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Background and Objective: During the COVID-19 vaccination campaign, over 34,000 reports of heavy menstrual bleeding following the administration of COVID-19 vaccines originating in the Economic European Area were submitted to EudraVigilance, the European Union database of suspected adverse drug reactions. More than 90% of these reports were sent by consumers while the remaining by healthcare professionals. Public concerns regarding menstruation disorders in COVID-19 vaccinees were also covered by the media. We investigated the impact of media attention on the reporting trends of heavy menstrual bleeding to EudraVigilance., Methods: We used media outlets published in the Economic European Area on menstrual disorders and COVID-19 vaccines from the beginning of the vaccination campaign in the Economic European Area (1 January, 2021) until December 2022 (i.e., after the regulatory request to add the adverse event to the product information) and spontaneous reports from EudraVigilance., Results: We found that the publication of safety updates from regulatory authorities and subsequent coverage in media outlets preceded increased reporting to EudraVigilance. Furthermore, the heavy menstrual bleeding reported in the cases occurred several weeks or months earlier and were not submitted to the respective date. The analysis suggests that the spikes in reporting of heavy menstrual bleeding were to some extent influenced by media coverage in some countries., Conclusions: Consumer reporting to the European Union spontaneous data collection system, EudraVigilance, was of high value for regulatory safety reviews, albeit the reporting behaviours were not free of the influence of the media. These sources of information can be investigated to understand the context of safety concerns of public health interest., (© 2024. The Author(s).)

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) continues to be a global threat due to its ability to evolve and generate new subvariants, leading to new waves of infection. Additionally, other coronaviruses like Middle East respiratory syndrome coronavirus (MERS-CoV, formerly known as hCoV-EMC), which first emerged in 2012, persist and continue to present a threat of severe illness to humans. The continued identification of novel coronaviruses, coupled with the potential for genetic recombination between different strains, raises the possibility of new coronavirus clades of global concern emerging. As a result, there is a pressing need for pan-CoV therapeutic drugs and vaccines. After the extensive optimization of an HCV protease inhibitor screening hit, a novel 3CLPro inhibitor (MK-7845) was discovered and subsequently profiled. MK-7845 exhibited nanomolar in vitro potency with broad spectrum activity against a panel of clinical SARS-CoV-2 subvariants and MERS-CoV. Furthermore, when administered orally, MK-7845 demonstrated a notable reduction in viral burdens by >6 log orders in the lungs of transgenic mice infected with SARS-CoV-2 (K18-hACE2 mice) and MERS-CoV (K18-hDDP4 mice).

Linezolid is a drug with proven human antitubercular activity whose use is limited to highly drug-resistant patients because of its toxicity. This toxicity is related to its mechanism of action─linezolid inhibits protein synthesis in both bacteria and eukaryotic mitochondria. A highly selective and potent series of oxazolidinones, bearing a 5-aminomethyl moiety (in place of the typical 5-acetamidomethyl moiety of linezolid), was identified. Linezolid-resistant mutants were cross-resistant to these molecules but not vice versa. Resistance to the 5-aminomethyl molecules mapped to an N-acetyl transferase (Rv0133) and these mutants remained fully linezolid susceptible. Purified Rv0133 was shown to catalyze the transformation of the 5-aminomethyl oxazolidinones to their corresponding N-acetylated metabolites, and this transformation was also observed in live cells of Mycobacterium tuberculosis . Mammalian mitochondria, which lack an appropriate N-acetyltransferase to activate these prodrugs, were not susceptible to inhibition with the 5-aminomethyl analogues. Several compounds that were more potent than linezolid were taken into C3HeB/FeJ mice and were shown to be highly efficacious, and one of these ( 9 ) was additionally taken into marmosets and found to be highly active. Penetration of these 5-aminomethyl oxazolidinone prodrugs into caseum was excellent. Unfortunately, these compounds were rapidly converted into the corresponding 5-alcohols by mammalian metabolism which retained antimycobacterial activity but resulted in substantial mitotoxicity.

Although smallpox has been eradicated, other orthopoxviruses continue to be a public health concern as exemplified by the ongoing Mpox (formerly monkeypox) global outbreak. While medical countermeasures (MCMs) previously approved by the Food and Drug Administration for the treatment of smallpox have been adopted for Mpox, previously described vulnerabilities coupled with the questionable benefit of at least one of the therapeutics during the 2022 Mpox outbreak reinforce the need for identifying and developing other MCMs against orthopoxviruses. Here, we screened a panel of Merck proprietary small molecules and identified a novel nucleoside inhibitor with potent broad-spectrum antiviral activity against multiple orthopoxviruses. Efficacy testing of a 7-day dosing regimen of the orally administered nucleoside in a murine model of severe orthopoxvirus infection yielded a dose-dependent increase in survival. Treated animals had greatly reduced lesions in the lung and nasal cavity, particularly in the 10 µg/mL dosing group. Viral levels were also markedly lower in the UMM-766-treated animals. This work demonstrates that this nucleoside analog has anti-orthopoxvirus efficacy and can protect against severe disease in a murine orthopox model.IMPORTANCEThe recent monkeypox virus pandemic demonstrates that members of the orthopoxvirus, which also includes variola virus, which causes smallpox, remain a public health issue. While currently FDA-approved treatment options exist, risks that resistant strains of orthopoxviruses may arise are a great concern. Thus, continued exploration of anti-poxvirus treatments is warranted. Here, we developed a template for a high-throughput screening assay to identify anti-poxvirus small-molecule drugs. By screening available drug libraries, we identified a compound that inhibited orthopoxvirus replication in cell culture. We then showed that this drug can protect animals against severe disease. Our findings here support the use of existing drug libraries to identify orthopoxvirus-targeting drugs that may serve as human-safe products to thwart future outbreaks., Competing Interests: K.P.K., D.O., C.R.Q., J.P.T., and C.C. are employees of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co. Inc., Rahway, NJ, USA, and may own stock or hold stock options in Merck & Co. Inc., Rahway, NJ, USA.

As SARS-CoV-2 continues to circulate, antiviral treatments are needed to complement vaccines. The virus's main protease, 3CLPro, is an attractive drug target in part because it recognizes a unique cleavage site, which features a glutamine residue at the P1 position and is not utilized by human proteases. Herein, we report the invention of MK-7845, a novel reversible covalent 3CLPro inhibitor. While most covalent inhibitors of SARS-CoV-2 3CLPro reported to date contain an amide as a Gln mimic at P1, MK-7845 bears a difluorobutyl substituent at this position. SAR analysis and X-ray crystallographic studies indicate that this group interacts with His163, the same residue that forms a hydrogen bond with the amide substituents typically found at P1. In addition to promising in vivo efficacy and an acceptable projected human dose with unboosted pharmacokinetics, MK-7845 exhibits favorable properties for both solubility and absorption that may be attributable to the unusual difluorobutyl substituent.

The Mycobacterium abscessus drug development pipeline is poorly populated, with particularly few validated target-lead couples to initiate de novo drug discovery. Trimethoprim, an inhibitor of dihydrofolate reductase (DHFR) used for the treatment of a range of bacterial infections, is not active against M. abscessus . Thus, evidence that M. abscessus DHFR is vulnerable to pharmacological intervention with a small molecule inhibitor is lacking. Here, we show that the pyrrolo-quinazoline PQD-1, previously identified as a DHFR inhibitor active against Mycobacterium tuberculosis , exerts whole cell activity against M. abscessus . Enzyme inhibition studies showed that PQD-1, in contrast to trimethoprim, is a potent inhibitor of M. abscessus DHFR and over-expression of DHFR causes resistance to PQD-1, providing biochemical and genetic evidence that DHFR is a vulnerable target and mediates PQD-1's growth inhibitory activity in M. abscessus . As observed in M. tuberculosis , PQD-1 resistant mutations mapped to the folate pathway enzyme thymidylate synthase (TYMS) ThyA. Like trimethoprim in other bacteria, PQD-1 synergizes with the dihydropteroate synthase (DHPS) inhibitor sulfamethoxazole (SMX), offering an opportunity to exploit the successful dual inhibition of the folate pathway and develop similarly potent combinations against M. abscessus . PQD-1 is active against subspecies of M. abscessus and a panel of clinical isolates, providing epidemiological validation of the target-lead couple. Leveraging a series of PQD-1 analogs, we have demonstrated a dynamic structure-activity relationship (SAR). Collectively, the results identify M. abscessus DHFR as an attractive target and PQD-1 as a chemical starting point for the discovery of novel drugs and drug combinations that target the folate pathway in M. abscessus ., Competing Interests: C.J.B., A.E.M., E.B.N., D.B.O., and R.W. are employees of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Objective: The objective of this scoping review was to identify and map existing preoperative interventions, referred to as prehabilitation, in adult patients at home awaiting elective coronary artery bypass grafting surgery. This review also sought to report feasibility and patient experiences to shape clinical practice and underpin a future systematic review., Introduction: As patients age, comorbidities become more common. Strategies to improve postoperative outcomes and to accelerate recovery are required in patients undergoing coronary artery bypass grafting. Prehabilitation refers to a proactive process of increasing functional capacity before surgery to improve the patient's ability to withstand upcoming physiologic stress and, thus, avoid postoperative complications., Inclusion Criteria: Studies that included adult patients waiting for coronary artery bypass grafting surgery at home and that described interventions optimizing preoperative physical and psychological health in any setting were included., Methods: The JBI methodology for conducting scoping reviews was used to identify relevant studies in MEDLINE (PubMed), CINAHL (EBSCOhost), Cochrane Library, Embase (Ovid), Scopus, SweMed+, PsycINFO (EBSCOhost), and PEDro. Gray literature was identified searching Google Scholar, ProQuest Dissertations and Theses, MedNar, OpenGrey, NICE Evidence search, and SIGN. Studies in Danish, English, German, Norwegian, and Swedish were considered for inclusion, with no geographical or cultural limitations, or date restrictions. Two independent reviewers screened titles and abstracts, and studies meeting the inclusion criteria were imported into Covidence. Sixty-seven studies from November 1987 to September 2022 were included. The data extraction tool used for the included papers was developed in accordance with the review questions and tested for adequacy and comprehensiveness with the first 5 studies by the same 2 independent reviewers. The tool was then edited to best reflect the review questions. Extracted findings are described and supported by figures and tables., Results: Sixty-seven studies were eligible for inclusion, representing 28,553 participants. Analyses of extracted data identified various preoperative interventions for optimizing postoperative and psychological outcomes for adult patients awaiting elective coronary artery bypass grafting surgery. Based on similarities, interventions were grouped into 5 categories. Eighteen studies reported on multimodal interventions, 17 reported on psychological interventions, 14 on physical training interventions, 13 on education interventions, and 5 on oral health interventions., Conclusion: This scoping review provides a comprehensive summary of strategies that can be applied when developing a prehabilitation program for patients awaiting elective coronary artery bypass surgery. Although prehabilitation has been tested extensively and appears to be feasible, available evidence is mostly based on small studies. For patients undergoing elective coronary artery bypass grafting to derive benefit from prehabilitation, methodologically robust clinical trials and knowledge synthesis are required to identify optimal strategies for patient selection, intervention design, adherence, and intervention duration. Future research should also consider the cost-effectiveness of prehabilitation interventions before surgery. Finally, there is a need for more qualitative studies examining whether individual interventions are meaningful and appropriate to patients, which is an important factor if interventions are to be effective., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 JBI.)

Novel bacterial topoisomerase inhibitors (NBTIs) are the newest members of gyrase inhibitor broad-spectrum antibacterial agents, represented by the most advanced member, gepotidacin, a 4-amino-piperidine linked NBTI, which is undergoing phase III clinical trials for treatment of urinary tract infections (UTI). We have extensively reported studies on oxabicyclooctane linked NBTIs, including AM-8722. The present study summarizes structure activity relationship (SAR) of AM-8722 leading to identification of 7-fluoro-1-cyanomethyl-1,5-naphthyridin-2-one based NBTI (16, AM-8888) with improved potency and spectrum (MIC values of 0.016-4 μg/mL), with Pseudomonas aeruginosa being the least sensitive strain (MIC 4 μg/mL)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper: The authors were gainfully employed either at Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ 07033, USA or Kyorin Pharmaceutical, Tokyo and declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Drug resistance to first-line antimalarials-including artemisinin-is increasing, resulting in a critical need for the discovery of new agents with novel mechanisms of action. In collaboration with the Walter and Eliza Hall Institute and with funding from the Wellcome Trust, a phenotypic screen of Merck's aspartyl protease inhibitor library identified a series of plasmepsin X (PMX) hits that were more potent than chloroquine. Inspired by a PMX homology model, efforts to optimize the potency resulted in the discovery of leads that, in addition to potently inhibiting PMX, also inhibit another essential aspartic protease, plasmepsin IX (PMIX). Further potency and pharmacokinetic profile optimization efforts culminated in the discovery of WM382 , a very potent dual PMIX/X inhibitor with robust in vivo efficacy at multiple stages of the malaria parasite life cycle and an excellent resistance profile., Competing Interests: The authors declare no competing financial interest., (© 2022 American Chemical Society.)

Tricyclic pyrrolopyrimidines (TPPs) are a new class of antibacterials inhibiting the ATPase of DNA gyrase. TPP8, a representative of this class, is active against Mycobacterium abscessus in vitro . Spontaneous TPP8 resistance mutations mapped to the ATPase domain of M. abscessus DNA gyrase, and the compound inhibited DNA supercoiling activity of recombinant M. abscessus enzyme. Further profiling of TPP8 in macrophage and mouse infection studies demonstrated proof-of-concept activity against M. abscessus ex vivo and in vivo .

Rising antimicrobial resistance challenges our ability to combat bacterial infections. The problem is acute for tuberculosis (TB), the leading cause of death from infection before COVID-19. Here, we developed a framework for multiple pharmaceutical companies to share proprietary information and compounds with multiple laboratories in the academic and government sectors for a broad examination of the ability of β-lactams to kill Mycobacterium tuberculosis (Mtb). In the TB Drug Accelerator (TBDA), a consortium organized by the Bill & Melinda Gates Foundation, individual pharmaceutical companies collaborate with academic screening laboratories. We developed a higher order consortium within the TBDA in which four pharmaceutical companies (GlaxoSmithKline, Sanofi, MSD, and Lilly) collectively collaborated with screeners at Weill Cornell Medicine, the Infectious Disease Research Institute (IDRI), and the National Institute of Allergy and Infectious Diseases (NIAID), pharmacologists at Rutgers University, and medicinal chemists at the University of North Carolina to screen ∼8900 β-lactams, predominantly cephalosporins, and characterize active compounds. In a striking contrast to historical expectation, 18% of β-lactams screened were active against Mtb, many without a β-lactamase inhibitor. One potent cephaloporin was active in Mtb-infected mice. The steps outlined here can serve as a blueprint for multiparty, intra- and intersector collaboration in the development of anti-infective agents.

Natural products provide a rich source of potential antimicrobials for treating infectious diseases for which drug resistance has emerged. Foremost among these diseases is tuberculosis. Assessment of the antimycobacterial activity of nargenicin, a natural product that targets the replicative DNA polymerase of Staphylococcus aureus , revealed that it is a bactericidal genotoxin that induces a DNA damage response in Mycobacterium tuberculosis ( Mtb ) and inhibits growth by blocking the replicative DNA polymerase, DnaE1. Cryo-electron microscopy revealed that binding of nargenicin to Mtb DnaE1 requires the DNA substrate such that nargenicin is wedged between the terminal base pair and the polymerase and occupies the position of both the incoming nucleotide and templating base. Comparative analysis across three bacterial species suggests that the activity of nargenicin is partly attributable to the DNA binding affinity of the replicative polymerase. This work has laid the foundation for target-led drug discovery efforts focused on Mtb DnaE1.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research and antiviral discovery are hampered by the lack of a cell-based virus replication system that can be readily adopted without biosafety level 3 (BSL-3) restrictions. Here, the construction of a noninfectious SARS-CoV-2 reporter replicon and its application in deciphering viral replication mechanisms and evaluating SARS-CoV-2 inhibitors are presented. The replicon genome is replication competent but does not produce progeny virions. Its replication can be inhibited by RdRp mutations or by known SARS-CoV-2 antiviral compounds. Using this system, a high-throughput antiviral assay has also been developed. Significant differences in potencies of several SARS-CoV-2 inhibitors in different cell lines were observed, which highlight the challenges of discovering antivirals capable of inhibiting viral replication in vivo and the importance of testing compounds in multiple cell culture models. The generation of a SARS-CoV-2 replicon provides a powerful platform to expand the global research effort to combat COVID-19., Competing Interests: Competing interest statement: All authors are employees of Merck and Company, Inc. A provisional patent application on the discoveries of this work has been filed., (Copyright © 2021 the Author(s). Published by PNAS.)

Since the initial report of the novel Coronavirus Disease 2019 (COVID-19) emanating from Wuhan, China, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spread globally. While the effects of SARS-CoV-2 infection are not completely understood, there appears to be a wide spectrum of disease ranging from mild symptoms to severe respiratory distress, hospitalization, and mortality. There are no Food and Drug Administration (FDA)-approved treatments for COVID-19 aside from remdesivir; early efforts to identify efficacious therapeutics for COVID-19 have mainly focused on drug repurposing screens to identify compounds with antiviral activity against SARS-CoV-2 in cellular infection systems. These screens have yielded intriguing hits, but the use of nonhuman immortalized cell lines derived from non-pulmonary or gastrointestinal origins poses any number of questions in predicting the physiological and pathological relevance of these potential interventions. While our knowledge of this novel virus continues to evolve, our current understanding of the key molecular and cellular interactions involved in SARS-CoV-2 infection is discussed in order to provide a framework for developing the most appropriate in vitro toolbox to support current and future drug discovery efforts., Competing Interests: All authors are employees of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA and may own stock or hold stock options in Merck & Co., Inc., Kenilworth, NJ, USA.

Objective: The objective of this scoping review is to identify and map existing preoperative interventions, referred to as prehabilitation, in adult patients at home awaiting coronary bypass grafting (CABG) surgery. This scoping review also seeks to examine the feasibility and patient experiences in order to inform clinical practice and underpin a future systematic review., Introduction: As patients age, comorbidities become more common. Strategies to improve postoperative outcomes and to accelerate recovery are required in patients undergoing CABG. Prehabilitation refers to a proactive process of increasing functional capacity before surgery to improve the patient's capacity to withstand upcoming physiologic stress and thus avoid postoperative complications., Inclusion Criteria: This scoping review will consider any studies including adult patients at home awaiting CABG surgery. Studies will provide information on any prehabilitation intervention to optimize preoperative physical and psychological health status. Studies conducted in any setting will be included., Methods: The methodology will follow the JBI recommendations for scoping reviews. Any published or unpublished source of information will be considered. Studies published in English, German, Danish, Swedish, and Norwegian will be included, with no geographical or cultural limitations. Retrieved papers will be screened by two independent reviewers, and a standardized tool will be used to extract data from each included source. The results will be presented as a map of the data extracted in a tabular form together with a narrative summary to provide a description of the existing evidence., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 JBI.)

A diesel engine has been a desirable machine due to its better fuel efficiency, reliability, and higher power output. It is widely used in transportations, locomotives, power generation, and industrial applications. The combustion of diesel fuel emits harmful emissions such as unburned hydrocarbons (HC), particulate matter (PM), nitrogen oxides (NO x ), and carbon monoxides (CO). This article presents data on the efficiency, combustion, and emission of a 4-stroke diesel engine. The engine is a 6.8 L turbocharged 6-cylinder Tier II diesel engine fitted with a common rail injection system. The test was carried out at the Powerhouse Energy Campus, Colorado State University Engines and Energy Conversion facility. The ISO Standard 8178:4 Cycle D2 cycle was adopted for this study consists of five test runs at 1800 rpm. During the testing, CO, carbon dioxide (CO 2 ), oxygen (O 2 ), NO x , PM, unburned HC as a total HC (THC), methane (CH 4 ), formaldehyde (CH 2 O), and volatile organic compound (VOC) emissions were measured. At the same time, the data acquisition system recorded the combustion data. The engine's performance is characterized by the brake specific fuel combustion (BSFC) and thermal efficiency. A dataset of correlations among the parameters was also presented in this article., Competing Interests: The authors have no conflict of interest to declare., (© 2020 The Author(s).)

Artemisin combination therapy (ACT) is the main treatment option for malaria, which is caused by the intracellular parasite Plasmodium. However, increased resistance to ACT highlights the importance of finding new drugs. Recently, the aspartic proteases Plasmepsin IX and X (PMIX and PMX) were identified as promising drug targets. In this study, we describe dual inhibitors of PMIX and PMX, including WM382, that block multiple stages of the Plasmodium life cycle. We demonstrate that PMX is a master modulator of merozoite invasion and direct maturation of proteins required for invasion, parasite development, and egress. Oral administration of WM382 cured mice of P. berghei and prevented blood infection from the liver. In addition, WM382 was efficacious against P. falciparum asexual infection in humanized mice and prevented transmission to mosquitoes. Selection of resistant P. falciparum in vitro was not achievable. Together, these show that dual PMIX and PMX inhibitors are promising candidates for malaria treatment and prevention., Competing Interests: Declaration of Interests A.F.C., M.R., P.F., Z.G., Z.L., J.M., D.B.O., B.E.S., J.K.T, T.T., and L.Z. have a patent Antimalarial Agents PCT/CN2019/100781 based on the compounds in this manuscript., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Sporadic fatal adverse events have been reported during treatment of multiple sclerosis with alemtuzumab. To provide a systematic overview, we searched the centralized European Medicines Agency database of suspected adverse reactions related to medicinal products (EudraVigilance) for fatal adverse events associated with treatment with alemtuzumab (Lemtrada®) for multiple sclerosis. Four independent reviewers with expertise on MS, clinical immunology, infectious diseases and clinical pharmacology reviewed the reports, and scored the likelihood for causality., Results: We identified nine cases with a probable and one case with a possible causal relationship between alemtuzumab treatment and a fatal adverse event. Six of these patients died within one month after treatment; one from intracerebral hemorrhage, two from acute multiple organ failure and septic shock, one from listeriosis, one from pneumonia and one from agranulocytosis. Four patients died several months after administration of alemtuzumab from either autoimmune hepatitis, immune-mediated thrombocytopenia, autoimmune hemolytic anemia or agranulocytosis. Four of the 10 cases had been published previously in case reports or congress abstracts. Fatal adverse events related to treatment with alemtuzumab occur more frequently than previously published in the literature. A significant proportion occurs in the first month after treatment.

Mycobacterium tuberculosis adenosine kinase (MtbAdoK) is an essential enzyme of Mtb and forms part of the purine salvage pathway within mycobacteria. Evidence suggests that the purine salvage pathway might play a crucial role in Mtb survival and persistence during its latent phase of infection. In these studies, we adopted a structural approach to the discovery, structure-guided design, and synthesis of a series of adenosine analogues that displayed inhibition constants ranging from 5 to 120 nM against the enzyme. Two of these compounds exhibited low micromolar activity against Mtb with half maximal effective inhibitory concentrations of 1.7 and 4.0 μM. Our selectivity and preliminary pharmacokinetic studies showed that the compounds possess a higher degree of specificity against MtbAdoK when compared with the human counterpart and are well tolerated in rodents, respectively. Finally, crystallographic studies showed the molecular basis of inhibition, potency, and selectivity and revealed the presence of a potentially therapeutically relevant cavity unique to the MtbAdoK homodimer.

Magnesium plays an important role in infection with Mycobacterium tuberculosis ( Mtb) as a signal of the extracellular environment, as a cofactor for many enzymes, and as a structural element in important macromolecules. Raltegravir, an antiretroviral drug that inhibits HIV-1 integrase is known to derive its potency from selective sequestration of active-site magnesium ions in addition to binding to a hydrophobic pocket. In order to determine if essential Mtb-related phosphoryl transfers could be disrupted in a similar manner, a directed screen of known molecules with integrase inhibitor-like pharmacophores ( N-alkyl-5-hydroxypyrimidinone carboxamides) was performed. Initial hits afforded compounds with low-micromolar potency against Mtb, acceptable cytotoxicity and PK characteristics, and robust SAR. Elucidation of the target of these compounds revealed that they lacked magnesium dependence and instead disappointingly inhibited a known promiscuous target in Mtb, decaprenylphosphoryl-β-d-ribose 2'-oxidase (DprE1, Rv3790).

Objective: Our aim was to identify natural products with anti-tubercular activity., Results: A set of ~ 500 purified natural product compounds was screened for inhibition against the human pathogen Mycobacterium tuberculosis. A series of cyclic hexapeptides with anti-tubercular activity was identified. Five analogs from a set of sixteen closely related compounds were active, with minimum inhibitory concentrations ranging from 2.3 to 8.9 μM. Eleven structural analogs had no significant activity (MIC > 20 μM) demonstrating structure activity relationship. Sequencing of resistant mutant isolates failed to identify changes accounting for the resistance phenotype.

Long-acting/extended-release drug formulations have proved very successful in diverse areas of medicine, including contraception, psychiatry and, most recently, human immunodeficiency virus (HIV) disease. Though challenging, application of this technology to anti-tuberculosis treatment could have substantial impact. The duration of treatment required for all forms of tuberculosis (TB) put existing regimens at risk of failure because of early discontinuations and treatment loss to follow-up. Long-acting injections, for example, administered every month, could improve patient adherence and treatment outcomes. We review the state of the science for potential long-acting formulations of existing tuberculosis drugs, and propose a target product profile for new formulations to treat latent tuberculous infection (LTBI). The physicochemical properties of some anti-tuberculosis drugs make them unsuitable for long-acting formulation, but there are promising candidates that have been identified through modeling and simulation, as well as other novel agents and formulations in preclinical testing. An efficacious long-acting treatment for LTBI, particularly for those co-infected with HIV, and if coupled with a biomarker to target those at highest risk for disease progression, would be an important tool to accelerate progress towards TB elimination.

Though phenotypic and target-based high-throughput screening approaches have been employed to discover new antibiotics, the identification of promising therapeutic candidates remains challenging. Each approach provides different information, and understanding their results can provide hypotheses for a mechanism of action (MoA) and reveal actionable chemical matter. Here, we describe a framework for identifying efficacy targets of bioactive compounds. High throughput biophysical profiling against a broad range of targets coupled with machine learning was employed to identify chemical features with predicted efficacy targets for a given phenotypic screen. We validate the approach on data from a set of 55 000 compounds in 24 historical internal antibacterial phenotypic screens and 636 bacterial targets screened in high-throughput biophysical binding assays. Models were built to reveal the relationships between phenotype, target, and chemotype, which recapitulated mechanisms for known antibacterials. We also prospectively identified novel inhibitors of dihydrofolate reductase with nanomolar antibacterial efficacy against Mycobacterium tuberculosis. Molecular modeling provided structural insight into target-ligand interactions underlying selective killing activity toward mycobacteria over human cells.

Studies directed at developing a broadly acting non-nucleoside inhibitor of HCV NS5B led to the discovery of a novel structural class of 5-aryl benzofurans that simultaneously interact with both the palm I and palm II binding regions. An initial candidate was potent in vitro against HCV GT1a and GT1b replicons, and induced multi-log reductions in HCV viral load when orally dosed to chronic GT1 infected chimpanzees. However, in vitro potency losses against clinically relevant GT1a variants prompted a further effort to develop compounds with sustained potency across a broader array of HCV genotypes and mutants. Ultimately, a biology and medicinal chemistry collaboration led to the discovery of the development candidate MK-8876. MK-8876 demonstrated a pan-genotypic potency profile and maintained potency against clinically relevant mutants. It demonstrated moderate bioavailability in rats and dogs, but showed low plasma clearance characteristics consistent with once-daily dosing. Herein we describe the efforts which led to the discovery of MK-8876, which advanced into Phase 1 monotherapy studies for evaluation and characterization as a component of an all-oral direct-acting drug regimen for the treatment of chronic HCV infection., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The growing prevalence of drug resistant bacteria is a significant global threat to human health. The antibacterial drug rifampin, which functions by inhibiting bacterial RNA polymerase (RNAP), is an important part of the antibacterial armamentarium. Here, in order to identify novel inhibitors of bacterial RNAP, we used affinity-selection mass spectrometry to screen a chemical library for compounds that bind to Escherichia coli RNAP. We identified a novel small molecule, MRL-436, that binds to RNAP, inhibits RNAP, and exhibits antibacterial activity. MRL-436 binds to RNAP through a binding site that differs from the rifampin binding site, inhibits rifampin-resistant RNAP derivatives, and exhibits antibacterial activity against rifampin-resistant strains. Isolation of mutants resistant to the antibacterial activity of MRL-436 yields a missense mutation in codon 622 of the rpoC gene encoding the RNAP β' subunit or a null mutation in the rpoZ gene encoding the RNAP ω subunit, confirming that RNAP is the functional cellular target for the antibacterial activity of MRL-436, and indicating that RNAP β' subunit residue 622 and the RNAP ω subunit are required for the antibacterial activity of MRL-436. Similarity between the resistance determinant for MRL-436 and the resistance determinant for the cellular alarmone ppGpp suggests a possible similarity in binding site and/or induced conformational state for MRL-436 and ppGpp.

Thiazolyl peptides are a class of natural products with potent Gram-positive antibacterial activities. Lack of aqueous solubility precluded this class of compounds from advancing to clinical evaluations. Nocathiacins and thiazomycins are sub-classes of thiazolyl peptides that are endowed with structural features amenable for chemical modifications. Semi-synthetic modifications of nocathiacin led to a series of analogs with improved water solubility, while retaining potency and antibacterial spectrum. We studied the activities of a selection of two natural products (nocathiacin and thiazomycin) as well as seven polar semi-synthetic analogs against twenty clinical strains of Mycobacterium tuberculosis with MDR phenotypes. Two compounds show useful activity against H37Rv strain with MIC values ⩽1 μM, two (⩽0.5 μm) and three (⩽10 μm). These two derivatives showed MIC values ⩽2.5 μm against most of the 20 MDR strains regardless their resistance profile. Specifically, these lack cross-resistance to rifampicin, isoniazid and moxifloxacin.

Background: Patients undergoing coronary artery bypass graft surgery often experience a range of problems and symptoms such as immobility, pain and insufficient sleep. Results from trials investigating testing in-hospital physical exercise or psychological intervention have been promising. However, no randomized clinical trials have tested a comprehensive rehabilitation programme consisting of both physical exercise and psycho-education in the early rehabilitation phase., Aims: The aims of the present SheppHeart pilot randomized clinical trial were to evaluate the feasibility of patient recruitment, patient acceptance of the intervention, safety and tolerability of the intervention., Methods and Design: Sixty patients admitted for coronary artery bypass graft were randomized 1:1:1:1 to: 1) physical exercise plus usual care, or 2) psycho-educational intervention plus usual care, or 3) physical exercise and psycho-educational plus usual care, or 4) usual care alone during a four week period after surgery., Results: The acceptability of trial participation was 67% during the three month recruitment period. In the physical exercise groups, patients complied with 59% of the total expected training sessions during hospitalization. Nine patients (30%) complied with >75% and nine patients (30%) complied with 50% of the planned exercise sessions. Eleven patients (42%) participated in ⩾75% of the four consultations and six patients (23%) participated in 50% of the psycho-educational programme., Conclusion: Comprehensive phase one rehabilitation combining physical exercise and psycho-education in coronary artery bypass graft patients shows reasonably high inclusion, feasibility and safety., (© The European Society of Cardiology 2015.)

Oxabicyclooctane-linked novel bacterial topoisomerase inhibitors (NBTIs) represent a new class of recently described antibacterial agents with broad-spectrum activity. NBTIs dually inhibit the clinically validated bacterial targets DNA gyrase and topoisomerase IV and have been shown to bind distinctly from known classes of antibacterial agents directed against these targets. Herein we report the molecular, cellular, and in vivo characterization of AM-8722 as a representative N-alkylated-1,5-naphthyridone left-hand-side-substituted NBTI. Consistent with its mode of action, macromolecular labeling studies revealed a specific effect of AM-8722 to dose dependently inhibit bacterial DNA synthesis. AM-8722 displayed greater intrinsic enzymatic potency than levofloxacin versus both DNA gyrase and topoisomerase IV from Staphylococcus aureus and Escherichia coli and displayed selectivity against human topoisomerase II. AM-8722 was rapidly bactericidal and exhibited whole-cell activity versus a range of Gram-negative and Gram-positive organisms, with no whole-cell potency shift due to the presence of DNA or human serum. Frequency-of-resistance studies demonstrated an acceptable rate of resistance emergence in vitro at concentrations 16- to 32-fold the MIC. AM-8722 displayed acceptable pharmacokinetic properties and was shown to be efficacious in mouse models of bacterial septicemia. Overall, AM-8722 is a selective and potent NBTI that displays broad-spectrum antimicrobial activity in vitro and in vivo., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Aspartyl proteases are important pharmacological targets. Historically aspartyl proteases have been commonly targeted with transition state derived peptidomimetics. The strategy to develop aspartyl protease inhibitors has undertaken a dramatic paradigm shift in the last 10 years. The pharmaceutical industry in 2005 disclosed several scaffolds or "head groups" that prompted the field to move beyond peptidomimetic derived inhibitors. Since the discovery of the first amino heterocycle aspartyl protease inhibitor, the amino hydantoin, industry and academia have positioned themselves for a foothold on the new molecular space, designing a variety of related "head groups". Both the design and synthetic efforts involved in constructing these scaffolds are varied and complex. Here we highlight the synthetic strategies used to access these amino heterocycle scaffolds.

Resistance to existing classes of antibiotics drives the need for discovery of novel compounds with unique mechanisms of action. Nargenicin A1, a natural product with limited antibacterial spectrum, was rediscovered in a whole-cell antisense assay. Macromolecular labeling in both Staphylococcus aureus and an Escherichia coli tolC efflux mutant revealed selective inhibition of DNA replication not due to gyrase or topoisomerase IV inhibition. S. aureus nargenicin-resistant mutants were selected at a frequency of ∼1 × 10(-9), and whole-genome resequencing found a single base-pair change in the dnaE gene, a homolog of the E. coli holoenzyme α subunit. A DnaE single-enzyme assay was exquisitely sensitive to inhibition by nargenicin, and other in vitro characterization studies corroborated DnaE as the target. Medicinal chemistry efforts may expand the spectrum of this novel mechanism antibiotic., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Oxabicyclooctane linked novel bacterial topoisomerase inhibitors (NBTIs) are new class of recently reported broad-spectrum antibacterial agents. They target bacterial DNA gyrase and topoisomerase IV and bind to a site different than quinolones. They show no cross-resistance to known antibiotics and provide opportunity to combat drug-resistant bacteria. A structure activity relationship of the C-2 substituted ether analogs of 1,5-naphthyridine oxabicyclooctane-linked NBTIs are described. Synthesis and antibacterial activities of a total of 63 analogs have been summarized representing alkyl, cyclo alkyl, fluoro alkyl, hydroxy alkyl, amino alkyl, and carboxyl alkyl ethers. All compounds were tested against three key strains each of Gram-positive and Gram-negative bacteria as well as for hERG binding activities. Many key compounds were also tested for the functional hERG activity. Six compounds were evaluated for efficacy in a murine bacteremia model of Staphylococcus aureus infection. Significant tolerance for the ether substitution (including polar groups such as amino and carboxyl) at C-2 was observed for S. aureus activity however the same was not true for Enterococcus faecium and Gram-negative strains. Reduced clogD generally showed reduced hERG activity and improved in vivo efficacy but was generally associated with decreased overall potency. One of the best compounds was hydroxy propyl ether (16), which mainly retained the potency, spectrum and in vivo efficacy of AM8085 associated with the decreased hERG activity and improved physical property., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Oxabicyclooctane linked 1,5-naphthyridinyl-pyridoxazinones are novel broad-spectrum bacterial topoisomerase inhibitors (NBTIs) targeting bacterial DNA gyrase and topoisomerase IV at a site different than quinolones. Due to lack of cross-resistance to known antibiotics they present excellent opportunity to combat drug-resistant bacteria. A structure activity relationship of the pyridoxazinone moiety is described in this Letter. Chemical synthesis and activities of NBTIs with substitutions at C-3, C-4 and C-7 of the pyridoxazinone moiety with halogens, alkyl groups and methoxy group has been described. In addition, substitutions of the linker NH proton and its transformation into amide analogs of AM-8085 and AM-8191 have been reported. Fluoro, chloro, and methyl groups at C-3 of the pyridoxazinone moiety retained the potency and spectrum. In addition, a C-3 fluoro analog showed 4-fold better oral efficacy (ED50 3.9 mg/kg) as compared to the parent AM-8085 in a murine bacteremia model of infection of Staphylococcus aureus. Even modest polarity (e.g., methoxy) is not tolerated at C-3 of the pyridoxazinone unit. The basicity and NH group of the linker is important for the activity when CH2 is at the linker position-8. However, amides (with linker position-8 ketone) with a position-7 NH or N-methyl group retained potency and spectrum suggesting that neither basicity nor hydrogen-donor properties of the linker amide NH is essential for the activity. This would suggest likely an altered binding mode of the linker position-7,8 amide containing compounds. The amides showed highly improved hERG (functional IC50 >30 μM) profile., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Novel bacterial topoisomerase inhibitors (NBTIs) are a new class of broad-spectrum antibacterial agents targeting bacterial Gyrase A and ParC and have potential utility in combating antibiotic resistance. (R)-Hydroxy-1,5-naphthyridinone left-hand side (LHS) oxabicyclooctane linked pyridoxazinone right-hand side (RHS) containing NBTIs showed a potent Gram-positive antibacterial profile. SAR around the RHS moiety, including substitutions around pyridooxazinone, pyridodioxane, and phenyl propenoids has been described. A fluoro substituted pyridoxazinone showed an MIC against Staphylococcus aureus of 0.5 μg/mL with reduced functional hERG activity (IC50 333 μM) and good in vivo efficacy [ED90 12 mg/kg, intravenous (iv) and 15 mg/kg, oral (p.o.)]. A pyridodioxane-containing NBTI showed a S. aureus MIC of 0.5 μg/mL, significantly improved hERG IC50 764 μM and strong efficacy of 11 mg/kg (iv) and 5 mg/kg (p.o.). A phenyl propenoid series of compounds showed potent antibacterial activity, but also showed potent hERG binding activity. Many of the compounds in the hydroxy-tricyclic series showed strong activity against Acinetobacter baumannii, but reduced activity against Escherichia coli and Pseudomonas aeruginosa. Bicyclic heterocycles appeared to be the best RHS moiety for the hydroxy-tricyclic oxabicyclooctane linked NBTIs., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Bacterial resistance is rapidly growing, necessitating the need to discover new agents. Novel bacterial topoisomerase inhibitors (NBTIs) are new class of broad-spectrum antibacterial agents targeting bacterial DNA gyrase and topoisomerase IV. This class of inhibitors binds to an alternative binding site relative to fluoroquinolones and shows no cross-resistance to quinolones. NBTIs consist of three structural motifs. A structure activity relationship of the left hand motif 1,5-naphthyridine of oxabicyclooctane-linked NBTIs is described. Fifty five compounds were evaluated against a panel of key Gram-positive and Gram-negative strains of bacteria, as well as for hERG activity and five compounds were tested for in vivo efficacy in murine model of Staphylococcus aureus infection. These studies suggest that only a narrow range (activating and deactivating) of substitutions at C-2 and C-7 are tolerated for optimal antibacterial activity and spectrum. An alkoxy (methoxy) and CN at C-2, and a halogen and hydroxyl at C-7, appeared to be preferred in this series. Substitutions on the other three carbons generally have detrimental effect on the activity. No clear hERG activity SAR emerged from these substitutions., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Novel bacterial topoisomerase inhibitors (NBTIs) represent a new class of broad-spectrum antibacterial agents targeting bacterial Gyrase A and ParC and have potential utility in combating antibiotic resistance. A series of novel oxabicyclooctane-linked NBTIs with new tricyclic-1,5-naphthyridinone left hand side moieties have been described. Compounds with a (R)-hydroxy-1,5-naphthyridinone moiety (7) showed potent antibacterial activity (e.g., Staphylococcus aureus MIC 0.25 μg/mL), acceptable Gram-positive and Gram-negative spectrum with rapidly bactericidal activity. The compound 7 showed intravenous and oral efficacy (ED50) at 3.2 and 27 mg/kg doses, respectively, in a murine model of bacteremia. Most importantly they showed significant attenuation of functional hERG activity (IC50 >170 μM). In general, lower logD attenuated hERG activity but also reduced Gram-negative activity. The co-crystal structure of a hydroxy-tricyclic NBTI bound to a DNA-gyrase complex exhibited a binding mode that show enantiomeric preference for R isomer and explains the activity and SAR. The discovery, synthesis, SAR and X-ray crystal structure of the left-hand-side tricyclic 1,5-naphthyridinone based oxabicyclooctane linked NBTIs are described., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

With the goal of identifying inhibitors of hepatitis C virus (HCV) NS3/4a protease that are potent against a wide range of genotypes and clinically relevant mutant viruses, several subseries of macrocycles were investigated based on observations made during the discovery of MK-5172. Quinazolinone-containing macrocycles were identified as promising leads, and optimization for superior cross-genotype and mutant enzyme potency as well as rat liver and plasma concentrations following oral dosing, led to the development of MK-2748. Additional investigation of a series of bis-macrocycles containing a fused 18- and 15-membered ring system were also optimized for the same properties, leading to the discovery of MK-6325. Both compounds display the broad genotype and mutant potency necessary for clinical development as next-generation HCV NS3/4a protease inhibitors., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Described here are synthesis and biological evaluations of diversified groups of over 57 ertapenem prodrugs which include alkyl, methylenedioxy, carbonate, cyclic carbonate, carbamate esters, and esters containing active transport groups (e.g., carboxyl, amino acid, fatty acids, cholesterol) and macrocyclic lactones linking the two carboxyl groups. Many of the prodrugs were rapidly hydrolyzed in rat plasma but not in human plasma and were stable in simulated gastrointestinal fluid. The diethyl ester prodrug showed the best total absorption (>30%) by intredeudenal dosing in dogs, which could potentially be improved by formulation development. However, its slow rate of the hydrolysis to ertapenem also led to the presence of large amounts of circulating monoester metabolites, which pose significant development challenges. This study also suggests that the size of susbtituents at C-2 of carbapenem (e.g., benzoic acid of ertapenem) has significant impact on the absorption and the hydrolysis of the prodrugs.

The composition of diesel exhaust has changed over the past decade due to the increased use of alternative fuels, like biodiesel, and to new regulations on diesel engine emissions. Given the changing nature of diesel fuels and diesel exhaust emissions, a need exists to understand the human health implications of switching to "cleaner" diesel engines run with particulate filters and engines run on alternative fuels like biodiesel. We exposed well-differentiated normal human bronchial epithelial cells to fresh, complete exhaust from a diesel engine run (1) with and without a diesel particulate filter and (2) using either traditional petro- or alternative biodiesel. Despite the lowered emissions in filter-treated exhaust (a 91-96% reduction in mass), significant increases in transcripts associated with oxidative stress and polycyclic aromatic hydrocarbon response were observed in all exposure groups and were not significantly different between exposure groups. Our results suggest that biodiesel and filter-treated diesel exhaust elicits as great, or greater a cellular response as unfiltered, traditional petrodiesel exhaust in a representative model of the bronchial epithelium., (© The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Clostridium difficile is the causative agent of C. difficile-associated diarrhea (CDAD), with increased risk in elderly populations. Kibdelomycin, a novel natural-product inhibitor of type II topoisomerase enzymes, was evaluated for activity against C. difficile and gastrointestinal anaerobic organisms. Toxigenic C. difficile isolates (n=168) from U.S. hospitals and anaerobic Gram-positive and Gram-negative organisms (n=598) from Chicago-area hospitals were tested. Kibdelomycin showed potent activity against toxigenic C. difficile (MIC90=0.25 μg/ml) and most Gram-positive aerobic organisms but had little activity against Bacteroides species (MIC50>32 μg/ml; n=270). Potent anti-C. difficile activity was also observed in the hamster model of C. difficile colitis. Dosing at 1.6 mg/kg (twice-daily oral dose) resulted in protection from a lethal infection and a 2-log reduction in C. difficile cecal counts. A 6.25-mg/kg twice-daily oral dose completely eliminated detectable C. difficile counts in cecal contents. A single 6.25-mg/kg oral dose showed that cecal contents were exposed to the drug at >2 μM (eightfold higher than the MIC), with no significant plasma exposure. These findings support further exploration of kibdelomycin for development of an anti-C. difficile agent.

The NS5A protein plays a critical role in the replication of HCV and has been the focus of numerous research efforts over the past few years. NS5A inhibitors have shown impressive in vitro potency profiles in HCV replicon assays, making them attractive components for inclusion in all oral combination regimens. Early work in the NS5A arena led to the discovery of our first clinical candidate, MK-4882 [2-((S)-pyrrolidin-2-yl)-5-(2-(4-(5-((S)-pyrrolidin-2-yl)-1H-imidazol-2-yl)phenyl)benzofuran-5-yl)-1H-imidazole]. While preclinical proof-of-concept studies in HCV-infected chimpanzees harboring chronic genotype 1 infections resulted in significant decreases in viral load after both single- and multiple-dose treatments, viral breakthrough proved to be a concern, thus necessitating the development of compounds with increased potency against a number of genotypes and NS5A resistance mutations. Modification of the MK-4882 core scaffold by introduction of a cyclic constraint afforded a series of tetracyclic inhibitors, which showed improved virologic profiles. Herein we describe the research efforts that led to the discovery of MK-8742, a tetracyclic indole-based NS5A inhibitor, which is currently in phase 2b clinical trials as part of an all-oral, interferon-free regimen for the treatment of HCV infection., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)