Antimicrobial activity of ceftazidime-avibactam against KPC-2-producing Enterobacterales: a cross-combination and dose-escalation titration study with relebactam and vaborbactam.

With the introduction of ceftazidime-avibactam worldwide, the antimicrobial activity of new ß-lactam/ß-lactamase inhibitors (BL/BLIs) needs to be investigated. From January 2020 to June 2023, Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales were collected. With a broth microdilution test of new BL/BLIs, cross-activity test with nine combinations of BLs and new BLIs and dose-escalation titration test for non-susceptible isolates were conducted to investigate inhibitory activities of new BLIs. A total of 188 isolates was collected and most isolates (186/188, 98.9%) carried the KPC-2 gene exclusively, while two isolates (1.1%) co-harbored NDM-1. Among the 186 KPC-2-producing isolates, 184 (98.9%) were susceptible to ceftazidime-avibactam, 173 (93.0%) to imipenem-relebactam, and 184 (98.9%) to meropenem-vaborbactam. All isolates non-susceptible to imipenem-relebactam or meropenem-vaborbactam became susceptible when avibactam replaced relebactam or vaborbactam, with 7 of 11 (63.6%) imipenem-relebactam non-susceptible isolates and both (100.0%) of the meropenem-vaborbactam non-susceptible isolates. When the minimum inhibitory concentrations (MICs) of BLs were compared using log2 scales, combinations with avibactam showed statistically significant efficacy in lowering MICs compared to relebactam and vaborbactam (all P < 0.05). In the dose-escalation test of new BLIs, increasing dose of all new BLIs corresponded to increased susceptibility to BLs. Ceftazidime-avibactam exhibited excellent susceptibility against KPC-2-producing Enterobacterales unless co-harboring metallo-ß-lactamase. The cross-combination test against non-susceptible isolates suggests that the inhibitory activity of avibactam was superior to those of relebactam or vaborbactam. Increasing the dose of new BLIs produced increased susceptibility to BLs, suggesting that high-concentration regimen need to be developed. IMPORTANCE: This study investigated 188 Klebsiella pneumoniae carbapenemase (KPC)-2-producing Enterobacterales collected from January 2020 to June 2023 in a tertiary care hospital of Korea. Most isolates were susceptible to ceftazidime-avibactam (98.9%) and meropenem-vaborbactam (98.9%), while susceptibility to imipenem-relebactam was lower (93.0%). The cross-combination test using nine combinations of the individual ß-lactams (BLs) and new ß-lactamase inhibitors (BLIs) showed that the inhibitory activity of avibactam was significantly superior to relebactam or vaborbactam when the Log2 MIC of BLs were compared for each combination with BLIs (all P < 0.05). The dose-escalation test of new BLIs demonstrated that increasing doses of new BLIs corresponded to increased susceptibility to BLs. Taken together, this study illustrates the excellent activity of ceftazidime-avibactam against KPC-2-producing Enterobacterales and suggests further investigation into high-concentration regimens for potentially non-susceptible clinical isolates.

Improved nonclinical safety profile of a novel, highly selective inhibitor of the immunoproteasome subunit LMP7 (M3258).

M3258 is the first selective inhibitor of the immunoproteasome subunit LMP7 (Large multifunctional protease 7) in early clinical development with the potential to improve therapeutic utility in patients of multiple myeloma (MM) or other hematological malignancies. Safety pharmacology studies with M3258 did not reveal any functional impairments of the cardiovascular system in several in vitro tests employing human cardiomyocytes and cardiac ion channels (including hERG), guinea pig heart refractory period and force contraction, and rat aortic contraction as well as in cardiovascular function tests in dogs. Following single dose M3258 administration to rats, no changes were observed on respiratory function by using whole body plethysmography, nor did it change (neuro)behavioral parameters in a battery of tests. Based on pivotal 4-week toxicity studies with daily oral dosing of M3258, the identified key target organs of toxicity were limited to the lympho-hematopoietic system in rats and dogs, and to the intestine with its local lymphoid tissues in dogs only. Importantly, the stomach, nervous system, heart, lungs, and kidneys, that may be part of clinically relevant toxicities as reported for pan-proteasome inhibitors, were spared with M3258. Therefore, it is anticipated that by targeting highly selective and potent inhibition of LMP7, the resulting favorable safety profile of M3258 together with the maintained potent anti-tumor activity as previously reported in mouse MM xenograft models, may translate into an improved benefit-risk profile in MM patients.

Advances in novel antibiotics to treat multidrug-resistant gram-negative bacterial infections.

Antimicrobial resistance is a growing threat to public health and an increasingly common problem for acute care physicians to confront. Several novel antibiotics have been approved in the past decade to combat these infections; however, physicians may be unfamiliar with how to appropriately utilize them. The purpose of this review is to evaluate novel antibiotics active against resistant gram-negative bacteria and highlight clinical information regarding their use in the acute care setting. This review focuses on novel antibiotics useful in the treatment of infections caused by resistant gram-negative organisms that may be seen in the acute care setting. These novel antibiotics include ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/cilistatin/relebactam, cefiderocol, plazomicin, eravacycline, and omadacycline. Acute care physicians should be familiar with these novel antibiotics so they can utilize them appropriately.

Discovery of boronic acid-based potent activators of tumor pyruvate kinase M2 and development of gastroretentive nanoformulation for oral dosing.

Several studies have established that cancer cells explicitly over-express the less active isoform of pyruvate kinase M2 (PKM2) is critical for tumorigenesis. The activation of PKM2 towards tetramer formation may increase affinity towards phosphoenolpyruvate (PEP) and avoidance of the Warburg effect. Herein, we describe the design, synthesis, and development of boronic acid-based molecules as activators of PKM2. The designed molecules were inspired by existing anticancer scaffolds and several fragments were assembled in the derivatives. 6a-6d were synthesized using a multi-step synthetic strategy in 55-70% yields, starting from cheap and readily available materials. The compounds were selectively cytotoxic to kill the cancerous cells at 80 nM, while they were non-toxic to the normal cells. The kinetic studies established the compounds as novel activators of PKM2 and (E/Z)-(4-(3-(2-((4-chlorophenyl)amino)-4-(dimethylamino)thiazol-5-yl)-2-(ethoxycarbonyl)-3-oxoprop-1-en-1-yl) phenyl)boronic acid (6c) emerged as the most potent derivative. 6c was further evaluated using various in silico tools to understand the molecular mechanism of tetramer formation. Docking studies revealed that 6c binds to the PKM2 dimer at the dimeric interface. Further to ascertain the binding site and mechanism of action, rigorous MD (molecular dynamics) simulations were undertaken, which led to the conclusion that 6c stabilizes the center of the dimeric interface that possibly promotes tetramer formation. We further planned to make a tablet of the developed molecule for oral delivery, but it was seriously impeded owing to poor aqueous solubility of 6c. To improve aqueous solubility and retain 6c at the lower gastrointestinal tract, thiolated chitosan-based nanoparticles (TCNPs) were prepared and further developed as tablet dosage form to retain anticancer potency in the excised goat colon. Our findings may provide a valuable pharmacological mechanism for understanding metabolic underpinnings that may aid in the clinical development of new anticancer agents targeting PKM2.

"Protocol for a phase 2, randomized, double-blind, placebo-controlled, safety and efficacy study of dutogliptin in combination with filgrastim in early recovery post-myocardial infarction": study protocol for a randomized controlled trial.

BACKGROUND: Regenerative therapies offer new approaches to improve cardiac function after acute ST-elevation myocardial infarction (STEMI). Previous trials using bone marrow cells, selected stem cell populations, or cardiac stem cell progenitors require invasive procedures and had so far inconclusive results. A less invasive approach utilizes granulocyte-colony stimulating factor (G-CSF) to mobilize stem cells to circulating blood and induce neovascularization and differentiation into endothelial cells and cardiomyocytes. Stromal cell-derived factor 1 alpha (SDF-1α) is an important chemokine for initiating stem cell migration and homing to ischemic myocardium. SDF-1α concentrations can be increased by inhibition of CD26/DPP4. Dutogliptin, a novel DPP4 inhibitor, combined with stem cell mobilization using G-CSF significantly improved survival and reduced infarct size in a murine model. METHODS: We test the safety and tolerability and efficacy of dutogliptin in combination with filgrastim (G-CSF) in patients with STEMI (EF < 45%) following percutaneous coronary intervention (PCI). Preliminary efficacy will be analyzed using cardiac magnetic resonance imaging (cMRI) to detect > 3.8% improvement in left ventricular ejection fraction (LV-EF) compared to placebo. One hundred forty subjects will be randomized to filgrastim plus dutogliptin or matching placebos. DISCUSSION: The REC-DUT-002 trial is the first to evaluate dutogliptin in combination with G-CSF in patients with STEMI. Results will lay the foundation for an appropriately powered cardiovascular outcome trial to test the efficacy of this combined pharmacological strategy. TRIAL REGISTRATION: EudraCT no.: 2018-000916-75 . Registered on 7 June 2018. IND number: 123717.

Combining bacteriophages with cefiderocol and meropenem/vaborbactam to treat a pan-drug resistant Achromobacter species infection in a pediatric cystic fibrosis patient.

Cystic fibrosis is associated with significant morbidity and early mortality due to recurrent acute and chronic lung infections. The chronic use of multiple antibiotics without pathogen eradication increases the possibility of extensive drug resistance or even pan-drug resistance (PDR). It is imperative that new or alternative treatment options be explored. We present a clinical case of a 10-year-old female cystic fibrosis patient, infected with a PDR Achromobacter spp. She was treated with cefiderocol, meropenem/vaborbactam, and bacteriophage therapy (Ax2CJ45ϕ2) during two separate admissions in an attempt to clear her infection and restore baseline pulmonary function. The Centers for Disease Control and Prevention confirmed antibiotic susceptibilities, which showed resistance to both cefiderocol and meropenem/vaborbactam. However, after using all three agents concomitantly during the second treatment course, our patient's pulmonary function improved dramatically, and the Achromobacter spp. could not be isolated from sputum samples obtained 8 and 16 weeks after completion of therapy. Overall, the treatment regimen consisting of cefiderocol, meropenem/vaborbactam, and bacteriophage was safe and well-tolerated in our patient.

Development of a bioavailable boron-containing PI-103 Bioisostere, PI-103BE.

PI-103 (7) is a potent dual phosphatidylinositol 3-kinase (PI3K)/mTOR inhibitor, but its rapid in vivo metabolism hinders its further clinical development. To improve the bioavailability of PI-103, we designed and synthesized a PI-103 bioisostere, PI-103BE (9) in which the phenolic hydroxyl group of PI-103 was replaced by a boronate, a structural modification known to enhance bioavailability of molecules containing phenolic hydroxyl moieties. In cell culture, PI-103BE is partially converted to its corresponding boronic acid (10) and to a lesser extent the active ingredient, PI-103. This mixture contributes to the in vitro activity of 9 that shows reduced potency compared to the parent compound. When administered to mice by oral gavage, 9 displays a significantly improved pharmacokinetic profile compared to PI-103, which shows no oral bioavailability at the same dose. Drug exposure of 9 as measured by the area under curve (AUC) value is 88.2 ng/mL*h for 7 and 8879.9 ng/mL*h for 10. When given by intraperitoneal injection (IP), the prodrug afforded an AUC of 32.3 ng/mL*h for 7 and 400.9 ng/mL*h for 10, compared to 9.7 ng/mL*h from PI-103 injection. In plasma from both pharmacokinetic studies, 9 is fully converted to 10 and 7, with the boronic acid metabolite (10) displaying antiproliferative activities comparable to 9, but weaker than 7. The boronic bioisostere of PI-103 thus offers an improved bioavailability that could be translated to in vivo efficacy of PI-103.

Meropenem/vaborbactam: a next generation ß-lactam ß-lactamase inhibitor combination.

INTRODUCTION: infections due to carbapenem-resistant Enterobacterales (CRE) constitute a worldwide threat and are associated with significant mortality, especially in fragile patients, and costs. Meropenem-vaborbactam (M/V) is a combination of a group 2 carbapenem with a novel cyclic boronic acid-based ß-lactamase inhibitor which has shown good efficacy against KPC carbapenemase-producing Klebsiella pneumoniae, which are amongst the most prevalent types of CRE. AREAS COVERED: This article reviews the microbiological and pharmacological profile and current clinical experience and safety of M/V in the treatment of infections caused by CRE. EXPERT OPINION: M/V is a promising drug for the treatment of infections due to KPC-producing CRE (KPC-CRE). It exhibited an almost complete coverage of KPC-CRE isolates from large surveillance studies and a low propensity for resistance selection, retaining activity also against strains producing KPC mutants resistant to ceftazidime-avibactam. Both meropenem and vaborbactam have a favorable pharmacokinetic profile, with similar kinetic properties, a good intrapulmonary penetration, and are efficiently cleared during continuous venovenous hemofiltration (CVVH). According to available data, M/V monotherapy is associated with higher clinical cure rates and lower rates of adverse events, especially in terms of nephrotoxicity, if compared to 'older' combination therapies.

An Update on Existing and Emerging Data for Meropenem-Vaborbactam.

PURPOSE: The search for new agents to treat multidrug-resistant gram-negative bacterial infections has been ongoing. Specifically, carbapenem-resistant Enterobacteriaceae (CRE) infections often exhibit multiple resistance mechanisms, including alterations in drug structure, bacterial efflux pumps, and drug permeability. Vaborbactam, a cyclic boronic acid pharmacophore, has the highest potency in vitro with meropenem as an inhibitor of class A carbapenemases, including Klebsiella pneumoniae carbapenemase (KPC). This combination product was approved by the US Food and Drug Administration for complicated urinary tract infections (cUTIs) in August 2017, and recent Phase III trial data have expanded the literature available. This article aimed to describe the literature regarding spectrum of activity, dosing and administration, including pharmacokinetic and pharmacodynamics properties, safety profile, and efficacy end points. METHODS: The terms meropenem, vaborbactam, RPX7009, and meropenem-vaborbactam were used to search for literature via PubMed, ClinicalTrials.gov, and published abstracts from 2013 to July 2019. Abstracts from IDWeek 2019 were also searched via these terms. Results were limited to availability in English. FINDINGS: Meropenem-vaborbactam covers a spectrum of gram-negative bacterial pathogens, including K pneumoniae, Escherichia coli, and Enterobacter cloacae complex. Although the addition of vaborbactam to meropenem results in MIC lowering for KPC-positive Enterobacteriaceae, in vitro data reveal limited activity against resistant strains of Acinetobacter species and Pseudomonas aeruginosa. Data from 2 Phase III studies compare the drug with available therapies for the following indications: cUTIs, acute pyelonephritis, hospital-acquired and ventilator-acquired bacterial pneumonia, bacteremia, and complicated intra-abdominal infections. Outcomes include an improvement in clinical success when compared with piperacillin-tazobactam (98.4% vs 94%; 95% CI, 0.7%-9.1%; P < 0.001 for noninferiority) for overall treatment of cUTIs and acute pyelonephritis and clinical cure (64.3% vs 33.3%; P = 0.04) when compared with best available therapy for CRE infections in various sites of infection. Adverse events have been described as mild to moderate, with few events requiring discontinuation of the drug therapy. IMPLICATIONS: Currently, meropenem-vaborbactam is approved for treatment of cUTIs and acute pyelonephritis; however, off-label use, in particular for CRE infections, appears beneficial. Clinical trials to date have found an improvement in clinical cure and potentially an improved tolerability compared with standard therapies. Most of the evidence for meropenem-vaborbactam activity and the role in therapy focuses on KPC-producing organisms; however, because in vitro activity has been found with some non-KPC-producing CRE, its role may be further described from upcoming in vivo cases and postmarketing research.

Evaluation of Hemodialysis Effect on Pharmacokinetics of Meropenem/Vaborbactam in End-Stage Renal Disease Patients Using Modeling and Simulation.

The objectives of this study were to evaluate the effect of hemodialysis (HD) on the pharmacokinetics (PK) of meropenem/vaborbactam, an approved beta-lactam/beta-lactamase inhibitor combination, and provide the rationale for the recommended timing of meropenem/vaborbactam administration relative to HD in end-stage renal disease (ESRD) patients. Population PK models were developed separately for meropenem and vaborbactam in subjects with normal renal function and different degrees of renal impairment, including those receiving HD. Simulations were performed to evaluate the exposure of meropenem and vaborbactam in ESRD patients who received a fixed dose of 0.5 g/0.5 g meropenem/vaborbactam every 12 hours as a 3-hour intravenous infusion under various drug administration schedules relative to HD. The probability of target attainment (PTA) analyses were conducted with pharmacokinetic/pharmacodynamic (PK/PD) targets of meropenem and vaborbactam. Simulations showed that HD reduces the accumulation of vaborbactam, but the exposure of vaborbactam is still above the PK/PD target regardless of whether meropenem/vaborbactam is administered predialysis or postdialysis. For meropenem, drug infusion completed right prior to initiation of HD may substantially reduce exposure leading to poor PTA results. In contrast, drug infusion completed at least 2 hours prior to initiation of HD is not predicted to result in efficacy loss based on PTA analysis. The results of simulation indicate that meropenem/vaborbactam infusion completed at least 2 hours prior to initiation of HD or administered immediately after the end of HD can avoid potential efficacy loss in ESRD patients.

Safety, tolerability, pharmacokinetics and pharmacodynamics of parenterally administered dutogliptin: A prospective dose-escalating trial.

AIMS: Animal studies suggest that inhibition of dipeptidyl peptidase 4 (DPP-IV) may improve heart function and survival after myocardial infarction by increasing cardiac myocytes' regenerative capacity. Parenterally administered dutogliptin may provide continuous strong DPP-IV inhibition to translate these results into humans. This trial investigated the safety and tolerability, as well as pharmacokinetics and pharmacodynamics, of parenterally administered dutogliptin after single and repeated doses. METHODS: In an open-label trial, volunteers received dutogliptin at increasing doses of 30-120 mg subcutaneously or 30 mg intravenously in the single-dose cohorts. Subjects in the multiple-dose cohort received 60, 90 or 120 mg dutogliptin subcutaneously once daily on 7 consecutive days. RESULTS: Forty healthy males were included in the trial. No related serious adverse events occurred. Mild local injection site reactions with no requirement for intervention comprised 147 of 153 (96%) related adverse events. Subcutaneous bioavailability was approximately 100%. Multiple injections at daily intervals did not lead to the accumulation of the study drug. The accumulation ratios based on AUC0-24h range from 0.90 to 1.03, supporting this argument. All subjects receiving ≥60 mg dutogliptin yielded a maximum DPP-IV inhibition >90%. The duration of DPP-IV inhibition over time increased in a dose-dependent manner and was highest in the 120-mg multiple-dosing cohort with a maximum AUEC0-24h of 342 h % (standard deviation: 73), translating into 86% DPP-IV inhibition 24 hours after dosing. CONCLUSION: Parenteral injection of dutogliptin was safe and subcutaneous bioavailability is excellent. DPP-IV inhibition increased dose dependently to >86% over 24 hours after multiple doses of 120 mg dutogliptin.

Spectral signal processing approaches for selective quantification of the recently FDA approved brand-new combination of Vaborbactam and Meropenem; for conformity assessment of bulk and batch release.

Vaborbactam (VBR) and Meropenem (MRP) is a recently approved combination for treatment of complicated urinary tract infection (cUTI). Three different signal processing approaches utilizing UV spectral data has been applied for quality assessment of Vabromere® injection. First, the simplest signal processing method, dual wavelength (DW) was developed, where VBR and MRP were determined at (234.0 & 291.0 nm) and (219.5 & 245.5 nm), respectively. The second one utilized signal processing through derivatization, where, each drug was determined without any interference. This was achieved at 250.0 & 318.0 nm for VBR and MRP, respectively. The third approach is the recently developed algorithm, pure component contribution (PCCA), which efficiently extracts the pure spectrum of each drug and therefore determination is achieved at their λmax with maximum sensitivity and lowest error. The applied methods were found to be linear in the concentration range of 5.00-100.00 µg/mL and 5.00-150.00 µg/mL, for VBR and MRP, respectively. Minimum solvent consumption and diminished preparation or extraction steps are achieved associated with accurate quantitation of VBR and MRP in bulk powders and injection. The developed methods were successfully compared to a reported HPLC method, where no significant difference was found regarding both accuracy and precision.

DPP8/DPP9 inhibition elicits canonical Nlrp1b inflammasome hallmarks in murine macrophages.

Activating germline mutations in the human inflammasome sensor NLRP1 causes palmoplantar dyskeratosis and susceptibility to Mendelian autoinflammatory diseases. Recent studies have shown that the cytosolic serine dipeptidyl peptidases DPP8 and DPP9 suppress inflammasome activation upstream of NLRP1 and CARD8 in human keratinocytes and peripheral blood mononuclear cells. Moreover, pharmacological inhibition of DPP8/DPP9 protease activity was shown to induce pyroptosis in murine C57BL/6 macrophages without eliciting other inflammasome hallmark responses. Here, we show that DPP8/DPP9 inhibition in macrophages that express a Bacillus anthracis lethal toxin (LeTx)-sensitive Nlrp1b allele triggered significantly accelerated pyroptosis concomitant with caspase-1 maturation, ASC speck assembly, and secretion of mature IL-1ß and IL-18. Genetic ablation of ASC prevented DPP8/DPP9 inhibition-induced caspase-1 maturation and partially hampered pyroptosis and inflammasome-dependent cytokine release, whereas deletion of caspase-1 or gasdermin D triggered apoptosis in the absence of IL-1ß and IL-18 secretion. In conclusion, blockade of DPP8/DPP9 protease activity triggers rapid pyroptosis and canonical inflammasome hallmarks in primary macrophages that express a LeTx-responsive Nlrp1b allele.

Discovery of a novel dipeptidyl boronic acid proteasome inhibitor for the treatment of multiple myeloma and triple-negative breast cancer.

A series of novel dipeptidyl boronic acid compounds were designed, synthesized and biologically investigated for the inhibition of the ß5 subunit of 20S proteasome and several compounds showed high activities with IC50 values of less than 10 nM. Some of these compounds potently inhibited the multiple myeloma (MM) cancer cell lines with IC50 values of less than 10 nM. It was reported that the inhibition of both ß2 and ß5 subunits strongly increased the cytotoxicity of proteasome inhibitors in solid tumor cells, so some of the compounds were evaluated for the inhibition of the ß2 subunit and the solid tumor triple-negative breast cancer cell line MDA-MB-231. The results showed that three compounds were active for both the ß2 subunit and the triple-negative breast cancer cell line MDA-MB-231. The in vivo pharmacokinetic results showed that compound 8t had good biological parameters for both ig and iv administrations. An in vivo pharmacodynamic experiment showed that compound 8t inhibited the ß5 subunit in whole blood more greatly than the marketed MLN9708 with the same dose at different time periods. A pathological analysis indicated that the injection of compound 8t in the tumor of a triple-negative breast cancer xenograft mice model led to tumor cell necrosis, nucleus condensation, deep staining, cell fragmentation, dissolution and neutrophil infiltration compared with the control group. The data in hand showed that compound 8t might be an effective candidate for the treatment of both MM and triple-negative breast cancer.

Pharmacokinetics of the Meropenem Component of Meropenem-Vaborbactam in the Treatment of KPC-Producing Klebsiella pneumoniae Bloodstream Infection in a Pediatric Patient.

Meropenem-vaborbactam is a new ß-lactam/ß-lactamase inhibitor combination designed to target Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae. Meropenem-vaborbactam was United States Food and Drug Administration-approved for complicated urinary tract infections in patients 18 years of age or older. An understanding of the pharmacokinetics of meropenem when given in combination with vaborbactam is important to understanding the dosing of meropenem-vaborbactam. In addition, the safety and efficacy of meropenem-vaborbactam in a pediatric patient have yet to be described in the literature. The authors conducted a retrospective single-patient chart review for a 4-year-old male patient with short bowel syndrome, colostomy and gastrojejunal tube, bronchopulmonary dysplasia, and a central line for chronic total parenteral nutrition and hydration management, complicated with multiple central line-associated bloodstream infections (BSIs). The patient was brought to our medical center with fever concerning for a BSI. On day 2, the patient was started on meropenem-vaborbactam at a dosage of 40 mg/kg every 6 hours infused over 3 hours for KPC-producing K. pneumoniae BSI. Meropenem serum concentrations obtained on day 5 of meropenem-vaborbactam therapy, immediately following the completion of the infusion and 1 hour after the infusion, were 51.3 and 13.6 µg/ml, respectively. Serum concentrations correlated to a volume of distribution of 0.59 L/kg and a clearance of 13.1 ml/min/kg. Repeat blood cultures remained negative, and meropenem-vaborbactam was continued for a total of 14 days. A meropenem-vaborbactam regimen of 40 mg/kg every 6 hours given over 3 hours was successful in providing a target attainment of 100% for meropenem serum concentrations above the minimum inhibitory concentration for at least 40% of the dosing interval and was associated with successful bacteremia clearance in a pediatric patient.

Meropenem-vaborbactam for adults with complicated urinary tract and other invasive infections.

INTRODUCTION: Complicated urinary tract infections are increasingly caused by multidrug-resistant organisms. Carbapenem-resistant Enterobacteriaceae (CRE) constitute a rising threat among uropathogens with significant morbidity and mortality. Meropenem-vaborbactam is a novel carbapenem and cyclic boronic acid-based beta-lactamase inhibitor combination with potent activity against subtypes of CRE. Areas covered: This article reviews mechanisms of carbapenem resistance, existing treatment options for CRE, and the current evidence to support the use of meropenem-vaborbactam for the treatment of infections caused by subtypes of CRE including complicated urinary tract infections. Expert commentary: Meropenem-vaborbactam is a superior treatment option for infections secondary to Klebsiella pneumoniae carbapenemase (KPC)-producing CRE. It is associated with higher rates of treatment success and lower rates of toxicity than traditional agents and demonstrates a potentially higher barrier to acquired antimicrobial resistance than ceftazidime-avibactam. At present, meropenem-vaborbactam should be regarded as a preferred treatment option for invasive infections secondary to KPC-producing CRE.

Facile dynamic one-step modular assembly based on boronic acid-diol for construction of a micellar drug delivery system.

Nano-assembled amphiphilic micelles with characteristics including facile control, a simplified construction procedure, convenient and efficient drug loading, and a controlled release at pathological sites are in high demand. This study reports a facile and dynamic one-step modular assembly strategy based on boronic acid-diol for constructing focus-responsive micellar drug delivery systems. In this manner, a dopamine modified hydrophilic building block, phenylboronic acid modified hydrophobic building block and drug molecules (Dox) spontaneously one-step assembled into drug encapsulated distinct core/shell micelles (Dox/PBAE-M) in mild physiological media. After a simple adjustment of weight ratios between these three building blocks, Dox/PBAE-M, with the highest Dox-loading capacity (22.4%) and optimal physical dimensions, was generated. Furthermore, the desirable pH-dependent disassembly of Dox/PBAE-M was independently verified by morphological changes alongside in vitro release of Dox in different simulated environments. The experimental results here demonstrated that Dox/PBAE-M kept structural integrity in normal physiological environments, while accomplishing a selective nano-disassembly and Dox release within acid endo/lysosomes. As a result, Dox/PBAE-M exhibited the highest cytotoxicity and apoptosis induction among all of the tested groups on the 4T1 breast cancer xenograft model. This newly proposed assembly strategy gave new insight into easy fabrication and disassembly of multi-functional micellar drug delivery systems.

Injectable dynamic covalent hydrogels of boronic acid polymers cross-linked by bioactive plant-derived polyphenols.

We report here the development of hydrogels formed at physiological conditions using PEG (polyethylene glycol) based polymers modified with boronic acids (BAs) as backbones and the plant derived polyphenols ellagic acid (EA), epigallocatechin gallate (EGCG), tannic acid (TA), nordihydroguaiaretic acid (NDGA), rutin trihydrate (RT), rosmarinic acid (RA) and carminic acid (CA) as linkers. Rheological frequency sweep and single molecule force spectroscopy (SMFS) experiments show that hydrogels linked with EGCG and TA are mechanically stiff, arising from the dynamic covalent bond formed by the polyphenol linker and boronic acid functionalized polymer. Stability tests of the hydrogels in physiological conditions revealed that gels linked with EA, EGCG, and TA are stable. We furthermore showed that EA- and EGCG-linked hydrogels can be formed via in situ gelation in pH 7.4 buffer, and provide long-term steady state release of bioactive EA. In vitro experiments showed that EA-linked hydrogel significantly reduced the viability of CAL-27 human oral cancer cells via gradual release of EA.