(s) in RCA: 3754] [Impact Index Per Article: 208.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The median-effect equation derived from the mass-action law principle at equilibrium-steady state via mathematical induction and deduction for different reaction sequences and mechanisms and different types of inhibition has been shown to be the unified theory for the Michaelis-Menten equation, Hill equation, Henderson-Hasselbalch equation, and Scatchard equation. It is shown that dose and effect are interchangeable via defined parameters. This general equation for the single drug effect has been extended to the multiple drug effect equation for n drugs. These equations provide the theoretical basis for the combination index (CI)-isobologram equation that allows quantitative determination of drug interactions, where CI < 1, = 1, and > 1 indicate synergism, additive effect, and antagonism, respectively. Based on these algorithms, computer software has been developed to allow automated simulation of synergism and antagonism at all dose or effect levels. It displays the dose-effect curve, median-effect plot, combination index plot, isobologram, dose-reduction index plot, and polygonogram for in vitro or in vivo studies. This theoretical development, experimental design, and computerized data analysis have facilitated dose-effect analysis for single drug evaluation or carcinogen and radiation risk assessment, as well as for drug or other entity combinations in a vast field of disciplines of biomedical sciences. In this review, selected examples of applications are given, and step-by-step examples of experimental designs and real data analysis are also illustrated. The merging of the mass-action law principle with mathematical induction-deduction has been proven to be a unique and effective scientific method for general theory development. The median-effect principle and its mass-action law based computer software are gaining increased applications in biomedical sciences, from how to effectively evaluate a single compound or entity to how to beneficially use multiple drugs or modalities in combination therapies.
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Affiliation(s)
- Ting-Chao Chou
- Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
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Zhang XQ, Sorensen M, Fung M, Schooley RT. Synergistic in vitro antiretroviral activity of a humanized monoclonal anti-CD4 antibody (TNX-355) and enfuvirtide (T-20). Antimicrob Agents Chemother 2006; 50:2231-3. [PMID: 16723592 PMCID: PMC1479151 DOI: 10.1128/aac.00761-05] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recently, antiretroviral agents directed at several steps involved in viral entry have been shown to reduce viral replication in vitro and in vivo. We have demonstrated a high level of in vitro synergistic antiretroviral activity for two entry inhibitors that are directed at sequential steps in the entry process.
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35
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Westby M, van der Ryst E. CCR5 antagonists: host-targeted antivirals for the treatment of HIV infection. Antivir Chem Chemother 2006; 16:339-54. [PMID: 16329283 DOI: 10.1177/095632020501600601] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The human chemokine receptors, CCR5 and CXCR4, are potential host targets for exogenous, small-molecule antagonists for the inhibition of HIV-1 infection. HIV-1 strains can be categorised by co-receptor tropism - their ability to utilise CCR5 (CCR5-tropic), CXCR4 (CXCR4-tropic) or both (dual-tropic) as a co-receptor for entry into susceptible cells. CCR5 may be the more suitable co-receptor target for small-molecule antagonists because a natural deletion in the CCR5 gene preventing its expression on the cell surface is not associated with any obvious phenotype, but can confer resistance to infection by CCR5-tropic strains - the most frequently sexually-transmitted strains. The current leading CCR5 antagonists in clinical development include maraviroc (UK-427,857, Pfizer), aplaviroc (873140, GlaxoSmithKline) and vicriviroc (SCH-D, Schering-Plough), which have demonstrated efficacy and tolerability in HIV-infected patients. Pharmacodynamic data also suggest that these compounds have a long plasma half-life and/or prolonged CCR5 occupancy, which may explain the delay in viral rebound observed following compound withdrawal in short-term monotherapy studies. A switch from CCR5 to CXCR4 tropism occurs spontaneously in approximately 50% of HIV-infected patients and has been associated with, but is not required for, disease progression. The possibility of a co-receptor tropism switch occurring under selection pressure by CCR5 antagonists is discussed. The completion of ongoing Phase lib/Ill studies of maraviroc, aplaviroc and vicriviroc will provide further insight into co-receptor tropism, HIV pathogenesis and the suitability of CCR5 antagonists as a potent new class of antiyirals for the treatment of HIV infection.
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36
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Debnath AK. Progress in identifying peptides and small-molecule inhibitors targeted to gp41 of HIV-1. Expert Opin Investig Drugs 2006; 15:465-78. [PMID: 16634685 DOI: 10.1517/13543784.15.5.465] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
During the last decade, a great number of activities have been geared in identifying newer targets for inhibiting HIV infection as well as understanding the targets for already identified anti-HIV-1 agents. The success in converting a proof-of-concept peptide T-20 (previously named DP-178), from the C-terminal heptad repeat (CHR) region of the envelope glycoprotein gp41 of HIV-1, to a drug named enfuvirtide was one of the phenomenal successes in HIV-1 drug discovery research that has been made in recent years. There were many reports of modifying peptides from the N-terminal heptad repeat and CHR regions with the objective of improving their activity. A few laboratories also reported the identification of small-molecule inhibitors that apparently bind to the hydrophobic cavity identified in the gp41 core structure and prevent the CHR peptide binding to the N-terminal heptad repeat peptide, thereby prevent the formation of the typical six-helix bundle, which has been thought to be necessary for the fusion between HIV and cell membranes.
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Affiliation(s)
- Asim K Debnath
- Laboratory of Molecular Modeling & Drug Design, Lindsley F. Kimball Research Institute of The New York Blood Centre, 310 East 67th Street, New York, NY 10021, USA.
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Fletcher S, Hamilton AD. Targeting protein-protein interactions by rational design: mimicry of protein surfaces. J R Soc Interface 2006; 3:215-33. [PMID: 16849232 PMCID: PMC1578744 DOI: 10.1098/rsif.2006.0115] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 01/27/2006] [Indexed: 11/12/2022] Open
Abstract
Protein-protein interactions play key roles in a range of biological processes, and are therefore important targets for the design of novel therapeutics. Unlike in the design of enzyme active site inhibitors, the disruption of protein-protein interactions is far more challenging, due to such factors as the large interfacial areas involved and the relatively flat and featureless topologies of these surfaces. Nevertheless, in spite of such challenges, there has been considerable progress in recent years. In this review, we discuss this progress in the context of mimicry of protein surfaces: targeting protein-protein interactions by rational design.
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Affiliation(s)
| | - Andrew D Hamilton
- Department of Chemistry, Yale UniversityPO Box 208107, New Haven, CT 06520-8107, USA
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38
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Strizki JM, Tremblay C, Xu S, Wojcik L, Wagner N, Gonsiorek W, Hipkin RW, Chou CC, Pugliese-Sivo C, Xiao Y, Tagat JR, Cox K, Priestley T, Sorota S, Huang W, Hirsch M, Reyes GR, Baroudy BM. Discovery and characterization of vicriviroc (SCH 417690), a CCR5 antagonist with potent activity against human immunodeficiency virus type 1. Antimicrob Agents Chemother 2006; 49:4911-9. [PMID: 16304152 PMCID: PMC1315929 DOI: 10.1128/aac.49.12.4911-4919.2005] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inhibiting human immunodeficiency virus type 1 (HIV-1) infection by blocking the host cell coreceptors CCR5 and CXCR4 is an emerging strategy for antiretroviral therapy. Currently, several novel coreceptor inhibitors are being developed in the clinic, and early results have proven promising. In this report, we describe a novel CCR5 antagonist, vicriviroc (formerly SCH-D or SCH 417690), with improved antiviral activity and pharmacokinetic properties compared to those of SCH-C, a previously described CCR5 antagonist. Like SCH-C, vicriviroc binds specifically to the CCR5 receptor and prevents infection of target cells by CCR5-tropic HIV-1 isolates. In antiviral assays, vicriviroc showed potent, broad-spectrum activity against genetically diverse and drug-resistant HIV-1 isolates and was consistently more active than SCH-C in inhibiting viral replication. This compound demonstrated synergistic anti-HIV activity in combination with drugs from all other classes of approved antiretrovirals. Competition binding assays revealed that vicriviroc binds with higher affinity to CCR5 than SCH-C. Functional assays, including inhibition of calcium flux, guanosine 5'-[35S]triphosphate exchange, and chemotaxis, confirmed that vicriviroc acts as a receptor antagonist by inhibiting signaling of CCR5 by chemokines. Finally, vicriviroc demonstrated diminished affinity for the human ether a-go-go related gene transcript ion channel compared to SCH-C, suggesting a reduced potential for cardiac effects. Vicriviroc represents a promising new candidate for the treatment of HIV-1 infection.
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Affiliation(s)
- Julie M Strizki
- Department of Antiviral Therapy, Schering-Plough Research Institute, 2015 Galloping Hill Road, K15, E405C/4945, Kenilworth, New Jersey 07033, USA.
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Abstract
Enfuvirtide (Fuzeon), a fusion inhibitor, is indicated in combination with other antiretroviral agents in the treatment of HIV infection in treatment-experienced adults and children aged >6 years. The addition of subcutaneous enfuvirtide to an optimised antiretroviral background regimen improved the virological and immunological response in treatment-experienced HIV-infected patients in the two large, well designed TORO (T-20 vs Optimised Regimen Only) trials. Although injection-site reactions occurred almost universally in enfuvirtide recipients, they were rarely treatment-limiting. Enfuvirtide was otherwise generally well tolerated. The challenge for clinicians is in determining the appropriate timing for enfuvirtide initiation, which requires consideration of the likelihood of a better virological response with the construction of an active background regimen versus the potential for a low rate of adherence to therapy in patients in the early stages of treatment and/or disease development. Enfuvirtide is a novel antiretroviral that is effective in HIV-infected patients whose treatment options are limited by multi-class antiretroviral resistance.
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Tremblay CL, Giguel F, Chou TC, Dong H, Takashima K, Hirsch MS. TAK-652, a Novel CCR5 Inhibitor, has Favourable Drug Interactions with other Antiretrovirals in Vitro. Antivir Ther 2005. [DOI: 10.1177/135965350501000801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Cécile L Tremblay
- Massachusetts General Hospital, Infectious Diseases Unit, Harvard Medical School, Cambridge, MA, USA
- Centre Hospitalier de l'Université de Montréal, Montréal, Canada
| | - Françoise Giguel
- Massachusetts General Hospital, Infectious Diseases Unit, Harvard Medical School, Cambridge, MA, USA
| | - Ting-Chao Chou
- Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | | | | | - Martin S Hirsch
- Massachusetts General Hospital, Infectious Diseases Unit, Harvard Medical School, Cambridge, MA, USA
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Cilliers T, Willey S, Sullivan WM, Patience T, Pugach P, Coetzer M, Papathanasopoulos M, Moore JP, Trkola A, Clapham P, Morris L. Use of alternate coreceptors on primary cells by two HIV-1 isolates. Virology 2005; 339:136-44. [PMID: 15992849 DOI: 10.1016/j.virol.2005.05.027] [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] [Received: 03/14/2005] [Revised: 03/30/2005] [Accepted: 05/25/2005] [Indexed: 10/25/2022]
Abstract
Two HIV-1 isolates (CM4 and CM9) able to use alternate HIV-1 coreceptors on transfected cell lines were tested for their sensitivity to inhibitors of HIV-1 entry on primary cells. CM4 was able to use CCR5 and Bob/GPR15 efficiently in transfected cells. The R5 isolate grew in Delta32/Delta32 CCR5 PBMC in the absence or presence of AMD3100, a CXCR4-specific inhibitor, indicating that it uses a receptor other than CCR5 or CXCR4 on primary cells. It was insensitive to the CCR5 entry inhibitors RANTES and PRO140, but was partially inhibited by vMIP-1, a chemokine that binds CCR3, CCR8, GPR15 and CXCR6. The coreceptor used by this isolate on primary cells is currently unknown. CM9 used CCR5, CXCR4, Bob/GPR15, CXCR6, CCR3, and CCR8 on transfected cells and was able to replicate in the absence or presence of AMD3100 in Delta32/Delta32 CCR5 PBMC. It was insensitive to eotaxin, vMIP-1 and I309 when tested individually, but was inhibited completely when vMIP-1 or I309 was combined with AMD3100. Both I309 and vMIP-1 bind CCR8, strongly suggesting that this isolate can use CCR8 on primary cells. Collectively, these data suggest that some HIV-1 isolates can use alternate coreceptors on primary cells, which may have implications for strategies that aim to block viral entry.
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Affiliation(s)
- Tonie Cilliers
- AIDS Virus Research Unit, National Institute for Communicable Diseases, Private Bag X4, Sandringham 2131, Johannesburg, South Africa
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Krambovitis E, Porichis F, Spandidos DA. HIV entry inhibitors: a new generation of antiretroviral drugs. Acta Pharmacol Sin 2005; 26:1165-73. [PMID: 16174430 DOI: 10.1111/j.1745-7254.2005.00193.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
AIDS is presently treatable, and patients can have a good prognosis due to the success of highly active antiretroviral therapy (HAART), but it is still not curable or preventable. High toxicity of HAART, and the emergence of drug resistance add to the imperative to continue research into new strategies and interventions. Considerable progress in the understanding of HIV attachment and entry into host cells has suggested new possibilities for rationally designing agents that interfere with this process. The approval and introduction of the fusion inhibitor enfuvirtide (Fuzeon) for clinical use signals a new era in AIDS therapeutics. Here we review the crucial steps the virus uses to achieve cell entry, which merit attention as potential targets, and the compounds at pre-clinical and clinical development stages, reported to effectively inhibit cell entry.
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Affiliation(s)
- Elias Krambovitis
- Department of Applied Biochemistry and Immunology, Institute of Molecular Biology and Biotechnology, Vassilika Vouton, Heraklion, Crete, Greece.
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Tremblay CL, Giguel F, Guan Y, Chou TC, Takashima K, Hirsch MS. TAK-220, a novel small-molecule CCR5 antagonist, has favorable anti-human immunodeficiency virus interactions with other antiretrovirals in vitro. Antimicrob Agents Chemother 2005; 49:3483-5. [PMID: 16048964 PMCID: PMC1196290 DOI: 10.1128/aac.49.8.3483-3485.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
TAK-220 is a CCR5 antagonist, part of the new class of anti-human immunodeficiency virus type 1 (anti-HIV-1) entry inhibitors. We evaluated the anti-HIV-1 interactions between TAK-220 and various antiretrovirals in vitro. Synergy was observed with all drugs at the 90 and 95% inhibitory concentrations. The favorable drug interactions observed suggest that further clinical evaluation is warranted.
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Affiliation(s)
- Cécile L Tremblay
- Massachusetts General Hospital, 65 Landsdowne St., Room 419, Cambridge, MA 02139, USA.
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Adkison KK, Shachoy-Clark A, Fang L, Lou Y, O'Mara K, Berrey MM, Piscitelli SC. Pharmacokinetics and short-term safety of 873140, a novel CCR5 antagonist, in healthy adult subjects. Antimicrob Agents Chemother 2005; 49:2802-6. [PMID: 15980352 PMCID: PMC1168695 DOI: 10.1128/aac.49.7.2802-2806.2005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
873140 is a novel CCR5 antagonist with potent in vitro anti-human immunodeficiency virus (HIV) activity. This study was a double-blind, randomized, placebo-controlled, single- and repeat-dose escalation investigation of the safety, pharmacokinetics, and food effect of 873140 in 70 adult subjects. During single-dose escalation, three cohorts (each composed of 10 subjects, with 8 subjects receiving the active drug and 2 subjects receiving the placebo [8 active and 2 placebo]) received doses of 50, 200, 400, 800, and 1,200 mg after an overnight fast, or 400 mg plus a standard high-fat breakfast in an alternating panel design. During repeat-dose escalation, four cohorts (each with 8 active and 2 placebo) received doses of 200, 400, 600, or 800 mg every 12 h (BID) for 8 days. Laboratory safety tests, vital signs, and electrocardiograms (ECGs) were performed at regular intervals, and blood samples were obtained for pharmacokinetics. Single and repeat doses of 50 mg to 800 mg were well tolerated, with no serious adverse events and no grade 3 or 4 adverse events. The mild-to-moderate side effects were primarily gastrointestinal and included abdominal cramping, nausea, and diarrhea. No specific trends in laboratory parameters or clinically significant ECG changes were noted. Plasma 873140 concentrations increased rapidly; the median time to maximum concentration of drug in serum was 1.75 to 5 h. The median area under the plasma concentration-time profile (AUC) and the maximum concentration of drug in serum (C(max)) ranged from 127 ng.h/ml and 24 ng/ml at 200 mg BID to 329 ng.h/ml and 100 ng/ml at 800 mg BID, respectively. Food consumption increased the AUC and C(max) by a mean of 1.7- and 2.2-fold, respectively. The pharmacokinetic and safety profile supports the continued investigation of 873140 with HIV-infected subjects.
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Affiliation(s)
- Kimberly K Adkison
- GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, North Carolina 27709, USA
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Abstract
The severe acute respiratory syndrome (SARS) epidemic brought into the spotlight the need for rapid development of effective anti-viral drugs against newly emerging viruses. Researchers have leveraged the 20-year battle against AIDS into a variety of possible treatments for SARS. Most prominently, based solely on viral genome information, silencers of viral genes, viral-enzyme blockers and viral-entry inhibitors were suggested as potential therapeutic agents for SARS. In particular, inhibitors of viral entry, comprising therapeutic peptides, were based on the recently launched anti-HIV drug enfuvirtide. This could represent one of the most direct routes from genome sequencing to the discovery of antiviral drugs.
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Reeves JD, Lee FH, Miamidian JL, Jabara CB, Juntilla MM, Doms RW. Enfuvirtide resistance mutations: impact on human immunodeficiency virus envelope function, entry inhibitor sensitivity, and virus neutralization. J Virol 2005; 79:4991-9. [PMID: 15795284 PMCID: PMC1069568 DOI: 10.1128/jvi.79.8.4991-4999.2005] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enfuvirtide (ENF/T-20/Fuzeon), the first human immunodeficiency virus (HIV) entry inhibitor to be licensed, targets a structural intermediate of the entry process. ENF binds the HR1 domain in gp41 after Env has bound CD4, preventing conformational changes needed for membrane fusion. Mutations in HR1 that confer ENF resistance can arise following ENF therapy. ENF resistance mutations were introduced into an R5- and X4-tropic Env to examine their impact on fusion, infection, and sensitivity to different classes of entry inhibitors and neutralizing antibodies. HR1 mutations could reduce infection and fusion efficiency and also delay fusion kinetics, likely accounting for their negative impact on viral fitness. HR1 mutations had minimal effect on virus sensitivity to other classes of entry inhibitors, including those targeting CD4 binding (BMS-806 and a CD4-specific monoclonal antibody [MAb]), coreceptor binding (CXCR4 inhibitor AMD3100 and CCR5 inhibitor TAK-779), or fusion (T-1249), indicating that ENF-resistant viruses can remain sensitive to other entry inhibitors in vivo. Some HR1 mutations conferred increased sensitivity to a subset of neutralizing MAbs that likely target fusion intermediates or with epitopes preferentially exposed following receptor interactions (17b, 48D, 2F5, 4E10, and IgGb12), as well as sera from some HIV-positive individuals. Mechanistically, enhanced neutralization correlated with reduced fusion kinetics, indicating that, in addition to steric constraints, kinetics may also limit virus neutralization by some antibodies. Therefore, escape from ENF comes at a cost to viral fitness and may confer enhanced sensitivity to humoral immunity due to prolonged exposure of epitopes that are not readily accessible in the native Env trimer. Resistance to other entry inhibitors was not observed.
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Affiliation(s)
- Jacqueline D Reeves
- Department of Microbiology, University of Pennsylvania, 225 Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, USA.
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Abstract
Highly active antiretroviral therapy (HAART) has led to major declines in morbidity and mortality of HIV-1-infected individuals, but the increasing prevalence of drug-resistant viral isolates, combined with the toxicity and other limitations of current treatments, make the development of new therapies a high priority. As knowledge of viral entry has expanded, this step of the viral life cycle has become a target for novel therapeutic strategies. An emerging group of antiretrovirals, known collectively as entry inhibitors, targets several distinct steps in viral entry including CD4 binding, chemokine receptor engagement and the structural changes in the viral envelope required for fusion between viral and cellular membranes. Many entry inhibitors are in various stages of clinical development, with one already licensed for use. This review will provide an overview of the mechanisms involved in the entry process, highlight promising entry blockers under development and discuss several considerations related to treatment that are unique to this class of antiretroviral drugs.
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Affiliation(s)
- Brian Tomkowicz
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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50
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Abstract
Current targets for antiretroviral therapy (ART) include the viral enzymes reverse transcriptase and protease. The use of a combination of inhibitors targeting these enzymes can reduce viral load for a prolonged period and delay disease progression. However, complications of ART, including the emergence of viruses resistant to current drugs, are driving the development of new antiretroviral agents targeting not only the reverse transcriptase and protease enzymes but novel targets as well. Indeed, enfuvirtide, an inhibitor targeting the viral envelope protein (Env) was recently approved for use in combination therapy in individuals not responding to current antiretroviral regimens. Emerging drug targets for ART include: (i) inhibitors that directly or indirectly target Env; (ii) the HIV enzyme integrase; and (iii) inhibitors of maturation that target the substrate of the protease enzyme. Env mediates entry of HIV into target cells via a multistep process that presents three distinct targets for inhibition by viral and cellular-specific agents. First, attachment of virions to the cell surface via nonspecific interactions and CD4 binding can be blocked by inhibitors that include cyanovirin-N, cyclotriazadisulfonamide analogues, PRO 2000, TNX 355 and PRO 542. In addition, BMS 806 can block CD4-induced conformational changes. Secondly, Env interactions with the co-receptor molecules can be targeted by CCR5 antagonists including SCH-D, maraviroc (UK 427857) and aplaviroc (GW 873140), and the CXCR4 antagonist AMD 070. Thirdly, fusion of viral and cellular membranes can be inhibited by peptides such as enfuvirtide and tifuvirtide (T 1249). The development of entry inhibitors has been rapid, with an increasing number entering clinical trials. Moreover, some entry inhibitors are also being evaluated as candidate microbicides to prevent mucosal transmission of HIV. The integrase enzyme facilitates the integration of viral DNA into the host cell genome. The uniqueness and specificity of this reaction makes integrase an attractive drug target. However, integrase inhibitors have been slow to reach clinical development, although recent contenders, including L 870810, show promise. Inhibitors that target viral maturation via a unique mode of action, such as PA 457, also have potential. In addition, recent advances in our understanding of cellular pathways involved in the life cycle of HIV have also identified novel targets that may have potential for future antiretroviral intervention, including interactions between the cellular proteins APOBEC3G and TSG101, and the viral proteins Vif and p6, respectively. In summary, a number of antiretroviral agents in development make HIV entry, integration and maturation emerging drug targets. A multifaceted approach to ART, using combinations of inhibitors that target different steps of the viral life cycle, has the best potential for long-term control of HIV infection. Furthermore, the development of microbicides targeting HIV holds promise for reducing HIV transmission events.
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Affiliation(s)
- Jacqueline D Reeves
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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