Vericiguat in Patients with Heart Failure and Reduced Ejection Fraction.

BACKGROUND: The effect of vericiguat, a novel oral soluble guanylate cyclase stimulator, in patients with heart failure and reduced ejection fraction who had recently been hospitalized or had received intravenous diuretic therapy is unclear. METHODS: In this phase 3, randomized, double-blind, placebo-controlled trial, we assigned 5050 patients with chronic heart failure (New York Heart Association class II, III, or IV) and an ejection fraction of less than 45% to receive vericiguat (target dose, 10 mg once daily) or placebo, in addition to guideline-based medical therapy. The primary outcome was a composite of death from cardiovascular causes or first hospitalization for heart failure. RESULTS: Over a median of 10.8 months, a primary-outcome event occurred in 897 of 2526 patients (35.5%) in the vericiguat group and in 972 of 2524 patients (38.5%) in the placebo group (hazard ratio, 0.90; 95% confidence interval [CI], 0.82 to 0.98; P = 0.02). A total of 691 patients (27.4%) in the vericiguat group and 747 patients (29.6%) in the placebo group were hospitalized for heart failure (hazard ratio, 0.90; 95% CI, 0.81 to 1.00). Death from cardiovascular causes occurred in 414 patients (16.4%) in the vericiguat group and in 441 patients (17.5%) in the placebo group (hazard ratio, 0.93; 95% CI, 0.81 to 1.06). The composite of death from any cause or hospitalization for heart failure occurred in 957 patients (37.9%) in the vericiguat group and in 1032 patients (40.9%) in the placebo group (hazard ratio, 0.90; 95% CI, 0.83 to 0.98; P = 0.02). Symptomatic hypotension occurred in 9.1% of the patients in the vericiguat group and in 7.9% of the patients in the placebo group (P = 0.12), and syncope occurred in 4.0% of the patients in the vericiguat group and in 3.5% of the patients in the placebo group (P = 0.30). CONCLUSIONS: Among patients with high-risk heart failure, the incidence of death from cardiovascular causes or hospitalization for heart failure was lower among those who received vericiguat than among those who received placebo. (Funded by Merck Sharp & Dohme [a subsidiary of Merck] and Bayer; VICTORIA ClinicalTrials.gov number, NCT02861534.).

Classification of Heart Failure Events by Severity: Insights From the VICTORIA Trial.

BACKGROUND: Hospitalization due to heart failure (HFH) is a major source of morbidity, consumes significant economic resources and is a key endpoint in HF clinical trials. HFH events vary in severity and implications, but they are typically considered equivalent when analyzing clinical trial outcomes. OBJECTIVES: We aimed to evaluate the frequency and severity of HF events, assess treatment effects and describe differences in outcomes by type of HF event in VICTORIA (Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction). METHODS: VICTORIA compared vericiguat with placebo in patients with HF with reduced ejection fraction (< 45%) and a recent worsening HF event. All HFHs were prospectively adjudicated by an independent clinical events committee (CEC) whose members were blinded to treatment assignment. We evaluated the frequency and clinical impact of HF events by severity, categorized by highest intensity of HF treatment (urgent outpatient visit or hospitalization treated with oral diuretics, intravenous diuretics, intravenous vasodilators, intravenous inotropes, or mechanical support) and treatment effect by event categories. RESULTS: In VICTORIA, 2948 HF events occurred in 5050 enrolled patients. Overall total CEC HF events for vericiguat vs placebo were 43.9 vs 49.1 events/100 patient-years (P = 0.01). Hospitalization for intravenous diuretics was the most common type of HFH event (54%). HF event types differed markedly in their clinical implications for both in-hospital and post-discharge events. We observed no difference in the distribution of HF events between randomized treatment groups (P = 0.78). CONCLUSION: HF events in large global trials vary significantly in severity and clinical implications, which may have implications for more nuanced trial design and interpretation. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT02861534).

WCK 1152, WCK 1153: Discovery and structure activity relationship for the treatment of resistant pneumococcal and staphylococcal respiratory infections.

Novel antibacterial agents needed constantly to counter the ever emergent resistance development to commercially available drugs; one of the effective synthetic antibacterial classes is fluoroquinolone (FQ). This study includes structure activity relationship based design and synthesis of novel fluoroquinolone molecules active against resistant pathogens bearing mutations of DNA gyrase and/or topoisomerase IV which also express efflux pumps. Here, series of compounds were prepared by treating 1-cyclopropyl-6,7-difluoro-8-methoxy-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid as a core with various 4-substituted-3,3-dialkyl piperidines as side chains, through conventional synthetic approaches. Subsequently, antibacterial activities of these fluoroquinolones were examined against Streptococcus pneumoniae, SPN 5844 (Moxi resistant DNA gyrase and topo IV mutant) and SPN 706 (FQ efflux positive). The current manuscript covers >50 examples of fluoroquinolone NCEs, amongst 20 NCEs have shown MIC in the range of (0.4 to >6.25 µg/ml) for SPN 5844 and (0.1-12.5 µg/ml) for SPN 706 strains. During the course of this study; WCK 919, comprising two chiral isomers; WCK 1152 and WCK 1153 were emerged as lead among the different series synthesized. Advance studies suggested either WCK 1152 or WCK 1153 are the worthy candidates for further clinical developments for respiratory infections caused by resistant pneumococci and staphylococci. However, on the basis of in house preclinical work, WCK 1152 had been selected for phase-1 domestic clinical trials.

WCK 4034: A promising oxazolidinone for treating gram positive infections.

Increased resistance to gram positive infections have highlighted the limitations of currently available drug treatments including penicillins, macrolides and glycopeptides. As an alternative to address these challenges; Linezolid, the first antibiotic from oxazolidinone class, have shown the promising activities against such infections, although associated toxicological issues limiting the use of linezolid for prolonged treatments. In order to circumvent disadvantages allied with the marketed drugs, we herein reporting the synthesis of WCK 4034, an oxazolidinone antibiotic through our structure activity relationship (SAR) program. Through this exercise, WCK 4034, has shown competitive MIC values against Methicillin Sensitive S. aureus (MSSA, Sta-001), Methicillin Resistant S. aureus (MRSA, Sta-032), S. pneumoniae ATCC 49619 and H. influenza ATCC 35054 species as like linezolid. Although with an additional advantage; WCK 4034 has been found superior during dog PK studies as compare to Linezolid. With the preliminary studies in our hand, we herein assuming these improved pharmacokinetic values would be helpful. Moreover, WCK 4034 has successfully completed pre-clinical studies and ready to enter the clinical space, and paved the way for in house development of other oxazolidinone NCEs.

Medication use by US patients with pulmonary hypertension associated with chronic obstructive pulmonary disease: a retrospective study of administrative data.

BACKGROUND: Pulmonary hypertension (PH) is a serious complication of chronic obstructive pulmonary disease (COPD). While clinical guidelines recommend specific drug therapies for pulmonary arterial hypertension (PAH), these drug therapies are not recommended for PH due to lung disease. METHODS: This was a retrospective cohort study using the Optum® Clinformatics® Data Mart from January 2009-September 2019. An algorithm was designed to identify adults with ≥ 2 ICD-9-CM or ICD-10-CM diagnosis codes for PH and with ≥ 2 diagnosis codes for COPD. Sensitivity analyses were conducted among subgroups of patients with evidence of a right heart catheterization (RHC) or pulmonary function test (PFT). Patient characteristics, medications used, and durations of use of PAH and COPD medications were analyzed. RESULTS: A total of 25,975 patients met the study inclusion criteria. Their mean age was 73.5 (SD 10.0) years and 63.8% were female. Medications targeting PAH were prescribed to 643 (2.5%) patients, most frequently a phosphodiesterase-5 inhibitor (2.1%) or an endothelin receptor antagonist (0.75%). Medications for COPD were prescribed to 17,765 (68.4%) patients, most frequently an inhaled corticosteroid (57.4%) or short-acting beta agonist (50.4%). The median durations of use ranged from 4.9 to 12.8 months for PAH medications, and from 0.4 to 5.9 months for COPD medications. Of the subgroup of patients with RHC (N = 2325), 257 (11.1%) were prescribed a PAH medication and 1670 (71.8%) used a COPD medication. Of the subgroup with a PFT (N = 2995), 58 (1.9%) were prescribed a PAH medication and 2100 (70.1%) a COPD medication. CONCLUSIONS: Patients with PH associated with COPD were identified in a US administrative claims database. Very few of these patients received any of the medications recommended for PAH, and only about two thirds received medications for COPD.

Preclinical safety evaluation of levonadifloxacin, a novel anti-methicillin-resistant Staphyloccocus aureus benzoquinolizine fluoroquinolone by intravenous and oral administration.

Fluoroquinolone (FQ) antibacterials have drawn heightened attention from various international regulatory agencies due to their class-specific side effects. Levonadifloxacin is a novel broad spectrum benzoquinolizine FQ active against methicillin-resistant Staphyloccocus aureus (MRSA). Owing to FQ-associated safety concerns, extensive preclinical safety pharmacology (central nervous system and cardiac safety) and toxicology studies (subacute repeat-dose toxicity, genotoxicity, phototoxicity and chondrotoxicity) of levonadifloxacin were performed at relatively high doses. Intravenous (IV) and oral studies were conducted using WCK 771 (l-arginine salt of levonadifloxacin) and WCK 2349 (l-alanine ester prodrug of levonadifloxacin), respectively. Safety pharmacology studies following single dose revealed no adverse effects on central nervous system (including seizure) in mice and cardiovascular system (hERG and monkey telemetry). In repeat-dose toxicity studies, except for IV bolus dosing related effects in rat (hyperactivity, mild convulsion, polypnoea and injection site irritation) and dog (emesis and salivation), no other adverse findings limiting the dosing duration were observed. No major biochemical, haematological, gross or histopathological changes suggestive of damage to vital organs were observed in either WCK 771- or WCK 2349-treated groups. WCK 771 and WCK 2349 were found to be nongenotoxic; however, they showed weak phototoxicity that was comparable with levofloxacin. WCK 771 showed chondrotoxicity in the Beagle dog pups on repeat-dose administration; however, the severity level was lower than ofloxacin. Overall, preclinical safety studies helped establish wider safety margin for WCK 771 and WCK 2349 that supports administration of higher therapeutic doses in humans by both IV and oral routes, thereby enabling safe anti-MRSA treatment.

Ensuring robustness in the quality of antibiotic susceptibility test discs for four novel antibiotics.

Antibiotic susceptibility test (AST) discs are used as an in-vitro diagnostic tool to select the appropriate antibiotic to treat an infection. Generally, the concentration of the drug loaded on to the AST discs is measured by studying its activity against quality control organisms. This methodology has several limitations-it is time consuming, requires trained manpower, has a wider acceptance criteria of zone of inhibitions-causing ambiguity in judging smaller variations in drug concentration. To overcome these issues, we have developed and validated high-performance liquid chromatographic (HPLC) methods for the determination of strength of AST discs for in-house researched antibiotics, namely Levonadifloxacin/WCK 771, Nafithromycin/WCK 4873, Cefepime-Tazobactam/WCK 4282, and Cefepime-Zidebactam/WCK 5222. The drugs were extracted from the AST discs using an appropriate solvent. The developed methods are simple, accurate, precise, reproducible, rugged, and robust. They are efficient in terms of time, and can be easily conducted in a quality control laboratory during release as well as stability evaluation of AST disc. Application of HPLC methods for the determination of strength of AST discs ensures flawless quality and, consequently, a better selection of drugs to treat bacterial infections in clinics.

In vitro evolution of cefepime/zidebactam (WCK 5222) resistance in Pseudomonas aeruginosa: dynamics, mechanisms, fitness trade-off and impact on in vivo efficacy.

OBJECTIVES: To study the dynamics, mechanisms and fitness cost of resistance selection to cefepime, zidebactam and cefepime/zidebactam in Pseudomonas aeruginosa. METHODS: WT P. aeruginosa PAO1 and its ΔmutS derivative (PAOMS) were exposed to stepwise increasing concentrations of cefepime, zidebactam and cefepime/zidebactam. Selected mutants were characterized for change in susceptibility profiles, acquired mutations, fitness, virulence and in vivo susceptibility to cefepime/zidebactam. Mutations were identified through WGS. In vitro fitness was assessed by measuring growth in minimal medium and human serum-supplemented Mueller-Hinton broth. Virulence was determined in Caenorhabditis elegans and neutropenic mice lung infection models. In vivo susceptibility to a human-simulated regimen (HSR) of cefepime/zidebactam was studied in neutropenic mice lung infection. RESULTS: Resistance development was lower for the cefepime/zidebactam combination than for the individual components and high-level resistance was only achieved for PAOMS. Cefepime resistance development was associated with mutations leading to the hyperexpression of AmpC or MexXY-OprM, combined with PBP3 mutations and/or large chromosomal deletions involving galU. Zidebactam resistance was mainly associated with mutations in PBP2. On the other hand, resistance to cefepime/zidebactam required multiple mutations in genes encoding MexAB-OprM and its regulators, as well as PBP2 and PBP3. Cumulatively, these mutations inflicted significant fitness cost and cefepime/zidebactam-resistant mutants (MIC = 16-64 mg/L) remained susceptible in vivo to the HSR. CONCLUSIONS: Development of cefepime/zidebactam resistance in P. aeruginosa required multiple simultaneous mutations that were associated with a significant impairment of fitness and virulence.

Representativeness of the VICTORIA Trial Population in Clinical Practice: Analysis of the PINNACLE Registry.

BACKGROUND: In the VerICiguaT Global Study in Subjects with Heart Failure with Reduced Ejection Fraction (VICTORIA) trial, vericiguat reduced the risk of mortality due to cardiovascular problems and of hospitalization due to heart failure (HF) among patients with HF with reduced ejection fraction (HFrEF) and recent worsening HF events (WHFEs). The representativeness of the VICTORIA population of patients with WHFE in clinical practice is unknown. METHODS AND RESULTS: Patients with HF and ejection fraction <45% were identified in the Practice Innovation And Clinical Excellence (PINNACLE) registry and were stratified by the occurrence of WHFEs. Characteristics and outcomes of patients in the PINNACLE registry with and without WHFEs were compared to the VICTORIA population. Of the 14,180 PINNACLE patients identified with HFrEF, 26.5% had had a WHFE. The VICTORIA population was similar to PINNACLE patients with WHFEs in mean age (67.3 vs 66.7), ejection fraction (28.9% vs 28.3%), body mass index (26.8 vs 27.6), and comorbidity burden. The rate of hospitalization because of HF at 1 year was 29.6% in the placebo group of VICTORIA, compared to 35.8% in PINNACLE patients with WHFEs and 13.3% in patients without WHFEs. CONCLUSIONS: The PINNACLE patients with WHFEs meeting the VICTORIA definition resembled the VICTORIA population in characteristics and outcomes, suggesting that VICTORIA's population may be generalizable to patients with WHFEs in clinical practice.

Design and synthesis of an oral prodrug alalevonadifloxacin for the treatment of MRSA infection.

Levonadifloxacin is a parenteral anti-MRSA benzoquinolizine antibacterial drug recently launched as, EMROK in India to treat acute bacterial skin and skin structure infections (ABSSSI) in hospitalized patients. As a step down therapy an oral form of levonadifloxacin with comparable PK/PD was needed because the levonadifloxacin exhibits very poor oral absorption. To improve the drugability in terms of oral absorption a pro-drug approach was evaluated. Structurally levonadifloxacin provides two sites amenable for ester or amide formation, a carboxyl function of benzoquinolizine pharmacophore and hydroxyl group on piperidine side chain. Several aliphatic, aromatic and amino acid esters of C-2 carboxylic acid, C-4-hydroxyl piperidine and double esters at both C-2, C-4 positions were synthesized. The cleavage of prodrugs was studied in vitro as well as in animal models to access their suitability as prodrug function. Among C-2 carboxylic ester prodrugs, daloxate (WCK 2320) showed highest cleavage in serum as well as in liver enzyme; however its stability in aqueous solution was unfavorable. In contrast, most of the esters at the hydroxyl group like propionyl ester (WCK 2305) and amino acid esters such as l-alanine (WCK 2349), l-valine (WCK 2630) were cleaved readily releasing active drug. Thus, indicating C-4-hydroxyl piperidine was amenable site for enzymatic cleavage over esters of C-2 carboxylic acid. Additionally, amino acid esters provided an opportunity to make salt, facilitating improved aqueous solubility. Methanesulfonate salt of l-alanine ester of levonadifloxacin (WCK 2349) was successfully developed and launched as oral prodrug alalevonadifloxacin (EMROK-O).

Assessment of the in vitro cytochrome P450 (CYP) inhibition potential of nafithromycin, a next generation lactone ketolide antibiotic.

Nafithromycin is a next generation lactone ketolide antibiotic slated to enter phase III clinical development in India for the treatment of CABP as a shorter 800 mg-OD X3 day therapeutic regimen. Nafithromycin exhibits potent activity against MDR Streptococcus pneumoniae including erythromycin and telithromycin-resistant resistant strains. Older macrolides/ketolides are reported to be potent inhibitors of CYP3A4/5. To facilitate comparative assessment of drug-drug interaction potential, CYP inhibitory activities of nafithromycin was evaluated in comparison with clarithromycin, telithromycin, cethromycin and solithromycin. CYP inhibitory activities were assessed against key CYP isoforms (CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and CYP3A4/5) using human liver microsomes. Additionally, time-dependent inhibition (TDI), metabolism-based inhibition (MBI) and k inact /K I activities were also investigated for CYP3A4/5. Nafithromycin did not inhibit key CYP enzymes and was found to be a weak inhibitor of CYP3A4/5. Comparator antibiotics were found to be potent inhibitors with 2- to 50-fold leftward shifts in CYP3A4/5 IC50 values, while such shift was not noted for nafithromycin. k inact /K I ratio of nafithromycin was 3- to 153-fold lower than comparator drugs, further substantiating its lower affinity for CYP3A4/5. In sum, weaker inhibition and lower k inact /K I ratio for CYP3A4/5, points towards nafithromycin's lower propensities towards clinical drug-drug interactions as compared to other macrolides/ketolides antibiotics.

Preclinical safety evaluation of nafithromycin (WCK 4873) with emphasis on liver safety in rat and dog.

Ketolide antibiotics are known to cause hepatic injury. Nafithromycin, a novel lactone ketolide was therefore assessed for hepatic safety through range of preclinical in vitro (metabolic stability, CYP inhibition/induction assays) and in vivo (mass balance and repeat dose toxicity) studies. Repeat-dose toxicity studies in rat and dog revealed that nafithromycin did not cause adverse hematological, biochemical and histopathological changes suggestive of systemic or hepatobiliary safety concern at exposures 3-8 fold higher than targeted therapeutic exposures. The only histological finding noticed was reversible phospholipidosis, mainly in lung and lymphoid organs but not in liver, indicating lower nafithromycin accumulation in liver. This observation was corroborated with lack of biologically relevant elevation of hepatic enzymes linked to hepatic injury. In vitro studies showed that nafithromycin undergoes moderate CYP3A mediated metabolism. Unlike other ketolides, nafithromycin and its metabolites showed weak inhibition of CYP3A isoform and lacked CYP2D6 inhibition. Due to hydrophilic nature, nafithromycin in addition to hepatic clearance is also eliminated unchanged by kidneys in significant amount, thereby minimizing hepatic burden. Based on the scientifically integrated evidences such as moderate metabolism, weak CYP inhibition, lack of CYP induction, minimal accumulation in liver, nafithromycin showed promising hepatic safety profile suitable for its intended community-based usage.

Asymptomatic SARS-CoV-2 Infection and COVID-19 Mortality During an Outbreak Investigation in a Skilled Nursing Facility.

BACKGROUND: Outbreaks of coronavirus disease 2019 (COVID-19) have been reported in nursing homes and assisted living facilities; however, the extent of asymptomatic and presymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in this high-risk population remains unclear. METHODS: We conducted an investigation of the first known outbreak of SARS-CoV-2 at a skilled nursing facility (SNF) in Illinois on 15 March 2020 and followed residents for 30 days. We tested 126/127 residents for SARS-CoV-2 via reverse-transcription polymerase chain reaction and performed symptom assessments. We calculated the point prevalence of SARS-CoV-2 and assessed symptom onset over 30-day follow-up to determine: (1) the proportion of cases who were symptomatic, presymptomatic, and asymptomatic and (2) incidence of symptoms among those who tested negative. We used the Kaplan-Meier method to determine the 30-day probability of death for cases. RESULTS: Of 126 residents tested, 33 had confirmed SARS-CoV-2 on 15 March. Nineteen (58%) had symptoms at the time of testing, 1 (3%) developed symptoms over follow-up, and 13 (39%) remained asymptomatic. Thirty-five residents who tested negative on 15 March developed symptoms over follow-up; of these, 3 were re-tested and 2 were positive. The 30-day probability of death among cases was 29%. CONCLUSIONS: SNFs are particularly vulnerable to SARS-CoV-2, and residents are at risk of severe outcomes. Attention must be paid to preventing outbreaks in these and other congregate care settings. Widespread testing and infection control are key to help prevent COVID-19 morbidity and mortality in these high-risk populations.

Levonadifloxacin, a Novel Benzoquinolizine Fluoroquinolone, Modulates Lipopolysaccharide-Induced Inflammatory Responses in Human Whole-Blood Assay and Murine Acute Lung Injury Model.

Fluoroquinolones are reported to possess immunomodulatory activity; hence, a novel benzoquinolizine fluoroquinolone, levonadifloxacin, was evaluated in lipopolysaccharide-stimulated human whole-blood (HWB) and mouse acute lung injury (ALI) models. Levonadifloxacin significantly mitigated the inflammatory responses in an HWB assay through inhibition of proinflammatory cytokines and in the ALI model by lowering lung total white blood cell count, myeloperoxidase, and cytokine levels. The immunomodulatory effect of levonadifloxacin, along with promising antibacterial activity, is expected to provide clinical benefits in the treatment of infections.

Effective inhibition of PBPs by cefepime and zidebactam in the presence of VIM-1 drives potent bactericidal activity against MBL-expressing Pseudomonas aeruginosa.

OBJECTIVES: The combination of cefepime and the novel ß-lactam enhancer zidebactam (WCK 5222) is under development for the treatment of difficult-to-treat Gram-negative infections. Against MBL-producing pathogens, cefepime and zidebactam induce cell elongation and spheroplast formation, indicating PBP3 and PBP2 dysfunction, respectively, having a potent bactericidal effect as a combination. The objective of the present study was to determine the mechanistic basis of the bactericidal effect of cefepime/zidebactam on MBL-expressing pathogens. METHODS: Pseudomonal PBP-binding affinities of cefepime, zidebactam and imipenem were assessed at different timepoints and also in the presence of purified VIM-1 using a Bocillin FL competition assay. The antibacterial activity of cefepime/zidebactam against three VIM-expressing Pseudomonas aeruginosa isolates was assessed by time-kill and neutropenic mouse lung/thigh infection studies. RESULTS: Amidst cefepime-hydrolysing concentrations of VIM-1, substantial cefepime binding to target PBPs was observed. High-affinity binding of zidebactam to PBP2 remained unaltered in the presence of VIM-1; however, MBL addition significantly affected imipenem PBP2 binding. Furthermore, the rate of cefepime binding to the primary target PBP3 was found to be higher compared with the imipenem PBP2 binding rate. Finally, complementary PBP inhibition by cefepime/zidebactam resulted in enhanced bactericidal activity in time-kill and neutropenic mouse lung/thigh infection studies against VIM-6-, VIM-10- and VIM-11-expressing P. aeruginosa, thus revealing the mechanistic basis of ß-lactam enhancer action. CONCLUSIONS: For the first time ever (to the best of our knowledge), this study demonstrates that in the presence of VIM-1 MBL, ß-lactamase-labile cefepime and ß-lactamase-stable zidebactam produce effective inhibition of respective target PBPs. For cefepime, this seems to be a result of a faster rate of PBP binding, which helps it overcome ß-lactamase-mediated hydrolysis.

Activity of cefepime/zidebactam against MDR Escherichia coli isolates harbouring a novel mechanism of resistance based on four-amino-acid inserts in PBP3.

BACKGROUND: Recent reports reveal the emergence of Escherichia coli isolates harbouring a novel resistance mechanism based on four-amino-acid inserts in PBP3. These organisms concomitantly expressed ESBLs or/and serine-/metallo-carbapenemases and were phenotypically detected by elevated aztreonam/avibactam MICs. OBJECTIVES: The in vitro activities of the investigational antibiotic cefepime/zidebactam and approved antibiotics (ceftazidime/avibactam, ceftolozane/tazobactam, imipenem/relebactam and others) were determined against E. coli isolates harbouring four-amino-acid inserts in PBP3. METHODS: Whole-genome sequenced E. coli isolates (n = 89) collected from a large tertiary care hospital in Southern India (n = 64) and from 12 tertiary care hospitals located across India (n = 25) during 2016-18, showing aztreonam/avibactam MICs ≥1 mg/L (≥4 times the aztreonam epidemiological cut-off) were included in this study. The MICs of antibiotics were determined using the reference broth microdilution method. RESULTS: Four-amino-acid inserts [YRIK (n = 30) and YRIN (n = 53)] were found in 83/89 isolates. Among 83 isolates, 65 carried carbapenemase genes [blaNDM (n = 39), blaOXA-48-like (n = 11) and blaNDM + blaOXA-48-like (n = 15)] and 18 isolates produced ESBLs/class C ß-lactamases only. At least 16 unique STs were noted. Cefepime/zidebactam demonstrated potent activity, with all isolates inhibited at ≤1 mg/L. Comparator antibiotics including ceftazidime/avibactam and imipenem/relebactam showed limited activities. CONCLUSIONS: E. coli isolates concurrently harbouring four-amino-acid inserts in PBP3 and NDM are an emerging therapeutic challenge. Assisted by the PBP2-binding action of zidebactam, the cefepime/zidebactam combination overcomes both target modification (PBP3 insert)- and carbapenemase (NDM)-mediated resistance mechanisms in E. coli.

The Pathologic Peritoneal Cancer Index (PCI) Strongly Differs From the Surgical PCI in Peritoneal Metastases Arising From Various Primary Tumors.

BACKGROUND: The surgical peritoneal cancer index (sPCI) is calculated based on a subjective evaluation of the extent of peritoneal disease during surgery. The pathologic PCI (pPCI) may be a more accurate and objective method for determining the PCI. This study aimed to compare the sPCI and pPCI and to study the potential pitfalls and clinical implications of using the pPCI. METHODS: This prospective study (July to December 2018) included all patients undergoing cytoreductive surgery (CRS). The pPCI was calculated for each patient and compared with the sPCI. The impact of potential confounding factors on the difference between pPCI and sPCI was evaluated. RESULTS: Among 191 patients undergoing CRS at four centers, the pPCI and sPCI were concordant for 37 patients (19.3%). The pPCI was lower than the sPCI for 125 patients (65.4%) and higher for 29 patients (15.1%). The concordance between the two groups was maximum for gastric cancer (38.8%) and colorectal cancer (27.6%) and least for mesothelioma (6.7%) and rare primary tumors (5.6%) (p = 0.04). The difference was 0 to 3 points for 119 patients (62.3%), 4 to 5 points for 27 patients (14.1%), and more than 5 points for 45 patients (23.5%). The rate of concordance was not influenced by the use of neoadjuvant chemotherapy (NACT) (p = 0.4), but the difference was greater when NACT was used (p = 0.03). CONCLUSIONS: The pPCI strongly differs from the sPCI for patients undergoing CRS for peritoneal disease and may provide a more accurate evaluation of the peritoneal disease extent. Further studies are needed to determine its prognostic value compared with sPCI, and consensus guidelines are needed for calculating it.

Assessment of in vitro inhibitory effects of novel anti MRSA benzoquinolizine fluoroquinolone WCK 771 (levonadifloxacin) and its metabolite on human liver cytochrome P450 enzymes.

WCK 771 (INN: levonadifloxacin) is a novel antibacterial agent belonging to benzoquinolizine subclass of fluoroquinolones which is under clinical development as a parenteral formulation and its prodrug WCK 2349 (INN: alalevonadifloxacin) as an oral option. Both the drugs have been approved recently in India based on phase III trial completed for ABSSSI.In vitro CYP inhibition potential of levonadifloxacin and its sulfate metabolite (WCK 2146) were assessed in this study. The inhibitory effects of levonadifloxacin and its sulfate metabolite were assessed for seven key human liver CYP isoforms 1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4 using human liver microsome (HLM) employing validated LC-MS/MS method.The results showed that levonadifloxacin and its metabolite did not inhibit enzyme activity of any of the key CYP isoforms (1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4) even at supra therapeutic concentrations (12-24X, Clinical Cmax: 25-35µg/mL).These in vitro CYP inhibition studies of levonadifloxacin and its sulfate metabolite indicate lack of potential for pharmacokinetic drug interactions of levonadifloxacin when co-administered with drugs which are substrate of these isoforms. Therefore, further clinical studies evaluating CYP mediated drug-drug interactions are not warranted for levonadifloxacin and alalevonadifloxacin.

In Vivo Pharmacokinetic/Pharmacodynamic Targets of Levonadifloxacin against Staphylococcus aureus in a Neutropenic Murine Lung Infection Model.

Levonadifloxacin is a novel benzoquinolizine subclass of fluoroquinolone, active against quinolone-resistant Staphylococcus aureus A phase 3 trial for levonadifloxacin and its oral prodrug was recently completed. The present study identified area under the concentration-time curve for the free, unbound fraction of a drug divided by the MIC (fAUC/MIC) as an efficacy determinant for levonadifloxacin in a neutropenic murine lung infection model. Mean plasma fAUC/MIC requirement for static and 1 log10 kill effects against 9 S. aureus were 8.1 ± 6.0 and 25.8 ± 12.3, respectively. These targets were employed in the selection of phase 3 doses.