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Zhu VZ, Horton MB, Haeusler GM, Yong MK. The emergence of letermovir and maribavir drug-resistant mutations: from clinical trials to real-world studies. Curr Opin Infect Dis 2024:00001432-990000000-00187. [PMID: 39331647 DOI: 10.1097/qco.0000000000001065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2024]
Abstract
PURPOSE OF REVIEW Cytomegalovirus (CMV) infection is associated with severe clinical disease and high morbidity in immunocompromised hosts. Letermovir and maribavir, are two recently developed antiviral drugs used in the prevention and treatment of resistant and refractory CMV. Following the publication of landmark randomized trials and increased use, both clinical trial data and real-world experience has reported the development of antiviral drug resistance. The aim of this review was to comprehensively review the published literature on letermovir and maribavir drug resistance and to describe the clinical scenarios in which they may emerge. RECENT FINDINGS For letermovir, the most frequently detected resistance mutations occur in the UL56 gene (C325Y/W/F) and confer total resistance. Maribavir resistance mutations most often occur in the UL97 gene and resistance-associated variants (RAVs) T409M, H411Y, C480F have all been detected. The clinical context in which letermovir and maribavir resistance occurs include high viral loads at initiation, intensified immunosuppression, subtherapeutic drug exposure because of poor adherence, drug interactions, and inadequate central nervous system (CNS) penetration. Emergence of resistance mutations generally occurs within the first 3 months of initiation. SUMMARY The detection of letermovir and maribavir resistance mutations highlights an ongoing clinical challenge in the management of CMV.
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Affiliation(s)
- Violet Z Zhu
- National Centre for Infections in Cancer, Peter MacCallum Cancer Centre, Melbourne
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville
| | - Miles B Horton
- Immunology Division, Walter & Eliza Hall Institute of Medical Research, Melbourne
- Department of Medical Biology, The University of Melbourne
| | - Gabrielle M Haeusler
- National Centre for Infections in Cancer, Peter MacCallum Cancer Centre, Melbourne
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville
- Department of Infectious Diseases, The Royal Children's Hospital Melbourne
- Clinical Infections, Murdoch Childrens Research Institute
| | - Michelle K Yong
- National Centre for Infections in Cancer, Peter MacCallum Cancer Centre, Melbourne
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville
- Department of Infectious Diseases, Peter MacCallum Cancer Centre, Melbourne, Australia
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Monday LM, Keri V, Chandrasekar PH. Advances in pharmacotherapies for cytomegalovirus infection: what is the current state of play? Expert Opin Pharmacother 2024; 25:685-694. [PMID: 38717943 DOI: 10.1080/14656566.2024.2353627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 05/07/2024] [Indexed: 06/12/2024]
Abstract
INTRODUCTION Cytomegalovirus (CMV) remains a serious opportunistic infection in hematopoietic cell transplant (HCT) and solid-organ transplant (SOT) recipients. Traditional anti-CMV drugs are limited by toxicities and the development of resistance. Letermovir and maribavir are newly approved antivirals for the prevention and treatment of CMV. AREAS COVERED Prior reviews have discussed use of letermovir for prevention of CMV after HCT and maribavir for resistant or refractory (R/R) CMV post HCT or SOT. Subsequent data have expanded their use including letermovir for primary CMV prophylaxis in high-risk renal transplant recipients and new recommendations for extending prophylaxis through day + 200 in certain HCT patients. Data on the use of maribavir for first asymptomatic CMV infection post-HCT has also been published. This review compares the pharmacology of anti-CMV agents and discusses the updated literature of these new drugs in the prevention and treatment of CMV. EXPERT OPINION Letermovir and maribavir are much needed tools that spare toxicities of ganciclovir, foscarnet, and cidofovir. High cost is a challenge preventing their integration into clinical practice in resource-limited countries. Transplant centers need to exercise restraint in overuse to avoid resistance, particularly in the setting of high viral loads.
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Affiliation(s)
- Lea M Monday
- Division of Infectious Diseases, Department of Medicine, Wayne State University, Detroit, MI, USA
| | - Vishakh Keri
- Division of Infectious Diseases, Department of Medicine, Wayne State University, Detroit, MI, USA
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Liang H, Gong S, Gui G, Wang H, Jiang L, Li X, Fan J. Secretion of IFN-γ by specific T cells in HCMV infection. Heliyon 2024; 10:e28177. [PMID: 38533049 PMCID: PMC10963622 DOI: 10.1016/j.heliyon.2024.e28177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 03/13/2024] [Accepted: 03/13/2024] [Indexed: 03/28/2024] Open
Abstract
One major risk for recipients undergoing allogeneic hematopoietic stem cell transplants (allo-HSCTs) is infection with the human cytomegalovirus (HCMV). For HCMV treatment, it is especially crucial to be able to differentiate between recipients who are at high risk of reactivation and those who are not. In this study, HCMV-DNA was collected from 60 HLA-A*02 allo-HSCT recipients before and after transplantation. After transplantation, the release of interferon (IFN)-γ by T cells specific to HCMV was assessed using the enzyme-linked immunospot assay (ELISPOT). The results show that the median viral load (VL) was significantly higher in the HCMV persistent-infection group compared to the non-persistent-infection group (p = 0.002), and that the late-infection rate was considerably higher in the high-VL group compared to the low-VL group (p = 0.014). The uninfected group had a considerably higher median IFN-γ spot-forming cell (SFC) count than the persistent-infection group (p = 0.001), and IFN-γ SFC counts correlated negatively and linearly with VLs (r = -0.397, p = 0.002). The immune-response groups showed significantly difference in median VL (p = 0.018), and the high immune response group had a reduced late-infection rate than the no/low immune response groups (p = 0.049). Our study showed that allo-HSCT recipients with a high VL at an early transplantation stage were at high risk for late HCMV infection. Further HCMV reactivation can be prevented by HCMV-specific T cells secreting enough IFN-γ.
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Affiliation(s)
- Hanying Liang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, PR China
| | - Shengnan Gong
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, PR China
| | - Genyong Gui
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, PR China
| | - Huiqi Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, PR China
| | - Lili Jiang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, PR China
| | - Xuejie Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, PR China
| | - Jun Fan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, PR China
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Hume J, Lowry K, Whiley DM, Irwin AD, Bletchly C, Sweeney EL. Application of the ViroKey® SQ FLEX assay for detection of cytomegalovirus antiviral resistance. J Clin Virol 2023; 167:105556. [PMID: 37566984 DOI: 10.1016/j.jcv.2023.105556] [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: 05/16/2023] [Revised: 07/13/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023]
Abstract
BACKGROUND Cytomegalovirus (CMV) is a viral infection which establishes lifelong latency, often reactivating and causing disease in immunosuppressed individuals, including haematopoietic stem cell transplant (HSCT) recipients. Treatment can be problematic due to antiviral resistance which substantially increases the risk of patient mortality. Diagnostic testing capabilities for CMV antiviral resistance in Australia and elsewhere have traditionally relied on gene-specific Sanger sequencing approaches, however, are now being superseded by next generation sequencing protocols. OBJECTIVE Provide a snapshot of local mutations and explore the feasibility of the ViroKeyࣨ® SQ FLEX Genotyping Assay (Vela Diagnostics Pty Ltd) by examining sequencing success. METHOD Performed sequencing on adult (n = 38) and paediatric (n = 81) plasma samples, over a large range of viral loads (above and below the assay recommended threshold of ≥1,000 International Units (IU)/mL; noting most of our paediatric samples have loads <1,000 IU/mL). RESULTS Eleven test runs (including three repeat runs; 14 to 15 samples per run) were conducted, and four runs were deemed valid. The overall individual sample success rate for the four evaluable test runs was 71.2% (42/59 samples); 80.4% (37/46) samples ≥1,000 IU/mL were valid. Ten clinically important antiviral resistance mutations were detected, the most common being A594V in the UL97 gene, found in 6 (5%) samples. CONCLUSIONS A range of technical issues were experienced, however with improvement this platform could be a useful addition to routine pathology workflows, providing timely antiviral resistance results for patients undergoing HSCT.
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Affiliation(s)
- Jocelyn Hume
- Faculty of Medicine, The University of Queensland Centre for Clinical Research (UQCCR), The University of Queensland, Brisbane, Queensland, Australia; Pathology Queensland Central Laboratory, Brisbane, Queensland, Australia
| | - Kym Lowry
- Faculty of Medicine, The University of Queensland Centre for Clinical Research (UQCCR), The University of Queensland, Brisbane, Queensland, Australia; Queensland Paediatric Infectious Diseases (QPID) Sakzewski Laboratory, Centre for Children's Health Research, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - David M Whiley
- Faculty of Medicine, The University of Queensland Centre for Clinical Research (UQCCR), The University of Queensland, Brisbane, Queensland, Australia; Pathology Queensland Central Laboratory, Brisbane, Queensland, Australia
| | - Adam D Irwin
- Faculty of Medicine, The University of Queensland Centre for Clinical Research (UQCCR), The University of Queensland, Brisbane, Queensland, Australia; Infection Management and Prevention Service, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - Cheryl Bletchly
- Pathology Queensland Central Laboratory, Brisbane, Queensland, Australia
| | - Emma L Sweeney
- Faculty of Medicine, The University of Queensland Centre for Clinical Research (UQCCR), The University of Queensland, Brisbane, Queensland, Australia.
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Bini Viotti J, Dammann F, Jimenez Jimenez AM, Anderson AD, Morris MI, Camargo JF, Raja M. Emergence of maribavir resistance after CMV treatment in hematopoietic stem cell transplant recipient. Ann Hematol 2023; 102:2283-2284. [PMID: 37183208 DOI: 10.1007/s00277-023-05265-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/03/2023] [Indexed: 05/16/2023]
Affiliation(s)
- Julia Bini Viotti
- Jackson Health System, Miami Transplant Institute, Miami, FL, USA
- Division of Infectious Disease, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Fabian Dammann
- Jackson Health System, Miami Transplant Institute, Miami, FL, USA
- Division of Infectious Disease, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Antonio Martin Jimenez Jimenez
- Division of Transplantation and Cellular Therapy, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Anthony D Anderson
- Department of Pharmacy Services, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Michele I Morris
- Division of Infectious Disease, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jose F Camargo
- Division of Infectious Disease, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Mohammed Raja
- Division of Infectious Disease, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA.
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CMV antiviral stewardship: navigating obstacles to facilitate target attainment. Curr Opin Organ Transplant 2023; 28:8-14. [PMID: 36579682 DOI: 10.1097/mot.0000000000001032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW Despite the availability of potent antivirals, consensus guidelines and decades of research, cytomegalovirus (CMV) continues to be associated with negative outcomes after solid organ transplant. This has been attributed to postprophylaxis CMV infection and a lack of development of CMV-specific cell mediated immunity (CMI). A shift from a focus on antiviral prevention to a focus on CMI target attainment is needed to improve CMV outcomes after transplantation. RECENT FINDINGS There are many obstacles to CMI target attainment. Antiviral stewardship programs (AVS) have been employed to improve patient outcomes through appropriate antiviral use, reduction of unnecessary exposure and resistance mitigation. By focusing on the patient's unique substrate of conglomerate risk factors and addressing these factors specifically with evidenced based methodology, the AVS can address these obstacles, increasing rates of CMI and subsequently reducing risk of future CMV infection and negative outcomes. SUMMARY With its multidisciplinary composition utilizing decades of experience from antimicrobial stewardship principles and practices, the AVS is uniquely poised to facilitate the shift from a focus on prevention to CMI target attainment and be the supporting pillar for the frontline transplant clinician caring for transplant patients with CMV.
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Kleiboeker HL, Descourouez JL, Schulz LT, Mandelbrot DA, Odorico JS, Rice JP, Saddler CM, Smith JA, Jorgenson MR. Maribavir for the Management of Cytomegalovirus in Adult Transplant Recipients: A Review of the Literature and Practical Considerations. Ann Pharmacother 2022; 57:597-608. [PMID: 36003036 DOI: 10.1177/10600280221118959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE To review the efficacy and safety of maribavir for management of cytomegalovirus (CMV) in solid organ transplant recipients. DATA SOURCES A literature search of PubMed and the Cochrane Controlled Trials Register (1960 to early July 2022) was performed using the following search terms: maribavir, 1263W94, and cytomegalovirus. STUDY SELECTION AND DATA EXTRACTION All relevant English-language studies were reviewed and considered, with a focus on phase 3 trials. DATA SYNTHESIS Maribavir, an orally available benzimidazole riboside with minimal adverse effects, was originally studied for universal prophylaxis in phase 3 trials but failed to demonstrate noninferiority over placebo and oral ganciclovir. It was effective for preemptive treatment in a dose-finding Phase 2 study. Maribavir is FDA approved for treatment of refractory/resistant CMV infection based on improved response rate at 8 weeks compared with investigator-assigned therapy (IAT) when initiated at median viral loads less than approximately 10 000 IU/mL (55.7% vs 23.9%, P < 0.001). Recurrence after 8-week treatment for refractory/resistant CMV was high (maribavir 50% vs IAT 39%). Significant drug interactions exist and must be managed by a pharmacotherapy expert to prevent harm. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE The addition of maribavir to the antiviral armamentarium should improve the management of refractory/resistant CMV, allowing early transition from toxic, high-cost, intravenous agents such as foscarnet and outpatient management. Optimal timing of initiation, duration, and potential alternative uses are unclear. CONCLUSION Future studies are needed to fully elucidate the role of maribavir in the management of CMV after transplant.
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Affiliation(s)
- Hanna L Kleiboeker
- Department of Pharmacy, University of Wisconsin Hospital and Clinics, Madison, WI, USA
| | - Jillian L Descourouez
- Department of Pharmacy, University of Wisconsin Hospital and Clinics, Madison, WI, USA
| | - Lucas T Schulz
- Department of Pharmacy, University of Wisconsin Hospital and Clinics, Madison, WI, USA
| | - Didier A Mandelbrot
- Department of Medicine, Division of Nephrology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Jon S Odorico
- Department of Surgery, Division of Transplantation, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - John P Rice
- Department of Medicine, Division of Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Christopher M Saddler
- Department of Medicine, Division of Infectious Diseases, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Jeannina A Smith
- Department of Medicine, Division of Infectious Diseases, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Margaret R Jorgenson
- Department of Pharmacy, University of Wisconsin Hospital and Clinics, Madison, WI, USA
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Yong MK, Shigle TL, Kim YJ, Carpenter PA, Chemaly RF, Papanicolaou GA. American Society for Transplantation and Cellular Therapy Series: #4 - Cytomegalovirus treatment and management of resistant or refractory infections after hematopoietic cell transplantation. Transplant Cell Ther 2021; 27:957-967. [PMID: 34560310 DOI: 10.1016/j.jtct.2021.09.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 09/15/2021] [Indexed: 11/29/2022]
Abstract
The Practice Guidelines Committee of the American Society of Transplantation and Cellular Therapy (ASTCT) partnered with its Transpl. Infect. Dis. Special Interest Group (TID-SIG) to update its 2009 compendium-style infectious disease guidelines for hematopoietic cell transplantation (HCT). A new approach was employed with the goal of better serving clinical providers by publishing each standalone topic in the infectious diseases series as a concise format of frequently asked questions (FAQ), tables, and figures. Adult and pediatric infectious diseases and HCT content experts developed and answered FAQs. Topics were finalized with harmonized recommendations that were made by assigning an A through E strength of recommendation paired with a level of supporting evidence graded I through III. The fourth topic in the series focuses on the management and treatment of cytomegalovirus (CMV) resistant and refractory infections. The diagnosis, definitions of resistant and refractory CMV, risk factors, virological genotypes and treatment algorithms are reviewed.
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Affiliation(s)
- Michelle K Yong
- Department of Infectious Diseases, Peter MacCallum Cancer Centre, Melbourne, Victoria, 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria, 3000, Australia; Department of Infectious Diseases, Royal Melbourne Hospital, Melbourne Victoria, 3050, Australia.
| | - Terri Lynn Shigle
- Division of Pharmacy, The University of Texas MD Anderson Cancer Centre, Houston, TX, USA
| | - Yae-Jean Kim
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Paul A Carpenter
- Clinical Research Division, Fred Hutchinson Cancer Research Centre, Seattle, WA, USA
| | - Roy F Chemaly
- Department of Infectious Diseases, Infection Control, & Employee Health, The University of Texas MD Anderson Cancer Centre, Houston, TX, USA
| | - Genovefa A Papanicolaou
- Infectious Diseases Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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Limaye AP, Babu TM, Boeckh M. Progress and Challenges in the Prevention, Diagnosis, and Management of Cytomegalovirus Infection in Transplantation. Clin Microbiol Rev 2020; 34:34/1/e00043-19. [PMID: 33115722 PMCID: PMC7920732 DOI: 10.1128/cmr.00043-19] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hosts with compromised or naive immune systems, such as individuals living with HIV/AIDS, transplant recipients, and fetuses, are at the highest risk for complications from cytomegalovirus (CMV) infection. Despite substantial progress in prevention, diagnostics, and treatment, CMV continues to negatively impact both solid-organ transplant (SOT) and hematologic cell transplant (HCT) recipients. In this article, we summarize important developments in the field over the past 10 years and highlight new approaches and remaining challenges to the optimal control of CMV infection and disease in transplant settings.
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Affiliation(s)
- Ajit P Limaye
- Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Tara M Babu
- Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
- Department of Infectious Diseases, Overlake Medical Center, Bellevue, Washington, USA
| | - Michael Boeckh
- Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
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Resistant or refractory cytomegalovirus infections after hematopoietic cell transplantation: diagnosis and management. Curr Opin Infect Dis 2020; 32:565-574. [PMID: 31567572 DOI: 10.1097/qco.0000000000000607] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Refractory or resistant cytomegalovirus (CMV) infections are challenging complications after hematopoietic cell transplantation (HCT). Most refractory or resistant CMV infections are associated with poor outcomes and increased mortality. Prompt recognition of resistant or refractory CMV infections, understanding the resistance pathways, and the treatment options in HCT recipients are imperative. RECENT FINDINGS New definitions for refractory and resistant CMV infections in HCT recipients have been introduced for future clinical trials. Interestingly, refractory CMV infections are more commonly encountered in HCT recipients when compared with resistant CMV infections. CMV terminase complex mutations in UL56, UL89, and UL51 could be associated with letermovir resistance; specific mutations in UL56 are the most commonly encountered in clinical practice. Finally, brincidofovir, maribavir, letermovir, and CMV-specific cytotoxic T-cell therapy expanded our treatment options for refractory or resistant CMV infections. SUMMARY Many advances have been made to optimize future clinical trials for management of refractory or resistant CMV infections, and to better understand new resistance mechanisms to novel drugs. New drugs or strategies with limited toxicities are needed to improve outcomes of difficult to treat CMV infections in HCT recipients.
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Chou S, Song K, Wu J, Bo T, Crumpacker C. Drug resistance mutations and associated phenotypes detected in clinical trials of maribavir for treatment of cytomegalovirus infection. J Infect Dis 2020; 226:576-584. [PMID: 32726419 PMCID: PMC9441206 DOI: 10.1093/infdis/jiaa462] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/24/2020] [Indexed: 01/26/2023] Open
Abstract
Background In separate phase 2 trials, 120 patients received maribavir for cytomegalovirus (CMV) infection failing conventional therapy (trial 202) and 119 received maribavir for asymptomatic infection (trial 203). Overall, 172 cleared their CMV infection (CMV DNA <200 copies/mL) within 6 weeks. Methods Baseline and posttreatment plasma samples were tested for mutations in viral genes UL97, UL54, and/or UL27. Selected viral mutants were phenotyped for drug susceptibility. Results Baseline samples revealed UL54 mutations newly phenotyped as conferring resistance to standard DNA polymerase inhibitor(s), including K493N, P497S, K513T, L565V, V823A, A987V, and E989D. Of 29 patients (including 25 from trial 202) who cleared but later experienced recurrent CMV infection while on maribavir, 23 had available UL97 genotyping data; 17 had known resistance mutations (T409M or H411Y) and 5 additional had UL97 C480F alone. The newly phenotyped mutation C480F conferred high-grade maribavir resistance and low-grade ganciclovir resistance. Among 25 who did not respond to >14 days of therapy, 9 showed T409M or H411Y and 4 others showed C480F alone. Conclusions After maribavir therapy (400–1200 mg twice daily), UL97 mutations T409M, H411Y, or C480F emerge to confer maribavir resistance in patients with recurrent CMV infection while on therapy or no response to therapy. Clinical Trials Registration NCT01611974 and EudraCT 2010-024247-32.
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Affiliation(s)
- Sunwen Chou
- Oregon Health & Science University and VA Health Care System, Portland OR
| | - Kening Song
- Shire Human Genetic Therapies Inc., Lexington MA, a Takeda Company
| | - Jingyang Wu
- Shire Human Genetic Therapies Inc., Lexington MA, a Takeda Company
| | - Tien Bo
- Shire Human Genetic Therapies Inc., Lexington MA, a Takeda Company
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Advances in the genotypic diagnosis of cytomegalovirus antiviral drug resistance. Antiviral Res 2020; 176:104711. [PMID: 31940472 DOI: 10.1016/j.antiviral.2020.104711] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/22/2019] [Accepted: 01/09/2020] [Indexed: 12/20/2022]
Abstract
Cytomegalovirus (CMV) drug resistance mutation maps are updated with recent information for polymerase inhibitors, the terminase inhibitor letermovir and the UL97 kinase inhibitor maribavir. Newly mapped mutations and their phenotypes provide more detail on cross-resistance properties and suggest the need to expand the CMV gene regions covered in diagnostic testing. Next-generation deep sequencing technology offers a more sensitive, higher resolution view of emerging antiviral resistance and is recommended for use in clinical trials. Issues of standardization and diagnostic utility in comparison with traditional Sanger sequencing remain unresolved. Quality control is important for the accurate and reproducible detection of mutant viral populations in clinical specimens.
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The Third International Consensus Guidelines on the Management of Cytomegalovirus in Solid-organ Transplantation. Transplantation 2019; 102:900-931. [PMID: 29596116 DOI: 10.1097/tp.0000000000002191] [Citation(s) in RCA: 733] [Impact Index Per Article: 146.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite recent advances, cytomegalovirus (CMV) infections remain one of the most common complications affecting solid organ transplant recipients, conveying higher risks of complications, graft loss, morbidity, and mortality. Research in the field and development of prior consensus guidelines supported by The Transplantation Society has allowed a more standardized approach to CMV management. An international multidisciplinary panel of experts was convened to expand and revise evidence and expert opinion-based consensus guidelines on CMV management including prevention, treatment, diagnostics, immunology, drug resistance, and pediatric issues. Highlights include advances in molecular and immunologic diagnostics, improved understanding of diagnostic thresholds, optimized methods of prevention, advances in the use of novel antiviral therapies and certain immunosuppressive agents, and more savvy approaches to treatment resistant/refractory disease. The following report summarizes the updated recommendations.
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Andronova VL. [Modern ethiotropic chemotherapy of human cytomegalovirus infection: clinical effectiveness, molecular mechanism of action, drug resistance, new trends and prospects. Part 2.]. Vopr Virusol 2019; 63:250-260. [PMID: 30641020 DOI: 10.18821/0507-4088-2018-63-6-250-260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 12/12/2017] [Indexed: 11/17/2022]
Abstract
A number of synthetic compounds, such as the nucleoside analog ganciclovir, its L-valine ester (a metabolic precursor of ganciclovir) and pyrophosphate analog foscarnet, are permitted for the treatment of HCMVrelated diseases in the WHO European Region. The viral DNA- polymerase is used by all these drugs as a biotarget. However, the usage of standard anti-CMV therapy is accompanied by severe side effects, as well as the development of drug resistance in the virus, mainly in conditions of immunodefciency. In this review, we focused on viral proteins of interest as new potential targets and their inhibitors, such as the inhibitor of human CMV terminology, lethermovir, which showed great activity in the third phase of clinical trials, inhibitors of viral cyclin-dependent kinase (maribavir, cyclopropavir) and a number of compounds exhibiting anti-HCMV-activity, undergoing only preclinical trials in the experiment. Inclusion of new anti-CMV agents that are active against GСV/PFA/CDV-resistant strains of CMV into standard prophylactic and therapeutic regimens, will allow to increase the effectiveness of anti-CMV therapy, including in cases when standard therapy is ineffective. Areas covered: the international databases such as A MEDLINE, PubMed, eLIBRARY.RU, ClinicalTrials.gov., etc. with the purpose of obtaining information on compounds showing selective action against the human cytomegalovirus, the most promising for the development of drugs.
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Affiliation(s)
- V L Andronova
- National Research Centre for Epidemiology and Microbiology named after the honorary academician N.F. Gamaleya, Moscow, 123098, Russian Federation
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15
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Migliori E, Chang M, Muranski P. Restoring antiviral immunity with adoptive transfer of ex-vivo generated T cells. Curr Opin Hematol 2018; 25:486-493. [PMID: 30281036 DOI: 10.1097/moh.0000000000000461] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW Latent viruses such as cytomegalovirus (CMV), Epstein-Barr virus (EBV) and adenovirus (ADV) often reactivate in immunocompromised patients, contributing to poor clinical outcomes. A rapid reconstitution of antiviral responses via adoptive transfer of virus-specific T cells (VSTs) can prevent or eradicate even refractory infections. Here, we evaluate this strategy and the associated methodological, manufacturing and clinical advances. RECENT FINDINGS From the early pioneering but cumbersome efforts to isolate CMV-specific T cell clones, new approaches and techniques have been developed to provide quicker, safer and broader-aimed ex-vivo antigen-specific cells. New manufacturing strategies, such as the use of G-Rex flasks or 'priming' with a library of overlapping viral peptides, allow for culturing greater numbers of cells that could be patient-specific or stored in cell banks for off-the-shelf applications. Rapid isolation of T cells using major histocompatibility complex tetramer or cytokine capture approaches, or genetic reprogramming of cells to target viral antigens can accelerate the generation of potent cellular products. SUMMARY Advances in the ex-vivo generation of VSTs in academic medical centres and as off-the-shelf blood bank-based or commercially produced reagents are likely to result in broader accessibility and possible manufacturing cost reduction of these cell products, and will open new therapeutic prospects for vulnerable and critically ill immunocompromised patients.
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Affiliation(s)
- Edoardo Migliori
- Columbia Center for Translational Immunology (CCTI), Division of Hematology/Oncology, Columbia University Medical Center, New York, New York, USA
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Chou S, Ercolani RJ, Derakhchan K. Antiviral activity of maribavir in combination with other drugs active against human cytomegalovirus. Antiviral Res 2018; 157:128-133. [PMID: 30040968 PMCID: PMC6097806 DOI: 10.1016/j.antiviral.2018.07.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/15/2018] [Accepted: 07/19/2018] [Indexed: 12/11/2022]
Abstract
The human cytomegalovirus (CMV) UL97 kinase inhibitor maribavir is in Phase III clinical trials as antiviral therapy, including use for infections refractory or resistant to standard therapy. To assess its activity in combination with approved and experimental CMV antivirals, and with the mTor inhibitor rapamycin (sirolimus), drug effects were tested by in vitro checkerboard assays and the data were analyzed using a three dimensional model based on an independent effects definition of additive interactions. Baseline virus and representative drug-resistant mutants were tested. According to the volume of synergy at 95% confidence, maribavir showed additive interactions with foscarnet, cidofovir, letermovir and GW275175X when tested against wild type and mutant viruses, strong antagonism with ganciclovir, and strong synergy with rapamycin, the latter suggesting a potentially useful therapeutic combination.
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Affiliation(s)
- Sunwen Chou
- Division of Infectious Diseases, Oregon Health & Science University, USA; Portland Veterans Affairs Health Care System, OR USA.
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Affiliation(s)
- Margaret L Green
- University of Washington, 1959 NE Pacific Street, Box 359930, Seattle, WA 98195, USA; Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA.
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Bowman LJ, Melaragno JI, Brennan DC. Letermovir for the management of cytomegalovirus infection. Expert Opin Investig Drugs 2016; 26:235-241. [PMID: 27998189 DOI: 10.1080/13543784.2017.1274733] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Cytomegalovirus (CMV) is a major cause of morbidity and mortality in immunocompromised patients. Available antivirals are fraught with adverse effects and risk for the development of CMV resistance. Letermovir is a novel antiviral in the late stages of drug development for the treatment and prevention of CMV. Areas covered: A MEDLINE search of the MeSH terms 'letermovir,' 'cytomegalovirus,' 'hematopoietic stem cell transplant,' and 'solid organ transplant,' was last conducted on 15 August 2016. Articles were selected on the basis of their contribution to current knowledge about letermovir. Expert opinion: Letermovir's mechanism of action, pharmacokinetic and pharmacodynamic profile, and favorable efficacy and safety make it an attractive option for both the prevention and treatment of CMV in immunocompromised patients. The lack of cross-resistance with other antivirals and the absence of myelosuppression are two prominent characteristics of letermovir that could support broad use of this product following FDA-approval. One major limitation is its lack of activity against other herpesviruses, which are commonly seen in immunocompromised hosts. We believe that with additional clinical efficacy data, this medication could emerge as a primary option for the prevention and treatment of CMV in the immunocompromised patient population.
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Affiliation(s)
- Lyndsey J Bowman
- a Department of Pharmacy , Tampa General Hospital , Tampa , FL , USA
| | | | - Daniel C Brennan
- c Division of Nephrology , Washington University School of Medicine , St. Louis , MO , USA
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Maffini E, Giaccone L, Festuccia M, Brunello L, Busca A, Bruno B. Treatment of CMV infection after allogeneic hematopoietic stem cell transplantation. Expert Rev Hematol 2016; 9:585-96. [PMID: 27043241 DOI: 10.1080/17474086.2016.1174571] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Despite a remarkable reduction in the past decades, cytomegalovirus (CMV) disease in allogeneic hematopoietic stem cell transplant (HSCT) recipients remains a feared complication, still associated with significant morbidity and mortality. Today, first line treatment of CMV infection/reactivation is still based on dated antiviral compounds Ganciclovir (GCV), Foscarnet (FOS) and Cidofovir (CDF) with their burdensome weight of side effects. Maribavir (MBV), Letermovir (LMV) and Brincidofovir (BDF) are three new promising anti-CMV drugs without myelosuppressive properties or renal toxic effects that are under investigation in randomized phase II and III trials. Adoptive T-cell therapy (ATCT) in CMV infection possesses a strong rationale, demonstrated by several proof of concept studies; its feasibility is currently under investigation by clinical trials. ATCT from third-party and naïve donors could meet the needs of HSCT recipients of seronegative donors and cord blood grafts. In selected patients such as recipients of T-cell depleted grafts, ATCT, based on CMV-specific host T-cells reconstitution kinetics, would be of value in the prophylactic and/or preemptive CMV treatment. Vaccine-immunotherapy has the difficult task to reduce the incidence of CMV reactivation/infection in highly immunocompromised HSCT patients. Newer notions on CMV biology may represent the base to flush out the Troll of transplantation.
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Affiliation(s)
- Enrico Maffini
- a Department of Oncology, SSCVD Trapianto di Cellule Staminali , A.O.U. Città della Salute e della Scienza di Torino , Torino , Italy.,b Department of Molecular Biotechnology and Health Sciences , University of Torino , Torino , Italy
| | - Luisa Giaccone
- a Department of Oncology, SSCVD Trapianto di Cellule Staminali , A.O.U. Città della Salute e della Scienza di Torino , Torino , Italy.,b Department of Molecular Biotechnology and Health Sciences , University of Torino , Torino , Italy
| | - Moreno Festuccia
- a Department of Oncology, SSCVD Trapianto di Cellule Staminali , A.O.U. Città della Salute e della Scienza di Torino , Torino , Italy.,b Department of Molecular Biotechnology and Health Sciences , University of Torino , Torino , Italy
| | - Lucia Brunello
- a Department of Oncology, SSCVD Trapianto di Cellule Staminali , A.O.U. Città della Salute e della Scienza di Torino , Torino , Italy.,b Department of Molecular Biotechnology and Health Sciences , University of Torino , Torino , Italy
| | - Alessandro Busca
- a Department of Oncology, SSCVD Trapianto di Cellule Staminali , A.O.U. Città della Salute e della Scienza di Torino , Torino , Italy
| | - Benedetto Bruno
- a Department of Oncology, SSCVD Trapianto di Cellule Staminali , A.O.U. Città della Salute e della Scienza di Torino , Torino , Italy.,b Department of Molecular Biotechnology and Health Sciences , University of Torino , Torino , Italy
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Abstract
PURPOSE OF REVIEW The purpose of this study is to provide updated information on diagnosis of cytomegalovirus (CMV) drug resistance, treatments for drug-resistant infection and potential uses of experimental antiviral compounds. RECENT FINDINGS For established CMV antivirals, uncommon viral UL97 kinase and UL54 DNA polymerase drug resistance mutations are sporadically described that expand an extensive existing database. Some novel mutations reported from treated patients have no drug-resistant phenotype and may be genotyping artefacts. Next-generation sequencing technology may enable earlier detection of emerging resistance mutations in treated patients. Management options for drug-resistant infection include optimization of host defenses, antiviral dose escalation, substitutions or combinations of standard or experimental antivirals. Maribavir and letermovir have antiviral targets distinct from the classic DNA polymerase. UL97 mutations elicited by ganciclovir and maribavir are different, although a single p-loop mutation can confer significant cross-resistance. High-grade resistance mutations in the UL56 terminase gene are readily selected in vitro under letermovir and await clinical correlation. SUMMARY Technical advancements can enhance the accurate and timely genotypic detection of drug resistance. Antivirals undergoing clinical trial offer the prospect of new viral targets and drug combinations, but unresolved issues exist with regard to their therapeutic potential for drug-resistant CMV and their genetic barriers to resistance.
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Cherng BPZ, Tan TT, Tan BH. Resistant cytomegalovirus infection in renal transplant recipients. PROCEEDINGS OF SINGAPORE HEALTHCARE 2015. [DOI: 10.1177/2010105815611811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Resistant cytomegalovirus infection is a significant problem in the transplant population including renal transplant recipients. A combination of factors including receipt of potent immunosuppression, high viral loads and suboptimal levels of anti-cytomegalovirus antivirals leads to emergence of resistant strains. Reports of associated poor graft survival and mortality demonstrate the potential pathogenic nature of such strains. Genotypic and phenotypic resistance testing are available for laboratory diagnosis of resistant cytomegalovirus infection and may help guide therapy. Various agents, including novel and newly minted antivirals and treatment approaches have been employed, with variable success. Thus, in spite of major advances in both diagnostics and therapeutics, management of resistant cytomegalovirus infection in renal transplant recipients remains a challenging prospect.
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Affiliation(s)
| | - Thuan Tong Tan
- Department of Infectious Diseases, Singapore General Hospital, Singapore
| | - Ban Hock Tan
- Department of Infectious Diseases, Singapore General Hospital, Singapore
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Rapid In Vitro Evolution of Human Cytomegalovirus UL56 Mutations That Confer Letermovir Resistance. Antimicrob Agents Chemother 2015; 59:6588-93. [PMID: 26259791 DOI: 10.1128/aac.01623-15] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 08/03/2015] [Indexed: 11/20/2022] Open
Abstract
Letermovir (LMV) is an experimental cytomegalovirus terminase inhibitor undergoing phase 3 clinical trials. Viral mutations have been described at UL56 codons 231 to 369 that confer widely variable levels of LMV resistance. In this study, 15 independent experiments propagating an exonuclease mutant viral strain in escalating LMV concentrations replicated 6 of the 7 published UL56 mutations and commonly elicited additional resistance-conferring mutations at UL56 codons 231, 236, 237, 244, 257, 261, 325, and 329. Mutations were first detected earlier in LMV (median, 3 passages) than in 8 parallel experiments with foscarnet (median, 15 passages). As LMV concentrations increased, the typical initial UL56 change F261L, which confers low-grade resistance, combined or was replaced with mutations conferring higher-grade resistance, eventually enabling normal viral growth in 30 μM LMV (>5,000-fold the 50% effective concentration [EC50] for the wild type). At high LMV concentrations, the UL56 changes C325F/R were commonly detected, as well as a combination of changes at codons 236, 257, 329, and/or 369. Recombinant viruses containing individual UL56 mutations and combinations were constructed to confirm their resistance phenotypes and normal growth in cell culture. Several double and triple mutants showed much higher LMV resistance than the respective single mutants, particularly those including changes at both codons 236 and 257. The multiplicity of pathways to high-grade LMV resistance with minimal viral growth impact suggests a low viral genetic barrier and the need for close monitoring during treatment of active infection.
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Gardner TJ, Cohen T, Redmann V, Lau Z, Felsenfeld D, Tortorella D. Development of a high-content screen for the identification of inhibitors directed against the early steps of the cytomegalovirus infectious cycle. Antiviral Res 2014; 113:49-61. [PMID: 25446405 DOI: 10.1016/j.antiviral.2014.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 10/16/2014] [Accepted: 10/20/2014] [Indexed: 01/06/2023]
Abstract
Human cytomegalovirus (CMV) is a latent and persistent virus whose proliferation increases morbidity and mortality of immune-compromised individuals. The current anti-CMV therapeutics targeting the viral DNA polymerase or the major immediate-early (MIE) gene locus are somewhat effective at limiting CMV-associated disease. However, due to low bioavailability, severe toxicity, and the development of drug resistant CMV strains following prolonged treatment, current anti-CMV therapeutics are insufficient. To help address this shortfall, we established a high-content assay to identify inhibitors targeting CMV entry and the early steps of infection. The infection of primary human fibroblasts with a variant of the CMV laboratory strain AD169 expressing a chimeric IE2-yellow fluorescence protein (YFP) (AD169IE2-YFP) provided the basis for the high-content assay. The localization of IE2-YFP to the nucleus shortly following an AD169IE2-YFP infection induced a robust fluorescent signal that was quantified using confocal microscopy. The assay was optimized to achieve outstanding assay fitness and high Z' scores. We then screened a bioactive chemical library consisting of 2080 compounds and identified hit compounds based on the decrease of fluorescence signal from IE2-YFP nuclear expression. The hit compounds likely target various cellular processes involved in the early steps of infection including capsid transport, chromatin remodeling, and viral gene expression. Extensive secondary assays confirmed the ability of a hit compound, convallatoxin, to inhibit infection of both laboratory and clinical CMV strains and limit virus proliferation. Collectively, the data demonstrate that we have established a robust high-content screen to identify compounds that limit the early steps of the CMV life cycle, and that novel inhibitors of early infection events may serve as viable CMV therapeutics.
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Affiliation(s)
- Thomas J Gardner
- Icahn School of Medicine at Mount Sinai, Department of Microbiology, New York, NY 10029, USA
| | - Tobias Cohen
- Icahn School of Medicine at Mount Sinai, Department of Microbiology, New York, NY 10029, USA
| | - Veronika Redmann
- Icahn School of Medicine at Mount Sinai, Department of Microbiology, New York, NY 10029, USA
| | - Zerlina Lau
- Icahn School of Medicine at Mount Sinai, Integrated Screening Core, Experimental Therapeutics Institute, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Dan Felsenfeld
- Icahn School of Medicine at Mount Sinai, Integrated Screening Core, Experimental Therapeutics Institute, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Domenico Tortorella
- Icahn School of Medicine at Mount Sinai, Department of Microbiology, New York, NY 10029, USA
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Sellar RS, Peggs KS. Therapeutic strategies for cytomegalovirus infection in haematopoietic transplant recipients: a focused update. Expert Opin Biol Ther 2014; 14:1121-6. [DOI: 10.1517/14712598.2014.908847] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Differential properties of cytomegalovirus pUL97 kinase isoforms affect viral replication and maribavir susceptibility. J Virol 2014; 88:4776-85. [PMID: 24522923 DOI: 10.1128/jvi.00192-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The human cytomegalovirus (HCMV)-encoded kinase pUL97 is required for efficient viral replication. Previous studies described two isoforms of pUL97, the full-length isoform (M1) and a smaller isoform likely resulting from translation initiation at codon 74 (M74). Here, we report the detection of a third pUL97 isoform during viral infection resulting from translation initiation at codon 157 (isoform M157). The consistent expression of isoform M157 as a minor component of pUL97 during infection with clinical and laboratory-adapted HCMV strains was suppressed when codon 157 was mutagenized. Viral mutants expressing specific isoforms were generated to compare their growth and drug susceptibility phenotypes, as well as pUL97 intracellular localization patterns and kinase activities. The exclusive expression of isoform M157 resulted in substantially reduced viral growth and resistance to the pUL97 inhibitor maribavir while retaining susceptibility to ganciclovir. Confocal imaging demonstrated reduced nuclear import of amino-terminal deletion isoforms compared to isoform M1. Isoform M157 showed reduced efficiency of various substrate protein interactions and autophosphorylation, whereas Rb phosphorylation was preserved. These results reveal differential properties of pUL97 isoforms that affect viral replication, with implications for the antiviral efficacy of maribavir. IMPORTANCE The HCMV UL97 kinase performs important functions in viral replication that are targeted by the antiviral drug maribavir. Here, we describe a naturally occurring short isoform of the kinase that when expressed by itself in a recombinant virus results in altered intracellular localization, impaired growth, and high-level resistance to maribavir compared to those of the predominant full-length counterpart. This is another factor to consider in explaining why maribavir appears to have variable antiviral activity in cell culture and in vivo.
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Bommer M, Michel D. Prevention of cytomegalovirus disease in patients with impaired cell-mediated immunity – is there a need for maribavir? Expert Opin Orphan Drugs 2013. [DOI: 10.1517/21678707.2013.842166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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