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Overmars RJ, Krullaars Z, Mesplède T. Investigational drugs for HIV: trends, opportunities and key players. Expert Opin Investig Drugs 2023; 32:127-139. [PMID: 36751107 DOI: 10.1080/13543784.2023.2178415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
INTRODUCTION Since the first antiretroviral drug was described, the field of HIV treatment and prevention has undergone two drug-based revolutions: the first one, enabled by the virtually concomitant discovery of non-nucleoside reverse transcriptase and protease inhibitors, was the inception of combined antiretroviral therapy. The second followed the creation of integrase strand-transfer inhibitors with improved safety, potency, and resistance profiles. Long-acting antiretroviral drugs, including broadly neutralizing antibodies, now offer the opportunity for a third transformational change in HIV management. AREAS COVERED Our review focused on HIV treatment and prevention with investigational drugs that offer the potential for infrequent dosing, including drugs not yet approved for clinical use. We also discussed approved drugs for which administration modalities or formulations are being optimized. We performed a literature search in published manuscripts, conference communications, and registered clinical trials. EXPERT OPINION While the field focuses on extending dosing intervals, we identify drug tissue penetration as an understudied opportunity to improve HIV care. We repeat that self-administration remains an essential milestone to reach the full potential of long-acting drugs. Treatments and prevention strategies based on broadly neutralizing antibodies require a deeper understanding of their antiretroviral properties.
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Affiliation(s)
- Ronald J Overmars
- Viroscience Department, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Zoë Krullaars
- Viroscience Department, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Thibault Mesplède
- Viroscience Department, Erasmus Medical Center, Rotterdam, The Netherlands
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Orkin C, Cahn P, Castagna A, Emu B, Harrigan P, Kuritzkes DR, Nelson M, Schapiro J. Opening the door on entry inhibitors in HIV: Redefining the use of entry inhibitors in heavily treatment experienced and treatment-limited individuals living with HIV. HIV Med 2022; 23:936-946. [PMID: 35293094 PMCID: PMC9546304 DOI: 10.1111/hiv.13288] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/21/2022] [Accepted: 02/16/2022] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Entry inhibitors are a relatively new class of antiretroviral therapy and are typically indicated in heavily treatment experienced individuals living with HIV. Despite this, there is no formal definition of 'heavily treatment experienced'. Interpretation of this term generally includes acknowledgement of multidrug resistance and reflects the fact that patients in need of further treatment options may have experienced multiple lines of therapy. However, it fails to recognize treatment limiting factors including contraindications, age-associated comorbidities, and difficulty adhering to regimens. METHODS This manuscript follows a roundtable discussion and aims to identify the unmet needs of those living with HIV who are in need of further treatment options, to broaden the definition of heavily treatment experienced and to clarify the use of newer agents, with an emphasis on the potential role of entry inhibitors, in this population. RESULTS/CONCLUSIONS Within the entry inhibitor class, mechanisms of action differ between agents; resistance to one subclass does not confer resistance to others. Combinations of entry inhibitors should be considered in the same regimen, and if lack of response is seen to one entry inhibitor another can be tried. When selecting an entry inhibitor, physicians should account for patient preferences and needs as well as agent-specific clinical characteristics. Absence of documented multidrug resistance should not exclude an individual from treatment with an entry inhibitor; entry inhibitors are a valuable treatment option for all individuals who are treatment limited or treatment exhausted. We should advocate for additional clinical trials that help define the role of entry inhibitors in people with exhausted/limited ART options other than drug resistance.
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Affiliation(s)
| | - Pedro Cahn
- Fundacion HuespedBuenos AiresArgentina
- Buenos Aires University Medical SchoolBuenos AiresArgentina
| | - Antonella Castagna
- Vita‐Salute San Raffaele UniversitySan Raffaele Scientific InstituteMilanItaly
| | - Brinda Emu
- Yale School of MedicineNew HavenConnecticutUSA
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Yan H, Wu T, Chen Y, Jin H, Li L, Zhu Y, Chong H, He Y. Design of a Bispecific HIV Entry Inhibitor Targeting the Cell Receptor CD4 and Viral Fusion Protein Gp41. Front Cell Infect Microbiol 2022; 12:916487. [PMID: 35711654 PMCID: PMC9197378 DOI: 10.3389/fcimb.2022.916487] [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] [Received: 04/09/2022] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
Given the high variability and drug-resistance problem by human immunodeficiency virus type 1 (HIV-1), the development of bispecific or multi-specific inhibitors targeting different steps of HIV entry is highly appreciated. We previously generated a very potent short-peptide-based HIV fusion inhibitor 2P23. In this study, we designed and characterized a bifunctional inhibitor termed 2P23-iMab by genetically conjugating 2P23 to the single-chain variable fragment (scFv) of ibalizumab (iMab), a newly approved antibody drug targeting the cell receptor CD4. As anticipated, 2P23-iMab could bind to the cell membrane through CD4 anchoring and inhibit HIV-1 infection as well as viral Env-mediated cell-cell fusion efficiently. When tested against a large panel of HIV-1 pseudoviruses with different subtypes and phenotypes, 2P23-iMab exhibited dramatically improved inhibitory activity than the parental inhibitors; especially, it potently inhibited the viruses not being susceptible to iMab. Moreover, 2P23-iMab had a dramatically increased potency in inhibiting two panels of HIV-1 mutants that are resistant to T-20 or 2P23 and the infections of HIV-2 and simian immunodeficiency virus (SIV). In conclusion, our studies have provided new insights into the design of novel bispecific HIV entry inhibitors with highly potent and broad-spectrum antiviral activity.
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Affiliation(s)
- Hongxia Yan
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tong Wu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yue Chen
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hongliang Jin
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Li Li
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuanmei Zhu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Huihui Chong
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuxian He
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Putterill B, Rono C, Makhubela B, Meyer D, Gama N. Triazolyl Ru(II), Os(II), and Ir(III) complexes as potential HIV-1 inhibitors. Biometals 2022; 35:771-784. [PMID: 35699796 DOI: 10.1007/s10534-022-00400-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 05/18/2022] [Indexed: 11/26/2022]
Abstract
Infection by the human immunodeficiency virus, which gives rise to acquired immunodeficiency syndrome, is still a major global health challenge, with millions of people being affected. The use of combination antiretroviral therapy has been a great success, leading to reduced mortality rates over the years. Although successful, these drugs are associated with various side effects, necessitating the development of new treatment strategies. This study investigated three metal-based complexes that were previously shown to possess some anticancer activity. The complexes were investigated against three pseudoviruses, which consisted of HIV-1 subtype C (CAP 210 and Du 156) and subtype A (Q 23). These complexes inhibited viral entry at low micromolar concentrations, with IC50 values ranging from 5.34 to 7.41 µM for N-aryl-1H-1,2,3-triazole-based cyclometalated ruthenium-(II) (A), 2.35-8.09 µM for N-aryl-1H-1,2,3-triazole-based cyclometalated iridium-(III) (B) and 2.59-4.18 µM for N-aryl-1H-1,2,3-triazole-based cyclometalated osmium-(II) complex (C). This inhibition was significant, with no significant inhibition from the ligand alone at similar concentrations. Additionally, these concentrations were non-toxic to mammalian cells. The complexes were further analysed for their potential mechanism of action using in silico docking (Maestro 12.2), which indicated that the activity is potentially due to their interaction with the CCR5 co-receptor. The predicted interaction involved amino acids (Glu 283, Tyr 251 and Tyr 108) that are essential for the interaction of the chemokine receptor with viral gp120.
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Affiliation(s)
- Brandon Putterill
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0083, South Africa
| | - Charles Rono
- Department of Chemical Sciences, Faculty of Science, Research Centre for Synthesis and Catalysis, University of Johannesburg, Johannesburg, 2006, South Africa
| | - Banothile Makhubela
- Department of Chemical Sciences, Faculty of Science, Research Centre for Synthesis and Catalysis, University of Johannesburg, Johannesburg, 2006, South Africa
| | - Debra Meyer
- The Deans Office and Department of Biochemistry, Faculty of Science, University of Johannesburg, Johannesburg, 2006, South Africa
| | - Ntombenhle Gama
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0083, South Africa.
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Rose R, Gartland M, Li Z, Zhou N, Cockett M, Beloor J, Lataillade M, Ackerman P, Krystal M. Clinical evidence for a lack of cross-resistance between temsavir and ibalizumab or maraviroc. AIDS 2022; 36:11-18. [PMID: 34628442 PMCID: PMC8654283 DOI: 10.1097/qad.0000000000003097] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/21/2021] [Accepted: 10/02/2021] [Indexed: 01/10/2023]
Abstract
BACKGROUND Temsavir (TMR), the active agent of the gp120-directed attachment inhibitor fostemsavir (FTR), the CD4-directed attachment inhibitor ibalizumab (IBA), and the CCR5 antagonist maraviroc (MVC) are antiretroviral agents that target steps in HIV-1 viral entry. Although mechanisms of inhibition of the three agents are different, it is important to understand whether there is potential for cross-resistance between these agents, as all involve interactions with gp120. METHODS Envelopes derived from plasma samples from participants in the BRIGHTE study who experienced protocol-derived virologic failure (PDVF) and were co-dosed with FTR and either IBA or MVC were analyzed for susceptibility to the agents. Also, CCR5-tropic MVC-resistant envelopes from the MOTIVATE trials were regenerated and studies were performed to understand whether susceptibility to multiple agents were linked. RESULTS The cloned envelopes exhibited reduced susceptibility to TMR and resistance to the co-dosed agent. At PDVF, emergent or preexisting amino acid substitutions were present at TMR positions of interest. When amino acid substitutions at these positions were reverted to the consensus sequence, full susceptibility to TMR was restored without effecting resistance to the co-dosed agent. In addition, five envelopes from MOTIVATE were regenerated and exhibited R5-tropic-MVC-resistance. Only one exhibited reduced susceptibility to TMR and it contained an M426L polymorphism. When reverted to 426M, full sensitivity for TMR was restored, but it remained MVC resistant. CONCLUSION The data confirm that decreased susceptibility to TMR and resistance to IBA or MVC are not linked and that there is no cross-resistance between either of these two agents and FTR.
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6
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Wensel D, Williams S, Dixon DP, Ward P, McCormick P, Concha N, Stewart E, Hong X, Mazzucco C, Pal S, Ding B, Fellinger C, Krystal M. Novel Bent Conformation of CD4 Induced by HIV-1 Inhibitor Indirectly Prevents Productive Viral Attachment. J Mol Biol 2021; 434:167395. [PMID: 34896364 DOI: 10.1016/j.jmb.2021.167395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 10/19/2022]
Abstract
GSK3732394 is a multi-specific biologic inhibitor of HIV entry currently under clinical evaluation. A key component of this molecule is an adnectin (6940_B01) that binds to CD4 and inhibits downstream actions of gp160. Studies were performed to determine the binding site of the adnectin on CD4 and to understand the mechanism of inhibition. Using hydrogen-deuterium exchange with mass spectrometry (HDX), CD4 peptides showed differential rates of deuteration (either enhanced or slowed) in the presence of the adnectin that mapped predominantly to the interface of domains 2 and 3 (D2-D3). In addition, an X-ray crystal structure of an ibalizumab Fab/CD4(D1-D4)/adnectin complex revealed an extensive interface between the adnectin and residues on CD4 domains D2-D4 that stabilize a novel T-shaped CD4 conformation. A cryo-EM map of the gp140/CD4/GSK3732394 complex clearly shows the bent conformation for CD4 while bound to gp140. Mutagenic analyses on CD4 confirmed that amino acid F202 forms a key interaction with the adnectin. In addition, amino acid L151 was shown to be a critical indirect determinant of the specificity for binding to the human CD4 protein over related primate CD4 molecules, as it appears to modulate CD4's flexibility to adopt the adnectin-bound conformation. The significant conformational change of CD4 upon adnectin binding brings the D1 domain of CD4 in proximity to the host cell membrane surface, thereby re-orienting the gp120 binding site in a direction that is inaccessible to incoming virus due to a steric clash between gp160 trimers on the virus surface and the target cell membrane.
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Affiliation(s)
- David Wensel
- ViiV Healthcare, 36 East Industrial Road, Branford, CT 06405, USA.
| | - Shawn Williams
- GlaxoSmithKline, 1250 S Collegeville Road, Collegeville, PA 19426, USA.
| | - David P Dixon
- GlaxoSmithKline, Gunnels Wood Road, Stevenage SG1 2NY, UK.
| | - Paris Ward
- GlaxoSmithKline, 1250 S Collegeville Road, Collegeville, PA 19426, USA.
| | - Patti McCormick
- GlaxoSmithKline, 1250 S Collegeville Road, Collegeville, PA 19426, USA.
| | - Nestor Concha
- GlaxoSmithKline, 1250 S Collegeville Road, Collegeville, PA 19426, USA.
| | - Eugene Stewart
- GlaxoSmithKline, 1250 S Collegeville Road, Collegeville, PA 19426, USA.
| | - Xuan Hong
- GlaxoSmithKline, 1250 S Collegeville Road, Collegeville, PA 19426, USA.
| | - Charles Mazzucco
- ViiV Healthcare, 36 East Industrial Road, Branford, CT 06405, USA.
| | - Shreya Pal
- ViiV Healthcare, 36 East Industrial Road, Branford, CT 06405, USA.
| | - Bo Ding
- ViiV Healthcare, 36 East Industrial Road, Branford, CT 06405, USA.
| | | | - Mark Krystal
- ViiV Healthcare, 36 East Industrial Road, Branford, CT 06405, USA.
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Reactivation of Hepatitis B After Ibalizumab Therapy for Multidrug-Resistant Human Immunodeficiency Virus. ACG Case Rep J 2021; 8:e00594. [PMID: 34549064 PMCID: PMC8443835 DOI: 10.14309/crj.0000000000000594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 02/16/2021] [Indexed: 11/17/2022] Open
Abstract
Despite the decreasing morbidity associated with the human immunodeficiency virus (HIV), a large percentage of persons with HIV have at least 1 drug resistance mutation. Ibalizumab, a recently approved drug, targets multidrug-resistant HIV. We present a case of reactivation of hepatitis B after initiation of ibalizumab therapy.
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8
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Gathe JC, Hardwicke RL, Garcia F, Weinheimer S, Lewis ST, Cash RB. Efficacy, Pharmacokinetics, and Safety Over 48 Weeks With Ibalizumab-Based Therapy in Treatment-Experienced Adults Infected With HIV-1: A Phase 2a Study. J Acquir Immune Defic Syndr 2021; 86:482-489. [PMID: 33427765 PMCID: PMC7899216 DOI: 10.1097/qai.0000000000002591] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 11/17/2020] [Indexed: 12/01/2022]
Abstract
ABSTRACT Ibalizumab, a humanized monoclonal antibody targeting CD4, blocks HIV-1 entry into cells and is the first Food and Drug Adminstration-approved long-acting agent for HIV-1 treatment. In this phase 2a study, 82 HIV-infected adults failing antiretroviral therapy were assigned an individually optimized background regimen (OBR) and randomized 1:1:1 to arm A (15 mg/kg ibalizumab q2wk), arm B (10 mg/kg weekly for 9 weeks, then q2wk), or placebo. Subjects with an inadequate response at week 16 were permitted to cross over to a new OBR plus 15 mg/kg ibalizumab q2wk. At week 16, viral load (VL) reduction was significantly greater than placebo (0.26 log10) in arms A (1.07 log10; P = 0.002) and B (1.33 log10; P < 0.001); CD4+ T cell counts increased significantly in arm A. After week 16, 11/27 (arm B) and 19/27 (placebo) subjects crossed over to OBR plus 15 mg/kg ibalizumab; 8/28 in arm A initiated a new OBR. Ibalizumab treatment resulted in VL reduction at week 24 (-0.77 and -1.19 log10 for arms A and B, respectively, versus -0.32 log10 for placebo) and 48 weeks (-0.54 and -0.77 versus -0.22 log10). Compared with placebo, VL differences were statistically significant for arm B at week 24 (P = 0.001) and week 48 (P = 0.027). CD4+ T cell counts increased significantly by week 48 in both arm A and arm B, relative to placebo. No ibalizumab-related serious adverse events were reported. The durable antiviral activity and tolerability of ibalizumab support its use in treating individuals harboring multidrug-resistant HIV-1.
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Affiliation(s)
| | - Robin L. Hardwicke
- University of Texas, John P and Katherine G McGovern Medical School, Houston, TX
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Abstract
The innate immune system is comprised of both cellular and humoral players that recognise and eradicate invading pathogens. Therefore, the interplay between retroviruses and innate immunity has emerged as an important component of viral pathogenesis. HIV-1 infection in humans that results in hematologic abnormalities and immune suppression is well represented by changes in the CD4/CD8 T cell ratio and consequent cell death causing CD4 lymphopenia. The innate immune responses by mucosal barriers such as complement, DCs, macrophages, and NK cells as well as cytokine/chemokine profiles attain great importance in acute HIV-1 infection, and thus, prevent mucosal capture and transmission of HIV-1. Conversely, HIV-1 has evolved to overcome innate immune responses through RNA-mediated rapid mutations, pathogen-associated molecular patterns (PAMPs) modification, down-regulation of NK cell activity and complement receptors, resulting in increased secretion of inflammatory factors. Consequently, epithelial tissues lining up female reproductive tract express innate immune sensors including anti-microbial peptides responsible for forming primary barriers and have displayed an effective potent anti-HIV activity during phase I/II clinical trials.
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10
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Abstract
PURPOSE OF REVIEW Combination antiretroviral therapy (cART) has had dramatic effects on morbidity and mortality for persons living with HIV (PLWH). Despite significant progress in treatment efficacy, tolerability, and reducing pill burden, new agents are needed to address issues of resistance, drug-drug interactions, end organ disease, and adherence. This review covers novel ART agents recently approved or in development. RECENT FINDINGS Capsid inhibitors (CAI) demonstrate high potency and potential for extended-duration dosing in pre-clinical trials. While previous maturation inhibitors (MI) were hampered by issues of drug resistance, a recent phase IIa trial for a second-generation MI demonstrated promising antiviral activity. A phase I trial to evaluate a transdermal implant of islatravir, a nucleoside reverse transcriptase translocation inhibitor (NRTTI), maintained concentrations above the target pharmacokinetic threshold at 12 weeks. The attachment inhibitor fostemsavir is available in the USA for compassionate use in multi-drug-resistant (MDR) HIV. New antiretroviral agents show promise for both extended-duration dosing and MDR HIV.
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Affiliation(s)
- Mary C Cambou
- David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
| | - Raphael J Landovitz
- David Geffen School of Medicine, University of California, Los Angeles, CA, USA
- UCLA Center for Clinical AIDS Research & Education (CARE), Division of Infectious Diseases, University of California, Los Angeles, CA, USA
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11
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Abstract
PURPOSE OF REVIEW Antiretroviral options for patients infected with multiclass resistant HIV-1 warrant the development of new agents with unique mechanisms of action and modes of delivery. Here we review one such agent, ibalizumab, a parenteral CD4 postattachment inhibitor that has demonstrated efficacy as part of combination antiretroviral therapy in the treatment of HIV-1. RECENT FINDINGS In a phase III clinical trial in HIV-infected participants with multiclass antiretroviral drug resistance, the intravenous administration of ibalizumab led to declines in plasma HIV-1 RNA more than 0.5 log in 83% of participants at 1 week. An optimized background antiretroviral regimen was then added, and plasma HIV-1 RNA became less than 50 copies/ml in 43% of participants at 24 weeks. Adverse effects of ibalizumab were uncommon and generally low grade. Ibalizumab was approved by the US Food and Drug Administration on March 16, 2018, under the trade name Trogarzo. SUMMARY Ibalizumab has demonstrated both safety and efficacy in the treatment of HIV-1 infection. Its primary use will be in the setting of multidrug resistant virus as part of combination antiretroviral therapy. Further enhancements of ibalizumab to prolong its clearance and broaden its activity are in development.
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Venanzi Rullo E, Ceccarelli M, Condorelli F, Facciolà A, Visalli G, D'Aleo F, Paolucci I, Cacopardo B, Pinzone MR, Di Rosa M, Nunnari G, Pellicanò GF. Investigational drugs in HIV: Pros and cons of entry and fusion inhibitors (Review). Mol Med Rep 2019; 19:1987-1995. [PMID: 30628713 DOI: 10.3892/mmr.2019.9840] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 11/29/2018] [Indexed: 11/06/2022] Open
Abstract
Despite the profound changes and improvements reached in the field of HIV treatment, tolerability and adherence to highly active antiretroviral therapy remains a challenge. Furthermore, multi-experienced patients could take advantage of drugs with different mechanisms of action to combat the spread of resistance to actual therapy. For these reasons identification of new HIV drugs is crucial. Among all the molecules that at present are under investigation, entry and fusion inhibitors pose an interesting class owing to their peculiar characteristics, including prevention of entry of the virus into the human cells. In this study, we reviewed articles, clinical trials, and conference communications about all the drugs under investigation belonging to the class of entry and fusion inhibitors that are at least in phase I clinical trials.
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Affiliation(s)
- Emmanuele Venanzi Rullo
- Department of Clinical and Experimental Medicine, Unit of Infectious Diseases, University of Messina, I-90124 Messina, Italy
| | - Manuela Ceccarelli
- Department of Clinical and Experimental Medicine, Unit of Infectious Diseases, University of Messina, I-90124 Messina, Italy
| | - Fabrizio Condorelli
- Department of Pharmacological Sciences, University of Eastern Piedmont 'A. Avogadro', I-13100 Novara, Italy
| | - Alessio Facciolà
- Department of Clinical and Experimental Medicine, Unit of Infectious Diseases, University of Messina, I-90124 Messina, Italy
| | - Giuseppa Visalli
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, I-90124 Messina, Italy
| | - Francesco D'Aleo
- Department of Clinical and Experimental Medicine, Unit of Infectious Diseases, University of Messina, I-90124 Messina, Italy
| | - Ivana Paolucci
- Department of Clinical and Experimental Medicine, Unit of Infectious Diseases, University of Messina, I-90124 Messina, Italy
| | - Bruno Cacopardo
- Department of Clinical and Experimental Medicine, University of Catania, I-95123 Catania, Italy
| | - Marilia Rita Pinzone
- Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michele Di Rosa
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, University of Catania, I-95123 Catania, Italy
| | - Giuseppe Nunnari
- Department of Clinical and Experimental Medicine, Unit of Infectious Diseases, University of Messina, I-90124 Messina, Italy
| | - Giovanni F Pellicanò
- Department of Human Pathology of the Adult and the Developmental Age 'G. Barresi', Unit of Infectious Diseases, University of Messina, I-98122 Messina, Italy
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13
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Emu B, Fessel J, Schrader S, Kumar P, Richmond G, Win S, Weinheimer S, Marsolais C, Lewis S. Phase 3 Study of Ibalizumab for Multidrug-Resistant HIV-1. N Engl J Med 2018; 379:645-654. [PMID: 30110589 DOI: 10.1056/nejmoa1711460] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Ibalizumab, a humanized IgG4 monoclonal antibody, blocks the entry of human immunodeficiency virus type 1 (HIV-1) by noncompetitive binding to CD4. METHODS In this single-group, open-label, phase 3 study, we enrolled 40 adults with multidrug-resistant (MDR) HIV-1 infection in whom multiple antiretroviral therapies had failed. All the patients had a viral load of more than 1000 copies of HIV-1 RNA per milliliter. After a 7-day control period in which patients continued to receive their current therapy, a loading dose of 2000 mg of ibalizumab was infused; the viral load was quantified 7 days later. Through week 25 of the study, patients received 800 mg of ibalizumab every 14 days, combined with an individually optimized background regimen including at least one fully active agent. The primary end point was the proportion of patients with a decrease in viral load of at least 0.5 log10 copies per milliliter from baseline (day 7) to day 14. RESULTS A total of 31 patients completed the study. The mean baseline viral load was 4.5 log10 copies per milliliter, and the mean CD4 count was 150 per microliter. Of the 40 patients in the intention-to-treat population, 33 (83%) had a decrease in viral load of at least 0.5 log10 copies per milliliter from baseline (P<0.001 for the comparison with the control period). The mean viral-load decrease was 1.1 log10 copies per milliliter. During the control period, 1 patient, who received the optimized background regimen prematurely, had a decrease in viral load of 0.5 log10 copies per milliliter. At week 25, patients who had received ibalizumab plus an optimized background regimen had a mean decrease of 1.6 log10 copies per milliliter from baseline; 43% of the patients had a viral load of less than 50 copies per milliliter, and 50% had a viral load of less than 200 copies per milliliter. Among 10 patients who had virologic failure or rebound, in vitro testing identified 9 who had a lower degree of susceptibility to ibalizumab than at baseline. The most common adverse event was diarrhea (in 20% of patients). Four patients died from causes related to underlying illnesses; 1 had a serious adverse event (the immune reconstitution inflammatory syndrome) that was deemed to be related to ibalizumab therapy. CONCLUSIONS In patients with MDR HIV-1 infection who had advanced disease and limited treatment options, ibalizumab had significant antiviral activity during a 25-week study. Evidence of the emergence of diminished ibalizumab susceptibility was observed in vitro in patients who had virologic failure. (Funded by the Orphan Products Clinical Trials Grants Program of the Food and Drug Administration and TaiMed Biologics; TMB-301 ClinicalTrials.gov number, NCT02475629 .).
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Affiliation(s)
- Brinda Emu
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
| | - Jeffrey Fessel
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
| | - Shannon Schrader
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
| | - Princy Kumar
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
| | - Gary Richmond
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
| | - Sandra Win
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
| | - Steven Weinheimer
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
| | - Christian Marsolais
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
| | - Stanley Lewis
- From the Yale School of Medicine, New Haven, CT (B.E.); Kaiser Foundation Research Institute (J.F.) and Quest Clinical Research (S. Win), San Francisco; Schrader Clinic, Houston (S.S.); Georgetown University, Washington, DC (P.K.); Nova Southeastern University, Ft. Lauderdale, FL, and Florida International University, Miami (G.R.); TaiMed Biologics, Irvine, CA (S. Weinheimer, S.L.); and Theratechnologies, Montreal (C.M.)
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14
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Iacob SA, Iacob DG. Ibalizumab Targeting CD4 Receptors, An Emerging Molecule in HIV Therapy. Front Microbiol 2017; 8:2323. [PMID: 29230203 PMCID: PMC5711820 DOI: 10.3389/fmicb.2017.02323] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 11/10/2017] [Indexed: 11/13/2022] Open
Abstract
The HIV infection is responsible for the most devastating global pandemic of the last century. More than 39 million people have died of HIV/AIDS since 1981. The development of the antiretroviral (ARV) treatment begins with the discovery of zidovudine a nucleoside reverse transcriptase inhibitor. This breakthrough was followed by other ARV drug classes and representatives. Presently, HIV treatment employs 27 ARV representatives belonging to five different classes. Despite the proven benefits of ARV treatment and its long-term control of the HIV infection, there is an increasing concern about the numerous adverse effects and resistance to current ARV drugs. Therefore, the new HIV treatment strategies focus on the development of new ARV agents with a high genetic barrier to resistance and low toxicity. Monoclonal antibodies (MAbs) belong to a new drug class with encouraging results in the treatment of cancer, autoimmune disorders and most recently against HIV infection. The advantages of using MAbs for HIV treatment are related to their antiviral effect, lack of toxicity, good resistance profile, additional synergy with other ARV drug classes and ability to restore CD4 T-cell responses. The current article is a short summary of ibalizumab, an anti-CD4 monoclonal antibody that interferes with HIV viral entry. Current studies on ibalizumab have underlined its antiviral potential, minimal adverse effects, and lack of crossed resistance with other ARV agents thus supporting its further therapeutic use in multidrug resistant HIV-infected patients.
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Affiliation(s)
- Simona A Iacob
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Diana G Iacob
- National Institute for Infectious Diseases "Prof.dr. Matei Bals", Bucharest, Romania
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15
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Discovery and Characterization of a Novel CD4-Binding Adnectin with Potent Anti-HIV Activity. Antimicrob Agents Chemother 2017; 61:AAC.00508-17. [PMID: 28584151 DOI: 10.1128/aac.00508-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/30/2017] [Indexed: 02/08/2023] Open
Abstract
A novel fibronectin-based protein (Adnectin) HIV-1 inhibitor was generated using in vitro selection. This inhibitor binds to human CD4 with a high affinity (3.9 nM) and inhibits viral entry at a step after CD4 engagement and preceding membrane fusion. The progenitor sequence of this novel inhibitor was selected from a library of trillions of Adnectin variants using mRNA display and then further optimized for improved antiviral and physical properties. The final optimized inhibitor exhibited full potency against a panel of 124 envelope (gp160) proteins spanning 11 subtypes, indicating broad-spectrum activity. Resistance profiling studies showed that this inhibitor required 30 passages (151 days) in culture to acquire sufficient resistance to result in viral titer breakthrough. Resistance mapped to the loss of multiple potential N-linked glycosylation sites in gp120, suggesting that inhibition is due to steric hindrance of CD4-binding-induced conformational changes.
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16
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Yokoyama M, Nomaguchi M, Doi N, Kanda T, Adachi A, Sato H. In silico Analysis of HIV-1 Env-gp120 Reveals Structural Bases for Viral Adaptation in Growth-Restrictive Cells. Front Microbiol 2016; 7:110. [PMID: 26903989 PMCID: PMC4746247 DOI: 10.3389/fmicb.2016.00110] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 01/21/2016] [Indexed: 12/17/2022] Open
Abstract
Variable V1/V2 and V3 loops on human immunodeficiency virus type 1 (HIV-1) envelope-gp120 core play key roles in modulating viral competence to recognize two infection receptors, CD4 and chemokine-receptors. However, molecular bases for the modulation largely remain unclear. To address these issues, we constructed structural models for a full-length gp120 in CD4-free and -bound states. The models showed topologies of gp120 surface loop that agree with those in reported structural data. Molecular dynamics simulation showed that in the unliganded state, V1/V2 loop settled into a thermodynamically stable arrangement near V3 loop for conformational masking of V3 tip, a potent neutralization epitope. In the CD4-bound state, however, V1/V2 loop was rearranged near the bound CD4 to support CD4 binding. In parallel, cell-based adaptation in the absence of anti-viral antibody pressures led to the identification of amino acid substitutions that individually enhance viral entry and growth efficiencies in association with reduced sensitivity to CCR5 antagonist TAK-779. Notably, all these substitutions were positioned on the receptors binding surfaces in V1/V2 or V3 loop. In silico structural studies predicted some physical changes of gp120 by substitutions with alterations in viral replication phenotypes. These data suggest that V1/V2 loop is critical for creating a gp120 structure that masks co-receptor binding site compatible with maintenance of viral infectivity, and for tuning a functional balance of gp120 between immune escape ability and infectivity to optimize HIV-1 replication fitness.
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Affiliation(s)
- Masaru Yokoyama
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases Tokyo, Japan
| | - Masako Nomaguchi
- Department of Microbiology, Institute of Biomedical Sciences, Tokushima University Graduate School Tokushima, Japan
| | - Naoya Doi
- Department of Microbiology, Institute of Biomedical Sciences, Tokushima University Graduate School Tokushima, Japan
| | - Tadahito Kanda
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious DiseasesTokyo, Japan; Department of Research Promotion, Division of Infectious Disease Research, Japan Agency for Medical Research and DevelopmentTokyo, Japan
| | - Akio Adachi
- Department of Microbiology, Institute of Biomedical Sciences, Tokushima University Graduate School Tokushima, Japan
| | - Hironori Sato
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases Tokyo, Japan
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17
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Monoclonal antibodies to host cellular receptors for the treatment and prevention of HIV-1 infection. Curr Opin HIV AIDS 2016; 10:144-50. [PMID: 25700204 DOI: 10.1097/coh.0000000000000146] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Clinically relevant monoclonal antibodies (mAb) to host cellular receptors have been generated to both the CD4 receptor and the CCR5 coreceptor, cell surface proteins critical for HIV-1 entry. Ibalizumab is a novel humanized mAb that binds to a conformational epitope on CD4 and blocks entry of HIV-1. It has broad and potent antiviral activity in vitro and in vivo. PRO 140 is a humanized mAb that binds to the CCR5 coreceptor and inhibits CCR5-tropic HIV-1 by interfering with viral entry. Antiviral activity has been demonstrated both in vitro against R5 viruses and in vivo in HIV-1-infected individuals harboring CCR5-tropic virus. RECENT FINDINGS Both antibodies have been administered intravenously in early-phase clinical trials, and current emphasis is on the development of formulations that can be administered subcutaneously. Most recently, bispecific antibodies combining either ibalizumab or PRO 140 with anti-Env broadly neutralizing antibodies have been constructed with vastly improved in-vitro neutralizing profiles, and may offer substantial advantages in the clinic. SUMMARY mAb to host cellular receptors particularly when combined with broadly neutralizing antibodies in novel conformations may offer advances in both the treatment and prevention of HIV-1 infection.
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18
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Hou W, Fang C, Liu J, Yu H, Qi J, Zhang Z, Yuan R, Xiong D, Gao S, Adam Yuan Y, Li S, Gu Y, Xia N. Molecular insights into the inhibition of HIV-1 infection using a CD4 domain-1-specific monoclonal antibody. Antiviral Res 2015; 122:101-11. [PMID: 26259811 DOI: 10.1016/j.antiviral.2015.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 08/01/2015] [Accepted: 08/07/2015] [Indexed: 12/19/2022]
Abstract
An HIV-1 infection in a host cell occurs through an ordered process that involves HIV-1 attachment to the host's cellular CD4 receptor, co-receptor binding to CCR5 or CXCR4, and the subsequent fusion with the cellular membrane. The natural viral entry pathway into a host cell provides an opportunity to develop agents for the treatment of HIV-1 infections. Several engineered monoclonal antibodies specifically targeting CD4 have shown antiviral activities in clinical trials. Here, we report on an anti-CD4 mAb (15A7) that displays a unique binding specificity for domain 1 of CD4, whose epitope partially overlaps with the gp120 binding region. Moreover, 15A7 displays a much stronger binding affinity to CD4(+) cell lines after HIV infection. 15A7 is able to block and neutralize a broad range of primary HIV-1 isolates and T cell-line passage strains. Notably, the bivalent F(ab')2 form of 15A7 is more effective than the Fab form in blocking HIV-1 infection, which is further supported by molecular docking analyses. Together, these results suggest that this novel antibody may exert its antiviral activity by blocking gp120 targeting to the CD4 receptor or competing with gp120 for CD4 receptor binding and might present post-attachment neutralization activity. This antibody could provide a new candidate to efficiently block HIV-1 infection or provide new starting materials for HIV treatment, especially when HIV-1-resistant strains against the current CD4 mAb treatments have already been identified.
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Affiliation(s)
- Wangheng Hou
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China
| | - Chu Fang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China
| | - Jiayan Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China
| | - Hai Yu
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Jialong Qi
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Zhiqing Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China
| | - Ruixue Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China
| | - Dan Xiong
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China
| | - Shuangquan Gao
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Y Adam Yuan
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China; National University of Singapore (Suzhou) Research Institute, Suzhou 215123, China
| | - Shaowei Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China; National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Ying Gu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China; National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China.
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361005, China; National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
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19
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Pegu A, Yang ZY, Boyington JC, Wu L, Ko SY, Schmidt SD, McKee K, Kong WP, Shi W, Chen X, Todd JP, Letvin NL, Huang J, Nason MC, Hoxie JA, Kwong PD, Connors M, Rao SS, Mascola JR, Nabel GJ. Neutralizing antibodies to HIV-1 envelope protect more effectively in vivo than those to the CD4 receptor. Sci Transl Med 2015; 6:243ra88. [PMID: 24990883 DOI: 10.1126/scitranslmed.3008992] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
HIV-1 infection depends on effective viral entry mediated by the interaction of its envelope (Env) glycoprotein with specific cell surface receptors. Protective antiviral antibodies generated by passive or active immunization must prevent these interactions. Because the HIV-1 Env is highly variable, attention has also focused on blocking the HIV-1 primary cell receptor CD4. We therefore analyzed the in vivo protective efficacy of three potent neutralizing monoclonal antibodies (mAbs) to HIV-1 Env compared to an antibody against the CD4 receptor. Protection was assessed after mucosal challenge of rhesus macaques with simian/HIV (SHIV). Despite its comparable or greater neutralization potency in vitro, the anti-CD4 antibody did not provide effective protection in vivo, whereas the HIV-1-specific mAbs VRC01, 10E8, and PG9, targeting the CD4 binding site, membrane-proximal, and V1V2 glycan Env regions, respectively, conferred complete protection, albeit at different relative potencies. These findings demonstrate the protective efficacy of broadly neutralizing antibodies directed to the HIV-1 Env and suggest that targeting the HIV-1 Env is preferable to the cell surface receptor CD4 for the prevention of HIV-1 transmission.
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Affiliation(s)
- Amarendra Pegu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Zhi-yong Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Jeffrey C Boyington
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Lan Wu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Sung-Youl Ko
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Stephen D Schmidt
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Krisha McKee
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Wing-Pui Kong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Wei Shi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Xuejun Chen
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - John-Paul Todd
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Norman L Letvin
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA. Division of Viral Pathogenesis, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, RE113, P. O. Box 15732, Boston, MA 02115, USA
| | - Jinghe Huang
- HIV-Specific Immunity Section, Laboratory of Immunoregulation, NIAID, NIH, Bethesda, MD 20892, USA
| | - Martha C Nason
- Biostatistics Research Branch, NIAID, NIH, Bethesda, MD 20892, USA
| | - James A Hoxie
- Biostatistics Research Branch, NIAID, NIH, Bethesda, MD 20892, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - Mark Connors
- HIV-Specific Immunity Section, Laboratory of Immunoregulation, NIAID, NIH, Bethesda, MD 20892, USA
| | - Srinivas S Rao
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA.
| | - Gary J Nabel
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 40 Convent Drive, Bethesda, MD 20892, USA.
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Abstract
INTRODUCTION Highly active antiretroviral therapy has been the big paradigm for transforming HIV infection in a chronic disease. However, it requires lifelong administration as the HIV provirus integrated within infected cells cannot be eliminated and virus replication resumes following antiviral discontinuation. Cumulative toxicities, incomplete immune restoration, elevated cost, drug-drug interactions and selection of drug-resistant viruses are well-known limitations of prolonged HIV medication. AREAS COVERED The first proof-of-concept that HIV infection could be cured was the Berlin patient. By blocking infection of target cells, gene therapy may allow viral clearance from carriers or prevention of infection in newly exposed individuals. Advances in the field of gene-targeting strategies, T-cell-based approaches and human stem cells are revolutionizing the field. A series of ongoing and planned trials are testing gene therapy as HIV cure. The ultimate goal is the elimination of latent viral reservoirs in HIV-infected persons and the need for lifelong antiretroviral therapy. Following a search in PubMed, we have reviewed current gene therapy strategies investigated for HIV infection as well as the latest communications on HIV eradication presented at international conferences. EXPERT OPINION Multiple efforts are underway to reproduce the Berlin patient situation by engineering autologous T cells or hematopoietic stem cells resistant to HIV infection. There is no doubt that the major challenge is the elimination of latent viral reservoirs. With this goal in mind, we have entered a new era in the hope for HIV cure.
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Affiliation(s)
- Carmen de Mendoza
- Puerta de Hierro Research Institute and University Hospital, Department of Internal Medicine , Majadahonda, Madrid , Spain
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21
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Rational design and characterization of the novel, broad and potent bispecific HIV-1 neutralizing antibody iMabm36. J Acquir Immune Defic Syndr 2014; 66:473-83. [PMID: 24853313 DOI: 10.1097/qai.0000000000000218] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Although broadly neutralizing monoclonal antibodies (bNAbs) have always been considered to be a potential therapeutic option for the prophylaxis and treatment of HIV infection, their lack of breadth against all HIV variants has been one of the limiting factors. To provide sufficient neutralization breadth and potency against diverse viruses, including neutralization escape mutants, strategies to combine different bNAbs have been explored recently. METHODS We rationally designed and engineered a novel bispecific HIV-1-neutralizing antibody (bibNAb), iMabm36. The potency and breadth of iMabm36 against HIV were extensively characterized in vitro. RESULTS iMabm36 comprises the anti-CD4 Ab ibalizumab (iMab) linked to 2 copies of the single-domain Ab m36, which targets a highly conserved CD4-induced epitope. iMabm36 neutralizes a majority of a large, multiclade panel of pseudoviruses (96%, n = 118) at an IC50 concentration of less than 10 µg/mL, with 83% neutralized at an IC50 concentration of less than 0.1 µg/mL. In addition, iMabm36 neutralizes a small panel of replication-competent transmitted-founder viruses to 100% inhibition at a concentration of less than 0.1 µg/mL in a peripheral blood mononuclear cell-based neutralizing assay. Mechanistically, the improved antiviral activity of iMabm36 is dependent on both the CD4-binding activity of the iMab component and the CD4i-binding activity of the m36 component. After characterizing that viral resistance to iMabm36 neutralization was due to mutations residing in the bridging sheet of gp120, an optimized m36 variant was engineered that, when fused to iMab, improved antiviral activity significantly. CONCLUSIONS The interdependency of this dual mechanism of action enables iMabm36 to potently inhibit HIV-1 entry. These results demonstrate that mechanistic-based design of bibNAbs can generate potential preventive and therapeutic candidates for HIV/AIDS.
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22
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Menéndez-Arias L, Alvarez M. Antiretroviral therapy and drug resistance in human immunodeficiency virus type 2 infection. Antiviral Res 2013; 102:70-86. [PMID: 24345729 DOI: 10.1016/j.antiviral.2013.12.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 12/02/2013] [Accepted: 12/06/2013] [Indexed: 12/19/2022]
Abstract
One to two million people worldwide are infected with the human immunodeficiency virus type 2 (HIV-2), with highest prevalences in West African countries, but also present in Western Europe, Asia and North America. Compared to HIV-1, HIV-2 infection undergoes a longer asymptomatic phase and progresses to AIDS more slowly. In addition, HIV-2 shows lower transmission rates, probably due to its lower viremia in infected individuals. There is limited experience in the treatment of HIV-2 infection and several antiretroviral drugs used to fight HIV-1 are not effective against HIV-2. Effective drugs against HIV-2 include nucleoside analogue reverse transcriptase (RT) inhibitors (e.g. zidovudine, tenofovir, lamivudine, emtricitabine, abacavir, stavudine and didanosine), protease inhibitors (saquinavir, lopinavir and darunavir), and integrase inhibitors (raltegravir, elvitegravir and dolutegravir). Maraviroc, a CCR5 antagonist blocking coreceptor binding during HIV entry, is active in vitro against CCR5-tropic HIV-2 but more studies are needed to validate its use in therapeutic treatments against HIV-2 infection. HIV-2 strains are naturally resistant to a few antiretroviral drugs developed to suppress HIV-1 propagation such as nonnucleoside RT inhibitors, several protease inhibitors and the fusion inhibitor enfuvirtide. Resistance selection in HIV-2 appears to be faster than in HIV-1. In this scenario, the development of novel drugs specific for HIV-2 is an important priority. In this review, we discuss current anti-HIV-2 therapies and mutational pathways leading to drug resistance.
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Affiliation(s)
- Luis Menéndez-Arias
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain.
| | - Mar Alvarez
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain
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23
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Abstract
The human immunodeficiency virus (HIV) enters cells through a series of molecular interactions between the HIV envelope protein and cellular receptors, thus providing many opportunities to block infection. Entry inhibitors are currently being used in the clinic, and many more are under development. Unfortunately, as is the case for other classes of antiretroviral drugs that target later steps in the viral life cycle, HIV can become resistant to entry inhibitors. In contrast to inhibitors that block viral enzymes in intracellular compartments, entry inhibitors interfere with the function of the highly variable envelope glycoprotein as it continuously adapts to changing immune pressure and available target cells in the extracellular environment. Consequently, pathways and mechanisms of resistance for entry inhibitors are varied and often involve mutations across the envelope gene. This review provides a broad overview of entry inhibitor resistance mechanisms that inform our understanding of HIV entry and the design of new inhibitors and vaccines.
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Affiliation(s)
- Christopher J De Feo
- Office of Vaccine Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, 8800 Rockville Pike, Bethesda, MD 20892, USA.
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24
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Abstract
PURPOSE OF REVIEW Clinical trials of oral preexposure prophylaxis (PrEP) have focused on regimens of tenofovir (TDF) with or without emtricitabine (FTC). However, TDF may be associated with toxicities (renal, bone), and FTC may select for drug resistance. Both are also first-line drugs for HIV treatment. In this review, we discuss agents that might serve as alternatives to TDF/FTC for HIV PrEP. RECENT FINDINGS Several drug characteristics are important to consider when selecting agents for PrEP with the most critical being safety, tolerability, adequate penetration into target tissues for prevention of HIV infection, and long-lasting activity with convenient dosing. With these factors in mind, we review five potentially useful agents for PrEP. The first group includes drugs that are already Food and Drug Administration approved (maraviroc, raltegravir) with attributes that make them attractive for PrEP. The second group includes investigational agents with long-lasting activity that are being developed in parenteral form (rilpivirine-long acting, S/GSK1265744, ibalizumab). SUMMARY Future PrEP drugs may give clinicians the flexibility to select agents on the basis of individual patient needs and preferences.
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Kang Y, Guo J, Chen Z. Closing the door to human immunodeficiency virus. Protein Cell 2013; 4:86-102. [PMID: 23479426 DOI: 10.1007/s13238-012-2111-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 11/22/2012] [Indexed: 10/27/2022] Open
Abstract
The pandemic of human immunodeficiency virus type one (HIV-1), the major etiologic agent of acquired immunodeficiency disease (AIDS), has led to over 33 million people living with the virus, among which 18 million are women and children. Until now, there is neither an effective vaccine nor a therapeutic cure despite over 30 years of efforts. Although the Thai RV144 vaccine trial has demonstrated an efficacy of 31.2%, an effective vaccine will likely rely on a breakthrough discovery of immunogens to elicit broadly reactive neutralizing antibodies, which may take years to achieve. Therefore, there is an urgency of exploring other prophylactic strategies. Recently, antiretroviral treatment as prevention is an exciting area of progress in HIV-1 research. Although effective, the implementation of such strategy faces great financial, political and social challenges in heavily affected regions such as developing countries where drug resistant viruses have already been found with growing incidence. Activating latently infected cells for therapeutic cure is another area of challenge. Since it is greatly difficult to eradicate HIV-1 after the establishment of viral latency, it is necessary to investigate strategies that may close the door to HIV-1. Here, we review studies on non-vaccine strategies in targeting viral entry, which may have critical implications for HIV-1 prevention.
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Affiliation(s)
- Yuanxi Kang
- AIDS Institute and Department of Microbiology of Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
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Anti-CD4 monoclonal antibody ibalizumab exhibits breadth and potency against HIV-1, with natural resistance mediated by the loss of a V5 glycan in envelope. J Acquir Immune Defic Syndr 2013; 62:1-9. [PMID: 23023102 DOI: 10.1097/qai.0b013e3182732746] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Passive immunization for the prevention of HIV-1 infection is currently being reenergized. The anti-CD4 monoclonal antibody ibalizumab has demonstrated safety and efficacy in phase 1 and 2 clinical trials for treatment of HIV-1 infection and is undergoing a phase 1 clinical trial in HIV-1 uninfected individuals for prevention. Here, we sought to assess ibalizumab antiviral breadth and potency and to identify determinants of natural preexisting resistance. METHODS Ibalizumab breadth and potency was assessed against a large clinically relevant panel of HIV-1 pseudoviruses (n = 116) commonly used to assess vaccine candidates. Determinants of resistance were assessed by sequence analysis. RESULTS Ibalizumab neutralized 92% and 66% of viruses as defined by 50% and 80% inhibition, respectively. Median in vitro neutralization potency by IC50 was 0.03 μg/mL, substantially lower than the broadly neutralizing mAbs, PG9, or VRC01. The dominant determinant of resistance was the absence of a potential N-linked glycosylation site (PNGS) at the V5 N-terminus (P < 0.001), with the V2 loop length possibly influencing the degree of resistance afforded by the absence of the V5 N-terminal PNGS (P = 0.001). Other significant independent correlates of resistance included PNGS at position 386 and the side chain length of residue 375. Ibalizumab exhibited complementary resistance to VRC01 (P = 0.006) and sCD4 (P < 0.001), in part mediated by the V5 PNGS. CONCLUSIONS Ibalizumab breadth and potency compared favorably with broadly neutralizing anti-HIV-1 monoclonal antibodies, supporting the clinical development of ibalizumab, alone or in combination, for HIV-1 prevention.
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Flego M, Ascione A, Cianfriglia M, Vella S. Clinical development of monoclonal antibody-based drugs in HIV and HCV diseases. BMC Med 2013; 11:4. [PMID: 23289632 PMCID: PMC3565905 DOI: 10.1186/1741-7015-11-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 01/04/2013] [Indexed: 12/21/2022] Open
Abstract
Today there are many licensed antiviral drugs, but the emergence of drug resistant strains sometimes invalidates the effects of the current therapies used in the treatment of infectious diseases. Compared to conventional antiviral drugs, monoclonal antibodies (mAbs) used as pharmacological molecules have particular physical characteristics and modes of action, and, therefore, they should be considered as a distinct therapeutic class. Despite being historically validated, antibodies may represent a novel tool for combatting infectious diseases. The current high cost of mAbs' production, storage and administration (by injection only) and the consequent obstacles to development are outweighed by mAbs' clinical advantages. These are related to a low toxicity combined with high specificity and versatility, which allows a specific antibody to mediate various biological effects, ranging from the virus neutralization mechanisms to the modulation of immune responses.This review briefly summarizes the recent technological advances in the field of immunoglobulin research, and the current status of mAb-based drugs in clinical trials for HIV and HCV diseases. For each clinical trial the available data are reported and the emerging conceptual problems of the employed mAbs are highlighted.This overview helps to give a clear picture of the efficacy and challenges of the mAbs in the field of these two infectious diseases which have such a global impact.
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Affiliation(s)
- Michela Flego
- Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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Abstract
Antibody-based therapeutics have been successfully used for the treatment of various diseases and as research tools. Several well characterized, broadly neutralizing monoclonal antibodies (bnmAbs) targeting HIV-1 envelope glycoproteins or related host cell surface proteins show sterilizing protection of animals, but they are not effective when used for therapy of an established infection in humans. Recently, a number of novel bnmAbs, engineered antibody domains (eAds), and multifunctional fusion proteins have been reported which exhibit exceptionally potent and broad neutralizing activity against a wide range of HIV-1 isolates from diverse genetic subtypes. eAds could be more effective in vivo than conventional full-size antibodies generated by the human immune system. Because of their small size (12∼15 kD), they can better access sterically restricted epitopes and penetrate densely packed tissue where HIV-1 replicates than the larger full-size antibodies. HIV-1 possesses a number of mechanisms to escape neutralization by full-size antibodies but could be less likely to develop resistance to eAds. Here, we review the in vitro and in vivo antiviral efficacies of existing HIV-1 bnmAbs, summarize the development of eAds and multispecific fusion proteins as novel types of HIV-1 inhibitors, and discuss possible strategies to generate more potent antibody-based candidate therapeutics against HIV-1, including some that could be used to eradicate the virus.
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Affiliation(s)
- Rui Gong
- Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Institutes of Health, Frederick, MD 21702-1201, USA.
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29
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Chen W, Dimitrov DS. Monoclonal antibody-based candidate therapeutics against HIV type 1. AIDS Res Hum Retroviruses 2012; 28:425-34. [PMID: 21827278 DOI: 10.1089/aid.2011.0226] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Treatment of HIV-1 infection has been highly successful with small molecule drugs. However, resistance still develops. In addition, long-term use can lead to toxicity with unpredictable effects on health. Finally, current drugs do not lead to HIV-1 eradication. The presence of the virus leads to chronic inflammation, which can result in increased morbidity and mortality after prolonged periods of infection. Monoclonal antibodies (mAbs) have been highly successful during the past two decades for therapy of many diseases, primarily cancers and immune disorders. They are relatively safe, especially human mAbs that have evolved in humans at high concentrations to fight diseases and long-term use may not lead to toxicities. Several broadly neutralizing mAbs (bnmAbs) against HIV-1 can protect animals but are not effective when used for therapy of an established infection. We have hypothesized that HIV-1 has evolved strategies to effectively escape neutralization by full-size antibodies in natural infections but not by smaller antibody fragments. Therefore, a promising direction of research is to discover and exploit antibody fragments as potential candidate therapeutics against HIV-1. Here we review several bnmAbs and engineered antibody domains (eAds), their in vitro and in vivo antiviral efficacy, mechanisms used by HIV-1 to escape them, and strategies that could be effective to develop more powerful mAb-based HIV-1 therapeutics.
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Affiliation(s)
- Weizao Chen
- Protein Interactions Group, Center for Cancer Research Nanobiology Program, National Cancer Institute (NCI)-Frederick, National Institutes of Health (NIH), Frederick, Maryland
| | - Dimiter S. Dimitrov
- Protein Interactions Group, Center for Cancer Research Nanobiology Program, National Cancer Institute (NCI)-Frederick, National Institutes of Health (NIH), Frederick, Maryland
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Fessel WJ, Anderson B, Follansbee SE, Winters MA, Lewis ST, Weinheimer SP, Petropoulos CJ, Shafer RW. The efficacy of an anti-CD4 monoclonal antibody for HIV-1 treatment. Antiviral Res 2011; 92:484-7. [PMID: 22001594 DOI: 10.1016/j.antiviral.2011.09.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 08/18/2011] [Accepted: 09/28/2011] [Indexed: 11/26/2022]
Abstract
The availability of 24 antiretroviral (ARV) drugs within six distinct drug classes has transformed HIV-1 infection (AIDS) into a treatable chronic disease. However, the ability of HIV-1 to develop resistance to multiple classes continues to present challenges to the treatment of many ARV treatment-experienced patients. In this case report, we describe the response to ibalizumab, an investigational CD4-binding monoclonal antibody (mAb), in a patient with advanced immunodeficiency and high-level five-class antiretroviral resistance. After starting an ibalizumab-based salvage regimen, the patient had an approximately 4.0 log(10) reduction in viral load. An inadvertently missed infusion at week 32 led to the rapid loss of virologic response and decreased susceptibility to the remainder of the patient's salvage therapy regimen. Following the reinstitution of ibalizumab, phenotypic and genotypic resistance to ibalizumab was detected. Nonetheless, plasma HIV-1 RNA levels stabilized at ∼2.0 log(10) copies/ml below pre-ibalizumab levels. Continued ARV drug development may yield additional clinical and public health benefits. This report illustrates the promise of mAbs for HIV-1 therapy in highly treatment-experienced patients. Therapeutic mAbs may also have a role in pre-exposure prophylaxis in high-risk uninfected populations and may facilitate directly observed therapy (DOT) if two or more synergistic long acting agents become available.
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Affiliation(s)
- W Jeffrey Fessel
- Kaiser Permanente Medical Care Program - Northern California, San Francisco, 94118, United States.
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31
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HIV microbicides: state-of-the-art and new perspectives on the development of entry inhibitors. Future Med Chem 2011; 2:1141-59. [PMID: 21426161 DOI: 10.4155/fmc.10.203] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Since the discovery of HIV at the beginning of the 1980s, numerous efforts have been devoted to the search of an efficient vaccine. There are at least 25 drugs available for HIV treatment, but no cure is available. The observation that therapy for HIV disease is life long and that these drugs are associated with a number of side effects underlines the need for approaches aimed at preventing rather than treating infection. Additionally, the economic burden of treatment for the HIV infection occupies an increasing share of healthcare expenditure, making current practices likely to become difficult to sustain in the long run. Unfortunately, no effective vaccine for this disease is foreseeable in the near future. Microbicides could be an alternate way to build preventative approaches to HIV infection. Strategies based on preventing the virus from reaching its target cells seem to have some room for development and application. In this review we explore the state-of-the-art of available microbicides, focusing on HIV entry inhibitors. In addition, we discuss new compounds that show anti-HIV activity, which could be effective candidates.
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32
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Singh IP, Chauthe SK. Small molecule HIV entry inhibitors: Part II. Attachment and fusion inhibitors: 2004-2010. Expert Opin Ther Pat 2011; 21:399-416. [PMID: 21342055 DOI: 10.1517/13543776.2011.550876] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The first US FDA approved HIV entry inhibitor drug Enfuvirdine belongs to the fusion inhibitor category. Earlier efforts in this area were focused on peptides and monoclonal antibodies; recently, the focus has shifted towards the development of small molecule HIV attachment and fusion inhibitors. They can be used for prophylactic purposes and also hold potential for the development of HIV microbicides. AREAS COVERED In a previous paper ('Small molecule HIV entry inhibitors: Part I'), we reviewed patents and patent applications for small molecule chemokine receptor antagonists from major pharmaceutical companies. In this paper, the development of small molecule HIV attachment and fusion inhibitors is discussed in detail. It covers patents and patent applications for small molecule HIV attachment and fusion inhibitors published between 2004 and 2010 and related literature with a focus on recent developments based on lead generation and lead modification. EXPERT OPINION To augment the potency of currently available antiretroviral drug combinations and to fight drug-resistant virus variants, more effective drugs which target additional steps in the viral replication cycle are urgently needed. HIV attachment and fusion processes are such targets. Inhibitors of these targets will provide additional options for the treatment of HIV drug-resistant strains. Small molecule HIV attachment inhibitors such as BMS-378806 and analogs from Bristol Myers Squibb, N-aryl piperidine derivatives from Propharmacon, and NBD-556 and NBD-557 from New York Blood Center may have potential as vaginal microbicidal agents and can be an economical alternative to monoclonal antibodies.
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Affiliation(s)
- Inder Pal Singh
- National Institute of Pharmaceutical Education and Research (NIPER), Department of Natural Products, Sector-67, S.A.S. Nagar, Punjab 160062, India.
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33
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Freeman MM, Seaman MS, Rits-Volloch S, Hong X, Kao CY, Ho DD, Chen B. Crystal structure of HIV-1 primary receptor CD4 in complex with a potent antiviral antibody. Structure 2011; 18:1632-41. [PMID: 21134642 DOI: 10.1016/j.str.2010.09.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 09/07/2010] [Accepted: 09/29/2010] [Indexed: 10/18/2022]
Abstract
Ibalizumab is a humanized, anti-CD4 monoclonal antibody. It potently blocks HIV-1 infection and targets an epitope in the second domain of CD4 without interfering with immune functions mediated by interaction of CD4 with major histocompatibility complex (MHC) class II molecules. We report here the crystal structure of ibalizumab Fab fragment in complex with the first two domains (D1-D2) of CD4 at 2.2 Å resolution. Ibalizumab grips CD4 primarily by the BC-loop (residues 121-125) of D2, sitting on the opposite side of gp120 and MHC-II binding sites. No major conformational change in CD4 accompanies binding to ibalizumab. Both monovalent and bivalent forms of ibalizumab effectively block viral infection, suggesting that it does not need to crosslink CD4 to exert antiviral activity. While gp120-induced structural rearrangements in CD4 are probably minimal, CD4 structural rigidity is dispensable for ibalizumab inhibition. These results could guide CD4-based immunogen design and lead to a better understanding of HIV-1 entry.
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Affiliation(s)
- Michael M Freeman
- Division of Molecular Medicine, Children's Hospital, and Department of Pediatrics, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115, USA
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34
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Loss of asparagine-linked glycosylation sites in variable region 5 of human immunodeficiency virus type 1 envelope is associated with resistance to CD4 antibody ibalizumab. J Virol 2011; 85:3872-80. [PMID: 21289125 DOI: 10.1128/jvi.02237-10] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Ibalizumab (formerly TNX-355) is a first-in-class, monoclonal antibody inhibitor of CD4-mediated human immunodeficiency type 1 (HIV-1) entry. Multiple clinical trials with HIV-infected patients have demonstrated the antiviral activity, safety, and tolerability of ibalizumab treatment. A 9-week phase Ib study adding ibalizumab monotherapy to failing drug regimens led to transient reductions in HIV viral loads and the evolution of HIV-1 variants with reduced susceptibility to ibalizumab. This report characterizes these variants by comparing the phenotypic susceptibilities and envelope (env) sequences of (i) paired baseline and on-treatment virus populations, (ii) individual env clones from selected paired samples, and (iii) env clones containing site-directed mutations. Viruses with reduced susceptibility to ibalizumab were found to exhibit reduced susceptibility to the anti-CD4 antibody RPA-T4. Conversely, susceptibility to soluble CD4, which targets the HIV-1 gp120 envelope protein, was enhanced. No changes in susceptibility to the fusion inhibitor enfuvirtide or the CCR5 antagonist maraviroc were observed. Functionally, viruses with reduced ibalizumab susceptibility also displayed high levels of infectivity relative to those of paired baseline viruses. Individual env clones exhibiting reduced ibalizumab susceptibility contained multiple amino acid changes in different regions relative to the paired baseline clones. In particular, clones with reduced susceptibility to ibalizumab contained fewer potential asparagine-linked glycosylation sites (PNGSs) in variable region 5 (V5) than did paired ibalizumab-susceptible clones. The reduction in ibalizumab susceptibility due to the loss of V5 PNGSs was confirmed by site-directed mutagenesis. Taken together, these findings provide important insights into resistance to this new class of antiretroviral drug.
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35
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Matthias LJ, Azimi I, Tabrett CA, Hogg PJ. Reduced monomeric CD4 is the preferred receptor for HIV. J Biol Chem 2010; 285:40793-9. [PMID: 20974843 PMCID: PMC3003380 DOI: 10.1074/jbc.m110.190579] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Indexed: 11/06/2022] Open
Abstract
CD4 is a co-receptor for binding of T cells to antigen-presenting cells and the primary receptor for the human immunodeficiency virus type 1 (HIV). CD4 exists in three different forms on the cell surface defined by the state of the domain 2 cysteine residues: an oxidized monomer, a reduced monomer, and a covalent dimer linked through the domain 2 cysteines. The disulfide-linked dimer is the preferred immune co-receptor. The form of CD4 that is preferred by HIV was examined in this study. HIV entry and envelope-mediated cell-cell fusion were tested using cells expressing comparable levels of wild-type or disulfide bond mutant CD4 in which the domain 2 cysteines were mutated to alanine. Eliminating the domain 2 disulfide bond increased entry of HIV reporter viruses and enhanced HIV envelope-mediated cell-cell fusion 2-4-fold. These observations suggest that HIV enters susceptible cells preferably through monomeric reduced CD4, whereas dimeric CD4 is the preferred receptor for binding to antigen-presenting cells. Cleavage of the domain 2 disulfide bond is possibly involved in the conformational change in CD4 associated with fusion of the HIV and cell membranes.
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Affiliation(s)
- Lisa J. Matthias
- From the Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Iman Azimi
- From the Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Catherine A. Tabrett
- From the Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Philip J. Hogg
- From the Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales 2052, Australia
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36
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Hertje M, Zhou M, Dietrich U. Inhibition of HIV-1 Entry: Multiple Keys to Close the Door. ChemMedChem 2010; 5:1825-35. [DOI: 10.1002/cmdc.201000292] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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37
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Bruno CJ, Jacobson JM. Ibalizumab: an anti-CD4 monoclonal antibody for the treatment of HIV-1 infection. J Antimicrob Chemother 2010; 65:1839-41. [PMID: 20639524 DOI: 10.1093/jac/dkq261] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The majority of currently available agents for the treatment of HIV-1 infection act by targeting one of several intracellular steps in the viral life cycle. Despite improvements in efficacy and tolerability, the development of viral resistance to these agents is common and significant toxicity and adherence issues still occur. For this reason the development of safe, well tolerated antiviral agents that target a novel step in the viral life cycle remains important. Viral entry into host cells affords several potential extracellular targets for antiretroviral therapy. Ibalizumab, a humanized monoclonal antibody to CD4, the primary host cellular receptor for HIV-1 entry, has been shown to block HIV-1 entry in vitro. Early clinical trials have demonstrated significant antiviral efficacy with a >1 log(10) reduction in viral load when given as monotherapy. Its long half-life, which allows weekly dosing, and its administration as an intravenous infusion differentiate it from other currently available antiretroviral agents. These properties may prove useful in allowing improved drug delivery to patients who have had difficulty adhering to daily oral regimens. Its unique mode of action reduces the risk of cross-resistance with currently available antiretroviral agents, with the potential to expand the choices available to treat drug-resistant HIV-1.
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Affiliation(s)
- Christopher J Bruno
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
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38
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Epitope mapping of ibalizumab, a humanized anti-CD4 monoclonal antibody with anti-HIV-1 activity in infected patients. J Virol 2010; 84:6935-42. [PMID: 20463063 DOI: 10.1128/jvi.00453-10] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ibalizumab is a humanized monoclonal antibody that binds human CD4, the primary receptor for human immunodeficiency virus type 1 (HIV-1). With its unique specificity for domain 2 of CD4, this antibody potently and broadly blocks HIV-1 infection in vitro by inhibiting a postbinding step required for viral entry but without interfering with major histocompatibility complex class II (MHC-II)-mediated immune function. In clinical trials, ibalizumab has demonstrated anti-HIV-1 activity in patients without causing immunosuppression. Thus, a characterization of the ibalizumab epitope was conducted in an attempt to gain insight into the underlying mechanism of its antiviral activity as well as its safety profile. By studying mouse/human chimeric CD4 molecules and site-directed point mutants of CD4, amino acids L96, P121, P122, and Q163 in domain 2 were found to be important for ibalizumab binding, with E77 and S79 in domain 1 also contributing. All these residues appear to cluster on the interface between domains 1 and 2 of human CD4 on a surface opposite the site where gp120 and the MHC-II molecule bind on domain 1. Separately, the epitope of M-T441, a weakly neutralizing mouse monoclonal antibody that competes with ibalizumab, was localized entirely within domain 2 on residues 123 to 125 and 138 to 140. The results reported herein not only provide an appreciation for why ibalizumab has not had significant adverse immunological consequences in infected patients to date but also raise possible steric hindrance mechanisms by which this antibody blocks HIV-1 entry into a CD4-positive cell.
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Tilton JC, Doms RW. Entry inhibitors in the treatment of HIV-1 infection. Antiviral Res 2009; 85:91-100. [PMID: 19683546 DOI: 10.1016/j.antiviral.2009.07.022] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 07/21/2009] [Accepted: 07/30/2009] [Indexed: 11/15/2022]
Abstract
Infection of target cells by HIV is a complex, multi-stage process involving attachment to host cells and CD4 binding, coreceptor binding, and membrane fusion. Drugs that block HIV entry are collectively known as entry inhibitors, but comprise a complex group of drugs with multiple mechanisms of action depending on the stage of the entry process at which they act. Two entry inhibitors, maraviroc and enfuvirtide, have been approved for the treatment of HIV-1 infection, and a number of agents are in development. This review covers the entry inhibitors and their use in the management of HIV-1 infection. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.
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Affiliation(s)
- John C Tilton
- Department of Microbiology, University of Pennsylvania, 301C Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, United States.
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40
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Qian K, Morris-Natschke SL, Lee KH. HIV entry inhibitors and their potential in HIV therapy. Med Res Rev 2009; 29:369-93. [PMID: 18720513 DOI: 10.1002/med.20138] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This review discusses recent progress in the development of anti-HIV agents targeting the viral entry process. The three main classes (attachment inhibitors, co-receptor binding inhibitors, and fusion inhibitors) are further broken down by specific mechanism of action and structure. Many of these inhibitors are in advanced clinical trials, including the HIV maturation inhibitor bevirimat, from the authors' laboratories. In addition, the CCR5 inhibitor maraviroc has recently been FDA-approved. Possible roles for these agents in anti-HIV therapy, including treatment of virus resistant to current drugs, are also discussed.
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Affiliation(s)
- Keduo Qian
- Natural Products Research Laboratories, School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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41
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Juncadella IJ, Anguita J. The immunosuppresive tick salivary protein, Salp15. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 666:121-31. [PMID: 20054980 DOI: 10.1007/978-1-4419-1601-3_10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The interaction between Ixodid ticks and their mammalian hosts is a complex relationship. While the mammalian host tries to avoid the completion of the feeding process, the tick has devised strategies to counteract these attempts. Tick saliva contains a vast array of pharmacological activities that presumably aid the tick to evade host responses, including anticomplement, oxidative and innate and adaptive immune responses. The characterization of these activities has gained momentum in the last several years. One of the best studied activities present in tick saliva corresponds to the antigen known as Salp15, which binds specifically to the T-cell coreceptor CD4 resulting in the specific repression of CD4+ T-cell activation. We discuss here the current state of our knowledge of the mode of action of this salivary protein.
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Affiliation(s)
- Ignacio J Juncadella
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA 01003, USA
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42
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Mastrolorenzo A, Maresca A, Rusconi S, Supuran CT. Update on the development of HIV entry inhibitors. ACTA ACUST UNITED AC 2008. [DOI: 10.2217/17469600.2.5.479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
HIV fusion and entry are two steps in the viral lifecycle that can be targeted by several classes of antiviral drugs. The discovery of chemokines focused the attention on cellular co-receptors used by the virus for entering cells, and on the various steps of such processes that are subject to interactions with small molecules. Intense research has led to a wide range of effective compounds that are able to inhibit these initial steps of viral replication. All steps in the process of HIV entry into the cell may be targeted by specific compounds, grouped into three main classes (attachment inhibitors, co-receptor binding inhibitors and fusion inhibitors), which may be developed as novel antiretrovirals. Thus, several inhibitors of the gp120–CD4 interaction have been discovered (e.g., zintevir and BMS-378806). Small molecule chemokine receptor antagonists acting as HIV entry inhibitors have also been described recently, including those which interact with both the CXCR4 co-receptor (e.g., AMD3100, AMD3465, ALX40-4C, T22, T134 and T140) and CCR5 co-receptor antagonists (TAK-779, TAK-220, E913, AK-602 and NSC 651016 in clinical trials). Recently, a third family of antivirals started to be used clinically (in addition to reverse transcriptase and protease inhibitors), with the advent of enfuvirtide (T20), the first fusion inhibitor to be approved as an anti-HIV agent. Some of these compounds demonstrated in vitro synergism with other classes of antivirals, thus offering the rationale for their combination in therapies for HIV-infected individuals. Many HIV entry and fusion inhibitors are currently being investigated in controlled clinical trials, and a number of them are bioavailable as oral formulations. In 2007, the US FDA approved maraviroc as an anti-HIV agent. Maraviroc is the product of a medicinal chemistry effort initiated following identification of an imidazopyridine CCR5 ligand from a high-throughput screen of the Pfizer compound file. Maraviroc demonstrated potent antiviral activity against all CCR5-tropic HIV-1 viruses tested, including 43 primary isolates from various clades and diverse geographic origin. Maraviroc was active against 200 clinically derived HIV-1 envelope-recombinant pseudoviruses, 100 of which were derived from viruses resistant to existing drug classes. Furthermore, in October 2007, the FDA announced the approval of raltegravir for the treatment of HIV-1 infection as part of combination antiretroviral therapy in treatment-experienced patients with evidence of HIV-1 replication despite optimized background antiretroviral therapy. At present, raltegravir is the only drug in the integrase inhibitor class approved for clinical use. With the approval of raltegravir, oral agents targeting all three constitutive viral enzymes, reverse transcriptase, protease and integrase, are now represented in FDA-approved therapies.
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Affiliation(s)
- Antonio Mastrolorenzo
- Università degli Studi di Firenze, Dipartimento di Scienze Dermatologiche, Centro MTS, Via degli Alfani 37, I-50121 Florence, Italy
| | - Alfonso Maresca
- Università degli Studi di Firenze, Dipartimento di Chimica, Laboratorio di Chimica Bioinorganica, Via della Lastruccia, 3, Rm. 188, I-50019 Sesto Fiorentino (Florence), Italy
| | - Stefano Rusconi
- Dipartimento di Scienze Cliniche “Luigi Sacco”, Cattedra di Malattie Infettive e Tropicali, Università degli Studi, Ospedale Luigi Sacco, Via GB Grassi 74, 20157 Milano, Italy
| | - Claudiu T Supuran
- Università degli Studi di Firenze, Dipartimento di Chimica, Laboratorio di Chimica Bioinorganica, Via della Lastruccia, 3, Rm. 188, I-50019 Sesto Fiorentino (Florence), Italy
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Kaushik-Basu N, Basu A, Harris D. Peptide inhibition of HIV-1: current status and future potential. BioDrugs 2008; 22:161-75. [PMID: 18481899 DOI: 10.2165/00063030-200822030-00003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
More than 2 decades of intensive research has focused on defining replication mechanisms of HIV type 1 (HIV-1), the etiologic agent of AIDS. The delineation of strategies for combating this viral infection has yielded many innovative approaches toward this end. HIV-1 is a lentivirus in the family retroviridae that is relatively small with regard to both structure and genome size, having a diploid RNA genome of approximately 9 kb, with only three major genes and several gene products resulting from alternate splicing and translational frameshifting. Most marketed drugs for treating AIDS are inhibitors of HIV-1 reverse transcriptase or protease enzymes, but new targets include the integrase enzyme, cell surface interactions that facilitate viral entry, and also virus particle maturation and assembly. The emergence of drug-resistant variants of HIV-1 has been the main impediment to successful treatment of AIDS. Thus, there is a pressing need to develop novel treatment strategies targeting multiple stages of the virus life-cycle. Research efforts aimed at developing successful means for combating HIV-1 infection have included development of peptide inhibitors of HIV-1. This article summarizes past and current endeavors in the development of peptides that inhibit replication of HIV-1 and the role of peptide inhibitors in the search for new anti-HIV drugs.
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Affiliation(s)
- Neerja Kaushik-Basu
- Department of Biochemistry and Molecular Biology, UMDNJ-New Jersey Medical School, Newark, NJ 07103, USA.
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Schweizer A, Rusert P, Berlinger L, Ruprecht CR, Mann A, Corthésy S, Turville SG, Aravantinou M, Fischer M, Robbiani M, Amstutz P, Trkola A. CD4-specific designed ankyrin repeat proteins are novel potent HIV entry inhibitors with unique characteristics. PLoS Pathog 2008; 4:e1000109. [PMID: 18654624 PMCID: PMC2453315 DOI: 10.1371/journal.ppat.1000109] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 06/24/2008] [Indexed: 11/18/2022] Open
Abstract
Here, we describe the generation of a novel type of HIV entry inhibitor using the recently developed Designed Ankyrin Repeat Protein (DARPin) technology. DARPin proteins specific for human CD4 were selected from a DARPin DNA library using ribosome display. Selected pool members interacted specifically with CD4 and competed with gp120 for binding to CD4. DARPin proteins derived in the initial selection series inhibited HIV in a dose-dependent manner, but showed a relatively high variability in their capacity to block replication of patient isolates on primary CD4 T cells. In consequence, a second series of CD4-specific DARPins with improved affinity for CD4 was generated. These 2nd series DARPins potently inhibit infection of genetically divergent (subtype B and C) HIV isolates in the low nanomolar range, independent of coreceptor usage. Importantly, the actions of the CD4 binding DARPins were highly specific: no effect on cell viability or activation, CD4 memory cell function, or interference with CD4-independent virus entry was observed. These novel CD4 targeting molecules described here combine the unique characteristics of DARPins-high physical stability, specificity and low production costs-with the capacity to potently block HIV entry, rendering them promising candidates for microbicide development.
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Affiliation(s)
- Andreas Schweizer
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
| | - Peter Rusert
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
| | - Livia Berlinger
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
| | - Claudia R. Ruprecht
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
| | - Axel Mann
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
| | - Stéphanie Corthésy
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
| | - Stuart G. Turville
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Meropi Aravantinou
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Marek Fischer
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
| | - Melissa Robbiani
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | | | - Alexandra Trkola
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
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Juncadella IJ, Garg R, Bates TC, Olivera ER, Anguita J. The Ixodes scapularis salivary protein, salp15, prevents the association of HIV-1 gp120 and CD4. Biochem Biophys Res Commun 2007; 367:41-6. [PMID: 18162176 DOI: 10.1016/j.bbrc.2007.12.104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Accepted: 12/11/2007] [Indexed: 10/22/2022]
Abstract
Ixodes scapularis salivary protein, Salp15, inhibits CD4(+) T cell activation by binding to the most-extracellular domains of the CD4 molecule, potentially overlapping with the gp120-binding region. We now show that Salp15 inhibits the interaction of gp120 and CD4. Furthermore, Salp15 prevents syncytia formation between HL2/3 (a stable HeLa cell line expressing the envelope protein) and CD4-expressing cells. Salp15 prevented gp120-CD4 interaction at least partially through its direct interaction with the envelope glycoprotein. A phage display library screen provided the interacting residues in the C1 domain of gp120. These results provide a potential basis to define exposed gp120 epitopes for the generation of neutralizing vaccines.
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Affiliation(s)
- Ignacio J Juncadella
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 103 Paige Laboratory, 161 Holdsworth Way, Amherst, MA 01003, USA
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Huber M, Olson WC, Trkola A. Antibodies for HIV treatment and prevention: window of opportunity? Curr Top Microbiol Immunol 2007; 317:39-66. [PMID: 17990789 DOI: 10.1007/978-3-540-72146-8_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Monoclonal antibodies are routinely used as therapeutics in a number of disease settings and have thus also been explored as potential treatment for human immunodeficiency virus (HIV)-1 infection. Antibodies targeting viral antigens, and those directed to the cellular receptors, have been considered for use in prevention and therapy. For virus-targeted antibodies, attention has focused primarily on their neutralizing activity, but such antibodies also have the potential to exert antiviral effects via effector functions, such as antibody-dependent cellular cytotoxicity (ADCC), opsonization, or complement activation. Anti-cell antibodies act through occlusion or down-modulation of the viral receptors with notable impact in vivo, as recent trials have shown. This review summarizes the diverse specificities and modes of action of therapeutic antibodies against HIV-1 infection. Successes, challenges, and future opportunities of harnessing antibodies for therapy of HIV-1 infection are discussed.
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Affiliation(s)
- M Huber
- Division of Infectious Diseases, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland
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Schön A, Freire E. Strategies for targeting HIV-1 envelope glycoprotein gp120 in the development of new antivirals. ACTA ACUST UNITED AC 2007. [DOI: 10.2217/17469600.1.2.223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The efficacy of highly active antiretroviral therapy for the treatment of HIV-1/AIDS is continuously threatened by viral mutations that lower the potency of one or more of its components and by the occurrence of severe side effects that lead to poor patient compliance. There is an urgent need for the development of drugs against new viral targets. Among the most attractive targets for drug development is the viral envelope glycoprotein gp120, responsible for the initial step in viral infection. gp120 binds to the cell surface receptor CD4 and initiates the cascade of events that culminates with the entry of the virus into the cell. Two classes of drugs are being developed against gp120, drugs that block the attachment of the virus and drugs that inhibit the subsequent activation mechanism. Both approaches are discussed in this article.
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Affiliation(s)
- Arne Schön
- The Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
| | - Ernesto Freire
- The Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
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Abstract
Vaccine-induced antibodies that interfere with viral entry are the protective correlate of most existing prophylactic vaccines. However, for highly variable viruses such as HIV-1, the ability to elicit broadly neutralizing antibody responses through vaccination has proven to be extremely difficult. The major targets for HIV-1 neutralizing antibodies are the viral envelope glycoprotein trimers on the surface of the virus that mediate receptor binding and entry. HIV-1 has evolved many mechanisms on the surface of envelope glycoproteins to evade antibody-mediated neutralization, including the masking of conserved regions by glycan, quaternary protein interactions and the presence of immunodominant variable elements. The primary challenge in the development of an HIV-1 vaccine that elicits broadly neutralizing antibodies therefore lies in the design of suitable envelope glycoprotein immunogens that circumvent these barriers. Here, we describe neutralizing determinants on the viral envelope glycoproteins that are defined by their function in receptor binding or by rare neutralizing antibodies isolated from HIV-infected individuals. We also describe the nonvariable cellular receptors involved in the HIV-1 entry process, or other cellular proteins, and ongoing studies to determine if antibodies against these proteins have efficacy as therapeutic reagents or, in some cases, as vaccine targets to interfere with HIV-1 entry.
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Affiliation(s)
- S Phogat
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 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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Abstract
There are many promising new agents in development for the treatment of HIV type 1 (HIV-1). The targets of antiretroviral drugs include the three major HIV-1 enzymes (reverse transcriptase, protease, and integrase), final packaging and export of mature virions, and entry mediated by the CD4 receptor and the CCR5 and CXCR4 coreceptors. Drugs in development in existing classes are primarily designed to provide new options for those with resistance to existing agents. Novel agents such as those targeting integrase, entry inhibitors, and those targeting viral processing likely will be useful the treatment of antiretroviral-experienced patients. Depending on safety, efficacy, tolerability, and convenience of dosing, new agents may also alter the current treatment paradigms for first-line therapy. This review summarizes data on several drugs that could move forward into the clinical arena and affect the lives of those infected with HIV-1.
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Affiliation(s)
- Caitlin Reed
- Division of HIV Medicine, Harbor-UCLA Medical Center, 1124 West Carson Street, N-24, Torrance, CA 90502, USA
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