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Clinical Infectious Diseases : An... Sep 2022Therapies for refractory cytomegalovirus infections (with or without resistance [R/R]) in transplant recipients are limited by toxicities. Maribavir has multimodal... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Therapies for refractory cytomegalovirus infections (with or without resistance [R/R]) in transplant recipients are limited by toxicities. Maribavir has multimodal anti-cytomegalovirus activity through the inhibition of UL97 protein kinase.
METHODS
In this phase 3, open-label study, hematopoietic-cell and solid-organ transplant recipients with R/R cytomegalovirus were randomized 2:1 to maribavir 400 mg twice daily or investigator-assigned therapy (IAT; valganciclovir/ganciclovir, foscarnet, or cidofovir) for 8 weeks, with 12 weeks of follow-up. The primary endpoint was confirmed cytomegalovirus clearance at end of week 8. The key secondary endpoint was achievement of cytomegalovirus clearance and symptom control at end of week 8, maintained through week 16.
RESULTS
352 patients were randomized (235 maribavir; 117 IAT). Significantly more patients in the maribavir versus IAT group achieved the primary endpoint (55.7% vs 23.9%; adjusted difference [95% confidence interval (CI)]: 32.8% [22.80-42.74]; P < .001) and key secondary endpoint (18.7% vs 10.3%; adjusted difference [95% CI]: 9.5% [2.02-16.88]; P = .01). Rates of treatment-emergent adverse events (TEAEs) were similar between groups (maribavir, 97.4%; IAT, 91.4%). Maribavir was associated with less acute kidney injury versus foscarnet (8.5% vs 21.3%) and neutropenia versus valganciclovir/ganciclovir (9.4% vs 33.9%). Fewer patients discontinued treatment due to TEAEs with maribavir (13.2%) than IAT (31.9%). One patient per group had fatal treatment-related TEAEs.
CONCLUSIONS
Maribavir was superior to IAT for cytomegalovirus viremia clearance and viremia clearance plus symptom control maintained post-therapy in transplant recipients with R/R cytomegalovirus. Maribavir had fewer treatment discontinuations due to TEAEs than IAT. Clinical Trials Registration. NCT02931539 (SOLSTICE).
Topics: Antiviral Agents; Cytomegalovirus; Cytomegalovirus Infections; Dichlororibofuranosylbenzimidazole; Drug Resistance, Viral; Foscarnet; Ganciclovir; Humans; Valganciclovir; Viremia
PubMed: 34864943
DOI: 10.1093/cid/ciab988 -
Antimicrobial Agents and Chemotherapy Sep 2022Maribavir was approved by the U.S. Food and Drug Administration in November 2021 for the treatment of adult and pediatric patients with post-transplant cytomegalovirus... (Review)
Review
Maribavir was approved by the U.S. Food and Drug Administration in November 2021 for the treatment of adult and pediatric patients with post-transplant cytomegalovirus (CMV) infection/disease that is refractory to treatment (with or without genotypic resistance) with ganciclovir, valganciclovir, cidofovir, or foscarnet. Maribavir is an oral benzimidazole riboside with potent and selective multimodal anti-CMV activity. It utilizes a novel mechanism of action which confers activity against CMV strains that are resistant to traditional anti-CMV agents, and also offers a more favorable safety profile relative to the dose-limiting side effects of previously available therapies. Maribavir was initially studied as an agent for CMV prophylaxis in solid organ and hematopoietic stem cell recipients, but initial phase III trials failed to meet clinical efficacy endpoints. It has been more recently studied as a therapeutic agent at higher doses for refractory-resistant (R-R) CMV infections with favorable outcomes. After an overview of maribavir's chemistry and clinical pharmacology, this review will summarize clinical efficacy, safety, tolerability, and resistance data associated with maribavir therapy.
Topics: Adult; Anti-Infective Agents; Antiviral Agents; Benzimidazoles; Child; Cidofovir; Cytomegalovirus Infections; Dichlororibofuranosylbenzimidazole; Drug Resistance, Viral; Foscarnet; Ganciclovir; Humans; Valganciclovir
PubMed: 35916518
DOI: 10.1128/aac.02405-21 -
ACS Synthetic Biology Feb 2017The activation of silent natural product gene clusters is a synthetic biology problem of great interest. As the rate at which gene clusters are identified outpaces the...
The activation of silent natural product gene clusters is a synthetic biology problem of great interest. As the rate at which gene clusters are identified outpaces the discovery rate of new molecules, this unknown chemical space is rapidly growing, as too are the rewards for developing technologies to exploit it. One class of natural products that has been underrepresented is phosphonic acids, which have important medical and agricultural uses. Hundreds of phosphonic acid biosynthetic gene clusters have been identified encoding for unknown molecules. Although methods exist to elicit secondary metabolite gene clusters in native hosts, they require the strain to be amenable to genetic manipulation. One method to circumvent this is pathway refactoring, which we implemented in an effort to discover new phosphonic acids from a gene cluster from Streptomyces sp. strain NRRL F-525. By reengineering this cluster for expression in the production host Streptomyces lividans, utility of refactoring is demonstrated with the isolation of a novel phosphonic acid, O-phosphonoacetic acid serine, and the characterization of its biosynthesis. In addition, a new biosynthetic branch point is identified with a phosphonoacetaldehyde dehydrogenase, which was used to identify additional phosphonic acid gene clusters that share phosphonoacetic acid as an intermediate.
Topics: Biological Products; Hydrolases; Multigene Family; Phosphonoacetic Acid; Phosphorous Acids; Streptomyces; Synthetic Biology
PubMed: 28103011
DOI: 10.1021/acssynbio.6b00299 -
Molecular Aspects of Medicine 2013Transport of inorganic phosphate (Pi) across the plasma membrane is essential for normal cellular function. Members of two families of SLC proteins (SLC20 and SLC34) act... (Review)
Review
Transport of inorganic phosphate (Pi) across the plasma membrane is essential for normal cellular function. Members of two families of SLC proteins (SLC20 and SLC34) act as Na(+)-dependent, secondary-active cotransporters to transport Pi across cell membranes. The SLC34 proteins are expressed in specific organs important for Pi homeostasis: NaPi-IIa (SLC34A1) and NaPi-IIc (SLC34A3) fulfill essential roles in Pi reabsorption in the kidney proximal tubule and NaPi-IIb (SLC34A2) mediates Pi absorption in the gut. The SLC20 proteins, PiT-1 (SLC20A1), PiT-2 (SLC20A2) are expressed ubiquitously in all tissues and although generally considered as "housekeeping" transport proteins, the discovery of tissue-specific activity, regulatory pathways and gene-related pathophysiologies, is redefining their importance. This review summarizes our current knowledge of SLC20 and SLC34 proteins in terms of their basic molecular characteristics, physiological roles, known pathophysiology and pharmacology.
Topics: Foscarnet; Homeostasis; Humans; Kinetics; Models, Biological; Models, Molecular; Multigene Family; Protein Conformation; Sodium-Phosphate Cotransporter Proteins
PubMed: 23506879
DOI: 10.1016/j.mam.2012.07.007 -
Transplantation and Cellular Therapy Jun 2023Human herpesvirus 6 (HHV-6) reactivation is common after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is associated with higher mortality and... (Review)
Review
Human herpesvirus 6 (HHV-6) reactivation is common after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is associated with higher mortality and increased transplantation-related complications. We hypothesized that preemptive treatment with a short course of foscarnet at a lower cutpoint of plasma HHV-6 viral load would be effective in treating early HHV-6 reactivation, preventing complications and precluding hospitalization of these patients. We reviewed outcomes of adult patients (age ≥18 years) who received preemptive treatment with once-daily foscarnet 60 to 90 mg/kg for 7 days for HHV-6 reactivation after allo-HSCT at our institution between May 2020 and November 2022. Plasma HHV-6 viral load was monitored by quantitative PCR twice monthly in the first 100 days post-transplantation and twice weekly after reactivation until resolution. Eleven patients with a median age of 46 years (range, 23 to 73 years) were included in the analysis. HSCT was performed with a haploidentical donor in 10 patients and with an HLA-matched related donor in 1 patient. The most common diagnosis was acute leukemia (9 patients). Myeloablative and reduced-intensity conditioning regimens were used in 4 and 7 patients, respectively. Ten of the 11 patients received post-transplantation cyclophosphamide-based graft-versus-host disease prophylaxis. The median follow-up was 440 days (range, 174 to 831 days), and the median time to HHV-6 reactivation was 22 days post-transplantation (range, 15 to 89 days). The median viral load at first reactivation was 3,100 copies/mL (range, 210 to 118,000 copies/mL), and the median peak viral load was 11,300 copies/mL (range, 600 to 983,000 copies/mL). All patients received a short course of foscarnet at either 90 mg/kg/day (n = 7) or 60 mg/kg/day (n = 4). In all patients, plasma HHV-6 DNA was undetectable at completion of 1 week of treatment. No HHV-6 encephalitis or pneumonitis occurred. All patients achieved neutrophil and platelet engraftment after a median of 16 days (range, 8 to 22 days) and 26 days (range, 14 to 168 days), respectively, with no secondary graft failure. No complications related to foscarnet administration were noted. One patient with very high HHV-6 viremia had recurrent reactivation and received a second course of foscarnet as an outpatient. A short course of once-daily foscarnet is effective in treating early HHV-6 reactivation post-transplantation and may reduce the incidence of HHV-6-related and treatment-related complications and preclude hospitalization in these patients.
Topics: Adult; Humans; Young Adult; Middle Aged; Aged; Adolescent; Foscarnet; Herpesvirus 6, Human; Hematopoietic Stem Cell Transplantation; Transplantation, Homologous; DNA, Viral
PubMed: 36878429
DOI: 10.1016/j.jtct.2023.02.022 -
Frontiers in Cellular and Infection... 2017Many microorganisms produce phosphonates, molecules characterized by stable carbon-phosphorus bonds that store phosphorus or act as antimicrobials. The role of...
Many microorganisms produce phosphonates, molecules characterized by stable carbon-phosphorus bonds that store phosphorus or act as antimicrobials. The role of phosphonates in the marine biosphere is well characterized but the role of these molecules in the intestine is poorly understood. uses its virulence factors to influence the host immune response to compete with the host and normal microflora for nutrients. cannot produce phosphonates but encodes the enzymes to use them suggesting that it is exposed to phosphonates during its life cycle. The role of phosphonates during enteric salmonellosis is unexplored. We have previously shown that , encoding a putative regulator of phosphonate metabolism, is needed for colonization in calves. Here, we report that the necessity of in colonization of the murine intestine results from multiple factors. is needed for full activation of the type-3 secretion system-1 and for optimal invasion of epithelial cells. The Δ mutant grows poorly in phosphonoacetic acid (PA) as the sole phosphorus source, but can use 2-aminoethylphosphonate. PhnA, an enzyme required for PA breakdown, is not controlled by STM3602 suggesting an additional mechanism for utilization of PA in . Typhimurium. Finally, the requirement of for intestinal colonization differs depending on the composition of the microflora. Our data suggest that has multiple regulatory targets that are necessary for survival within the microbial community in the intestine. Determination of the members of the regulon may illuminate new pathways needed for colonization of the host.
Topics: Animals; Gene Expression Regulation, Bacterial; Intestines; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Phosphonoacetic Acid; Salmonella Infections, Animal; Salmonella enterica
PubMed: 28361036
DOI: 10.3389/fcimb.2017.00069 -
Journal of Enzyme Inhibition and... Dec 2018Small molecule inhibitors have a powerful blocking action on viral polymerases. The bioavailability of the inhibitor, nevertheless, often raise a significant selectivity...
Small molecule inhibitors have a powerful blocking action on viral polymerases. The bioavailability of the inhibitor, nevertheless, often raise a significant selectivity constraint and may substantially limit the efficacy of therapy. Phosphonoacetic acid has long been known to possess a restricted potential to block DNA biosynthesis. In order to achieve a better affinity, this compound has been linked with natural nucleotide at different positions. The structural context of the resulted conjugates has been found to be crucial for the acquisition by DNA polymerases. We show that nucleobase-conjugated phosphonoacetic acid is being accepted, but this alters the processivity of DNA polymerases. The data presented here not only provide a mechanistic rationale for a switch in the mode of DNA synthesis, but also highlight the nucleobase-targeted nucleotide functionalization as a route for enhancing the specificity of small molecule inhibitors.
Topics: DNA-Directed DNA Polymerase; Enzyme Inhibitors; HIV-1; Molecular Structure; Moloney murine leukemia virus; Nucleotides; Phosphonoacetic Acid
PubMed: 29372656
DOI: 10.1080/14756366.2017.1417275 -
Antimicrobial Agents and Chemotherapy Feb 2021The objectives of this study were to characterize the role of the , , and genes in fosfomycin resistance in and evaluate the use of sodium phosphonoformate (PPF) in...
The objectives of this study were to characterize the role of the , , and genes in fosfomycin resistance in and evaluate the use of sodium phosphonoformate (PPF) in combination with fosfomycin. Seven clinical isolates of and the reference strain (ATCC 700721) were used, and their genomes were sequenced. Δ, Δ, and Δ mutants were constructed from two isolates and ATCC 700721. Fosfomycin susceptibility testing was done by the gradient strip method. Synergy between fosfomycin and PPF was studied by checkerboard assay and analyzed using SynergyFinder. Spontaneous fosfomycin mutant frequencies at 64 and 512 mg/liter, activity using growth curves with fosfomycin gradient concentrations (0 to 256mg/liter), and time-kill assays at 64 and 307 mg/liter were evaluated with and without PPF (0.623 mM). The MICs of fosfomycin against the clinical isolates ranged from 16 to ≥1,024 mg/liter. The addition of 0.623 mM PPF reduced fosfomycin MIC between 2- and 8-fold. Deletion of led to a 32-fold decrease. Synergistic activities were observed with the combination of fosfomycin and PPF (most synergistic area at 0.623 mM). The lowest fosfomycin-resistant mutant frequencies were found in Δ mutants, with decreases in frequency from 1.69 × 10 to 1.60 × 10 for 64 mg/liter of fosfomycin. In the final growth monitoring and time-kill assays, fosfomycin showed a bactericidal effect only with the deletion of and not with the addition of PPF. We conclude that gene inactivation leads to a decrease in fosfomycin resistance in The pharmacological approach using PPF did not achieve enough activity, and the effect decreased with the presence of fosfomycin-resistant mutations.
Topics: Anti-Bacterial Agents; Foscarnet; Fosfomycin; Klebsiella pneumoniae; Microbial Sensitivity Tests; beta-Lactamases
PubMed: 33361305
DOI: 10.1128/AAC.01911-20 -
Dental Materials Journal Feb 2012This paper reviews the developments of dithiooctanoate monomers and acidic adhesive monomers, and their roles in multi-purpose primers and adhesives in promoting... (Review)
Review
This paper reviews the developments of dithiooctanoate monomers and acidic adhesive monomers, and their roles in multi-purpose primers and adhesives in promoting adhesion to multiple substrate materials. Novel dithiooctanoate monomers exhibited excellent bonding to precious metals and alloys when compared against conventional sulfur-containing monomers. Newly developed phosphonic acid monomers, endowed with a water-soluble nature, enabled sufficient demineralization of dental hard tissues and thus improved bonding to both ground enamel and dentin. The optimal combination for bonding to dental hard tissues and precious and non-precious metals and alloys was 5.0 wt% 10-methacryloyloxydecyl 6,8-dithiooctanoate (10-MDDT) and 1.0 wt% 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA). For bonding to dental porcelain, alumina, zirconia, and gold (Au) alloy, a ternary combination of silane coupling agent, acidic adhesive monomers, and dithiooctanoate monomers seemed promising. The latest development was a single-bottle, multi-purpose, self-etching adhesive which contained only acidic adhesive monomers and dithiooctanoate monomers but which produced strong adhesion to ground enamel and dentin, sandblasted zirconia, and Au alloy.
Topics: Caprylates; Dental Alloys; Dental Bonding; Dental Cements; Dental Enamel; Dentin; Humans; Methacrylates; Organophosphonates; Phosphonoacetic Acid; Phosphorous Acids; Sulfur Compounds
PubMed: 22277601
DOI: 10.4012/dmj.2011-139 -
Clinical Microbiology Reviews Oct 2010The study of human cytomegalovirus (HCMV) antiviral drug resistance has enhanced knowledge of the virological targets and the mechanisms of antiviral activity. The... (Review)
Review
The study of human cytomegalovirus (HCMV) antiviral drug resistance has enhanced knowledge of the virological targets and the mechanisms of antiviral activity. The currently approved drugs, ganciclovir (GCV), foscarnet (FOS), and cidofovir (CDV), target the viral DNA polymerase. GCV anabolism also requires phosphorylation by the virus-encoded UL97 kinase. GCV resistance mutations have been identified in both genes, while FOS and CDV mutations occur only in the DNA polymerase gene. Confirmation of resistance mutations requires phenotypic analysis; however, phenotypic assays are too time-consuming for diagnostic purposes. Genotypic assays based on sequencing provide more rapid results but are dependent on prior validation by phenotypic methods. Reports from many laboratories have produced an evolving list of confirmed resistance mutations, although differences in interpretation have led to some confusion. Recombinant phenotyping methods performed in a few research laboratories have resolved some of the conflicting results. Treatment options for drug-resistant HCMV infections are complex and have not been subjected to controlled clinical trials, although consensus guidelines have been proposed. This review summarizes the virological and clinical data pertaining to HCMV antiviral drug resistance.
Topics: Antiviral Agents; Cidofovir; Cytomegalovirus; Cytomegalovirus Infections; Cytosine; DNA-Directed DNA Polymerase; Drug Resistance, Viral; Foscarnet; Ganciclovir; Genome, Viral; Humans; Organophosphonates; Phosphotransferases (Alcohol Group Acceptor); Sequence Analysis, DNA
PubMed: 20930070
DOI: 10.1128/CMR.00009-10