1
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Acyclovir resistance in herpes simplex viruses: Prevalence and therapeutic alternatives. Biochem Pharmacol 2022; 206:115322. [DOI: 10.1016/j.bcp.2022.115322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/20/2022] [Accepted: 10/20/2022] [Indexed: 11/19/2022]
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2
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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: 7] [Impact Index Per Article: 3.5] [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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3
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Roy S, Sukla S, De A, Biswas S. Non-cytopathic herpes simplex virus type-1 isolated from acyclovir-treated patients with recurrent infections. Sci Rep 2022; 12:1345. [PMID: 35079057 PMCID: PMC8789845 DOI: 10.1038/s41598-022-05188-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 01/05/2022] [Indexed: 11/09/2022] Open
Abstract
Herpes simplex virus (HSV) usually produces cytopathic effect (CPE) within 24-72 h post-infection (P.I.). Clinical isolates from recurrent HSV infections in patients on Acyclovir therapy were collected between 2016 and 2019 and tested in cell cultures for cytopathic effects and further in-depth characterization. Fourteen such isolates did not show any CPE in A549 or Vero cell lines even at 120 h P.I. However, these cultures remained positive for HSV-DNA after several passages. Sequence analysis revealed that the non-CPE isolates were all HSV-1. Analysis of the thymidine kinase gene from the isolates revealed several previously reported and two novel ACV-resistant mutations. Immunofluorescence and Western blot data revealed a low-level expression of the immediate early protein, ICP4. Late proteins like ICP5 or capsid protein, VP16 were almost undetectable in these isolates. AFM imaging revealed that the non-CPE viruses had structural deformities compared to wild-type HSV-1. Our findings suggest that these strains are manifesting an unusual phenomenon of being non-CPE herpesviruses with low level of virus protein expressions over several passages. Probably these HSV-1 isolates are evolving towards a more "cryptic" form to establish chronic infection in the host thereby unraveling yet another strategy of herpesviruses to evade the host immune system.
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Affiliation(s)
- Subrata Roy
- Infectious Diseases and Immunology Division, CSIR- Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, West Bengal, 700032, India
| | - Soumi Sukla
- Infectious Diseases and Immunology Division, CSIR- Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, West Bengal, 700032, India
- Department of Pharmacology and Toxicology, National Institute of Pharmaceuticals Education and Research, 168, Maniktala Main Road, Kolkata, West Bengal, India
| | - Abhishek De
- Department of Dermatology, Calcutta National Medical College and Hospital, Kolkata, West Bengal, India
| | - Subhajit Biswas
- Infectious Diseases and Immunology Division, CSIR- Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, West Bengal, 700032, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India.
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4
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Characteristics of Helicase-primase Inhibitor Amenamevir-resistant Herpes Simplex Virus. Antimicrob Agents Chemother 2021; 65:e0049421. [PMID: 34228537 DOI: 10.1128/aac.00494-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antiherpetic drug amenamevir (AMNV) inhibits the helicase-primase complex of herpes simplex virus type 1 (HSV-1), HSV-2 and varicella-zoster virus directly as well as inhibiting the replication of these viruses. Although several mutated HSV viruses resistant to helicase-primase inhibitors have been reported, the mutations contributing to the resistance remain unclear as recombinant viruses containing a single mutation have not been analyzed. We obtained AMNV-resistant viruses with amino acid substitutions by several passages under AMNV-treatment. Twenty HSV-1 and 19 HSV-2 mutants with mutation(s) in UL5 helicase and/or UL52 primase, but not in co-factor UL8, were isolated. The mutations in UL5 were located downstream of motif IV, with UL5 K356N in HSV-1 and K355N in HSV-2, in particular, identified as having the highest frequency: 9/20 and 9/19, respectively. We generated recombinant AMNV-resistant HSV-1 with a single amino acid substitution using BAC mutagenesis. As a result, G352C in UL5 helicase and F360C/V and N902T in UL52 primase were identified as novel mutations. The virus with K356N in UL5 showed 10-fold higher AMNV resistance than did other mutants, and showed equivalent viral growth in vitro and virulence in vivo as the parent HSV-1, although other mutants showed attenuated virulence. All recombinant viruses were susceptible to the other antiherpetic drugs, acyclovir and foscarnet. In conclusion, based on BAC mutagenesis, this study identified for the first time mutations in UL5 and UL52 that contributed to AMNV resistance, and found that a mutant with the most frequent K356N mutation in HSV-1 maintained viral growth and virulence equivalent to the parent virus.
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5
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Current Drugs to Treat Infections with Herpes Simplex Viruses-1 and -2. Viruses 2021; 13:v13071228. [PMID: 34202050 PMCID: PMC8310346 DOI: 10.3390/v13071228] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/11/2021] [Accepted: 06/21/2021] [Indexed: 12/11/2022] Open
Abstract
Herpes simplex viruses-1 and -2 (HSV-1 and -2) are two of the three human alphaherpesviruses that cause infections worldwide. Since both viruses can be acquired in the absence of visible signs and symptoms, yet still result in lifelong infection, it is imperative that we provide interventions to keep them at bay, especially in immunocompromised patients. While numerous experimental vaccines are under consideration, current intervention consists solely of antiviral chemotherapeutic agents. This review explores all of the clinically approved drugs used to prevent the worst sequelae of recurrent outbreaks by these viruses.
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Piret J, Boivin G. Antiviral Drugs Against Herpesviruses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1322:1-30. [PMID: 34258735 DOI: 10.1007/978-981-16-0267-2_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The discovery of the nucleoside analogue, acyclovir, represented a milestone in the management of infections caused by herpes simplex virus and varicella-zoster virus. Ganciclovir, another nucleoside analogue, was then used for the management of systemic and organ-specific human cytomegalovirus diseases. The pyrophosphate analogue, foscarnet, and the nucleotide analogue, cidofovir, have been approved subsequently and constitute the second-line antiviral drugs. However, the viral DNA polymerase is the ultimate target of all these antiviral agents with a possible emergence of cross-resistance between these drugs. Recently, letermovir that targets the viral terminase complex was approved for the prophylaxis of human cytomegalovirus infections in hematopoietic stem cell transplant recipients. Other viral targets such as the protein kinase and the helicase-primase complex are also evaluated for the development of novel potent inhibitors against herpesviruses.
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Affiliation(s)
| | - Guy Boivin
- CHU de Québec-Laval University, Quebec City, QC, Canada.
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7
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Topalis D, Gillemot S, Snoeck R, Andrei G. Thymidine kinase and protein kinase in drug-resistant herpesviruses: Heads of a Lernaean Hydra. Drug Resist Updat 2018; 37:1-16. [PMID: 29548479 DOI: 10.1016/j.drup.2018.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Herpesviruses thymidine kinase (TK) and protein kinase (PK) allow the activation of nucleoside analogues used in anti-herpesvirus treatments. Mutations emerging in these two genes often lead to emergence of drug-resistant strains responsible for life-threatening diseases in immunocompromised populations. In this review, we analyze the binding of different nucleoside analogues to the TK active site of the three α-herpesviruses [Herpes Simplex Virus 1 and 2 (HSV-1 and HSV-2) and Varicella-Zoster Virus (VZV)] and present the impact of known mutations on the structure of the viral TKs. Furthermore, models of β-herpesviruses [Human cytomegalovirus (HCMV) and human herpesvirus-6 (HHV-6)] PKs allow to link amino acid changes with resistance to ganciclovir and/or maribavir, an investigational chemotherapeutic used in patients with multidrug-resistant HCMV. Finally, we set the basis for the understanding of drug-resistance in γ-herpesviruses [Epstein-Barr virus (EBV) and Kaposi's sarcoma associated herpesvirus (KSHV)] TK and PK through the use of animal surrogate models.
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Affiliation(s)
- Dimitri Topalis
- Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, 3000 Leuven, Belgium.
| | - Sarah Gillemot
- Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, 3000 Leuven, Belgium.
| | - Robert Snoeck
- Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, 3000 Leuven, Belgium.
| | - Graciela Andrei
- Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, 3000 Leuven, Belgium.
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8
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Abstract
PURPOSE OF REVIEW The mainstay of antiviral therapy for the alpha-herpesviruses [herpes simplex virus (HSV)-1, HSV-2, and varicella zoster virus (VZV)] over the past 40 years has been the nucleoside analogues such as aciclovir. Although conventional antiviral therapy has reduced mortality in severe disease, novel agents are needed to address the emergence of resistance and toxicity associated with current second-line therapy. Treatment and prophylaxis of VZV and HSV reactivations remains a challenge. RECENT FINDINGS A number of compounds have recently been evaluated in human clinical trials, amongst them brincidofovir, an intracellularly acting derivative of cidofovir currently undergoing phase III trials. The helicase-primase inhibitors are a new class of antiviral agent and may circumvent resistance to existing agents. Amenamevir and pritelivir are two examples of these agents that have been evaluated clinically along with novel nucleoside analogues such as valomaciclovir and FV-100. Tenofovir, an agent used in HIV and hepatitis B therapy, may also have a role in the prevention of HSV-2 acquisition and reduce viral shedding. SUMMARY Although several novel antiviral agents have undergone clinical trials in recent years, all are yet to gain licensure. Brincidofovir appears to be the candidate with most promise for adoption into routine practice in the near future.
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9
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Edlefsen PT, Birkmann A, Huang ML, Magaret CA, Kee JJ, Diem K, Goldner T, Timmler B, Stoelben S, Ruebsamen-Schaeff H, Zimmermann H, Warren T, Wald A, Corey L. No Evidence of Pritelivir Resistance Among Herpes Simplex Virus Type 2 Isolates After 4 Weeks of Daily Therapy. J Infect Dis 2016; 214:258-64. [PMID: 27056950 PMCID: PMC4918824 DOI: 10.1093/infdis/jiw129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/24/2016] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Pritelivir is a novel helicase-primase inhibitor in clinical development for treatment of herpes simplex virus type 2 (HSV-2) infections. In preclinical work, resistance-mediating mutations were identified in the HSV-2 genome at 3 loci in the UL5 gene and 1 locus in UL52. METHODS To evaluate whether daily pritelivir treatment results in emergence of resistance-mediating mutations, we analyzed HSV-2 strains detected in genital swab specimens from trial participants who were randomly assigned to receive different dosages of pritelivir. We sequenced resistance regions from 87 participants' samples, the UL5 gene in 73 samples from 44 participants, and the UL52 gene in 71 samples from 43 participants. RESULTS We found no evidence that pritelivir induced known resistance-mediating mutations or for amino acid variation at other loci. In one participant's HSV-2 isolate, we found a previously unidentified mutation close to the putative resistance-mediating region in UL5 and subsequently determined in vitro susceptibility to pritelivir. We characterized mutations from 32 cultivated HSV-2 isolates previously found to be susceptible to pritelivir in vitro and identified several novel mutations that most likely reflect preexisting variation in circulating HSV-2. CONCLUSIONS This study demonstrates evidence of retained susceptibility of HSV-2 to pritelivir in immunocompetent persons following daily therapy for up to 28 days.
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Affiliation(s)
- Paul T Edlefsen
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Biostatistics
| | | | - Meei-Li Huang
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Laboratory Medicine
| | - Craig A Magaret
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center
| | - Jia Jin Kee
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Biostatistics
| | - Kurt Diem
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Laboratory Medicine
| | | | | | | | | | | | | | - Anna Wald
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Laboratory Medicine Department of Epidemiology Department of Medicine, University of Washington, Seattle
| | - Lawrence Corey
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Laboratory Medicine Department of Medicine, University of Washington, Seattle
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10
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Sanchez MD, Ochoa AC, Foster TP. Development and evaluation of a host-targeted antiviral that abrogates herpes simplex virus replication through modulation of arginine-associated metabolic pathways. Antiviral Res 2016; 132:13-25. [PMID: 27192555 DOI: 10.1016/j.antiviral.2016.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 04/21/2016] [Accepted: 05/13/2016] [Indexed: 11/16/2022]
Abstract
Since their inception five decades ago, most antivirals have been engineered to disrupt a single viral protein or process that is essential for viral replication. This approach has limited the overall therapeutic effectiveness and applicability of current antivirals due to restricted viral specificity, a propensity for development of drug resistance, and an inability to control deleterious host-mediated inflammation. As obligate intracellular parasites, viruses are reliant on host metabolism and macromolecular synthesis pathways. Of these biosynthetic processes, many viruses, including Herpes simplex viruses (HSV), are absolutely dependent on the bioavailability of arginine, a non-essential amino acid that is critical for many physiological and pathophysiological processes associated with either facilitating viral replication or progression of disease. To assess if targeting host arginine-associated metabolic pathways would inhibit HSV replication, a pegylated recombinant human Arginase I (peg-ArgI) was generated and its in vitro anti-herpetic activity was evaluated. Cells continuously treated with peg-ArgI for over 48 h exhibited no signs of cytotoxicity or loss of cell viability. The antiviral activity of peg-ArgI displayed a classical dose-response curve with IC50's in the sub-nanomolar range. peg-ArgI potently inhibited HSV-1 and HSV-2 viral replication, infectious virus production, cell-to-cell spread/transmission and virus-mediated cytopathic effects. Not unexpectedly given its host-targeted mechanism of action, peg-ArgI showed similar effectiveness at controlling replication of single and multidrug resistant HSV-1 mutants. These findings illustrate that targeting host arginine-associated metabolic pathways is an effective means of controlling viral replicative processes. Further exploration into the breadth of viruses inhibited by peg-ArgI, as well as the ability of peg-ArgI to suppress arginine-associated virus-mediated pathophysiological disease processes is warranted.
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Affiliation(s)
- Maria Dulfary Sanchez
- Department of Microbiology, Immunology, and Parasitology, School of Medicine, Louisiana State University Health Sciences Center, USA; Department of Pediatrics, School of Medicine, Louisiana State University Health Sciences Center, USA; The Stanley S. Scott Cancer Center, School of Medicine, Louisiana State University Health Sciences Center, USA
| | - Augusto C Ochoa
- Department of Pediatrics, School of Medicine, Louisiana State University Health Sciences Center, USA; The Stanley S. Scott Cancer Center, School of Medicine, Louisiana State University Health Sciences Center, USA; The Louisiana Vaccine Center, New Orleans, LA, 70112, USA
| | - Timothy P Foster
- Department of Microbiology, Immunology, and Parasitology, School of Medicine, Louisiana State University Health Sciences Center, USA; Department of Ophthalmology, School of Medicine, Louisiana State University Health Sciences Center, USA; The Stanley S. Scott Cancer Center, School of Medicine, Louisiana State University Health Sciences Center, USA; The Louisiana Vaccine Center, New Orleans, LA, 70112, USA.
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11
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Silva-Mares D, Torres-López E, Rivas-Galindo VM. Antiherpetic Plants: A Review of Active Extracts, Isolated Compounds, and Bioassays. Nat Prod Commun 2016. [DOI: 10.1177/1934578x1601100434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Herpes simplex is a disease that is widely distributed throughout the world. It is caused by herpes simplex virus type 1 (HSV-1) and simplex virus type 2 (HSV-2). The drugs of choice for treatment are acyclovir (ACV), Penciclovir (PCV) and other guanine analogues, which have the same mechanism of action. However, due to the constant increase of ACV-resistant strains in immunocompromised patients, it is necessary to find new treatment alternatives. It has been shown that natural products are a good alternative for the treatment of these diseases as well as being an excellent source of compounds with anti-herpetic activity, which may be useful for the development of new drugs and act through a mechanism of action different from ACV and PCV. This paper compiles reports on extracts and compounds isolated from plants that have anti-herpetic activity. We present an analysis of the solvents most widely used for extraction from plants as well as cells and commonly used methods for evaluating cytotoxic and anti-herpetic activity. Families that have a higher number of plants with anti-herpetic activity are evaluated, and we also highlight the importance of studies of mechanisms of action of extracts and compounds with anti-herpetic activity.
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Affiliation(s)
- David Silva-Mares
- Departamento de Química Analítica, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey Nuevo León, México. C.P. 64460
| | - Ernesto Torres-López
- Departamento de Inmunología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey Nuevo León, México. C.P. 64460
| | - Verónica M. Rivas-Galindo
- Departamento de Química Analítica, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey Nuevo León, México. C.P. 64460
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12
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Pharmacokinetics-pharmacodynamics of the helicase-primase inhibitor pritelivir following treatment of wild-type or pritelivir-resistant virus infection in a murine herpes simplex virus 1 infection model. Antimicrob Agents Chemother 2014; 58:3843-52. [PMID: 24752278 DOI: 10.1128/aac.02641-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Herpes simplex virus (HSV) infections can cause considerable morbidity. Transmission of HSV-2 has become a major health concern, since it has been shown to promote transmission of other sexually transmitted diseases. Pritelivir (AIC316, BAY 57-1293) belongs to a new class of HSV antiviral compounds, the helicase-primase inhibitors, which have a mode of action that is distinct from that of antiviral nucleoside analogues currently in clinical use. Analysis of pharmacokinetic-pharmacodynamic parameters is a useful tool for the selection of appropriate doses in clinical trials, especially for compounds belonging to new classes for which no or only limited data on therapeutic profiles are available. For this purpose, the effective dose of pritelivir was determined in a comprehensive mouse model of HSV infection. Corresponding plasma concentrations were measured, and exposures were compared with efficacious concentrations derived from cell cultures. The administration of pritelivir at 10 mg/kg of body weight once daily for 4 days completely suppressed any signs of HSV infection in the animals. Associated plasma concentrations adjusted for protein binding stayed above the cell culture 90% effective concentration (EC90) for HSV-1 for almost the entire dosing interval. Interestingly, by increasing the dose 6-fold and prolonging the treatment duration to 8 days, it was possible to treat mice infected with an approximately 30-fold pritelivir-resistant but fully pathogenic HSV-1 virus. Corresponding plasma concentrations exceeded the EC90 of this mutant for <8 h, indicating that even suboptimal exposure to pritelivir is sufficient to achieve antiviral efficacy, possibly augmented by other factors such as the immune system.
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Helicase–primase inhibitors for herpes simplex virus: looking to the future of non-nucleoside inhibitors for treating herpes virus infections. Future Med Chem 2014; 6:45-55. [DOI: 10.4155/fmc.13.192] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Helicase–primase inhibitors (HPIs) are the first new family of potent herpes virus (herpes simplex and varicella-zoster virus) inhibitors to go beyond the preliminary stages of investigation since the emergence of the original nucleoside analog inhibitors. To consider the clinical future of HPIs, this review puts the exciting new findings with two HPIs, amenamevir and pritelivir, into the historical context of antiviral development for the prevention and treatment of herpes simplex virus over the last century and, on this basis, the authors speculate on the potential evolution of these and other non-nucleoside inhibitors in the future.
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14
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De Clercq E. Selective anti-herpesvirus agents. Antivir Chem Chemother 2013; 23:93-101. [PMID: 23343513 DOI: 10.3851/imp2533] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/24/2012] [Indexed: 10/27/2022] Open
Abstract
This review article focuses on the anti-herpesvirus agents effective against herpes simplex virus, varicella-zoster virus and cytomegalovirus, which have either been licensed for clinical use (idoxuridine, trifluridine, brivudin, acyclovir, valaciclovir, valganciclovir, famciclovir and foscarnet) or are under clinical development (CMX001 [the hexadecyloxypropyl prodrug of cidofovir], the helicase-primase inhibitor BAY 57-1293 [now referred to as AIC316], FV-100 [the valine ester of Cf 1743] and the terminase inhibitor letermovir [AIC246]).
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
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15
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Field HJ, Mickleburgh I. The helicase-primase complex as a target for effective herpesvirus antivirals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 767:145-59. [PMID: 23161010 DOI: 10.1007/978-1-4614-5037-5_7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Herpes simplex virus and varicella-zoster virus have been treated for more that half a century using nucleoside analogues. However, there is still an unmet clinical need for improved herpes antivirals. The successful compounds, acyclovir; penciclovir and their orally bioavailable prodrugs valaciclovir and famciclovir, ultimately block virus replication by inhibiting virus-specific DNA-polymerase. The helicase-primase (HP) complex offers a distinctly different target for specific inhibition of virus DNA synthesis. This review describes the synthetic programmes that have already led to two HP-inhibitors (HPI) that have commenced clinical trials in man. One of these (known as AIC 316) continues in clinical development to date. The specificity of HPI is reflected by the ability to select drug-resistant mutants. The role of HP-antiviral resistance will be considered and how the study of cross--resistance among mutants already shows subtle differences between compounds in this respect. The impact of resistance on the drug development in the clinic will also be considered. Finally, herpesvirus latency remains as the most important barrier to a therapeutic cure. Whether or not helicase primase inhibitors alone or in combination with nucleoside analogues can impact on this elusive goal remains to be seen.
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Chono K, Katsumata K, Kontani T, Shiraki K, Suzuki H. Characterization of virus strains resistant to the herpes virus helicase-primase inhibitor ASP2151 (Amenamevir). Biochem Pharmacol 2012; 84:459-67. [PMID: 22687623 DOI: 10.1016/j.bcp.2012.05.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 05/25/2012] [Accepted: 05/31/2012] [Indexed: 10/28/2022]
Abstract
ASP2151 is an antiherpes agent targeting the helicase-primase complex of herpes simplex virus (HSV)-1, HSV-2, and varicella-zoster virus (VZV). We characterized the ASP2151-resistant HSV-1 and HSV-2 variants or mutants based on findings from sequencing analysis, growth, pathogenicity, and susceptibility testing, identifying several single base-pair substitutions resulting in amino acid changes in the helicase and primase subunit of ASP2151-resistant mutants. Amino acid alterations in the helicase subunit were clustered near helicase motif IV in the UL5 helicase gene of both HSV-1 and HSV-2, while the primase subunit substitution associated with reduced susceptibility, R367H, was found in ASP2151-resistant HSV-1 mutants. However, while susceptibility in the ASP2151-resistant HSV mutants to existing antiherpes agents was equivalent to that in wild-type HSV strains, ASP2151-resistant HSV mutants showed attenuated in vitro growth capability and in vivo pathogenicity compared with the parent strains. Taken together, our present findings demonstrated that important amino acid substitutions associated with reduced susceptibilities of HSV-1 and HSV-2 to ASP2151 exist in both the helicase and primase subunits of the helicase-primase complex, and that mutations in this complex against ASP2151 might confer defects in viral replication and pathogenicity.
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Affiliation(s)
- Koji Chono
- Drug Discovery Research, Astellas Pharma Inc., Miyukigaoka 21, Tsukuba, Ibaraki 305-8585, Japan
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17
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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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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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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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20
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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: 338] [Impact Index Per Article: 24.1] [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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Chono K, Katsumata K, Kontani T, Kobayashi M, Sudo K, Yokota T, Konno K, Shimizu Y, Suzuki H. ASP2151, a novel helicase-primase inhibitor, possesses antiviral activity against varicella-zoster virus and herpes simplex virus types 1 and 2. J Antimicrob Chemother 2010; 65:1733-41. [PMID: 20534624 DOI: 10.1093/jac/dkq198] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To evaluate and describe the anti-herpesvirus effect of ASP2151, amenamevir, a novel non-nucleoside oxadiazolylphenyl-containing herpesvirus helicase-primase complex inhibitor. METHODS The inhibitory effect of ASP2151 on enzymatic activities associated with a recombinant HSV-1 helicase-primase complex was assessed. To investigate the effect on viral DNA replication, we analysed viral DNA in cells infected with herpesviruses [herpes simplex virus (HSV), varicella-zoster virus (VZV) and human cytomegalovirus]. Sequencing analyses were conducted on an ASP2151-resistant VZV mutant. In vitro and in vivo antiviral activities were evaluated using a plaque reduction assay and an HSV-1-infected zosteriform-spread model in mice. RESULTS ASP2151 inhibited the single-stranded DNA-dependent ATPase, helicase and primase activities associated with the HSV-1 helicase-primase complex. Antiviral assays revealed that ASP2151, unlike other known HSV helicase-primase inhibitors, exerts equipotent activity against VZV, HSV-1 and HSV-2 through prevention of viral DNA replication. Further, the anti-VZV activity of ASP2151 (EC(50), 0.038-0.10 microM) was more potent against all strains tested than that of aciclovir (EC(50), 1.3-27 microM). ASP2151 was also active against aciclovir-resistant VZV. Amino acid substitutions were found in helicase and primase subunits of ASP2151-resistant VZV. In a mouse zosteriform-spread model, ASP2151 was orally active and inhibited disease progression more potently than valaciclovir. CONCLUSIONS ASP2151 is a novel herpes helicase-primase inhibitor that warrants further investigation for the potential treatment of both VZV and HSV infections.
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Affiliation(s)
- Koji Chono
- Drug Discovery Research, Astellas Pharma Inc., Tokyo, Japan
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22
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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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Biswas S, Miguel RN, Sukla S, Field HJ. A mutation in helicase motif IV of herpes simplex virus type 1 UL5 that results in reduced growth in vitro and lower virulence in a murine infection model is related to the predicted helicase structure. J Gen Virol 2009; 90:1937-1942. [PMID: 19403757 DOI: 10.1099/vir.0.011221-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A variant was selected from a clinical isolate of herpes simplex virus type 1 (HSV-1) during a single passage in the presence of a helicase-primase inhibitor (HPI) at eight times the IC(50). The variant was approximately 40-fold resistant to the HPI BAY 57-1293 and it showed significantly reduced growth in tissue culture with a concomitant reduction in virulence in a murine infection model. The variant contained a single mutation (Asn342Lys) in the UL5 predicted functional helicase motif IV. The Asn342Lys mutation was transferred to a laboratory strain, PDK cl-1, and the recombinant acquired the expected resistance and reduced growth characteristics. Comparative modelling and docking studies predicted the Asn342 position to be physically distant from the HPI interaction pocket formed by UL5 and UL52 (primase). We suggest that this mutation results in steric/allosteric modification of the HPI-binding pocket, conferring an indirect resistance to the HPI. Slower growth and moderately reduced virulence suggest that this mutation might also interfere with the helicase-primase activity.
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Affiliation(s)
- Subhajit Biswas
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | | | - Soumi Sukla
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Hugh J Field
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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25
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Sarangi PP, Kim B, Rouse BT. Non-mitogenic anti-CD3F(ab')2 monoclonal antibody: a novel approach to control herpetic stromal keratitis. Invest Ophthalmol Vis Sci 2008; 49:5425-33. [PMID: 18689698 DOI: 10.1167/iovs.07-1638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Treatment with anti-CD3 antibody has been shown to ameliorate and reverse an existing immunopathological condition by inducing tolerance. The purpose of this study is to assess the therapeutic potential of non-Fc receptor (FcR) binding anti-CD3 monoclonal antibody (mAb), CD3F(ab')(2), for the treatment of herpes simplex virus (HSV)-induced stromal keratitis (SK). METHODS Balb/c and C57BL/6 mice were ocularly infected with HSV-1 strain RE (HSV-1RE). Infected animals were treated with CD3F(ab')(2). Development of SK starting from day 5 postinfection (p.i.), infiltration of inflammatory cells into the corneas and the generation of the immune response were compared with untreated animals using slit-lamp biomicroscopy, flow cytometry, and ELISA. RESULTS In vivo administration of CD3F(ab')(2) resulted in significant reduction in the severity and incidence of SK in the infected animals compared to untreated counterparts. Infiltration of fewer pathogenic CD4(+) T cells into the cornea, along with a lower percentage of cells that could be induced to express IFN-gamma, occurred with anti-CD3F(ab')(2) treatment. Similar observations were noted in the secondary lymphoid tissues. Additionally, an increase in the frequency of CD4(+)Foxp3(+) regulatory T cells was noticed in both cornea and lymphoid tissues of treated animals compared to untreated animals. Treatment with CD3F(ab')(2) also reduced the number of SSIEFARL peptide-specific CD8(+)IFN-gamma(+) T cells in the secondary lymphoid tissues. Furthermore, use of this reagent was moderately effective in limiting lesions in mice with established lesions. CONCLUSIONS Taken together, these results show that non-FcR binding anti-CD3 treatment could be useful in limiting SK lesions.
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Affiliation(s)
- Pranita P Sarangi
- Comparative and Experimental Medicine, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee 37996, USA
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Biswas S, Field HJ. Herpes simplex virus helicase-primase inhibitors: recent findings from the study of drug resistance mutations. Antivir Chem Chemother 2008; 19:1-6. [PMID: 18610552 DOI: 10.1177/095632020801900101] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
After several decades during which nucleoside analogues (especially acyclovir and penciclovir and their prodrugs) have benefited many patients suffering from herpes simplex virus (HSV) infections, the discovery of the helicase-primase inhibitors (HPIs) represents an interesting new approach. Although antiviral resistance has not been a major problem for nucleoside analogues in immunocompetent patients, the problem of acyclovir resistance in immunocompromised patients is well documented. Several HPIs are extremely potent antiviral compounds and may, therefore, offer an important alternative therapy in these patients. The potential for synergy, not just for the inhibition of virus replication but also to delay the appearance of drug-resistant virus, needs to be thoroughly investigated. The study of resistance to HPIs has been important towards understanding the mechanism of action of these compounds and confirming the target function. However, during the course of our studies on HPI resistance, we have made a number of interesting observations that may be relevant to their clinical use. This article draws attention to the major observations on HPI resistance reported by others and to our own recently published observations that have extended this expanding area of antiviral research.
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Affiliation(s)
- Subhajit Biswas
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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Mutations close to functional motif IV in HSV-1 UL5 helicase that confer resistance to HSV helicase-primase inhibitors, variously affect virus growth rate and pathogenicity. Antiviral Res 2008; 80:81-5. [PMID: 18539344 DOI: 10.1016/j.antiviral.2008.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 04/12/2008] [Accepted: 04/15/2008] [Indexed: 11/23/2022]
Abstract
Herpes simplex virus (HSV) helicase-primase (HP) is the target for a novel class of antiviral compounds, the helicase-primase inhibitors (HPIs), e.g. BAY 57-1293. Although mutations in herpesviruses conferring resistance to nucleoside analogues are commonly associated with attenuation in vivo, to date, this is not necessarily true for HPIs. HPI-resistant HSV mutants selected in tissue culture are reported to be equally pathogenic compared to parental virus in animal models. Here we demonstrate that a slow-growing HSV-1 mutant, with the BAY 57-1293-resistance mutation Gly352Arg in UL5 helicase, is clearly less virulent than its wild-type parent in a murine zosteriform infection model. This contrasts with published results obtained for a mutant containing a different HPI-resistance substitution (Gly352Val) at the same location, since this mutant was reported to be fully pathogenic. We believe our report to be the first to describe an HPI-resistant HSV-1 mutant, that is markedly less virulent in vivo and slowly growing in tissue culture compared to the parental strain. Another BAY 57-1293-resistant UL5 mutant (Lys356Gln), which showed faster growth characteristics in cell culture, however, was at least equally virulent compared to the parent strain.
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A single drug-resistance mutation in HSV-1 UL52 primase points to a difference between two helicase–primase inhibitors in their mode of interaction with the antiviral target. J Antimicrob Chemother 2008; 61:1044-7. [DOI: 10.1093/jac/dkn057] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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