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Andreev K, Jones JC, Seiler P, Kandeil A, Webby RJ, Govorkova EA. Genotypic and phenotypic susceptibility of emerging avian influenza A viruses to neuraminidase and cap-dependent endonuclease inhibitors. Antiviral Res 2024; 229:105959. [PMID: 38986873 DOI: 10.1016/j.antiviral.2024.105959] [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: 04/25/2024] [Revised: 07/01/2024] [Accepted: 07/05/2024] [Indexed: 07/12/2024]
Abstract
Avian influenza outbreaks, including ones caused by highly pathogenic A(H5N1) clade 2.3.4.4b viruses, have devastated animal populations and remain a threat to humans. Risk elements assessed for emerging influenza viruses include their susceptibility to approved antivirals. Here, we screened >20,000 neuraminidase (NA) or polymerase acidic (PA) protein sequences of potentially pandemic A(H5Nx), A(H7Nx), and A(H9N2) viruses that circulated globally in 2010-2023. The frequencies of NA or PA substitutions associated with reduced inhibition (RI) or highly reduced inhibition (HRI) by NA inhibitors (NAIs) (oseltamivir, zanamivir) or a cap-dependent endonuclease inhibitor (baloxavir) were low: 0.60% (137/22,713) and 0.62% (126/20,347), respectively. All tested subtypes were susceptible to NAIs and baloxavir at sub-nanomolar concentrations. A(H9N2) viruses were the most susceptible to oseltamivir, with IC50s 3- to 4-fold lower than for other subtypes (median IC50: 0.18 nM; n = 22). NA-I222M conferred RI of A(H5N1) viruses by oseltamivir (with a 26-fold IC50 increase), but NA-S246N did not reduce inhibition. PA-E23G, PA-K34R, PA-I38M/T, and the previously unreported PA-A36T caused RI by baloxavir in all subtypes tested. Avian A(H9N2) viruses endemic in Egyptian poultry predominantly acquired PA-I38V, which causes only a <3-fold decrease in the baloxavir EC50 and fails to meet the RI criteria. PA-E199A/D in A(H7Nx) and A(H9N2) viruses caused a 2- to 4-fold decrease in EC50 (close to the borderline for RI) and should be closely monitored. Our data indicate antiviral susceptibility is high among avian influenza A viruses with pandemic potential and present novel markers of resistance to existing antiviral interventions.
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Affiliation(s)
- Konstantin Andreev
- Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Jeremy C Jones
- Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Patrick Seiler
- Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Ahmed Kandeil
- Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN, USA; Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza, 12622, Egypt
| | - Richard J Webby
- Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Elena A Govorkova
- Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN, USA.
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2
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Chon I, Wagatsuma K, Saito R, Tang JW, Isamu S, Suzuki E, Shirahige Y, Kawashima T, Minato M, Kodo N, Masaki H, Hamabata H, Yoshioka S, Ichikawa Y, Sun Y, Li J, Otoguto T, Watanabe H. Detection of influenza A(H3N2) viruses with polymerase acidic subunit substitutions after and prior to baloxavir marboxil treatment during the 2022-2023 influenza season in Japan. Antiviral Res 2024; 229:105956. [PMID: 38969237 DOI: 10.1016/j.antiviral.2024.105956] [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: 11/24/2023] [Revised: 06/29/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024]
Abstract
Baloxavir marboxil (baloxavir), approved as an anti-influenza drug in Japan in March 2018, can induce reduced therapeutic effectiveness due to PA protein substitutions. We assessed PA substitutions in clinical samples from influenza-infected children and adults pre- and post-baloxavir treatment, examining their impact on fever and symptom duration. During the 2022-2023 influenza season, the predominant circulating influenza subtype detected by cycling-probe RT-PCR was A(H3N2) (n = 234), with a minor circulation of A(H1N1)pdm09 (n = 10). Of the 234 influenza A(H3N2) viruses collected prior to baloxavir treatment, 2 (0.8%) viruses carry PA/I38T substitution. One virus was collected from a toddler and one from an adult, indicating the presence of viruses with reduced susceptibility to baloxavir, without prior exposure to the drug. Of the 54 paired influenza A(H3N2) viruses collected following baloxavir treatment, 8 (14.8%) viruses carried E23 K/G, or I38 M/T substitutions in PA. Variant calling through next-generation sequencing (NGS) showed varying proportions (6-100 %), a polymorphism and a mixture of PA/E23 K/G, and I38 M/T substitutions in the clinical samples. These eight viruses were obtained from children aged 7-14 years, with a median fever duration of 16.7 h and a median symptom duration of 93.7 h, which were similar to those of the wild type. However, the delayed viral clearance associated with the emergence of PA substitutions was observed. No substitutions conferring resistance to neuraminidase inhibitors were detected in 37 paired samples collected before and following oseltamivir treatment. These findings underscore the need for ongoing antiviral surveillance, informing public health strategies and clinical antiviral recommendations for seasonal influenza.
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Affiliation(s)
- Irina Chon
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
| | - Keita Wagatsuma
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Reiko Saito
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Julian W Tang
- Respiratory Sciences, University of Leicester, Leicester, UK; Clinical Microbiology, University Hospitals of Leicester NHS Trust, Leicester, UK
| | | | | | | | | | | | | | | | | | - Sayaka Yoshioka
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Yusuke Ichikawa
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Yuyang Sun
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Jiaming Li
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Teruhime Otoguto
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Hisami Watanabe
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
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3
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Diaz J, Sears J, Chang CK, Burdick J, Law I, Sanders W, Linnertz C, Sylvester P, Moorman N, Ferris MT, Heise MT. U-CAN-seq: A Universal Competition Assay by Nanopore Sequencing. Viruses 2024; 16:636. [PMID: 38675976 PMCID: PMC11054411 DOI: 10.3390/v16040636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/09/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
RNA viruses quickly evolve subtle genotypic changes that can have major impacts on viral fitness and host range, with potential consequences for human health. It is therefore important to understand the evolutionary fitness of novel viral variants relative to well-studied genotypes of epidemic viruses. Competition assays are an effective and rigorous system with which to assess the relative fitness of viral genotypes. However, it is challenging to quickly and cheaply distinguish and quantify fitness differences between very similar viral genotypes. Here, we describe a protocol for using reverse transcription PCR in combination with commercial nanopore sequencing services to perform competition assays on untagged RNA viruses. Our assay, called the Universal Competition Assay by Nanopore Sequencing (U-CAN-seq), is relatively cheap and highly sensitive. We used a well-studied N24A mutation in the chikungunya virus (CHIKV) nsp3 gene to confirm that we could detect a competitive disadvantage using U-CAN-seq. We also used this approach to show that mutations to the CHIKV 5' conserved sequence element that disrupt sequence but not structure did not affect the fitness of CHIKV. However, similar mutations to an adjacent CHIKV stem loop (SL3) did cause a fitness disadvantage compared to wild-type CHIKV, suggesting that structure-independent, primary sequence determinants in this loop play an important role in CHIKV biology. Our novel findings illustrate the utility of the U-CAN-seq competition assay.
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Affiliation(s)
- Jennifer Diaz
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA; (J.D.)
| | - John Sears
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA; (J.D.)
| | - Che-Kang Chang
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA; (J.D.)
| | - Jane Burdick
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Isabella Law
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Wes Sanders
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA; (J.D.)
| | - Colton Linnertz
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Paul Sylvester
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Nathaniel Moorman
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA; (J.D.)
- The Rapidly Emerging Antiviral Drug Development Initiative (READDI), Chapel Hill, NC 275114, USA
| | - Martin T. Ferris
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Mark T. Heise
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA; (J.D.)
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
- The Rapidly Emerging Antiviral Drug Development Initiative (READDI), Chapel Hill, NC 275114, USA
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4
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Kohlbrand A, Stokes RW, Sankaran B, Cohen SM. Structural Studies of Inhibitors with Clinically Relevant Influenza Endonuclease Variants. Biochemistry 2024; 63:264-272. [PMID: 38190441 PMCID: PMC10851415 DOI: 10.1021/acs.biochem.3c00536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 01/10/2024]
Abstract
Vital to the treatment of influenza is the use of antivirals such as Oseltamivir (Tamiflu) and Zanamivir (Relenza); however, antiviral resistance is becoming an increasing problem for these therapeutics. The RNA-dependent RNA polymerase acidic N-terminal (PAN) endonuclease, a critical component of influenza viral replication machinery, is an antiviral target that was recently validated with the approval of Baloxavir Marboxil (BXM). Despite its clinical success, BXM has demonstrated susceptibility to resistance mutations, specifically the I38T, E23K, and A36 V mutants of PAN. To better understand the effects of these mutations on BXM resistance and improve the design of more robust therapeutics, this study examines key differences in protein-inhibitor interactions with two inhibitors and the I38T, E23K, and A36 V mutants. Differences in inhibitor binding were evaluated by measuring changes in binding to PAN using two biophysical methods. The binding mode of two distinct inhibitors was determined crystallographically with both wild-type and mutant forms of PAN. Collectively, these studies give some insight into the mechanism of antiviral resistance of these mutants.
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Affiliation(s)
- Alysia
J. Kohlbrand
- Department
of Chemistry and Biochemistry, University
of California, La Jolla, California 92093, United States
| | - Ryjul W. Stokes
- Department
of Chemistry and Biochemistry, University
of California, La Jolla, California 92093, United States
| | - Banumathi Sankaran
- The
Berkeley Center for Structural Biology, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Seth M. Cohen
- Department
of Chemistry and Biochemistry, University
of California, La Jolla, California 92093, United States
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5
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Taniguchi K, Noshi T, Omoto S, Sato A, Shishido T, Matsuno K, Okamatsu M, Krauss S, Webby RJ, Sakoda Y, Kida H. The impact of PA/I38 substitutions and PA polymorphisms on the susceptibility of zoonotic influenza A viruses to baloxavir. Arch Virol 2024; 169:29. [PMID: 38216710 PMCID: PMC10786730 DOI: 10.1007/s00705-023-05958-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/28/2023] [Indexed: 01/14/2024]
Abstract
Genetic reassortment of avian, swine, and human influenza A viruses (IAVs) poses potential pandemic risks. Surveillance is important for influenza pandemic preparedness, but the susceptibility of zoonotic IAVs to the cap-dependent endonuclease inhibitor baloxavir acid (BXA) has not been thoroughly researched. Although an amino acid substitution at position 38 in the polymerase acidic protein (PA/I38) in seasonal IAVs reduces BXA susceptibility, PA polymorphisms at position 38 are rarely seen in zoonotic IAVs. Here, we examined the impact of PA/I38 substitutions on the BXA susceptibility of recombinant A(H5N1) viruses. PA mutants that harbored I38T, F, and M were 48.2-, 24.0-, and 15.5-fold less susceptible, respectively, to BXA than wild-type A(H5N1) but were susceptible to the neuraminidase inhibitor oseltamivir acid and the RNA polymerase inhibitor favipiravir. PA mutants exhibited significantly impaired replicative fitness in Madin-Darby canine kidney cells at 24 h postinfection. In addition, in order to investigate new genetic markers for BXA susceptibility, we screened geographically and temporally distinct IAVs isolated worldwide from birds and pigs. The results showed that BXA exhibited antiviral activity against avian and swine viruses with similar levels to seasonal isolates. All viruses tested in the study lacked the PA/I38 substitution and were susceptible to BXA. Isolates harboring amino acid polymorphisms at positions 20, 24, and 37, which have been implicated in the binding of BXA to the PA endonuclease domain, were also susceptible to BXA. These results suggest that monitoring of the PA/I38 substitution in animal-derived influenza viruses is important for preparedness against zoonotic influenza virus outbreaks.
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Affiliation(s)
- Keiichi Taniguchi
- Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., Toyonaka, Osaka, Japan
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Takeshi Noshi
- Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., Toyonaka, Osaka, Japan
| | - Shinya Omoto
- Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., Toyonaka, Osaka, Japan
| | - Akihiko Sato
- Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., Toyonaka, Osaka, Japan
- International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan
- Institute for Vaccine Research and Development, HU-IVReD, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Takao Shishido
- Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., Toyonaka, Osaka, Japan.
| | - Keita Matsuno
- International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan
- Institute for Vaccine Research and Development, HU-IVReD, Hokkaido University, Sapporo, Hokkaido, Japan
- International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan
- One Health Research Center, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Masatoshi Okamatsu
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Scott Krauss
- St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Richard J Webby
- St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Yoshihiro Sakoda
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
- Institute for Vaccine Research and Development, HU-IVReD, Hokkaido University, Sapporo, Hokkaido, Japan
- International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan
- One Health Research Center, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Hiroshi Kida
- International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan
- Institute for Vaccine Research and Development, HU-IVReD, Hokkaido University, Sapporo, Hokkaido, Japan
- International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan
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6
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Wang X, Kim KW, Walker G, Stelzer‐Braid S, Scotch M, Rawlinson WD. Genome characterization of influenza A and B viruses in New South Wales, Australia, in 2019: A retrospective study using high-throughput whole genome sequencing. Influenza Other Respir Viruses 2024; 18:e13252. [PMID: 38288510 PMCID: PMC10824601 DOI: 10.1111/irv.13252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 12/22/2023] [Accepted: 12/23/2023] [Indexed: 02/01/2024] Open
Abstract
BACKGROUND During the 2019 severe influenza season, New South Wales (NSW) experienced the highest number of cases in Australia. This study retrospectively investigated the genetic characteristics of influenza viruses circulating in NSW in 2019 and identified genetic markers related to antiviral resistance and potential virulence. METHODS The complete genomes of influenza A and B viruses were amplified using reverse transcription-polymerase chain reaction (PCR) and sequenced with an Illumina MiSeq platform. RESULTS When comparing the sequencing data with the vaccine strains and reference sequences, the phylogenetic analysis revealed that most NSW A/H3N2 viruses (n = 68; 94%) belonged to 3C.2a1b and a minority (n = 4; 6%) belonged to 3C.3a. These viruses all diverged from the vaccine strain A/Switzerland/8060/2017. All A/H1N1pdm09 viruses (n = 20) showed genetic dissimilarity from vaccine strain A/Michigan/45/2015, with subclades 6B.1A.5 and 6B.1A.2 identified. All B/Victoria-lineage viruses (n = 21) aligned with clade V1A.3, presenting triple amino acid deletions at positions 162-164 in the hemagglutinin protein, significantly diverging from the vaccine strain B/Colorado/06/2017. Multiple amino acid substitutions were also found in the internal proteins of influenza viruses, some of which have been previously reported in hospitalized influenza patients in Thailand. Notably, the oseltamivir-resistant marker H275Y was present in one immunocompromised patient infected with A/H1N1pdm09 and the resistance-related mutation I222V was detected in another A/H3N2-infected patient. CONCLUSIONS Considering antigenic drift and the constant evolution of circulating A and B strains, we believe continuous monitoring of influenza viruses in NSW via the high-throughput sequencing approach provides timely and pivotal information for both public health surveillance and clinical treatment.
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Affiliation(s)
- Xinye Wang
- School of Biomedical Sciences, Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
- Virology Research Laboratory, Serology and Virology Division (SAViD), NSW Health PathologyPrince of Wales HospitalSydneyNew South WalesAustralia
| | - Ki Wook Kim
- Virology Research Laboratory, Serology and Virology Division (SAViD), NSW Health PathologyPrince of Wales HospitalSydneyNew South WalesAustralia
- Discipline of Paediatrics and Child Health, School of Clinical Medicine, Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Gregory Walker
- School of Biomedical Sciences, Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
- Virology Research Laboratory, Serology and Virology Division (SAViD), NSW Health PathologyPrince of Wales HospitalSydneyNew South WalesAustralia
| | - Sacha Stelzer‐Braid
- School of Biomedical Sciences, Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
- Virology Research Laboratory, Serology and Virology Division (SAViD), NSW Health PathologyPrince of Wales HospitalSydneyNew South WalesAustralia
| | - Matthew Scotch
- Biodesign Center for Environmental Health Engineering, Biodesign InstituteArizona State UniversityPhoenixArizonaUSA
- College of Health SolutionsArizona State UniversityPhoenixArizonaUSA
- Kirby InstituteUniversity of New South WalesSydneyNew South WalesAustralia
| | - William D. Rawlinson
- School of Biomedical Sciences, Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
- Virology Research Laboratory, Serology and Virology Division (SAViD), NSW Health PathologyPrince of Wales HospitalSydneyNew South WalesAustralia
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7
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Hickerson BT, Petrovskaya SN, Dickensheets H, Donnelly RP, Ince WL, Ilyushina NA. Impact of Baloxavir Resistance-Associated Substitutions on Influenza Virus Growth and Drug Susceptibility. J Virol 2023; 97:e0015423. [PMID: 37404185 PMCID: PMC10373543 DOI: 10.1128/jvi.00154-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 06/10/2023] [Indexed: 07/06/2023] Open
Abstract
Baloxavir marboxil (baloxavir) is a recently FDA-approved influenza virus polymerase acidic (PA) endonuclease inhibitor. Several PA substitutions have been demonstrated to confer reduced susceptibility to baloxavir; however, their impacts on measurements of antiviral drug susceptibility and replication capacity when present as a fraction of the viral population have not been established. We generated recombinant A/California/04/09 (H1N1)-like viruses (IAV) with PA I38L, I38T, or E199D substitutions and B/Victoria/504/2000-like virus (IBV) with PA I38T. These substitutions reduced baloxavir susceptibility by 15.3-, 72.3-, 5.4-, and 54.5-fold, respectively, when tested in normal human bronchial epithelial (NHBE) cells. We then assessed the replication kinetics, polymerase activity, and baloxavir susceptibility of the wild-type:mutant (WT:MUT) virus mixtures in NHBE cells. The percentage of MUT relative to WT virus necessary to detect reduced baloxavir susceptibility in phenotypic assays ranged from 10% (IBV I38T) to 92% (IAV E199D). While I38T did not alter IAV replication kinetics or polymerase activity, IAV PA I38L and E199D MUTs and the IBV PA I38T MUT exhibited reduced replication levels and significantly altered polymerase activity. Differences in replication were detectable when the MUTs comprised ≥90%, ≥90%, or ≥75% of the population, respectively. Droplet digital PCR (ddPCR) and next-generation sequencing (NGS) analyses showed that WT viruses generally outcompeted the respective MUTs after multiple replication cycles and serial passaging in NHBE cells when initial mixtures contained ≥50% of the WT viruses; however, we also identified potential compensatory substitutions (IAV PA D394N and IBV PA E329G) that emerged and appeared to improve the replication capacity of baloxavir-resistant virus in cell culture. IMPORTANCE Baloxavir marboxil, an influenza virus polymerase acidic endonuclease inhibitor, represents a recently approved new class of influenza antivirals. Treatment-emergent resistance to baloxavir has been observed in clinical trials, and the potential spread of resistant variants could diminish baloxavir effectiveness. Here, we report the impact of the proportion of drug-resistant subpopulations on the ability to detect resistance in clinical isolates and the impact of substitutions on viral replication of mixtures containing both drug-sensitive and drug-resistant variants. We also show that ddPCR and NGS methods can be successfully used for detection of resistant subpopulations in clinical isolates and to quantify their relative abundance. Taken together, our data shed light on the potential impact of baloxavir-resistant I38T/L and E199D substitutions on baloxavir susceptibility and other biological properties of influenza virus and the ability to detect resistance in phenotypic and genotypic assays.
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Affiliation(s)
- Brady T. Hickerson
- Division of Biotechnology Review and Research II, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Svetlana N. Petrovskaya
- Division of Biotechnology Review and Research III, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Harold Dickensheets
- Division of Biotechnology Review and Research II, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Raymond P. Donnelly
- Division of Biotechnology Review and Research II, Food and Drug Administration, Silver Spring, Maryland, USA
| | - William L. Ince
- Division of Antivirals, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Natalia A. Ilyushina
- Division of Biotechnology Review and Research II, Food and Drug Administration, Silver Spring, Maryland, USA
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8
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von Delft A, Hall MD, Kwong AD, Purcell LA, Saikatendu KS, Schmitz U, Tallarico JA, Lee AA. Accelerating antiviral drug discovery: lessons from COVID-19. Nat Rev Drug Discov 2023; 22:585-603. [PMID: 37173515 PMCID: PMC10176316 DOI: 10.1038/s41573-023-00692-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2023] [Indexed: 05/15/2023]
Abstract
During the coronavirus disease 2019 (COVID-19) pandemic, a wave of rapid and collaborative drug discovery efforts took place in academia and industry, culminating in several therapeutics being discovered, approved and deployed in a 2-year time frame. This article summarizes the collective experience of several pharmaceutical companies and academic collaborations that were active in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antiviral discovery. We outline our opinions and experiences on key stages in the small-molecule drug discovery process: target selection, medicinal chemistry, antiviral assays, animal efficacy and attempts to pre-empt resistance. We propose strategies that could accelerate future efforts and argue that a key bottleneck is the lack of quality chemical probes around understudied viral targets, which would serve as a starting point for drug discovery. Considering the small size of the viral proteome, comprehensively building an arsenal of probes for proteins in viruses of pandemic concern is a worthwhile and tractable challenge for the community.
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Affiliation(s)
- Annette von Delft
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
- Oxford Biomedical Research Centre, National Institute for Health Research, University of Oxford, Oxford, UK.
| | - Matthew D Hall
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | | | | | | | | | | | - Alpha A Lee
- PostEra, Inc., Cambridge, MA, USA.
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
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9
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Kuroda T, Fukao K, Yoshida S, Oka R, Baba K, Ando Y, Taniguchi K, Noshi T, Shishido T. In Vivo Antiviral Activity of Baloxavir against PA/I38T-Substituted Influenza A Viruses at Clinically Relevant Doses. Viruses 2023; 15:v15051154. [PMID: 37243240 DOI: 10.3390/v15051154] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
Although the prevalence of polymerase acidic (PA)/I38T strains of influenza virus with reduced susceptibility to baloxavir acid is low, there is a possibility of emergence under selective pressure. Furthermore, the virus may be transmitted between humans. We investigated the in vivo efficacy of baloxavir acid and oseltamivir phosphate against influenza A subtypes H1N1, H1N1pdm09, and H3N2, with PA/I38T substitution, at doses simulating human plasma concentrations. A pharmacokinetic/pharmacodynamic analysis was performed to strengthen the validity of the findings and the applicability in a clinical setting. Although the antiviral effect of baloxavir acid was attenuated in mice infected with PA/I38T-substituted viral strains compared with the wild type (WT), baloxavir acid significantly reduced virus titers at higher-but clinically relevant-doses. The virus titer reduction with baloxavir acid (30 mg/kg subcutaneous single dose) was comparable to that of oseltamivir phosphate (5 mg/kg orally twice daily) against H1N1 and H1N1pdm09 PA/I38T strains in mice, as well as the H3N2 PA/I38T strain in hamsters. Baloxavir acid demonstrated an antiviral effect against PA/I38T-substituted strains, at day 6, with no further viral rebound. In conclusion, baloxavir acid demonstrated dose-dependent antiviral effects comparable to that of oseltamivir phosphate, even though the degree of lung virus titer reduction was diminished in animal models infected with PA/I38T-substituted strains.
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Affiliation(s)
| | | | | | - Ryoko Oka
- Shionogi & Co., Ltd., Osaka 561-0825, Japan
| | - Kaoru Baba
- Shionogi TechnoAdvance Research, Co., Ltd., Osaka 561-0825, Japan
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10
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Saim-Mamoun A, Carbonneau J, Rhéaume C, Abed Y, Boivin G. Viral Fitness of Baloxavir-Resistant Recombinant Influenza B/Victoria- and B/Yamagata-like Viruses Harboring the I38T PA Change, In Vitro, Ex Vivo and in Guinea Pigs. Microorganisms 2023; 11:1095. [PMID: 37317069 DOI: 10.3390/microorganisms11051095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/06/2023] [Accepted: 04/20/2023] [Indexed: 06/16/2023] Open
Abstract
Seasonal influenza A and B viruses may cause severe infections requiring therapeutic interventions. Baloxavir, the latest antiviral drug approved against those infections, targets the endonuclease activity encoded by the polymerase acidic (PA) protein. While appearing effective at cessation of viral shedding, baloxavir demonstrated a low barrier of resistance. Herein, we aimed to assess the impact of PA-I38T substitution, a major marker of baloxavir-resistance, on the fitness of contemporary influenza B viruses. Recombinant wild-type (WT) influenza B/Phuket/2073/13 (B/Yamagata/16/88-like) and B/Washington/02/19 (B/Victoria/2/87-like) viruses and their respective PA-I38T mutants were used to evaluate replication kinetics in vitro, using A549 and Calu3 cells, and ex vivo, using nasal human airway epithelium (HAE) cells. Infectivity was also assessed in guinea pigs. In the B/Washington/02/19 background, there were no major differences between the recombinant WT virus and its I38T mutant when viral replication kinetics were evaluated in human lung cell lines and HAE as well as in nasal washes of experimentally infected guinea pigs. By contrast, the I38T mutation moderately impacted the B/Phuket/2073/13 viral fitness. In conclusion, contemporary influenza B viruses that may acquire baloxavir-resistance through the PA-I38T substitution could retain a significant level of fitness, highlighting the importance of monitoring the emergence of such variant.
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Affiliation(s)
- Amel Saim-Mamoun
- Research Center, Infectious Diseases of the CHU de Québec-CHUL, Laval University, Québec City, QC G1V 4G2, Canada
| | - Julie Carbonneau
- Research Center, Infectious Diseases of the CHU de Québec-CHUL, Laval University, Québec City, QC G1V 4G2, Canada
| | - Chantal Rhéaume
- Research Center, Infectious Diseases of the CHU de Québec-CHUL, Laval University, Québec City, QC G1V 4G2, Canada
| | - Yacine Abed
- Research Center, Infectious Diseases of the CHU de Québec-CHUL, Laval University, Québec City, QC G1V 4G2, Canada
| | - Guy Boivin
- Research Center, Infectious Diseases of the CHU de Québec-CHUL, Laval University, Québec City, QC G1V 4G2, Canada
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11
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Li J, Wagatsuma K, Sun Y, Sato I, Kawashima T, Saito T, Shimada Y, Ono Y, Kakuya F, Nagata N, Minato M, Kodo N, Suzuki E, Kitano A, Tanaka T, Aoki S, Chon I, Phyu WW, Watanabe H, Saito R. Factors associated with viral RNA shedding and evaluation of potential viral infectivity at returning to school in influenza outpatients after treatment with baloxavir marboxil and neuraminidase inhibitors during 2013/2014-2019/2020 seasons in Japan: an observational study. BMC Infect Dis 2023; 23:188. [PMID: 36991360 PMCID: PMC10054210 DOI: 10.1186/s12879-023-08140-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 03/07/2023] [Indexed: 03/31/2023] Open
Abstract
BACKGROUND This study assessed the differences in daily virus reduction and the residual infectivity after the recommended home stay period in Japan in patients infected with influenza and treated with baloxavir (BA), laninamivir (LA), oseltamivir (OS), and zanamivir (ZA). METHODS We conducted an observational study on children and adults at 13 outpatient clinics in 11 prefectures in Japan during seven influenza seasons from 2013/2014 to 2019/2020. Virus samples were collected twice from influenza rapid test-positive patients at the first and second visit 4-5 days after the start of treatment. The viral RNA shedding was quantified using quantitative RT-PCR. Neuraminidase (NA) and polymerase acidic (PA) variant viruses that reduce susceptibility to NA inhibitors and BA, respectively, were screened using RT-PCR and genetic sequencing. Daily estimated viral reduction was evaluated using univariate and multivariate analyses for the factors such as age, treatment, vaccination status, or the emergence of PA or NA variants. The potential infectivity of the viral RNA shedding at the second visit samples was determined using the Receiver Operator Curve based on the positivity of virus isolation. RESULTS Among 518 patients, 465 (80.0%) and 116 (20.0%) were infected with influenza A (189 with BA, 58 with LA, 181 with OS, 37 with ZA) and influenza B (39 with BA, 10 with LA, 52 with OS, 15 with ZA). The emergence of 21 PA variants in influenza A was detected after BA treatment, but NA variants were not detected after NAIs treatment. Multiple linear regression analysis showed that the daily viral RNA shedding reduction in patients was slower in the two NAIs (OS and LA) than in BA, influenza B infection, aged 0-5 years, or the emergence of PA variants. The residual viral RNA shedding potentially infectious was detected in approximately 10-30% of the patients aged 6-18 years after five days of onset. CONCLUSIONS Viral clearance differed by age, type of influenza, choice of treatment, and susceptibility to BA. Additionally, the recommended homestay period in Japan seemed insufficient, but reduced viral spread to some extent since most school-age patients became non-infectious after 5 days of onset.
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Affiliation(s)
- Jiaming Li
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata, 951-8510, Japan.
| | - Keita Wagatsuma
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata, 951-8510, Japan
| | - Yuyang Sun
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata, 951-8510, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Irina Chon
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata, 951-8510, Japan
| | - Wint Wint Phyu
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata, 951-8510, Japan
| | - Hisami Watanabe
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata, 951-8510, Japan
| | - Reiko Saito
- Division of International Health (Public Health), Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata, 951-8510, Japan
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12
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Delima GK, Ganti K, Holmes KE, Shartouny JR, Lowen AC. Influenza A virus coinfection dynamics are shaped by distinct virus-virus interactions within and between cells. PLoS Pathog 2023; 19:e1010978. [PMID: 36862762 PMCID: PMC10013887 DOI: 10.1371/journal.ppat.1010978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/14/2023] [Accepted: 02/07/2023] [Indexed: 03/03/2023] Open
Abstract
When multiple viral populations propagate within the same host environment, they often shape each other's dynamics. These interactions can be positive or negative and can occur at multiple scales, from coinfection of a cell to co-circulation at a global population level. For influenza A viruses (IAVs), the delivery of multiple viral genomes to a cell substantially increases burst size. However, despite its relevance for IAV evolution through reassortment, the implications of this positive density dependence for coinfection between distinct IAVs has not been explored. Furthermore, the extent to which these interactions within the cell shape viral dynamics at the level of the host remains unclear. Here we show that, within cells, diverse coinfecting IAVs strongly augment the replication of a focal strain, irrespective of their homology to the focal strain. Coinfecting viruses with a low intrinsic reliance on multiple infection offer the greatest benefit. Nevertheless, virus-virus interactions at the level of the whole host are antagonistic. This antagonism is recapitulated in cell culture when the coinfecting virus is introduced several hours prior to the focal strain or under conditions conducive to multiple rounds of viral replication. Together, these data suggest that beneficial virus-virus interactions within cells are counterbalanced by competition for susceptible cells during viral propagation through a tissue. The integration of virus-virus interactions across scales is critical in defining the outcomes of viral coinfection.
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Affiliation(s)
- Gabrielle K. Delima
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Ketaki Ganti
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Katie E. Holmes
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Jessica R. Shartouny
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Anice C. Lowen
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Emory Center of Excellence for Influenza Research and Response (Emory-CEIRR), Atlanta, Georgia, United States of America
- * E-mail:
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13
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Harding J, Bernasconi C, Williams S, Wildum S, Kinoshita M, Uehara T, Hurt AC. Investigating the transmission of baloxavir-resistant influenza viruses from treated index patients to untreated household contacts in the BLOCKSTONE study. Influenza Other Respir Viruses 2023; 17:e13079. [PMID: 36702798 PMCID: PMC9849088 DOI: 10.1111/irv.13079] [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: 11/08/2022] [Accepted: 11/15/2022] [Indexed: 01/20/2023] Open
Abstract
In a post-hoc analysis of the phase 3 BLOCKSTONE study (JapicCTI-184180), we investigated household transmission of baloxavir-resistant (PA/I38X) influenza viruses. Using baloxavir resistance rates from prior clinical trials and the rate of influenza transmission observed in the study, the predicted number of PA/I38X transmission events was 4.8, assuming wild type and PA/I38X viruses were equally transmissible. However, no PA/I38X viruses were observed. These results suggest a low potential for baloxavir-resistant influenza virus transmission from treated to untreated individuals, potentially due to reduced viral/transmission fitness for PA/I38X viruses and/or low viral titres at the time when resistant viruses arise.
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14
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Domingo E, García-Crespo C, Soria ME, Perales C. Viral Fitness, Population Complexity, Host Interactions, and Resistance to Antiviral Agents. Curr Top Microbiol Immunol 2023; 439:197-235. [PMID: 36592247 DOI: 10.1007/978-3-031-15640-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Fitness of viruses has become a standard parameter to quantify their adaptation to a biological environment. Fitness determinations for RNA viruses (and some highly variable DNA viruses) meet with several uncertainties. Of particular interest are those that arise from mutant spectrum complexity, absence of population equilibrium, and internal interactions among components of a mutant spectrum. Here, concepts, fitness measurements, limitations, and current views on experimental viral fitness landscapes are discussed. The effect of viral fitness on resistance to antiviral agents is covered in some detail since it constitutes a widespread problem in antiviral pharmacology, and a challenge for the design of effective antiviral treatments. Recent evidence with hepatitis C virus suggests the operation of mechanisms of antiviral resistance additional to the standard selection of drug-escape mutants. The possibility that high replicative fitness may be the driver of such alternative mechanisms is considered. New broad-spectrum antiviral designs that target viral fitness may curtail the impact of drug-escape mutants in treatment failures. We consider to what extent fitness-related concepts apply to coronaviruses and how they may affect strategies for COVID-19 prevention and treatment.
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Affiliation(s)
- Esteban Domingo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029, Madrid, Spain.
| | - Carlos García-Crespo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - María Eugenia Soria
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029, Madrid, Spain.,Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Av. Reyes Católicos 2, 28040, Madrid, Spain
| | - Celia Perales
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029, Madrid, Spain.,Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Av. Reyes Católicos 2, 28040, Madrid, Spain.,Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain
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15
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Assessing the fitness of a dual-antiviral drug resistant human influenza virus in the ferret model. Commun Biol 2022; 5:1026. [PMID: 36171475 PMCID: PMC9517990 DOI: 10.1038/s42003-022-04005-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/15/2022] [Indexed: 11/08/2022] Open
Abstract
Influenza antivirals are important tools in our fight against annual influenza epidemics and future influenza pandemics. Combinations of antivirals may reduce the likelihood of drug resistance and improve clinical outcomes. Previously, two hospitalised immunocompromised influenza patients, who received a combination of a neuraminidase inhibitor and baloxavir marboxil, shed influenza viruses resistant to both drugs. Here-in, the replicative fitness of one of these A(H1N1)pdm09 virus isolates with dual resistance mutations (NA-H275Y and PA-I38T) was similar to wild type virus (WT) in vitro, but reduced in the upper respiratory tracts of challenged ferrets. The dual-mutant virus transmitted well between ferrets in an airborne transmission model, but was outcompeted by the WT when the two viruses were co-administered. These results indicate the dual-mutant virus had a moderate loss of viral fitness compared to the WT virus, suggesting that while person-to-person transmission of the dual-resistant virus may be possible, widespread community transmission is unlikely.
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16
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Saim-Mamoun A, Abed Y, Carbonneau J, Boivin G. Generation and Characterization of Drug-Resistant Influenza B Viruses Selected In Vitro with Baloxavir Acid. Pathogens 2022; 11:pathogens11091048. [PMID: 36145480 PMCID: PMC9505253 DOI: 10.3390/pathogens11091048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/04/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Baloxavir marboxil (BXM) is an antiviral drug that targets the endonuclease of the influenza polymerase acidic (PA) protein. Antiviral resistance, mainly mediated by the I38T PA substitution, readily occurs in both A(H1N1) and A(H3N2) viruses following a single dose of BXM. Influenza B resistance to BXM remains poorly documented. We aimed to generate baloxavir-resistant contemporary influenza B/Yamagata/16/1988- and B/Victoria/2/1987-like viruses by in vitro passages under baloxavir acid (BXA) pressure to identify resistance mutations and to characterize the fitness of drug-resistant variants. Influenza B/Phuket/3073/2013 recombinant virus (rg-PKT13, a B/Yamagata/16/1988-like virus) and B/Quebec/MCV-11/2019 (MCV19, a B/Victoria/2/1987-like isolate) were passaged in ST6GalI-MDCK cells in the presence of increasing concentrations of BXA. At defined passages, viral RNA was extracted for sequencing the PA gene. The I38T PA substitution was selected in MCV19 after six passages in presence of BXA whereas no PA change was detected in rg-PKT13. The I38T substitution increased the BXA IC50 value by 13.7-fold in the MCV19 background and resulted in reduced viral titers compared to the wild type (WT) at early time points in ST6GalI-MDCK and at all time-points in human epithelial cells. By contrast, the I38T substitution had no impact on MCV19 polymerase activity, and this mutation was genetically stable over four passages. In conclusion, our results show a similar pathway of resistance to BXA in influenza B viruses highlighting the major role of the I38T PA substitution and suggest that I38T may differently impact the fitness of influenza variants depending on the viral type, subtype, or lineage.
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17
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Pleiotropic Effects of Influenza H1, H3, and B Baloxavir-Resistant Substitutions on Replication, Sensitivity to Baloxavir, and Interferon Expression. Antimicrob Agents Chemother 2022; 66:e0000922. [PMID: 35262375 DOI: 10.1128/aac.00009-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Baloxavir is an anti-influenza endonuclease inhibitor that targets the polymerase acidic (PA) protein of influenza A and B viruses. Our knowledge regarding the pleiotropic effects of baloxavir resistance-associated substitutions is limited. We generated recombinant A/California/04/09 (H1N1)-, A/Hong Kong/218849/2006 (H3N2)-, and B/Victoria/504/2000-like viruses that contained PA substitutions identified in baloxavir clinical trials and surveillance that could potentially be associated with baloxavir resistance. We characterized their susceptibility to baloxavir, impact on polymerase activity, viral growth, and ability to induce interferon (IFN) and IFN-stimulated genes expression in vitro. Four PA substitutions, H1N1 I38L/T, E199D, and B G199R, significantly reduced the sensitivity of the recombinant viruses to baloxavir (14.1-fold). We confirmed our findings by using the luciferase-based ribonucleoprotein minigenome assay and by using virus yield reduction assay in Calu-3 and normal human bronchial epithelial (NHBE) cells. We observed that I38L and E199D resulted in decreased viral replication of the H1N1 wild-type virus (1.4-fold) but the H1N1 I38T and B G199R substitutions did not significantly alter replication capacity in Calu-3 cells. In addition, H1N1 variants with PA I38L/T and E199D induced significantly higher levels of IFNB1 gene expression compared to the wild-type virus (4.2-fold). In contrast, the B variant, G199R, triggered the lowest levels of IFN genes in Calu-3 cells (1.6-fold). Because baloxavir is a novel anti-influenza therapeutic agent, identifying and characterizing substitutions associated with reduced sensitivity to baloxavir, as well as the impact of these substitutions on viral fitness, is paramount to the strategic implementation of this novel countermeasure.
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18
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Swine H1N1 Influenza Virus Variants with Enhanced Polymerase Activity and HA Stability Promote Airborne Transmission in Ferrets. J Virol 2022; 96:e0010022. [DOI: 10.1128/jvi.00100-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diverse IAVs circulate in animals, yet few acquire the viral traits needed to start a human pandemic. A stabilized HA and mammalian-adapted polymerase have been shown to promote the adaptation of IAVs to humans and ferrets (the gold-standard model for IAV replication, pathogenicity, and transmissibility).
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19
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Mhamdi Z, Carbonneau J, Venable MC, Baz M, Abed Y, Boivin G. Replication and transmission of an influenza A(H3N2) virus harboring the polymerase acidic I38T substitution, in guinea pigs. J Gen Virol 2021; 102. [PMID: 34661516 DOI: 10.1099/jgv.0.001659] [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: 11/18/2022] Open
Abstract
The polymerase acidic (PA) I38T substitution is a dominant marker of resistance to baloxavir. We evaluated the impact of I38T on the fitness of a contemporary influenza A(H3N2) virus. Influenza A/Switzerland/9715293/2013 (H3N2) wild-type (WT) virus and its I38T mutant were rescued by reverse genetics. Replication kinetics were compared using ST6GalI-MDCK and A549 cells and infectivity/contact transmissibility were evaluated in guinea pigs. Nasal wash (NW) viral titres were determined by TCID50 ml-1 in ST6GalI-MDCK cells. Competition experiments were performed and the evolution of viral population was assessed by droplet digital RT-PCR. I38T did not alter in vitro replication. I38T induced comparable titres vs the WT in guinea pigs NWs and the two viruses transmitted equally by direct contact. However, a 50 %:50 % mixture inoculum evolved to mean WT/I38T ratios of 71 %:29 % and 66.4 %:33.6 % on days 4 and 6 p.i., respectively. Contemporary influenza A(H3N2)-I38T PA variants may conserve a significant level of viral fitness.
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Affiliation(s)
- Zeineb Mhamdi
- Research Center in Infectious Diseases of the "CHU de Québec" and Laval University, Québec City, Québec, Canada
| | - Julie Carbonneau
- Research Center in Infectious Diseases of the "CHU de Québec" and Laval University, Québec City, Québec, Canada
| | - Marie-Christine Venable
- Research Center in Infectious Diseases of the "CHU de Québec" and Laval University, Québec City, Québec, Canada
| | - Mariana Baz
- Research Center in Infectious Diseases of the "CHU de Québec" and Laval University, Québec City, Québec, Canada
| | - Yacine Abed
- Research Center in Infectious Diseases of the "CHU de Québec" and Laval University, Québec City, Québec, Canada
| | - Guy Boivin
- Research Center in Infectious Diseases of the "CHU de Québec" and Laval University, Québec City, Québec, Canada
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20
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Baloxavir Treatment Delays Influenza B Virus Transmission in Ferrets and Results in Limited Generation of Drug-Resistant Variants. Antimicrob Agents Chemother 2021; 65:e0113721. [PMID: 34424039 DOI: 10.1128/aac.01137-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Clinical efficacy of the influenza antiviral baloxavir marboxil (baloxavir) is compromised by treatment-emergent variants harboring a polymerase acidic protein I38T (isoleucine-38-threonine) substitution. However, the fitness of I38T-containing influenza B viruses (IBVs) remains inadequately defined. After the pharmacokinetics of the compound were confirmed in ferrets, animals were injected subcutaneously with 8 mg/kg of baloxavir acid (BXA) at 24 h postinoculation with recombinant BXA-sensitive (BXA-Sen, I38) or BXA-resistant (BXA-Res, I38T) B/Brisbane/60/2008 (Victoria lineage) virus. BXA treatment of donor ferrets reduced virus replication and delayed transmission of the BXA-Sen but not the BXA-Res IBV. The I38 genotype remained dominant in the BXA-Sen-infected animals, even with BXA treatment. In competitive-mixture experiments, no transmission to aerosol contacts was seen from BXA-treated donors coinfected with the BXA-Sen and BXA-Res B/Brisbane/60/2008 viruses. However, in parallel mixed infections with the B/Phuket/3073/2013 (Yamagata lineage) virus background, BXA treatment failed to block airborne transmission of the BXA-Res virus, and the I38T genotype generally predominated. Therefore, the relative fitness of BXA-Res IBVs is complex and dependent on the virus backbone and within-host virus competition. BXA treatment of single-virus-infected ferrets hampers aerosol transmission of the BXA-Sen virus and does not readily generate BXA-Res variants, whereas mixed infections may result in propagation of BXA-Res IBVs of the Yamagata lineage. Our findings confirm the antiviral potency of baloxavir against IBVs, while supporting optimization of the dosing regimen to maximize clinical benefit.
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21
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Ison MG, Hayden FG, Hay AJ, Gubareva LV, Govorkova EA, Takashita E, McKimm-Breschkin JL. Influenza polymerase inhibitor resistance: Assessment of the current state of the art - A report of the isirv Antiviral group. Antiviral Res 2021; 194:105158. [PMID: 34363859 PMCID: PMC9012257 DOI: 10.1016/j.antiviral.2021.105158] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 12/31/2022]
Abstract
It is more than 20 years since the neuraminidase inhibitors, oseltamivir and zanamivir were approved for the treatment and prevention of influenza. Guidelines for global surveillance and methods for evaluating resistance were established initially by the Neuraminidase Inhibitor Susceptibility Network (NISN), which merged 10 years ago with the International Society for influenza and other Respiratory Virus Diseases (isirv) to become the isirv-Antiviral Group (isirv-AVG). With the ongoing development of new influenza polymerase inhibitors and recent approval of baloxavir marboxil, the isirv-AVG held a closed meeting in August 2019 to discuss the impact of resistance to these inhibitors. Following this meeting and review of the current literature, this article is intended to summarize current knowledge regarding the clinical impact of resistance to polymerase inhibitors and approaches for surveillance and methods for laboratory evaluation of resistance, both in vitro and in animal models. We highlight limitations and gaps in current knowledge and suggest some strategies for addressing these gaps, including the need for additional clinical studies of influenza antiviral drug combinations. Lessons learned from influenza resistance monitoring may also be helpful for establishing future drug susceptibility surveillance and testing for SARS-CoV-2.
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Affiliation(s)
- Michael G Ison
- Divisions of Infectious Diseases and Organ Transplantation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
| | - Frederick G Hayden
- Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, VA, USA.
| | - Alan J Hay
- The Francis Crick Institute, London, UK.
| | - Larisa V Gubareva
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Elena A Govorkova
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA.
| | - Emi Takashita
- National Institute of Infectious Diseases, Tokyo, Japan.
| | - Jennifer L McKimm-Breschkin
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria, Australia.
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22
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Hayden FG, Asher J, Cowling BJ, Hurt AC, Ikematsu H, Kuhlbusch K, Lemenuel-Diot A, Du Z, Meyers LA, Piedra PA, Takazono T, Yen HL, Monto AS. Reducing influenza virus transmission: the value of antiviral treatment. Clin Infect Dis 2021; 74:532-540. [PMID: 34245250 PMCID: PMC8834654 DOI: 10.1093/cid/ciab625] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Indexed: 11/16/2022] Open
Abstract
Prompt antiviral treatment has the potential to reduce influenza virus transmission to close contacts, but rigorous data on the magnitude of treatment effects on transmission are limited. Animal model data indicate that rapid reductions in viral replication after antiviral treatment reduce the risk of transmission. Observational and clinical trial data with oseltamivir and other neuraminidase inhibitors indicate that prompt treatment of household index patients seems to reduce the risk of illness in contacts, although the magnitude of the reported effects has varied widely across studies. In addition, the potential risk of transmitting drug-resistant variants exists with all approved classes of influenza antivirals. A controlled trial examining baloxavir treatment efficacy to reduce transmission, including the risk of transmitting virus with reduced baloxavir susceptibility, is currently in progress. If reduced transmission risk is confirmed, modeling studies indicate that early treatment could have major epidemiologic benefits in seasonal and pandemic influenza.
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Affiliation(s)
- Frederick G Hayden
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, USA
| | | | - Benjamin J Cowling
- School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | | | | | | | | | - Zhanwei Du
- School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Lauren Ancel Meyers
- Department of Integrative Biology and Statistics & Data Sciences, University of Texas, Austin, Texas, USA
| | - Pedro A Piedra
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, USA
| | - Takahiro Takazono
- Department of Infectious Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Hui-Ling Yen
- School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Arnold S Monto
- University of Michigan School of Public Health, Ann Arbor, Michigan, USA
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Goldhill DH, Yan A, Frise R, Zhou J, Shelley J, Gallego Cortés A, Miah S, Akinbami O, Galiano M, Zambon M, Lackenby A, Barclay WS. Favipiravir-resistant influenza A virus shows potential for transmission. PLoS Pathog 2021; 17:e1008937. [PMID: 34061908 PMCID: PMC8195362 DOI: 10.1371/journal.ppat.1008937] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 06/11/2021] [Accepted: 05/03/2021] [Indexed: 12/11/2022] Open
Abstract
Favipiravir is a nucleoside analogue which has been licensed to treat influenza in the event of a new pandemic. We previously described a favipiravir resistant influenza A virus generated by in vitro passage in presence of drug with two mutations: K229R in PB1, which conferred resistance at a cost to polymerase activity, and P653L in PA, which compensated for the cost of polymerase activity. However, the clinical relevance of these mutations is unclear as the mutations have not been found in natural isolates and it is unknown whether viruses harbouring these mutations would replicate or transmit in vivo. Here, we infected ferrets with a mix of wild type p(H1N1) 2009 and corresponding favipiravir-resistant virus and tested for replication and transmission in the absence of drug. Favipiravir-resistant virus successfully infected ferrets and was transmitted by both contact transmission and respiratory droplet routes. However, sequencing revealed the mutation that conferred resistance, K229R, decreased in frequency over time within ferrets. Modelling revealed that due to a fitness advantage for the PA P653L mutant, reassortment with the wild-type virus to gain wild-type PB1 segment in vivo resulted in the loss of the PB1 resistance mutation K229R. We demonstrated that this fitness advantage of PA P653L in the background of our starting virus A/England/195/2009 was due to a maladapted PA in first wave isolates from the 2009 pandemic. We show there is no fitness advantage of P653L in more recent pH1N1 influenza A viruses. Therefore, whilst favipiravir-resistant virus can transmit in vivo, the likelihood that the resistance mutation is retained in the absence of drug pressure may vary depending on the genetic background of the starting viral strain.
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Affiliation(s)
- Daniel H. Goldhill
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Ada Yan
- Department of Infectious Disease Epidemiology, Imperial College, London, United Kingdom
| | - Rebecca Frise
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Jie Zhou
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Jennifer Shelley
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Ana Gallego Cortés
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | | | | | | | | | | | - Wendy S. Barclay
- Department of Infectious Disease, Imperial College, London, United Kingdom
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