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Drug Metabolism and Disposition: the... Nov 2021Maribavir is in phase 3 clinical development for treatment of cytomegalovirus infection/disease in transplant recipients. Previous research conducted using only intact...
Maribavir is in phase 3 clinical development for treatment of cytomegalovirus infection/disease in transplant recipients. Previous research conducted using only intact cynomolgus monkeys indicated biliary secretion as the primary elimination pathway for maribavir and that maribavir undergoes enterohepatic recirculation (EHR). To clarify the exact mechanisms of maribavir's EHR behavior, we studied its clearance pathways using intravenously administered C-labeled maribavir in intact and bile duct-cannulated (BDC) monkeys and constructed a semi-physiologically based pharmacokinetic (PBPK) model. Total radioactivity metabolite profiles in plasma and excreta were quantitatively determined along with plasma maribavir concentrations. Intact animals showed significantly lower clearance and longer half-lives in both total radioactivity and parent concentration in plasma than BDC monkeys. The primary in vitro and in vivo metabolic pathway for maribavir in monkey is direct glucuronidation; -dealkylation and renal clearance are minor pathways. In BDC monkeys, 73% of dose was recovered as maribavir glucuronides in bile, and 3% of dose was recovered as parent in bile and feces; in intact animals' feces, 58% of dose was recovered as parent, and no glucuronides were detected. Therefore, EHR of maribavir occurs through biliary secretion of maribavir glucuronides, and this is followed by hydrolysis of glucuronides in the gut lumen and subsequent reabsorption of parent. A semi-PBPK model constructed from physiologic, in vitro, and in vivo BDC monkey data is capable of projecting maribavir's pharmacokinetic and EHR behavior in intact animals after intravenous or oral dosing and could be applied to modeling other xenobiotics that are subject to similar EHR processes. SIGNIFICANCE STATEMENT: Through both mass balance and semi-physiologically based pharmacokinetic (semi-PBPK) modeling approaches, this study mechanistically and quantitatively elucidates maribavir's enterohepatic recirculation (EHR) behavior in monkeys, which occurs via extensive direct glucuronidation, biliary secretion of these glucuronides, luminal hydrolysis of glucuronides to parent, and subsequent reabsorption of the parent. The study also identifies important drug- and animal-specific parameters that determine the EHR kinetics, and the semi-PBPK model is readily applicable to other drugs that undergo similar metabolic and recirculation mechanisms.
Topics: Animals; Antiviral Agents; Benzimidazoles; Bile; Biotransformation; Caco-2 Cells; Dealkylation; Feces; Gastrointestinal Transit; Glucuronides; Half-Life; Humans; Hydrolysis; Kidney; Macaca fascicularis; Male; Models, Biological; Ribonucleosides
PubMed: 34462268
DOI: 10.1124/dmd.121.000493 -
Current Treatment Options in Infectious... 2021Cytomegalovirus (CMV) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (Allo-HSCT). New strategies and methods... (Review)
Review
PURPOSE OF REVIEW
Cytomegalovirus (CMV) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (Allo-HSCT). New strategies and methods for prevention and management of CMV infection are urgently needed. We aim to review the new developments in diagnostics, prevention, and management strategies of CMV infection in Allo-HSCT recipients.
RECENT FINDINGS
The approval of the novel anti-CMV drug letermovir in 2017 has led to an increase in the use of antiviral prophylaxis as a preferred approach for prevention in many centers. Real-world studies have shown efficacy similar to the clinical trial. CMV-specific T cell-mediated immunity assays identify patients with immune reconstitution and predict disease progression. Phase 2 trials of maribavir have shown its efficacy as preemptive therapy and treatment of resistant and refractory CMV infections. Adoptive T cell therapy is an emerging option for treatment of refractory and resistant CMV. Of the different CMV vaccine trials, PepVax has shown promising results in a phase 1 trial.
SUMMARY
CMV cell-mediated immunity assays have potential to be used as an adjunctive test to develop individualized management plan by identifying the patients who develop immune reconstitution; however, further prospective interventional studies are needed. Maribavir and adoptive T cell therapy are promising new therapies for treatment of CMV infections. CMV vaccine trials for prevention are also under way.
PubMed: 34305463
DOI: 10.1007/s40506-021-00253-w -
Antiviral Research Sep 2021Because ganciclovir resistance mutations in the cytomegalovirus UL97 gene most commonly occur at codons 460, 520 and 590-607, diagnostic genotyping for drug resistance...
Because ganciclovir resistance mutations in the cytomegalovirus UL97 gene most commonly occur at codons 460, 520 and 590-607, diagnostic genotyping for drug resistance has often omitted the analysis of codons below 440. However, the UL97 kinase inhibitor maribavir selects for distinctive resistance mutations at codons 409 and 411, and ganciclovir/maribavir resistance mutations have also been described in the ATP binding region starting at codon 335. Expanded genotypic testing of UL97 codons 335-440 in 1535 clinical specimens disclosed 10 uncharacterized sequence variants that were phenotyped for ganciclovir and maribavir susceptibility. Notable findings included low-grade ganciclovir resistance conferred by amino acid substitutions K359N and E362D, decreased maribavir susceptibility of L348V, and maribavir hypersensitivity of V345I and E362D. Recently published substitutions F342Y and K359E/Q were also confirmed. The data indicate that mutations in the UL97 ATP binding region may arise in clinical specimens to affect the interpretation of ganciclovir and maribavir resistance. This region should now be included in the standard diagnostic genotyping of UL97, especially with the introduction of maribavir into therapeutic use.
Topics: Adenosine Triphosphate; Amino Acid Substitution; Antiviral Agents; Benzimidazoles; Codon; Cytomegalovirus; Cytomegalovirus Infections; Drug Resistance, Viral; Ganciclovir; Genotyping Techniques; Humans; Mutation; Phenotype; Phosphotransferases (Alcohol Group Acceptor); Ribonucleosides
PubMed: 34273445
DOI: 10.1016/j.antiviral.2021.105139 -
Nature Reviews. Microbiology Dec 2021Human cytomegalovirus (HCMV) is a herpesvirus that infects ~60% of adults in developed countries and more than 90% in developing countries. Usually, it is controlled by... (Review)
Review
Human cytomegalovirus (HCMV) is a herpesvirus that infects ~60% of adults in developed countries and more than 90% in developing countries. Usually, it is controlled by a vigorous immune response so that infections are asymptomatic or symptoms are mild. However, if the immune system is compromised, HCMV can replicate to high levels and cause serious end organ disease. Substantial progress is being made in understanding the natural history and pathogenesis of HCMV infection and disease in the immunocompromised host. Serial measures of viral load defined the dynamics of HCMV replication and are now used routinely to allow intervention with antiviral drugs in individual patients. They are also used as pharmacodynamic read-outs to evaluate prototype vaccines that may protect against HCMV replication and to define immune correlates of this protection. This novel information is informing the design of randomized controlled trials of new antiviral drugs and vaccines currently under evaluation. In this Review, we discuss immune responses to HCMV and countermeasures deployed by the virus, the establishment of latency and reactivation from it, exogenous reinfection with additional strains, pathogenesis, development of end organ disease, indirect effects of infection, immune correlates of control of replication, current treatment strategies and the evaluation of novel vaccine candidates.
Topics: Antiviral Agents; Cytomegalovirus; Cytomegalovirus Infections; Humans; Immunity; Immunocompromised Host; Randomized Controlled Trials as Topic; Viral Load; Virus Replication
PubMed: 34168328
DOI: 10.1038/s41579-021-00582-z -
Current Opinion in Infectious Diseases Aug 2021This review is an overview of recent advances in diagnostics, therapies, and prevention strategies for cytomegalovirus (CMV), focusing on solid-organ transplant and... (Review)
Review
PURPOSE OF REVIEW
This review is an overview of recent advances in diagnostics, therapies, and prevention strategies for cytomegalovirus (CMV), focusing on solid-organ transplant and hematopoietic stem cell transplant recipients.
RECENT FINDINGS
A randomized trial of prophylaxis vs preemptive therapy in donor-seropositive, recipient-seronegative liver transplant recipients found significantly less CMV disease in the preemptive group. Maribavir has shown promise for the treatment of resistant/refractory CMV and for uncomplicated CMV DNAemia. A post hoc mortality analysis, as well as emerging reports of real-world and off-label use, have expanded the spectrum of clinical experience with letermovir. The first interventional trials using CMV cell-mediated immune assays have been published and showed promising results for delineating antiviral strategies. New data from additional interventional trials are expected soon.
SUMMARY
The past 1-2 years have seen major developments in the area of CMV management in transplant recipients. Expanding diagnostic and therapeutic capabilities provide a foundation for optimizing strategies in the future, to reduce morbidity and mortality from CMV.
Topics: Antiviral Agents; Cytomegalovirus; Cytomegalovirus Infections; Hematopoietic Stem Cell Transplantation; Humans; Immunity, Cellular; Transplant Recipients
PubMed: 34074879
DOI: 10.1097/QCO.0000000000000746 -
Transplant Infectious Disease : An... Aug 2021As some of those who were lucky enough to have been mentored by Dr Francisco Marty in transplant infectious diseases, we stand with the larger medical community in...
As some of those who were lucky enough to have been mentored by Dr Francisco Marty in transplant infectious diseases, we stand with the larger medical community in mourning his untimely death and in commemorating him as a uniquely exceptional and talented physician, investigator, teacher, mentor, friend, artist, and human being.
Topics: Humans; Male; Physicians
PubMed: 34022099
DOI: 10.1111/tid.13645 -
Journal of Clinical Microbiology Feb 2021
PubMed: 33826526
DOI: 10.1128/JCM.00119-20 -
Journal of Clinical Microbiology Feb 2021
PubMed: 33826525
DOI: 10.1128/JCM.00118-20 -
The Journal of Infectious Diseases Sep 2021Two transplant recipients (1 kidney and 1 hematopoietic stem cell) received maribavir (MBV) after cytomegalovirus (CMV) infection clinically resistant to standard...
Two transplant recipients (1 kidney and 1 hematopoietic stem cell) received maribavir (MBV) after cytomegalovirus (CMV) infection clinically resistant to standard therapy. Both patients achieved CMV DNA clearance within 30 and 18 days; however, the UL97 C480F variant emerged, causing recurrent CMV infection after a cumulative 2 months of MBV and 15 or 4 weeks of ganciclovir treatment, respectively. C480F was not detected under ganciclovir before MBV treatment. Recombinant phenotyping showed that C480F conferred the highest level of MBV resistance and ganciclovir cross-resistance, with impaired viral growth. Clinical follow-up and genotypic and phenotypic studies are essential for the assessment and optimization of patients with suspected MBV resistance.
Topics: Adult; Antiviral Agents; Benzimidazoles; Cytomegalovirus; Cytomegalovirus Infections; Drug Resistance, Viral; Female; Ganciclovir; Hematopoietic Stem Cell Transplantation; Hematopoietic Stem Cells; Humans; Kidney Transplantation; Mutation; Organ Transplantation; Phosphotransferases (Alcohol Group Acceptor); Ribonucleosides; Transplant Recipients; Treatment Outcome
PubMed: 33475730
DOI: 10.1093/infdis/jiab029 -
International Journal of Molecular... Jan 2021Human cytomegalovirus (HCMV) is a human pathogenic herpesvirus associated with a variety of clinical symptoms. Current antiviral therapy is not always effective, so that...
Human cytomegalovirus (HCMV) is a human pathogenic herpesvirus associated with a variety of clinical symptoms. Current antiviral therapy is not always effective, so that improved drug classes and drug-targeting strategies are needed. Particularly host-directed antivirals, including pharmaceutical kinase inhibitors (PKIs), may help to overcome problems of drug resistance. Here, we focused on utilizing a selection of clinically relevant PKIs and determined their anticytomegaloviral efficacies. Particularly, PKIs directed to host or viral cyclin-dependent kinases, i.e., abemaciclib, LDC4297 and maribavir, exerted promising profiles against human and murine cytomegaloviruses. The anti-HCMV in vitro activity of the approved anti-cancer drug abemaciclib was confirmed in vivo using our luciferase-based murine cytomegalovirus (MCMV) animal model in immunocompetent mice. To assess drug combinations, we applied the Bliss independence checkerboard and Loewe additivity fixed-dose assays in parallel. Results revealed that (i) both affirmative approaches provided valuable information on anti-CMV drug efficacies and interactions, (ii) the analyzed combinations comprised additive, synergistic or antagonistic drug interactions consistent with the drugs' antiviral mode-of-action, (iii) the selected PKIs, especially LDC4297, showed promising inhibitory profiles, not only against HCMV but also other α-, β- and γ-herpesviruses, and specifically, (iv) the combination treatment with LDC4297 and maribavir revealed a strong synergism against HCMV, which might open doors towards novel clinical options in the near future. Taken together, this study highlights the potential of therapeutic drug combinations of current developmental/preclinical PKIs.
Topics: Aminopyridines; Animals; Antiviral Agents; Benzimidazoles; Cell Line; Cytomegalovirus; Cytomegalovirus Infections; Drug Combinations; Drug Resistance, Viral; Ganciclovir; Humans; Mice; Protein Kinase Inhibitors; Pyrazoles; Ribonucleosides; Triazines; Virus Replication
PubMed: 33430060
DOI: 10.3390/ijms22020575