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Birkmann A, Bonsmann S, Kropeit D, Pfaff T, Rangaraju M, Sumner M, Timmler B, Zimmermann H, Buschmann H, Ruebsamen-Schaeff H. Discovery, Chemistry, and Preclinical Development of Pritelivir, a Novel Treatment Option for Acyclovir-Resistant Herpes Simplex Virus Infections. J Med Chem 2022; 65:13614-13628. [PMID: 36202389 PMCID: PMC9620171 DOI: 10.1021/acs.jmedchem.2c00668] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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When the nucleoside analogue acyclovir was introduced
in the early
1980s, it presented a game-changing treatment modality for herpes
simplex virus infections. Since then, work has been ongoing to improve
the weaknesses that have now been identified: a narrow time window
for therapeutic success, resistance in immunocompromised patients,
little influence on frequency of recurrences, relatively fast elimination,
and poor bioavailability. The present Drug Annotation focuses on the
helicase–primase inhibitor pritelivir currently in development
for the treatment of acyclovir-resistant HSV infections and describes
how a change of the molecular target (from viral DNA polymerase to
the HSV helicase–primase complex) afforded improvement of the
shortcomings of nucleoside analogs. Details are presented for the
discovery process leading to the final drug candidate, the pivotal
preclinical studies on mechanism of action and efficacy, and on how
ongoing clinical research has been able to translate preclinical promises
into clinical use.
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Affiliation(s)
| | | | - Dirk Kropeit
- AiCuris Anti-Infective Cures AG, 42117 Wuppertal, Germany
| | - Tamara Pfaff
- AiCuris Anti-Infective Cures AG, 42117 Wuppertal, Germany
| | | | - Melanie Sumner
- AiCuris Anti-Infective Cures AG, 42117 Wuppertal, Germany
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Disturbed Yin-Yang balance: stress increases the susceptibility to primary and recurrent infections of herpes simplex virus type 1. Acta Pharm Sin B 2020; 10:383-398. [PMID: 32140387 PMCID: PMC7049575 DOI: 10.1016/j.apsb.2019.06.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 05/27/2019] [Accepted: 05/31/2019] [Indexed: 12/19/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1), a neurotropic herpes virus, is able to establish a lifelong latent infection in the human host. Following primary replication in mucosal epithelial cells, the virus can enter sensory neurons innervating peripheral tissues via nerve termini. The viral genome is then transported to the nucleus where it can be maintained without producing infectious progeny, and thus latency is established in the cell. Yin–Yang balance is an essential concept in traditional Chinese medicine (TCM) theory. Yin represents stable and inhibitory factors, and Yang represents the active and aggressive factors. When the organism is exposed to stress, especially psychological stress caused by emotional stimulation, the Yin–Yang balance is disturbed and the virus can re-engage in productive replication, resulting in recurrent diseases. Therefore, a better understanding of the stress-induced susceptibility to HSV-1 primary infection and reactivation is needed and will provide helpful insights into the effective control and treatment of HSV-1. Here we reviewed the recent advances in the studies of HSV-1 susceptibility, latency and reactivation. We included mechanisms involved in primary infection and the regulation of latency and described how stress-induced changes increase the susceptibility to primary and recurrent infections.
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Key Words
- 4E-BP, eIF4E-binding protein
- AD, Alzheimer's disease
- AKT, protein kinase B
- AMPK, AMP-dependent kinase
- BCL-2, B-cell lymphoma 2
- CNS, central nervous system
- CORT, corticosterone
- CPE, cytopathic effect
- CTCF, CCCTC-binding factor
- CTL, cytotoxic T lymphocyte
- CoREST, REST corepressor 1
- DAMPs, damage-associated molecular patterns
- DCs, dendritic cells
- DEX, dexamethasone
- GREs, GR response elements
- GRs, glucocorticoid receptors
- H3K9, histone H3 on lysines 9
- HCF-1, host cell factor 1
- HDACs, histone deacetylases
- HPA axis, hypothalamo–pituitary–adrenal axis
- HPK, herpetic simplex keratitis
- HPT axis, hypothalamic–pituitary–thyroid axis
- HSV-1
- HSV-1, herpes simplex virus type 1
- Herpes simplex virus type 1
- ICP, infected cell polypeptide
- IRF3, interferon regulatory factor 3
- KLF15, Krüppel-like transcription factor 15
- LAT, latency-associated transcripts
- LRF, Luman/CREB3 recruitment factor
- LSD1, lysine-specific demethylase 1
- Latency
- MAVS, mitochondrial antiviral-signaling protein
- MOI, multiplicity of infection
- ND10, nuclear domains 10
- NGF, nerve growth factor
- NK cells, natural killer cells
- OCT-1, octamer binding protein 1
- ORFs, open reading frames
- PAMPs, pathogen-associated molecular patterns
- PDK1, pyruvate dehydrogenase lipoamide kinase isozyme 1
- PI3K, phosphoinositide 3-kinases
- PML, promyelocytic leukemia protein
- PNS, peripheral nervous system
- PRC1, protein regulator of cytokinesis 1
- PRRs, pattern-recognition receptors
- PTMs, post-translational modifications
- RANKL, receptor activator of NF-κB ligands
- REST, RE1-silencing transcription factor
- ROS, reactive oxygen species
- Reactivation
- SGKs, serum and glucocorticoid-regulated protein kinases
- SIRT1, sirtuin 1
- Stress
- Susceptibility
- T3, thyroid hormone
- TCM, traditional Chinese medicine
- TG, trigeminal ganglia
- TK, thymidine kinase
- TRIM14, tripartite motif-containing 14
- TRKA, tropomyosin receptor kinase A
- TRM, tissue resident memory T cells
- cGAS, cyclic GMP-AMP synthase
- mTOR, mammalian target of rapamycin
- sncRNAs, small non-coding RNAs
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Koujah L, Suryawanshi RK, Shukla D. Pathological processes activated by herpes simplex virus-1 (HSV-1) infection in the cornea. Cell Mol Life Sci 2019; 76:405-419. [PMID: 30327839 PMCID: PMC6349487 DOI: 10.1007/s00018-018-2938-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/03/2018] [Accepted: 10/08/2018] [Indexed: 12/13/2022]
Abstract
Herpes simplex virus type-1 (HSV-1) is a ubiquitous pathogen that infects a large majority of the human population worldwide. It is also a leading cause of infection-related blindness in the developed world. HSV-1 infection of the cornea begins with viral entry into resident cells via a multistep process that involves interaction of viral glycoproteins and host cell surface receptors. Once inside, HSV-1 infection induces a chronic immune-inflammatory response resulting in corneal scarring, thinning and neovascularization. This leads to development of various ocular diseases such as herpes stromal keratitis, resulting in visual impairment and eventual blindness. HSV-1 can also invade the central nervous system and lead to encephalitis, a relatively common cause of sporadic fetal encephalitis worldwide. In this review, we discuss the pathological processes activated by corneal HSV-1 infection and existing antiviral therapies as well as novel therapeutic options currently under development.
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Affiliation(s)
- Lulia Koujah
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 W. Taylor St, Chicago, IL, 60612, USA
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Rahul K Suryawanshi
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 W. Taylor St, Chicago, IL, 60612, USA
| | - Deepak Shukla
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 W. Taylor St, Chicago, IL, 60612, USA.
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, 60612, USA.
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Andronova VL. MODERN ETHIOTROPIC CHEMOTHERAPY OF HERPESVIRUS INFECTIONS: ADVANCES, NEW TRENDS AND PERSPECTIVES. ALPHAHERPESVIRUSES (PART II). Vopr Virusol 2018; 63:149-159. [PMID: 36494970 DOI: 10.18821/0507-4088-2018-63-4-149-159] [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: 01/20/2020] [Indexed: 12/13/2022]
Abstract
A key role in the treatment of herpesviral infections is played by modified nucleosides and their predecessors - acyclovir, its L-valine ester (valaciclovir) and famciclovir (prodrug of penciclovir). The biological activity of compounds of this class is determined by their similarity to natural nucleosides. After phosphorylation by viral thymidine kinase and then cell enzymes to the triphosphate forms, acyclovir and penciclovir inhibit the activity of viral DNA polymerase and synthesis of viral DNA. The increasing role of herpesvirus infections in human infectious pathology, as well as the development of drug resistance in viruses, mainly in patients with immunodeficiencies of various origins, necessitate the search for new compounds possessing anti-herpesvirus activity, using as a biological target not DNA polymerase, but other viral proteins and enzymes, unique or different from cellular proteins, performing similar functions.
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Affiliation(s)
- V L Andronova
- National Research Center for Epidemiology and Microbiology named after the honorary academician N.F. Gamaleya
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5
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Abstract
Herpes simplex virus (HSV), a member of the Herpesviridae family, is a significant human pathogen that results in mucocutaneous lesions in the oral cavity or genital infections. Acyclovir (ACV) and related nucleoside analogues can successfully treat HSV infections, but the emergence of drug resistance to ACV has created a barrier for the treatment of HSV infections, especially in immunocompromised patients. There is an urgent need to explore new and effective tactics to circumvent drug resistance to HSV. This review summarises the current strategies in the development of new targets (the DNA helicase/primase (H/P) complex), new types of molecules (nature products) and new antiviral mechanisms (lethal mutagenesis of Janus-type nucleosides) to fight the drug resistance of HSV.
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6
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Sweeney NL, Hanson AM, Mukherjee S, Ndjomou J, Geiss BJ, Steel JJ, Frankowski KJ, Li K, Schoenen FJ, Frick DN. Benzothiazole and Pyrrolone Flavivirus Inhibitors Targeting the Viral Helicase. ACS Infect Dis 2015; 1:140-148. [PMID: 26029739 DOI: 10.1021/id5000458] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The flavivirus nonstructural protein 3 (NS3) is a protease and helicase, and on the basis of its similarity to its homologue encoded by the hepatitis C virus (HCV), the flavivirus NS3 might be a promising drug target. Few flavivirus helicase inhibitors have been reported, in part, because few specific inhibitors have been identified when nucleic acid unwinding assays have been used to screen for helicase inhibitors. To explore the possibility that compounds inhibiting NS3-catalyzed ATP hydrolysis might function as antivirals even if they do not inhibit RNA unwinding in vitro, we designed a robust dengue virus (DENV) NS3 ATPase assay suitable for high-throughput screening. Members of two classes of inhibitory compounds were further tested in DENV helicase-catalyzed RNA unwinding assays, assays monitoring HCV helicase action, subgenomic DENV replicon assays, and cell viability assays and for their ability to inhibit West Nile virus (Kunjin subtype) replication in cells. The first class contained analogues of NIH molecular probe ML283, a benzothiazole oligomer derived from the dye primuline, and they also inhibited HCV helicase and DENV NS3-catalyzed RNA unwinding. The most intriguing ML283 analogue inhibited DENV NS3 with an IC50 value of 500 nM and was active against the DENV replicon. The second class contained specific DENV ATPase inhibitors that did not inhibit DENV RNA unwinding or reactions catalyzed by HCV helicase. Members of this class contained a 4-hydroxy-3-(5-methylfuran-2-carbonyl)-2H-pyrrol-5-one scaffold, and about 20 μM of the most potent pyrrolone inhibited both DENV replicons and West Nile virus replication in cells by 50%.
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Affiliation(s)
- Noreena L. Sweeney
- Department of Chemistry and Biochemistry, University of Wisconsin—Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
| | - Alicia M. Hanson
- Department of Chemistry and Biochemistry, University of Wisconsin—Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
| | - Sourav Mukherjee
- Department of Chemistry and Biochemistry, University of Wisconsin—Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
| | - Jean Ndjomou
- Department of Chemistry and Biochemistry, University of Wisconsin—Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
| | - Brian J. Geiss
- Department
of Microbiology, Immunology, and Pathology, 1682 Campus Delivery, Colorado State University, Fort Collins, Colorado 80523, United States
| | - J. Jordan Steel
- Department
of Microbiology, Immunology, and Pathology, 1682 Campus Delivery, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Kevin J. Frankowski
- Specialized
Chemistry Center, University of Kansas, 2034 Becker Drive, Lawrence, Kansas 66047, United States
| | - Kelin Li
- Specialized
Chemistry Center, University of Kansas, 2034 Becker Drive, Lawrence, Kansas 66047, United States
| | - Frank J. Schoenen
- Specialized
Chemistry Center, University of Kansas, 2034 Becker Drive, Lawrence, Kansas 66047, United States
| | - David N. Frick
- Department of Chemistry and Biochemistry, University of Wisconsin—Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
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7
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James SH, Larson KB, Acosta EP, Prichard MN. Helicase-primase as a target of new therapies for herpes simplex virus infections. Clin Pharmacol Ther 2014; 97:66-78. [PMID: 25670384 DOI: 10.1002/cpt.3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/16/2014] [Indexed: 01/13/2023]
Abstract
The seminal discovery of acyclovir 40 years ago heralded the modern era of truly selective antiviral therapies and this drug remains the therapy of choice for herpes simplex virus infections. Yet by modern standards, its antiviral activity is modest and new drugs against novel molecular targets such as the helicase-primase have the potential to improve clinical outcome, particularly in high-risk patients. A brief synopsis of current therapies for these infections and clinical need is provided to help provide an initial perspective. The function of the helicase-primase complex is then summarized and the development of new inhibitors of the helicase-primase complex, such as pritelivir and amenamevir, is discussed. We review their mechanism of action, propensity for drug resistance, and pharmacokinetic characteristics and discuss their potential to advance current therapeutic options. Strategies that include combinations of these inhibitors with acyclovir are also considered, as they will likely maximize clinical efficacy.
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Affiliation(s)
- S H James
- Division of Infectious Diseases, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Wozniak M, Frost A, Itzhaki R. The helicase-primase inhibitor BAY 57–1293 reduces the Alzheimer’s disease-related molecules induced by herpes simplex virus type 1. Antiviral Res 2013; 99:401-4. [DOI: 10.1016/j.antiviral.2013.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/01/2013] [Accepted: 07/05/2013] [Indexed: 11/25/2022]
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Shadrick WR, Ndjomou J, Kolli R, Mukherjee S, Hanson AM, Frick DN. Discovering new medicines targeting helicases: challenges and recent progress. ACTA ACUST UNITED AC 2013; 18:761-81. [PMID: 23536547 PMCID: PMC4427233 DOI: 10.1177/1087057113482586] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Helicases are ubiquitous motor proteins that separate and/or rearrange nucleic acid duplexes in reactions fueled by adenosine triphosphate (ATP) hydrolysis. Helicases encoded by bacteria, viruses, and human cells are widely studied targets for new antiviral, antibiotic, and anticancer drugs. This review summarizes the biochemistry of frequently targeted helicases. These proteins include viral enzymes from herpes simplex virus, papillomaviruses, polyomaviruses, coronaviruses, the hepatitis C virus, and various flaviviruses. Bacterial targets examined include DnaB-like and RecBCD-like helicases. The human DEAD-box protein DDX3 is the cellular antiviral target discussed, and cellular anticancer drug targets discussed are the human RecQ-like helicases and eIF4A. We also review assays used for helicase inhibitor discovery and the most promising and common helicase inhibitor chemotypes, such as nucleotide analogues, polyphenyls, metal ion chelators, flavones, polycyclic aromatic polymers, coumarins, and various DNA binding pharmacophores. Also discussed are common complications encountered while searching for potent helicase inhibitors and possible solutions for these problems.
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Affiliation(s)
- William R Shadrick
- Department of Chemistry & Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
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10
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Abstract
Herpes simplex virus type 1 (HSV-1) establishes a latent infection in sensory neurons that can sometimes be reactivated. HSV-1 keratitis often recurs and can be vision threatening. Reactivation of the latent virus can be stimulated by stress, immunosuppression, trauma, adrenergic iontophoresis, and UV radiation. Healthy and asymptomatic individuals are known to shed HSV-1, and this is a major factor in the spread of the virus. We investigated the frequency of shedding of HSV-1 DNA in tears of dry eye patients and individuals with conjunctivitis. Subjects were divided into 3 groups: normal (12 eyes), dry eye (11 eyes), and conjunctivitis (15 eyes). Quantitative real-time polymerase chain reaction was used for HSV DNA detection. The incidences of HSV positivity in the normal, dry eye, and conjunctivitis groups were 1 of 12 (8.3%), 3 of 11 (27.3%), and 4 of 15 (26.7%), respectively. We have previously shown that bromfenac sodium eye drops, intramuscular adenosine monophosphate, and geldanamycin effectively lower HSV-1 recurrence rates in a mouse model. Recently, we also found that nuclear factor κ-B, an IκB kinase-β inhibitor, could be a candidate for reducing HSV-1 reactivation. We sampled recipients' corneal buttons during keratoplasty and performed polymerase chain reaction. Cytomegalovirus (CMV) DNA was detected in corneas obtained from some patients, and the copy number of the detected CMV DNA was quantified. CMV DNA-positive samples were taken from 2 of the 3 patients with ocular pemphigoid; thus, in future work, the relationship between CMV in the cornea and the incidence/onset of ocular diseases of the anterior segment needs to be evaluated.
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11
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Al-Dujaili LJ, Clerkin PP, Clement C, McFerrin HE, Bhattacharjee PS, Varnell ED, Kaufman HE, Hill JM. Ocular herpes simplex virus: how are latency, reactivation, recurrent disease and therapy interrelated? Future Microbiol 2011; 6:877-907. [PMID: 21861620 DOI: 10.2217/fmb.11.73] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Most humans are infected with herpes simplex virus (HSV) type 1 in early childhood and remain latently infected throughout life. While most individuals have mild or no symptoms, some will develop destructive HSV keratitis. Ocular infection with HSV-1 and its associated sequelae account for the majority of corneal blindness in industrialized nations. Neuronal latency in the peripheral ganglia is established when transcription of the viral genome is repressed (silenced) except for the latency-associated transcripts and microRNAs. The functions of latency-associated transcripts have been investigated since 1987. Roles have been suggested relating to reactivation, establishment of latency, neuronal protection, antiapoptosis, apoptosis, virulence and asymptomatic shedding. Here, we review HSV-1 latent infections, reactivation, recurrent disease and antiviral therapies for the ocular HSV diseases.
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Affiliation(s)
- Lena J Al-Dujaili
- Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, USA
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12
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Birkmann A, Hewlett G, Rübsamen-Schaeff H, Zimmermann H. Helicase–primase inhibitors as the potential next generation of highly active drugs against herpes simplex viruses. Future Virol 2011. [DOI: 10.2217/fvl.11.28] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Since the introduction of the nucleoside analogs decades ago, treatment of herpes simplex virus (HSV) infections has not seen much innovation, except for the development of their respective prodrugs. The inhibitors of the helicase–primase complex of HSV represent a very innovative approach to the treatment of herpesvirus disease, and this article considers the development of some representatives of this class of therapeutics. The molecular and biochemical features of the helicase–primase complex are considered and the development of three inhibitors of helicase–primase, BILS 179 BS, AIC316 and ASP2151, is described. The clinical development of AIC316 is at an advanced stage and displays general safety as well as favorable, long-lasting exposures in healthy volunteers. The first efficacy data from a Phase II trial with more than 150 HSV-2-positive subjects demonstrated dose-dependent antiviral activity.
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Affiliation(s)
- Alexander Birkmann
- AiCuris GmbH & Co. KG, Friedrich-Ebert-Str. 475, 42117 Wuppertal, Germany
| | - Guy Hewlett
- hbsc, Thienhausener Str. 37, 42781 Haan, Germany
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13
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Biswas S, Field HJ. Helicase-Primase Inhibitors: A New Approach to Combat Herpes Simplex Virus and Varicella Zoster Virus. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/9783527635955.ch6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Hobden JA, Kumar M, Kaufman HE, Clement C, Varnell ED, Bhattacharjee PS, Hill JM. In vitro synergism of trifluorothymidine and ganciclovir against HSV-1. Invest Ophthalmol Vis Sci 2011; 52:830-3. [PMID: 20861476 DOI: 10.1167/iovs.10-5671] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine whether trifluorothymidine (TFT) and ganciclovir (GCV) are synergistic against herpes simplex virus type 1 (HSV-1). METHODS TFT and GCV activity against 12 strains of HSV-1 (including an acyclovir-resistant strain) was measured by plaque-forming unit (PFU) inhibition. Cellular toxicity was assessed with an MTT dye reduction assay. Synergism was determined by calculating fractional inhibitory concentration (FIC indices) based on PFU reduction. RESULTS Concentrations of TFT resulting in 50% inhibition of PFUs (IC(50)) of acyclovir-susceptible HSV-1 strains ranged from 3.07 ± 0.36 to 12.52 ± 0.61 μM. GCV IC(50) values ranged from 0.40 ± 0.02 to 1.59 ± 0.14 μM. IC(50) values of TFT and GCV against the acyclovir-resistant strain were 15.40 ± 3.17 and 93.00 ± 9.64 μM, respectively. Concentrations of TFT or GCV resulting in 50% cell cytotoxicity (CC(50)) were 0.99 ± 0.01 and 92.91 ± 8.92 μM, respectively. TFT and GCV combined (10:1) were 10 times more potent against all acyclovir-susceptible HSV-1 strains. For 8 of 12 HSV-1 strains, the IC(50) of TFT and GCV combined was lower than the CC(50) of either drug. For acyclovir-susceptible HSV-1 strains, TFT and GCV combined generated a FIC index of <0.5, suggesting strong synergism between the two drugs. The FIC value for TFT and GCV combined against the acyclovir-resistant HSV-1 strain was 0.84, indicating nonantagonism. CONCLUSIONS TFT and GCV are synergistic against acyclovir-susceptible HSV-1 at concentrations significantly less toxic than if each antiviral were used as a sole agent.
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Affiliation(s)
- Jeffery A Hobden
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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15
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Field HJ, Biswas S. Antiviral drug resistance and helicase-primase inhibitors of herpes simplex virus. Drug Resist Updat 2010; 14:45-51. [PMID: 21183396 DOI: 10.1016/j.drup.2010.11.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 11/17/2022]
Abstract
A new class of chemical inhibitors has been discovered that interferes with the process of herpesvirus DNA replication. To date, the majority of useful herpesvirus antivirals are nucleoside analogues that block herpesvirus DNA replication by targeting the DNA polymerase. The new helicase-primase inhibitors (HPI) target a different enzyme complex that is also essential for herpesvirus DNA replication. This review will place the HPI in the context of previous work on the nucleoside analogues. Several promising highly potent HPI will be described with a particular focus on the identification of drug-resistance mutations. Several HPI have good pharmacological profiles and are now at the outset of phase II clinical trials. Provided there are no safety issues to stop their progress, this new class of compound will be a major advance in the herpesvirus antiviral field. Furthermore, HPI are likely to have a major impact on the therapy and prevention of herpes simplex virus and varicella zoster in both immunocompetent and immunocompromised patients alone or in combination with current nucleoside analogues. The possibility of acquired drug-resistance to HPI will then become an issue of great practical importance.
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Affiliation(s)
- Hugh J Field
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB30ES, United Kingdom.
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16
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Resistance of herpes simplex viruses to nucleoside analogues: mechanisms, prevalence, and management. Antimicrob Agents Chemother 2010; 55:459-72. [PMID: 21078929 DOI: 10.1128/aac.00615-10] [Citation(s) in RCA: 351] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Herpes simplex viruses (HSV) type 1 and type 2 are responsible for recurrent orolabial and genital infections. The standard therapy for the management of HSV infections includes acyclovir (ACV) and penciclovir (PCV) with their respective prodrugs valacyclovir and famciclovir. These compounds are phosphorylated by the viral thymidine kinase (TK) and then by cellular kinases. The triphosphate forms selectively inhibit the viral DNA polymerase (DNA pol) activity. Drug-resistant HSV isolates are frequently recovered from immunocompromised patients but rarely found in immunocompetent subjects. The gold standard phenotypic method for evaluating the susceptibility of HSV isolates to antiviral drugs is the plaque reduction assay. Plaque autoradiography allows the associated phenotype to be distinguished (TK-wild-type, TK-negative, TK-low-producer, or TK-altered viruses or mixtures of wild-type and mutant viruses). Genotypic characterization of drug-resistant isolates can reveal mutations located in the viral TK and/or in the DNA pol genes. Recombinant HSV mutants can be generated to analyze the contribution of each specific mutation with regard to the drug resistance phenotype. Most ACV-resistant mutants exhibit some reduction in their capacity to establish latency and to reactivate, as well as in their degree of neurovirulence in animal models of HSV infection. For instance, TK-negative HSV mutants establish latency with a lower efficiency than wild-type strains and reactivate poorly. DNA pol HSV mutants exhibit different degrees of attenuation of neurovirulence. The management of ACV- or PCV-resistant HSV infections includes the use of the pyrophosphate analogue foscarnet and the nucleotide analogue cidofovir. There is a need to develop new antiherpetic compounds with different mechanisms of action.
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Dropulic LK, Cohen JI. Update on new antivirals under development for the treatment of double-stranded DNA virus infections. Clin Pharmacol Ther 2010; 88:610-9. [PMID: 20881959 PMCID: PMC3426500 DOI: 10.1038/clpt.2010.178] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
All the currently available antiviral agents used in the treatment of double-stranded (ds) DNA viruses, with the exception of interferon-α, inhibit the same target, the viral DNA polymerase. With increasing reports of the development of resistance of herpes simplex virus (HSV), cytomegalovirus (CMV), and hepatitis B virus (HBV) to some of these drugs, new antiviral agents are needed to treat these infections. Additionally, no drugs have been approved to treat several DNA virus infections, including those caused by adenovirus, smallpox, molluscum contagiosum, and BK virus. We report the status of 10 new antiviral drugs for the treatment of dsDNA viruses. CMX-001 has broad activity against dsDNA viruses; 3 helicase-primase inhibitors, maribavir, and FV-100 have activity against certain herpesviruses; ST-246 inhibits poxviruses; GS-9191 inhibits papillomaviruses; and clevudine and emtricitabine are active against HBV. Most of these drugs have completed at least phase I trials in humans, and many are in additional clinical trials.
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Affiliation(s)
- Lesia K. Dropulic
- Medical Virology Section, Laboratory of Clinical Infectious Diseases, Bldg. 10, Room 11N234, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892
| | - Jeffrey I. Cohen
- Medical Virology Section, Laboratory of Clinical Infectious Diseases, Bldg. 10, Room 11N234, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892
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Shimomura Y, Higaki S, Watanabe K. Suppression of herpes simplex virus 1 reactivation in a mouse eye model by cyclooxygenase inhibitor, heat shock protein inhibitor, and adenosine monophosphate. Jpn J Ophthalmol 2010; 54:187-90. [PMID: 20577849 DOI: 10.1007/s10384-010-0803-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 02/24/2010] [Indexed: 11/29/2022]
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Sukla S, Biswas S, Birkmann A, Lischka P, Ruebsamen-Schaeff H, Zimmermann H, Field HJ. Effects of therapy using a helicase-primase inhibitor (HPI) in mice infected with deliberate mixtures of wild-type HSV-1 and an HPI-resistant UL5 mutant. Antiviral Res 2010; 87:67-73. [PMID: 20420855 DOI: 10.1016/j.antiviral.2010.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Revised: 04/19/2010] [Accepted: 04/20/2010] [Indexed: 10/19/2022]
Abstract
Point mutations in the HSV-1 UL5 (helicase) gene confer resistance to helicase-primase inhibitors (HPIs), e.g. BAY 57-1293. Such mutations normally occur at a frequency of < or =10(-6)PFU. However, individual HSV-1 laboratory strains and some clinical isolates contained resistance mutations (e.g. UL5: Lys356Asn) at 10(-4)PFU. To address the possibility that pre-existing mutants at high frequency might have an impact on therapy using HPIs, deliberate mixtures were prepared to contain the SC16 UL5: Lys356Asn mutant in SC16 wild-type in the proportion of 1/500 or 1/50PFU. Mice were infected in the neck-skin with 5x10(4)PFU/mouse of wt alone, mutant alone, or the respective mixture. The mutant could not be detected in infectious virus yields from mice inoculated with the 1/500 mixture. However, resistant mutant was recovered from some treated mice inoculated with the 1/50 mixture. All mice inoculated with mixtures remained responsive to BAY 57-1293-therapy with no increase in clinical signs compared to treatment of wt-infected mice.
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Affiliation(s)
- Soumi Sukla
- Department of Veterinary Medicine, University of Cambridge, United Kingdom
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Wilson SS, Fakioglu E, Herold BC. Novel approaches in fighting herpes simplex virus infections. Expert Rev Anti Infect Ther 2009; 7:559-68. [PMID: 19485796 DOI: 10.1586/eri.09.34] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The development of novel strategies to eradicate herpes simplex virus (HSV) is a global public health priority. While acyclovir and related nucleoside analogues provide successful modalities for treatment and suppression, HSV remains highly prevalent worldwide and is a major cofactor fueling the HIV epidemic. HSV is the predominant cause of genital ulcerative disease, and neonatal and sporadic infectious encephalitis. Asymptomatic shedding, which occurs more frequently than previously appreciated, contributes to viral transmission. Acyclovir resistance may be problematic for immunocompromised patients and highlights the need for new safe and effective agents. Ideally, vaccines to prevent infection, drugs to inhibit the establishment of or reactivation from latency, or vaginal microbicides to prevent sexual and perinatal transmission are needed to control the epidemic. This review summarizes current therapeutic options and strategies in development.
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Affiliation(s)
- Sarah S Wilson
- Department of Pediatrics, Albert Einstein College of Medicine, Forchheimer 702, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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Higaki S, Watanabe K, Itahashi M, Shimomura Y. Cyclooxygenase (COX)-inhibiting drug reduces HSV-1 reactivation in the mouse eye model. Curr Eye Res 2009; 34:171-6. [PMID: 19274523 DOI: 10.1080/02713680802650377] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE To examine the effects of COX inhibitors on suppressing HSV-1 reactivation in a mouse model. METHODS BALB/c mice were latently infected with HSV-1 and treated by 0.1% bromfenac Na eye drops, 0.1% pranoprofen eye drops, 0.1 mg oral etodolac 4 times/day, and saline for 4 days. After reactivating the latent HSV-1, we swabbed the mouse ocular surface for the culture of the infectious virus and assessed the viral loads in the eyes and trigeminal ganglia (TGs) using real-time PCR to determine the treatment efficacies. RESULTS With stimulated reactivation, 10 of 24 (41.7%), 5 of 10 (50.0%), 17 of 25 (68%), and 16 of 22 eyes (72.7%) showed positive swab results in the bromfenac Na, etodolac, pranoprofen, and saline groups, respectively; and a significant difference was seen only between the bromfenac Na and saline groups (p = 0.033). None of the three drug-treated groups showed any significant difference from the saline group in the viral DNA in the eyes and TGs (p > 0.05). CONCLUSIONS Bromfenac Na eye drops can suppress HSV-1 reactivation.
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Affiliation(s)
- Shiro Higaki
- Department of Ophthalmology, Kinki University School of Medicine, Osaka-Sayama, Japan.
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