First-in-human study of alpibectir (BVL-GSK098), a novel potent anti-TB drug.

Background: The clinical candidate alpibectir augments the activity of, and overcomes resistance to, the anti-TB drug ethionamide in vitro and in vivo.

Objectives: A Phase 1, double-blind, randomized, placebo-controlled study to investigate the safety, tolerability, pharmacokinetics (PK) and food effect of alpibectir administered as single and multiple oral doses in healthy volunteers (NCT04654143).

Methods: Eighty participants were randomized.

Design and synthesis of water-soluble prodrugs of rifabutin for intraveneous administration.

Acinetobacter baumannii is a gram-negative bacterium causing severe hospital-acquired infections such as bloodstream infections or pneumonia. Moreover, multidrug resistant A. baumannii becomes prevalent in many hospitals.

Rifabutin for infusion (BV100) for the treatment of severe carbapenem-resistant Acinetobacter baumannii infections.

Rifamycin antibiotics were discovered during the 1950s, and their main representative, rifampicin, remains a cornerstone treatment for TB. The clinical use of rifamycin is restricted to mycobacteria and Gram-positive infections because of its poor ability to penetrate the Gram-negative outer membrane. Rifabutin, a rifamycin antibiotic approved for the prevention of Mycobacterium avium complex disease, makes an exception to this rule by hijacking the iron uptake system of Acinetobacter baumannii, resulting in potent activity against this important Gram-negative pathogen.

In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms.

Background: Rifabutin, an oral drug approved to treat Mycobacterium avium infections, demonstrated potent activity against Acinetobacter baumannii in nutrient-limited medium enabled by rifabutin cellular uptake through the siderophore receptor FhuE.

Objectives: To determine rifabutin in vitro activity and resistance mechanisms in a large panel of A. baumannii isolates.

Antimicrobial activity of POL7306 tested against clinical isolates of Gram-negative bacteria collected worldwide.

Background: POL7306 belongs to a new class of peptidomimetic outer-membrane-protein-targeting antibiotics with a novel mechanism of action. POL7306 is in development for the treatment of infections caused by antimicrobial-resistant Gram-negative bacteria and has demonstrated low cytotoxicity and nephrotoxicity.

Methods: A total of 891 isolates were collected by the SENTRY Antimicrobial Surveillance Program from 134 medical centres in Europe (n = 424; 41 centres in 18 nations), the USA (n = 411 isolates from 67 centres), the Asia-Pacific region (n = 24; 15 centres in 6 nations) and Latin America (n = 32; 11 centres in 9 nations) and included 558 Enterobacterales, 310 non-fermenters and 23 fastidious organisms.

Susceptibility of Pseudomonas aeruginosa Recovered from Cystic Fibrosis Patients to Murepavadin and 13 Comparator Antibiotics.

The objective was to determine the antimicrobial susceptibility of isolates cultured from cystic fibrosis (CF) patients and explore associations between strain sequence type and susceptibility. Fourteen antibiotics and antibiotic combinations, including the novel antibacterial peptide murepavadin, were tested for activity against 414 isolates cultured from respiratory samples of CF patients. The complete genomes of the isolates were sequenced, and minimum spanning trees were constructed based on the sequence types (STs).

Author Correction: Chimeric peptidomimetic antibiotics against Gram-negative bacteria.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Chimeric peptidomimetic antibiotics against Gram-negative bacteria.

There is an urgent need for new antibiotics against Gram-negative pathogens that are resistant to carbapenem and third-generation cephalosporins, against which antibiotics of last resort have lost most of their efficacy. Here we describe a class of synthetic antibiotics inspired by scaffolds derived from natural products. These chimeric antibiotics contain a β-hairpin peptide macrocycle linked to the macrocycle found in the polymyxin and colistin family of natural products.

Pharmacokinetics, Tolerability, and Safety of Murepavadin, a Novel Antipseudomonal Antibiotic, in Subjects with Mild, Moderate, or Severe Renal Function Impairment.

This open-label, nonrandomized, single-dose, phase 1 study evaluated the pharmacokinetics and safety of murepavadin, a novel peptide antibiotic for the treatment of serious infections. The study was conducted in 32 subjects of either sex in 4 groups (up to 8 per group) with mild (group 1), moderate (group 2), and severe (group 3) renal function impairment or with normal renal function (group 4). The degree of renal impairment of the subjects was classified at screening according to the estimated creatinine clearance (CL) according to the Cockcroft-Gault equation.

Murepavadin activity tested against contemporary (2016-17) clinical isolates of XDR Pseudomonas aeruginosa.

Background: Murepavadin (POL7080) represents the first member of a novel class of outer membrane protein-targeting antibiotics. Murepavadin acts by binding to LPS transport protein D and is being developed for the treatment of hospital-acquired and ventilator-associated pneumonia caused by Pseudomonas aeruginosa.

Objectives: To evaluate the antimicrobial activity of murepavadin against XDR P.

Antimicrobial Activity of Murepavadin Tested against Clinical Isolates of Pseudomonas aeruginosa from the United States, Europe, and China.

Murepavadin (formerly POL7080), a 14-amino-acid cyclic peptide, and comparators were tested by the broth microdilution method against 1,219 isolates from 112 medical centers. Murepavadin (MIC, 0.12/0.

Murepavadin: a new antibiotic class in the pipeline.

With the increase in multi-drug resistant P. aeruginosa, antimicrobials with a novel mechanism of action are needed that can target these infections. Areas covered: Intravenous murepavadin is in Phase 3 development for the treatment of HABP/VABP due to P.

Pharmacokinetics and Safety of Intravenous Murepavadin Infusion in Healthy Adult Subjects Administered Single and Multiple Ascending Doses.

Murepavadin is the first in class of the outer membrane protein-targeting antibiotics (OMPTA) and a pathogen-specific peptidomimetic antibacterial with a novel, nonlytic mechanism of action targeting Murepavadin is being developed for the treatment of hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP). The pharmacokinetics (PK) and safety of single and multiple doses of murepavadin were investigated in healthy male subjects. Part A of the study was a double-blind, randomized, placebo-controlled, single-ascending-dose investigation in 10 sequential cohorts where each cohort comprised 6 healthy male subjects; 4 subjects were randomized to murepavadin, and 2 subjects were randomized to placebo.

The Role of Neutrophil Elastase Inhibitors in Lung Diseases.

In many respiratory diseases characterized by an intense inflammatory response, the balance between proteolytic enzymes (proteases, including elastases) and their inhibitors (proteinases inhibitors) is not neutral. Excess activity of neutrophil elastase (NE) and similar proteases has been reported to cause tissue damage and to alter the remodeling process in many clinical conditions such as pneumonia, respiratory distress, and acute lung injury (ALI). Several experimental NE inhibitors have been tested in preclinical and clinical studies of different conditions of inflammatory lung injury such as ALI and pneumonia, with contrasting results.

Efficacy of the Novel Antibiotic POL7001 in Preclinical Models of Pseudomonas aeruginosa Pneumonia.

The clinical development of antibiotics with a new mode of action combined with efficient pulmonary drug delivery is a priority against untreatable Pseudomonas aeruginosa lung infections. POL7001 is a macrocycle antibiotic belonging to the novel class of protein epitope mimetic (PEM) molecules with selective and potent activity against P. aeruginosa We investigated ventilator-associated pneumonia (VAP) and cystic fibrosis (CF) as indications of the clinical potential of POL7001 to treat P.

Inhibitory properties and X-ray crystallographic study of the binding of AR-101, AR-102 and iclaprim in ternary complexes with NADPH and dihydrofolate reductase from Staphylococcus aureus.

Iclaprim is a novel dihydrofolate reductase (DHFR) inhibitor belonging to the 2,4-diaminopyrimidine class of antibiotics, of which trimethoprim (TMP) is the most well known representative. Iclaprim exhibits potent bactericidal activity against major Gram-positive pathogens, notably methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) phenotypes, including TMP-resistant strains.

Increased hydrophobic interactions of iclaprim with Staphylococcus aureus dihydrofolate reductase are responsible for the increase in affinity and antibacterial activity.

Objectives: Iclaprim is a novel 2,4-diaminopyrimidine that exhibits potent, rapid bactericidal activity against major Gram-positive pathogens, including methicillin-susceptible Staphylococcus aureus and methicillin-resistant S. aureus, and is currently in clinical development for the treatment of complicated skin and skin structure infections. An understanding of the known mechanism of resistance to trimethoprim led to the design of this new inhibitor, with improved affinity towards dihydrofolate reductase (DHFR) from S.

Structure of human endothelin-converting enzyme I complexed with phosphoramidon.

Endothelin-converting enzyme I (ECE-1) is a mammalian type II integral membrane zinc-containing endopeptidase. ECE-1 catalyzes the final step in the biosynthesis of endothelins in a rate-limiting fashion, through post-translational conversion of the biologically inactive big endothelins. Endothelin-1 overproduction has been implicated in a heterogeneous list of diseases including systemic and pulmonary hypertension, stroke and asthma, cardiac and renal failure.

Structural studies of a bifunctional inhibitor of neprilysin and DPP-IV.

Neutral endopeptidase (NEP) is the major enzyme involved in the metabolic inactivation of a number of bioactive peptides including the enkephalins, substance P, endothelin, bradykinin and atrial natriuretic factor, as well as the incretin hormone glucagon-like peptide 1 (GLP-1), which is a potent stimulator of insulin secretion. The activity of GLP-1 is also rapidly abolished by the serine protease dipeptidyl peptidase IV (DPP-IV), which led to an elevated interest in inhibitors of this enzyme for the treatment of type II diabetes. A dual NEP/DPP-IV inhibitor concept is proposed, offering an alternative strategy for the treatment of type 2 diabetes.

Mapping the active site of Escherichia coli malonyl-CoA-acyl carrier protein transacylase (FabD) by protein crystallography.

Malonyl-CoA-acyl carrier protein transacylase (FabD; EC 2.3.1.

The crystal structure of E.coli 1-deoxy-D-xylulose-5-phosphate reductoisomerase in a ternary complex with the antimalarial compound fosmidomycin and NADPH reveals a tight-binding closed enzyme conformation.

The key enzyme in the non-mevalonate pathway of isoprenoid biosynthesis, 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) has been shown to be the target enzyme of fosmidomycin, an antimalarial, antibacterial and herbicidal compound. Here we report the crystal structure of selenomethionine-labelled Escherichia coli DXR in a ternary complex with NADPH and fosmidomycin at 2.2 A resolution.

Crystal structures of Staphylococcusaureus methionine aminopeptidase complexed with keto heterocycle and aminoketone inhibitors reveal the formation of a tetrahedral intermediate.

High-resolution crystal structures of Staphylococcus aureus methionine aminopeptidase I in complex with various keto heterocycles and aminoketones were determined, and the intermolecular ligand interactions with the enzyme are reported. The compounds are effective inhibitors of the S. aureus enzyme because of the formation of an uncleavable tetrahedral intermediate upon binding.

Structural analysis of neprilysin with various specific and potent inhibitors.

Neutral endopeptidase (NEP) is the major enzyme involved in the metabolic inactivation of a number of bioactive peptides including the enkephalins, substance P, endothelin, bradykinin and atrial natriuretic factor. Owing to the physiological importance of NEP in the modulation of nociceptive and pressor responses, there is considerable interest in inhibitors of this enzyme as novel analgesics and antihypertensive agents. Here, the crystal structures of the soluble extracellular domain of human NEP (residues 52-749) complexed with various potent and competitive inhibitors are described.